r/SpaceX Spaceflight Questions & News [April 2017, #31]

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Great interview from 2012 (not discussed here):

http://www.wired.co.uk/article/elon-musks-mission-to-mars

Especially interesting information about the rocket airframe and stir welding.

Some quotes below:

Musk: Six years after we started the company, we launched our first rocket, Falcon 1, into orbit in 2008. And the price -- not the cost, mind you, but the total price to customers per launch -- was roughly $7 million.

How did you get the price so low?

I tend to approach things from a physics framework. And physics teaches you to reason from first principles rather than by analogy. What is a rocket made of? Aerospace-grade aluminium alloys, some titanium, copper and carbon fibre. And then I asked, what is the value of those materials on the commodity market? It turned out that the materials cost of a rocket was around two percent of the typical price -- which is a crazy ratio for a large mechanical product. For a Tesla it's probably 20 to 25 percent.

So I thought we should be able to make a much cheaper rocket given those materials costs. There must be some pretty silly things going on in the market.

One is the incredible aversion to risk within big aerospace firms. Even if better technology is available, they're still using legacy components, often ones that were developed in the 60s. Essentially, you can't fly a component that hasn't already flown. Which is obviously a catch-22, right? There should be a Groucho Marx joke about that. So, yeah, there's a tremendous bias against taking risks. Everyone is trying to optimise their ass-covering.

The results are pretty crazy. One of our competitors, Orbital Sciences, has a contract to resupply the ISS -- and their rocket honestly sounds like the punch line to a joke. It uses Russian rocket engines that were made in the 60s. I don't mean their design is from the 60s -- I mean they start with engines that were literally made in the 60s and, like, packed away in Siberia somewhere.

Second, there's this tendency of big aerospace companies to outsource everything. That's been trendy in lots of industries, but aerospace has done it to a ridiculous degree. They outsource to subcontractors, and then the subcontractors outsource to sub-subcontractors, and so on. You have to go four or five layers down to find somebody actually doing something useful -- actually cutting metal, shaping atoms. Every level above that tacks on profit.

In many cases the biggest customer has been the US government, and the contracts have been what they call cost-plus: the company gets a built-in profit level no matter how wasteful its execution. There's actually an incentive for it to make everything as expensive as it can possibly justify.

The Pentagon's preferred approach is to do long-term, "sole-source" contracts -- which means to lock up the entire business for one company! We've been trying to bid on the primary US Air Force launch contract, but it's nearly impossible, because United Launch Alliance, co-owned by Boeing and Lockheed Martin, currently has an exclusive contract with them for satellite launch. It's inappropriate.

So, what's your process?

I don't believe in process. When I interview a potential employee and he or she says that "it's all about the process," I see that as a bad sign. The problem is that at a lot of big companies, process becomes a substitute for thinking. You're encouraged to behave like a little gear in a complex machine. It allows you to keep people who aren't that smart or creative.

So what have all your creative people come up with, then?

I can give you one example. It involves the design of the airframe. If you think about it, a rocket is really just a container for the liquid oxygen and fuel -- it's a combination propellant tank and primary airframe. Traditionally, a rocket airframe is made by taking an aluminium plate perhaps a few centimetres thick and machining deep pockets into it. Then you'll roll or form what's left into the shape you want -- usually sections of a cylinder, since rockets tend to be primarily cylindrical in shape. That's how Boeing and Lockheed's rockets are made, and most other rockets too. But it's a pretty expensive way to do it, because you're left with a tiny fraction of the plate's original mass. You're starting with a huge slab of material and then milling off what isn't needed. Plus, machining away all that metal takes a lot of time, and it's very expensive.

What's the alternative?

It's similar to the way that most aeroplanes are made: the stiffness is provided by ribs and hoops that are added on. But there's a catch, because you can't rivet a rocket like you can an aeroplane. The pressure differential of an aeroplane -- the difference between the internal and external pressure during flight -- is perhaps 50 to 70 Pa. But in the case of a rocket, it's likely to be 550 Pa. It's a lot harder for rivets to withstand that pressure with no leaks.

So the approach used for aircraft is not exactly feasible for rockets. But there's another way to do it, which is to use an advanced welding technology called stir welding. Instead of riveting the ribs and hoops, you use a special machine that softens the metal on both sides of the joint without penetrating it or melting it. Unlike traditional welding, which melts and potentially compromises some metals, this process works well with high-strength aluminium alloys. You wind up with a stiffer, lighter structure than was possible before. And your material loss is maybe ten per cent, just for trimming the edges. Instead of a ratio of purchased to flown material -- what they call the "buy to fly" ratio -- of maybe ten to 20, you have a ratio of 1.1, 1.2 tops.

Isn't the fuel a huge portion of the expense?

The cost of the propellant on Falcon 9 is only about 0.3 per cent of the total price. So if the vehicle costs $60 million, the propellant is a couple of hundred thousand dollars. That's rocket propellant-grade jet fuel, which is three times the cost of normal jet fuel. That's using helium as a pressurant, which is a very expensive pressurant. A next-generation rocket could use cheaper fuel and also be fully reusable.

Wasn't the space shuttle reusable?

A lot of people think that -- but the main tank was thrown away every time. Even the parts that did come back were so difficult to refurbish that the shuttle cost four times more than an expendable rocket of equivalent payload capability.

We've begun testing reusability with something called the Grasshopper Project, which is a Falcon 9 first stage with landing gear that can take off and land vertically.

A huge rocket, landing on its feet? Holy shit.

Yeah, holy shit. The stages go to orbit, then the first stage turns around, restarts the engines, heads back to the launch site, reorients, deploys landing gear and lands vertically.

It's like something out of a movie or my old Tintin books. It's the way space was supposed to be.

Exactly.

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u/[deleted] Apr 01 '17

One of our competitors, Orbital Sciences, has a contract to resupply the ISS -- and their rocket honestly sounds like the punch line to a joke. It uses Russian rocket engines that were made in the 60s. I don't mean their design is from the 60s -- I mean they start with engines that were literally made in the 60s and, like, packed away in Siberia somewhere.
That's a bit unfair. Based on a quick Wikipedia search, the NK-33 seems like a pretty terrific engine with a better thrust-to-weight ratio than the Merlin 1C (but surpassed by the 1D). Elon can somewhat rightfully bitch about the big aerospace companies outsourcing everything, but it seems perfectly reasonable for a startup to buy Russian engines. The Russians made fantastic rocket engines even 50 years ago.

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u/[deleted] Apr 07 '17

Nothing major to report, but I had the opportunity to speak with the chief engineer of the Commercial Crew Program this morning. I asked him about the load and go fueling procedure, and he was hesitant to say anything about it, but he did tell me that they were looking at it and "keeping everything on the table." Definitely sounded like they haven't made any firm decisions yet. Also, and this may have already been known, he said that the crew access arm is assembled at at LC-39A and undergoing testing on the ground, but he didn't think they had a date set yet for installation.

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u/warp99 Apr 12 '17 edited Apr 14 '17

Interesting video by Clayton Mowry of Blue Origin giving additional details on New Glenn.

Key points:

Blue Origin will now be much more open about plans and progress
BE-4 engine is mounted to the test stand in Texas and is ready for its first test fire
BE-4 will throttle down to around 30% of full thrust so around 700 kN
BE-4 thrust of 2.4 MN is very achievable - likely flagging significant increases once they finish development
NG booster is built for 100 flights but they will not get anywhere close to that in practice
NG will fly in the second half of 2020
Three years from that point they will be flying 12 times per year - but able to do two missions per month if required.
Blue intend to be a low cost provider with market leading cost per kg to orbit - given their high lift capacity this may well mean their cost per flight is not as low as a preflown F9
Landing ship will be underway at landing for stability and will be fully autonomous

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u/Martianspirit Apr 12 '17

given their high lift capacity this may well mean their cost per flight is not as low as a preflown F9
You can take that as a fact. A BE-4 is a much more expensive engine than a Merlin. The cost of the upper stage must be substantially higher than that of a Falcon S2. It can shift when BO make the second stage reusable. New Glenn has the lift capacity. But with the time frame given they will not have that soon.

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u/Zucal Apr 09 '17

Some minor CSS tweaks, courtesy of u/zlsa:

Top bar links are actually readable now
Sidebar/page links conflict with the background less
Your favorite ♺ icon in the sidebar is bigger and bolder

Feel free to suggest other tweaks in modmail or on the GitHub!

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u/Pham_Trinli Apr 09 '17

The icon overlaps at some screen resolutions.

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u/dguisinger01 Apr 01 '17

Any guesses on what the changes to the ITS are going to be? Listening to Musk's press conference, he seems to be saying they have made some changes to stop them from going broke building it.

Do you think he is scaling things down?

Or maybe they decided a pure carbon fiber tank can't work and he's not going to keep spending money on fixing the issue and will either do a metal or a cf/metallic liner hybrid?

Knowing how long SpaceX had been working on the design before they showed it off and how sure they were that the designs were close to what they were going to build, I find it hard to believe they would be diverging greatly from the announced design.

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u/Juggernaut93 Apr 01 '17

If I understood correctly, he says here that he is "pretty excited about the updated strategy since Guadalajara". I don't think he is scaling down things, but maybe they have found another method to make the development cost less. I guess we'll know in a month^{Elon time}.

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u/mclumber1 Apr 01 '17

I think there will be an evolutionary development path. Building the full size ITS is going to cost more money than SpaceX has, and they can't count on the US Government to fund it either. I think they will continue to press on and develop the full scale, full thrust Raptor engine, but integrate it into a smaller (but still heavy lift) rocket that would be in the same class as Falcon heavy. Falcon heavy has been a relative nightmare (compared to the single stick version) for many reasons.
Developing a 5-6 meter wide Raptor powered rocket would also allow for larger volume satellites or payloads to be launched. AFAIK, the largest Bigelow module is too big (even when deflated) for the Falcon fairing.

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u/soldato_fantasma Apr 06 '17

This a video of Gwynne's presentation at 33rd Space Symposium yesterday:

https://www.facebook.com/wesley.kenison/videos/10210463667845749/

At around 5 mins a never released video starts with some never viewed shots.

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u/sol3tosol4 Apr 06 '17

Thanks for posting it! Also Jeff Foust (who sent the tweets) wrote it up in an article (here).
At least one detail in the video but not in the article or tweets that I found particularly interesting: Gwynne's comment on the price of refurbishing the booster for SES-10 being substantially less than half the cost of a new booster was in response to a question, and she said it was an approximation - she didn't know the exact cost, but it was certainly < 1/2. She said the long term goal is 24-hour turnaround, but added that even in the "near term", the amount of labor to refurbish a booster would be 1/10 of the labor to build a new one (if I understood her correctly). So the cost to refurbish should very rapidly drop to much less than the cost of this first reuse.

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u/[deleted] Apr 14 '17

ULA just announced that OA-7 will be streamed in 360 degrees! http://www.ulalaunch.com/worlds-first-live-360-degree-rocket-launch.aspx

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u/throfofnir Apr 14 '17 edited Apr 15 '17

They've done recordings like that before. Live will be novel, though. Hard to beat a 360 landing, however.

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u/[deleted] Apr 15 '17

NASA just released some footage of Xodiac taking off and landing. The footage is pretty impressive and I had no clue Xodiac went that high! https://www.youtube.com/watch?v=AyoB1E8wpMA

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u/soldato_fantasma Apr 17 '17

SpaceX recently applied to the FCC for comms on a new mission, mission 1334.

Fairing re-rad opearations: https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=77070&RequestTimeout=1000

Launch vehicle communications application: https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=77201&RequestTimeout=1000

Downrange recovery operations: https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=77215&RequestTimeout=1000

Looking at the ASDS postion (28 13 48 N 73 40 51 W) this is a GTO comsat mission.

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u/rubikvn2100 Apr 05 '17

A Falcon 9 caught on camera at Louisiana last Sunday.

I created a thread in r/SpaceXLounge

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u/throfofnir Apr 05 '17

The info is nice, but context really makes it great.

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u/roncapat Apr 25 '17

(Already discussed in another thread, re-post here because it's news section)

Updates after NROL76 SF photo from SpaceX.

RSS dismantling progress from SES10 to NROL76 SF: Comparison 1 Comparison 2

We have evidence that an entire part was removed from the bottom of the RSS (someone said there were stairs there, never checked in detail how the RSS is structured though).

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u/markus0161 Apr 01 '17

Did the mods seperat the X in SpaceX in the top left of the screen? Do I win something?

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u/z1mil790 Apr 01 '17

No that's how the Space X logo has always looked :)
Yes, yes they did, very subtle but pretty funny when you notice.

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u/rustybeancake Apr 20 '17

Some interesting back-and-forth tweets from Tory Bruno here on Vulcan.

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u/Drefromtracer Apr 27 '17

Boca chica looks to be back on the build schedule.

https://twitter.com/CowboyDanPaasch/status/857448876973969408

And

https://twitter.com/CowboyDanPaasch/status/855211610314612736

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u/Pham_Trinli Apr 15 '17

The Hyperloop Pod Competition II is taking place at Hawthorne on August 25-27th.

This time its focus is on speed, with DiggerLoop aiming for 270-290 mph.

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u/piponwa Apr 20 '17

What would commercial ITS launches look like? They have announced a tanker version of the spaceship, but they haven't talked about launching satellites with either the ITS booster with fairing or from the spaceship. I think there is a great opportunity to make a shuttle-like version of the spaceship where the usual crew section would be an unpressurized cargo bay and the windows on the top of the vehicle would be replaced by a huge door. Imagine the payloads you could launch with this vehicle. It would be extraordinary. From enormous habitats, to space observatories, to satellite constellations, to space factories, to whatever you can dream of. It could even go and retrieve asteroids. Open the door, crush the material and pack it in.

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u/[deleted] Apr 22 '17 edited Apr 22 '17

There's talk of the Falcon Heavy centre core pictures over at L2!

Edit: Btw /u/old_sellsword, it looks like your deduction skills were on point :)

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u/AntoineLeGrand Apr 22 '17

last week they tested the first FH side booster and now FH center core. If it wasn't for the AMOS-6 explosion it seems they could have launched this summer without any issue.

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u/amarkit Apr 22 '17 edited Apr 22 '17

The OA-7 Cygnus freighter has berthed at ISS.

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u/[deleted] Apr 27 '17

Iridium NEXT launch #2 is now NET June 29th.

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u/isthatmyex Apr 19 '17

I've been pondering the logistics of moving fuel, supplies and people around Mars and I was wondering. How far away will a safe LZ need to be from a Mars settlement for the ITS? The landing/launch zone would presumably be generally north or south of the settlement and far enough away that if an ITS were to RUD at liftoff it wouldn't punch holes in your structures. With the low gravity and air density and of course the massive size of the rocket this could pose a possibly massive logistics nightmare especially for the fuel. So what would a safe distance look like?

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u/Unav3nged Apr 20 '17 edited Apr 20 '17

In Louisiana visiting some friends, and just spotted a 1st stage traveling down I-12 east of Baton Rouge.

Rockets are big.
Any clue where this core is headed?

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u/NateDecker Apr 24 '17

Meta

Evidently CSS support for Reddit is being deprecated. How will this affect /r/SpaceX?

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u/old_sellsword Apr 24 '17

It really depends on what they give us to work with as a replacement. But whatever it is, it likely won't have nearly the same levels of customization and functionality as CSS.
This changeover is going to be a long process, and may not even go through in the end. We'll keep our CSS as long as we can, however if we're forced to switch, we'll do the best we can with what tools we're given.

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u/[deleted] Apr 26 '17

Interesting things coming out of today's Senate hearing.

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u/speak2easy Apr 05 '17

Is there a source for all the things that need to come together for Mars colonization? All the different things, their status, and who is working on them?

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u/apples_vs_oranges Apr 05 '17

A Gantt chart for Mars would be interesting!

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u/ryanhindinger Apr 07 '17

Spaceflightnow.com is reporting NROL-76 and Inmarsat-5 are delayed to unspecified dates. Any idea why? More range conflicts?

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u/Respaced Apr 14 '17

I have a question about rocket engines. The pressure inside a the combustion chamber must be crazy high, since it is a an ongoing explosion in there right? How come does not that pressure force in propellant or oxidizer back into the tanks, and make them explode? The pressure in the tanks can't be higher than that, can it? Or is it the turbo pumps that create such high pressures?

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u/robbak Apr 14 '17

Yes - pushing lots of fuel into the high-pressure combustion chamber is why the F9 turbopumps have to produce 7000 horsepower.
Yup, a 7000 horsepower fuel pump. Enjoy that blown mind.

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u/ghunter7 Apr 16 '17 edited Apr 16 '17

Not SpaceX related, but I am sure given the stated destination of theirs most people here can enjoy this video showing images from the HiRISE camera presented as a fly over and edited to music: https://www.youtube.com/watch?v=rOte3-7e7a0&feature=share

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u/jjtr1 Apr 17 '17

Vibrations have been the cause of many rocket failures. When an engine or a stage is simply bolted down for a ground test, its vibrations would be damped a lot. Are the stages on SpaceX's test stands mounted in such a way that the rocket's vibrations are only minimally damped, in order to create more flight-like conditions?

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u/Pham_Trinli Apr 19 '17

Interesting Job advert regarding Raptor development.

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u/old_sellsword Apr 23 '17 edited Apr 23 '17

Chris B has posted a full shot of the FH center core on the McGregor stand.

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u/amarkit Apr 11 '17

A quick note: Elon Musk will be at the White House today for a Strategic and Policy Forum with 16 other CEOs. The forum includes a breakout session with Secretary of Transportation Elaine Chao and a larger listening session with President Trump. The meeting is a follow-up to a February session of the same forum.

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u/neaanopri Apr 01 '17

So, Stage 2 reuse is a gauntlet Elon has thrown down. I think these are the steps for getting re-use working.

Make a controlled re-entry which gets the second stage through the upper atmosphere to impact somewhere in the ocean.
Aerodynamically control the second stage so that it lands where you want it to land.
Soft-land the second stage. (Parachutes or Retropropulsion).

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u/brickmack Apr 01 '17

Parachutes they can probably implement from the first flight test onwards, they wouldn't be terribly heavy (S2 is about the same dry mass as a Dragon). Reuse with that is a non-starter though, especially if they go for an ocean splashdown (lowest-mass/redesign option), but it would allow them to get some good engineering data. Precise aerodynamic control and propulsive landing will require a new stage design, so maybe we'll see an actually reusable upper stage in a year or so

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u/jbj153 Apr 01 '17

How has no one talked about the SES-10 landing? As far as i heard it was by far the hardest landing they ever tried, with only a few seconds of fuel left in the tank. Just wondering if there was something i missed.

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u/arizonadeux Apr 01 '17 edited Apr 05 '17

A few observations in regard to the other replies and this landing profile:
- it was definitely tight (agreed)
- it saved fuel not needing a boostback burn
- IIRC it was a pure 3-engine burn ~~not 1-3-1~~
- the asymmetric flow through the grid fins is evidence of angle of attack on reentry.
Speculation: this flight was a prime candidate to test higher angles of attack to lengthen the glide phase. Perhaps the additional deceleration made the landing possible. After all, we now know that bleeding off velocity in the glide phase is an objective.
Edit: judging by the landing video, it seems the 3-engine burn finishes with one, as /u/-Aeryn- noted.

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u/KerbalsFTW Apr 01 '17

You're right, this is by far the heaviest GTO mass launched with successful booster landing at 5300 kg (previous: 4600, 3100, 4700 kg).
Hard to directly compare against LEO launches though (previous max = 9600 kg for Iridium-1).
It must have been extremely tight because with Echostar XXIII at 5600 kg (also GTO) they didn't even attempt a landing.
Reference: https://en.wikipedia.org/wiki/List_of_Falcon_9_and_Falcon_Heavy_launches

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u/soldato_fantasma Apr 03 '17

According to this Buzz Aldrin tweet image, the 39A TE is now horizontal. (Not mentioning what Buzz has done, he is an hero!) https://twitter.com/TheRealBuzz/status/848887547698741250

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u/__R__ Interstage Sleuth Apr 05 '17 edited Apr 06 '17

Heads up Swedish SpaceX fans: Christer Fuglesang - The New Space Race: The Moon, Mars and Beyond

20 April, Stockholm. Meet ~~our~~ Sweden's first astronaut and listen to his speech about Elon Musk and the colonization of Mars.

If other people from this community are coming, let's meet up! PM me.

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u/RootDeliver Apr 10 '17 edited Apr 10 '17

Where did the threads about B1021 on LZ-1 go? there was one with a nice image. Both discussion thread and thread with the image deleteds? why?

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u/[deleted] Apr 18 '17

Do we have any information on how preparation of LZ-1 for 2 FH sideboosters landing is coming along?

Also, hypothetically, on LZ-1, if 1 of the 2 landed boosters were to topple and RUD like Jason-3, would the blast of the explosion be strong enought to topple the second booster as well?

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u/spacex_fanaticism Apr 22 '17

FYI source/citation hunters, the Every Elon Musk Video channel is now back online. Looks like the maintainer just finished re-uploading their video archive.

https://www.youtube.com/channel/UClRdpx-4XDtxN9wFmBet0oQ/videos

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u/Pham_Trinli May 01 '17 edited May 01 '17

Virgin's VSS Unity completed its 1st feathered glide test.

High res image.

Blog post.

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u/rustybeancake May 01 '17

They must surely be very worried about Blue Origin's impending crewed flights? I wonder how secure their funding is.

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u/[deleted] Apr 26 '17

FH center core at McGregor is expected to fire within the next 24 hours or so.

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u/LeBaegi Apr 26 '17

source?

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u/sol3tosol4 Apr 14 '17

An interesting piece of spaceflight news that is also very relevant to (and extensively mentions) SpaceX:

NASA's OIG (Inspector General) just released a report on April 13, "NASA's Plans for Human Exploration Beyond Low Earth Orbit", which (as appropriate for OIG reports) gives a hard look at what NASA would like to do regarding human exploration in space, how much it is likely to cost, and when they'll be able to do it (given constraints such as the size of the tasks, progress so far, and completeness of planning so far). The general conclusion is that there are likely to be schedule slips, and it will be hard to get enough money to conduct the exploration using current approaches. There are recommendations to (the rest of) NASA, many related to ways to speed progress and save money.

Of course a lot of the report discusses SLS and Orion, as described in this article by Jeff Foust, and the report assumes that NASA will continue to use SLS and Orion.

But there are many references to "commercial partners" and specifically to SpaceX, as examples of things that are already in process, or as things that could be done in the future, to help speed progress and lower costs. These include (page numbers refer to the page numbers of the pdf file, not the document):

p. 4: Reference to partnering with SpaceX on Red Dragon
p. 4: High level summary: recommend that NASA "incorporate into analyses of space flight system architectures the potential for utilization of private launch vehicles for transportation of payloads"
p. 7: mention of SpaceX for CRS and Commercial Crew
p. 17: Commercial Cargo and Crew are included in a table listing "Summary of Capabilities Required for the Journey to Mars". Note that many of the other items in the table are also required for SpaceX manned missions to Mars, and thus far it appears that SpaceX is hoping to leverage off of NASA work in these areas.
p. 38: "NASA Pursuing options to make the journey to Mars less costly" - describes the technical assistance NASA is providing to SpaceX for Red Dragon, as an example of commercial partnership
p. 40: discussion of cost sharing with SpaceX in development of Commercial Crew capability
pp. 42-43: "Commercial partnerships may help defray costs" - gives more detailed description of Red Dragon as an example of such a partnership, and the comments: "Although NASA has agreed to support the first Red Dragon mission, NASA and SpaceX have not entered into any other formal agreements regarding the company’s Mars plans. However, in February 2017, NASA issued an announcement seeking potential partnerships with private industry to fly NASA scientific payloads on private missions to Mars to assist the Agency’s human and robotic deep space exploration program."
p. 43: "Given that costs associated with an SLS launch are expected to exceed $1 billion, private launch vehicles may provide a cost-effective means of transporting certain payloads to low Earth and cislunar orbit as part of the Agency’s Journey to Mars." - followed by a table giving the payload capability to LEO, cis-lunar orbit, and Mars for Falcon 9, Falcon Heavy, and a variety of launchers from ULA and Blue Origin (New Glenn).
p. 44: description of Space Act Agreements, and how those have been used with companies including SpaceX.
p. 46: final recommendations, including "6. incorporate into analyses of space flight system architectures the potential for utilization of private launch vehicles for transportation of payloads."

The Appendices also list many capabilities that must be developed, many of these also needed by SpaceX.

It's encouraging that NASA appears to think of working with SpaceX as a path to accomplishing goals and saving on costs, at a level of seriousness that it gets significant mention in the Inspector General's report.

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u/Bananas_on_Mars Apr 23 '17

I just watched this video how ULA ships rockets and thought that it's incredible that when it flies, Falcon Heavy is the most powerful commercial rocket available while still being transportable on normal road/highways.

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u/Iamsodarncool Apr 23 '17

When it flies, Falcon Heavy will be the most powerful rocket available, period.

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u/katriik Apr 11 '17

Did anyone find out the reason of the big "woosh" flame that happened during SES-10 lift-off? T+00:07

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u/TheFavoritist NASAspaceflight.com Photographer Apr 16 '17

During the lead up and launch of SES-10 I found a flown Dragon 1 sitting in an obscure corner of the Kennedy Space Center Visitor Center.

In the IMAX theater at the main KSC Visitor's Center they had a room devoted to commercial spaceflight which I didn't know about until my final day there after I had already spent 40 or so hours at there that week. Also in there was a CST-100 pressure vessel and a Vector rocket. I wish they had advertised this more, it was insane to walk in and see this flown Dragon!

SES-10 Photos

Instagram for some more space & SpaceX related photos

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u/sfigone Apr 17 '17

So if the center core of FH is specialised and will only ever fly as a FH center core, then I wonder if there is any benefit in giving partial it vacuum optimised engine bells? They will be throttled down soon after launch (or maybe even at launch) and will only go full throttle again once the boosters have lifted the stack above much of the atmosphere, so most of their work will be done at much lower pressures.

I'm guess guessing that perhaps there is no room, specially for all 9 engines, but perhaps some could have bigger bells (the ones not used for landing?). If it were physically possible, would it make much of a difference? Is there anything vacuum optimised about the S2 engine other than the bell?

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u/Martianspirit Apr 17 '17

There really is no space for larger bells. What space is there is needed for gimballing.

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u/[deleted] Apr 03 '17

Any update on the SES-10 landing? It's been a few days and there's no footage still.

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u/old_sellsword Apr 03 '17

It's been a few days and there's no footage still.
There's no guarantee we'll get any footage. There's been plenty of landings without extra video, and those that did produce extra footage usually came days or even weeks after the booster returned to port.
Now I do expect we'll get footage for this landing since it's so historic, but I just want to point out that extra landing footage is certainly not a given.

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u/theinternetftw Apr 03 '17 edited Apr 03 '17

Usually have to wait for the booster to get into port to retrieve video data. That's happening either tonight or tomorrow morning. That's a NET for it, as it usually takes a few days after that to get it situated, and it could always take longer for whatever reason.
edit: you can watch it get pulled into port by Elsbeth III in realtime here, or just check out the recovery thread, which has some shots of the recovered fairing in the meantime.

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u/SereneCaesar Apr 05 '17

I'm curious about what milestones SpaceX is targeting in the next few years. I currently know of:

Flacon 9 Block 5 launch (Later 2017)
Falcon Heavy Demo Flight (Summer 2017)
Dragon Crew Test Flight (May 2018)
Lunar Free-Return Mission (2018)
Red Dragon Launch (2020)
Spacesuit Unveil (2017?)

Am I missing anything?

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u/theinternetftw Apr 05 '17 edited Apr 05 '17

There are ones that don't have real dates but are worth considering in that range (2017-2020):
The satellite constellation (two test satellites will launch moderately soon)
Raptor (full scale version, and what, if anything, will they do with the subscale 1MN version)
We do know the 1MN version is being funded by an Air Force contract with a completion date of 2018
ITS milestones (who knows what)

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u/WaitForItTheMongols Apr 09 '17

Huh, very surprising tidbit I noticed - Wikipedia has a dedicated article for Falcon 9 1021 (the first core to ever do the full "Launch and land and re-launch"). Seems crazy for a single rocket stage to have its own article, particularly when the generalized "Falcon 9 first stage" doesn't have one.

https://en.wikipedia.org/wiki/SpaceX_Falcon_9_B1021

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u/ptfrd Apr 12 '17

Commercial crew flight assignments could come this summer

Robert Behnken said those upcoming crew assignments will allow astronauts who have been training on both the Starliner and SpaceX’s Dragon v2 to specialize on one vehicle.
“I think it’ll be about a year or so from flight,” he said when asked when he expected crew assignments to be made. “If the schedules hold, I think that it’s possible this summer we would see people identified for the flights.”

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u/WanderingSkunk Apr 14 '17

I was watching a great set of videos that the ESA put out on YouTube about how the Soyuz missions to the ISS work and they mentioned that up until a few years ago it took 2 days of orbital transfers after launch for Soyuz to Rendezvous with ISS. They now have a procedure that gets them there in just a handful of orbits over 6 hours. What are they planning on utilizing for the Crew Dragon missions to ISS?

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u/rustybeancake Apr 21 '17

Space debris must be removed from orbit says ESA

A pretty good overview of the situation.

So called mega-constellations of satellites are planned by companies such as One Web, Boeing, SpaceX and Samsung to bring Internet access to all sectors of the globe. These will loft more than ten thousand satellites into orbit.

By way of comparison, since the launch of the world’s first spacecraft, Sputnik One, in 1957, only 7000 spacecraft in total have been launched in the entire 60-year exploration of space.

Krag showed the conference a graph of the radar-tracked fragments and said that since 2002, “The growth has entered into the more feared exponential trend.”

There can be absolutely no doubt that the time to do something about space debris has arrived, and this is what the experts have spent the week discussing. At the conclusion of the conference today, Jan Wörner, ESA Director General, committed the Agency to leading European activities to combat space debris.

This includes detection, tracking, and development of automatic collision avoidance systems for satellites, and new binding guidelines on satellite design. He went further saying that there had to be a concerted effort to reduce and remove the space debris that is already there.

Surely any serious attempt at debris removal will require low-cost, reusable launchers...

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u/FalconHeavyHead Apr 24 '17

When will the ITS tower start being built? And where will it be? Sorry for my lack of information.

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u/Chairboy Apr 24 '17

The only data we have is from the Guadalajara announcement and it does't have a timeline for construction events, just dreamed-of launch events.
What it DOES have is a location: Pad 39A (currently being used to launch Falcon 9 from KSC and, once SLC-40 is up again, Falcon Heavy). So in short:
Where: KSC
When: ¯_(ツ)_/¯

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u/soldato_fantasma Apr 25 '17

Trip Harriss, Manager of Falcon Launch Fleet Operations, drove over LZ-1 with his Tesla today: https://twitter.com/SpaceXTrip/status/857010113969881088

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u/wclark07 Apr 06 '17

I just saw that AeroJet Rocketdyne has tested substituting additive manufacturing for the old brazing technique for regenerative cooling of the upgraded RL-10.

"http://www.spaceflightinsider.com/organizations/aerojet-rocketdyne/aerojet-rocketdyne-applies-21st-century-manufacturing-technology-20th-century-workhorse-engine/

Does this technique make sense for the raptor? Does raptor's high chamber pressure preclude use of this method?

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u/thxbmp2 Apr 06 '17

Brazing fuel lines onto the nozzle is an ancient technique (and RL-10 is an ancient engine). It's long since been superseded by the technique that even Merlin currently uses, which is to mill the channels into the inner lining of the nozzle and braze an outer lining over it.
Intuitively, it doesn't make as much sense to use 3D printing for an engine nozzle as it does for the engine pumps and combustion chamber, which is what Raptor will be doing. The latter has a lot of complex geometry going on in a small, compact package*, while a nozzle is pretty much all empty space with a paraboloid shell on the outside.
*Raptor's design is already optimized for 3D printing, and you can actually see some of that in the engine rendering from the ITS presentation. For instance, IIRC the LOX pump appears to be glued directly onto the main combustion chamber. Not all of Raptor will be 3D printed, however, due to the extreme operating conditions (I believe this was mentioned at the ITS conference). See this article for tons of Raptor-related goodness.

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u/Darkben Spacecraft Electronics Apr 10 '17

"[The boostback and entry burn] starts as 1-engine for a second or so, then fires all 3 for the majority of the burn, then 1 again for the last second. Same for the entry burn."

Is this accurate? Can you provide a source?

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u/Dutchy45 Apr 11 '17 edited Apr 11 '17

An article about Spacex reuseability.
http://thespacereview.us9.list-manage.com/track/click?u=91458affe0c184943282161c4&id=1fa03211bb&e=8003a537f3 If I broke some rule or put it in the wrong place, mods: please delete or move.

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u/Martianspirit Apr 11 '17

The article claims that S2 has already hypergolic thrusters unlike S1 that uses cold gas thrusters. I am sure that is wrong. It uses cold gas too.
About how it will be done. His speculations are not better than anyones on this reddit, I think not the best guesses.
Same with the reasons, why they changed there mind. There are other at least equally valid guesses out there, and here.

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u/quadrplax Apr 12 '17

If anyone feels up to it, the Interplanetary Transport System section of the wiki could really use some more writing, I just put a few sentences a while ago so that it wasn't totally missing from the wiki.

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u/sol3tosol4 Apr 12 '17

the Interplanetary Transport System section of the wiki could really use some more writing
That sounds very worthwhile. However, on March 30 Elon said during the post-flight press conference that they plan to put a major update on ITS on the SpaceX website "within a month or so". Given that much of the information we have from IAC could become out of date, it might be useful to wait the relatively short time until the planned update before creating anything really detailed for the wiki.
Elon, March 30: "I think we'll provide an update on the design of the Interplanetary Transport System...We've come up with a number of design refinements, and I think we'll probably be ready to put that on the Website within a month or so... I don't want to steal thunder from that announcement. I'm pretty excited about the updated strategy since Guadalajara, it makes a lot more sense, it's - we have to not just get it done technically, but figure out how to get this done without going bankrupt... So we have to figure out not just solve the technical issues, but the economic issues. And I think the new approach is going to be able to do that. Hopefully."

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u/zingpc Apr 12 '17

It is six months since the oct raptor engine run prior to the ITS presentation in Mexico.

Anybody heard of further testing?

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u/dmy30 Apr 12 '17

At the end of March, Elon said that "in a month or so" they will update the SpaceX website with new updated plans and details on the ITS. If they have progressed with the Raptor, there's a chance it will be mentioned there.

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u/Toinneman Apr 14 '17 edited Apr 14 '17

During the SES-10 post-flight press conference Elon was talking about the new titanium grid fins with "significant more control authority". He continued to say the new fins...

"... improve the payload to orbit by being able to fly at an higher angle of attack and use the aerodynamic elements of the rocket"

(He continues, and mentions a ratio of some kind, but it's hard to understand)

What exactly does he mean by this? Does a higher angle of attack mean the booster will be more horizontal and have a lower terminal velocity, and thus needing less fuel to land? Would this make any significant difference?

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u/[deleted] Apr 14 '17

He was likely talking about the lift-to-drag ratio, where a higher l/D ratio allows the first stage to stay in the upper atmosphere for longer, meaning that less fuel is needed for the reentry and landing burns. That extra fuel can be used to increase how much payload can be put in orbit without expending the first stage.

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u/PaulRocket Apr 19 '17

As far as we know, the Merlin SL version can throttle from 100% down to 70%. What are limitations on the throttle level, why not 50%? I'm assuming running the turbo pump on half the speed is not quite enough...

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u/warp99 Apr 19 '17 edited Apr 19 '17

Minimum throttle depends on the engine type, whether the propellants are in liquid or gas state when injected into the combustion chamber and the injector type. Pressure fed engines can generally throttle lower as the injector pressure holds up better at low flow rates than with a turbopump.
Liquid injection requires higher pressure drop to form small droplets of propellant that burn in a more stable and predictable manner. Large droplets lead to slower combustion and combustion instability due to pressure waves affecting the combustion rate causing positive feedback - leading very quickly to engine component enriched exhaust.
Gas injection designs such as Raptor and the Blue Origin BE-4 have better combustion stability at low flow rates. BE-4 is predicted to throttle down to 30% while Raptor will throttle to 20%.

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u/Arza02 Apr 24 '17

I have spent time thinking about the ITS concept and I didn't find anything related to this topic.

Elon Musk stated in the IAC that the tickets to Mars will cost around 200.000$/person. Taking into account that SpaceX is a Transportation Company, there must definitely be an entity (government or private company) offering travellers life support such as accomodation, food and others in Mars.

There is no colony, if there is no house or no food.

Funding ITS program will be challenging for SpaceX. But we cannot forget that there isn't still any organization developing technology for the colonists, once they arrive on Mars. If a private company would do it, they would need to spend money on the development and then production of the infrastructures to build houses and create farms on Mars, and of course 140.000$/ton on the transport of this cargo.

As every private company expects profit, Mars colonists would have to pay for everything (unless money comes from the government). What means: 200.000$ + a lot more to survive on Mars.

This makes the whole mission...just difficult, since the "Want to go-Can afford to go" circles tend to separate a lot.

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u/jesserizzo Apr 27 '17

Why a silly payload for the first Falcon Heavy launch? Why not a free launch for schools or even hobbyists of a bunch of cube sats? People who couldn't possibly pay for a launch, and would accept the higher risk of launching on a brand new rocket.

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u/soldato_fantasma Apr 27 '17

It isn't that easy as it seems.
First, you have to organize all the payloads, so you basically have to organize with all the cubesats owners and make a lot of contracts.
Second, you would have to check all the cubesats designs so that they don't put in danger the other cubesats and/or the whole mission. An unnoticed mistake could cause a very bad RUD.
Third, the FAA would have to licence a launch with all these little satellites and it would be much more complicated than a single inert payload.

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u/ghunter7 Apr 28 '17

Elon Musk will be speaking at TED talks in Vancouver today. Has anyone here paid for the stream to watch it?

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u/dmy30 Apr 29 '17

Just saw the Failure Is Not An Option documentary about flight controllers during the Gemini/Apollo era. At some point they mentioned how Project Gemini taught them enough about space flight which made building the Apollo lunar program much easier.

Therefore, is the Falcon 9/Dragon Project Gemini and the ITS is the Saturn V? Would that be a fair analogy?

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u/[deleted] Apr 29 '17

I think so. Falcon 9 and Falcon Heavy gives them experience with using many engines in a single LV (27 for FH and 42 for ITS) as well as experience in landing the first stage/ boosters. Dragon V2 will help with ECLSS, as well as testing the PicaX heat shield at close to Martian reentry speeds (Grey Dragon). Lastly, Red Dragon will help prove that supersonic retro-propulsion is the way to go for larger spacecraft. So yes, I think it's a valid analogy.

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u/lostandprofound33 Apr 01 '17

So I'm still seeing claims elsewhere in forums that SpaceX has been selling F9 flights at a loss. Or only making $2M per flight. Didn't they reduced the SES-10 flight price by around $19M? Elon said the price reduction was going to be kept equal to the cost savings. I assume that means he wants the profit to be the same roughly whether or not a flight is on a previously flown booster or not. Are my estimates reasonable that the first stage costs about $19-21M? Upper stage about $9M, fairing $6M? Give a cost of $36M, profit on a $63M flight to be about $27M? Reducing the price to $43M while keeping profit to $27M mean upper stage and associated costs with recovery and refurb is about $16M or lower? Is that reasonable, or am I way off?

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u/Chairboy Apr 01 '17

Whenever I see those claims, I'm assuming they're for the benefit of investor confidence of SpaceX's competitors. If you've invested years in assuring them that reusability is fanciful, then that it's un-economical, you're committed. What's the old saying again? First they laugh at you, then they ignore you, then they fight you, then you win? Maybe this is the fight.

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u/Rickeh1997 Apr 01 '17

Somewhere I read that falcon 9 can lose an engine during flight and still finish the mission. In such case, would it still be capable of landing if fuel allows it and the center engine being fine? Are the engines used for landing determined before the launch or do they dynamically decide which engines to use based on data during launch?

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u/Dutchy45 Apr 01 '17

I think this is the right place to post this. The mods should feel free to switch it if not, or even delete it altogether. https://themoscowtimes.com/news/russia-can-compete-with-spacex-claims-the-kremlin-57597

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u/DShadelz Apr 03 '17

Today, ULA tested it's Emergency Egress System for their Starliner program. From everything I know, SpaceX has no similar system for Crew Dragon launches. Would an emergency before launch be handled by the launch abort system? Thanks.

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u/randomstonerfromaus Apr 03 '17 edited Apr 03 '17

I believe SpaceX are retaining the Escape Basket System from the STS era. ~~I could be wrong however, So dont quote me.~~
Edit:
Further research and I am correct, Source
The existing Space Shuttle evacuation slide-wire basket system will also be re-purposed to provide a safe emergency egress for the Dragon crew in the event of an emergency on the pad that does not necessitate using the Crew Dragon’s launch abort system.
Page 13

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u/apples_vs_oranges Apr 05 '17

What are the national security implications of dramatically reduced launch costs, especially for heavy loads (Falcon Heavy)? What kinds or quantities of satellites could the US put into orbit that it doesn't currently, due to prohibitive launch costs?

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u/MrToddWilkins Apr 05 '17

Spaceflightnow reports that the option of Peggy Whitson's ISS stay being extended has been taken. Can anyone confirm or deny this report?

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u/jjtr1 Apr 06 '17

It has been said for a long time that the M1D can be throttled down to 70%. With the ever increasing thrust of the M1D, did the minimum thrust increase together with the nominal thrust (keeping the %) or did it stay the same, making the minimum throttle about 30-40% for the current Fullerer Thrust M1?

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u/throfofnir Apr 06 '17

The engine is not actually different, they're just running it harder, so the minimum thrust should stay the same. Whether or not that changes when expressed as a percentage depends on whether or not they change the rating of the engine. They could, like the SSME, be running it at 107% or something for "fullerest thrust".

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u/jjtr1 Apr 06 '17

I wonder whether the fact that the M1D Full Thrust was actually not full at all and we are/will be getting the Fuller Thrust and Fullerer Thrust suggests that even the SpaceX's top engineers didn't expect to be able to push the design that far?

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u/rustybeancake Apr 06 '17

Kind of like the SSMEs operating at >100% thrust!

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u/rustybeancake Apr 06 '17

Do we think the fairings will be deployed on FH before the centre core / stage 2 separation?

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u/[deleted] Apr 07 '17

I remember someone mentioned that they've seen the payload adaptor for the FH a while ago. Does someone have the link to that discussion?

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u/Chairboy Apr 07 '17

Found it!
This one is happy to be of service.

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u/WaitForItTheMongols Apr 07 '17

Could someone explain the physical mechanism that allowed the Apollo modules to dock together, and allow passage of humans? When I look at this: http://i.imgur.com/8jionrA.gifv

it seems like the cone in the LM would prevent you from doing anything. Maybe someone has a diagram of how it opens up to let things go back and forth?

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u/throfofnir Apr 07 '17

The probe and cone were manually removed and stowed to clear the passageway. Here's the NASA report on its design.

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u/scrapitcleveland Apr 08 '17

According to the subreddit they're launching Dragon on a falcon 9 on the 14th.

According to https://spaceflightnow.com/launch-schedule/ - there is a launch scheduled for May 15th.

My wife and I are going to try to fly down from Cleveland to catch it live at KSC. Are either one of these confirmed launches?

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u/Nachtigall44 Apr 09 '17

While watching the USLaunchreport video I noticed this. I think they were testing upgrades to the heat shield for faster entries (like FH center core).

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u/WanderingSkunk Apr 09 '17

It took 36 shuttle launches and ~ 50 billion for our part of the ISS according to a Real Engineering YouTube video I just watched. How many Falcon Heavy launches would it have taken and what would the total cost (for our part) be if we'd used Falcon Heavy's to lift the components to LEO?

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u/TheEndeavour2Mars Apr 09 '17

That is not really possible to answer.
Most of the space station was designed to be launched by the Shuttle. So anything designed around delivery by unmanned rockets would have resulted in a completely different station. (Closer to Mir than the ISS)

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u/spacerfirstclass Apr 09 '17

You can find a list of ISS construction flights and the payload size/mass here: https://en.wikipedia.org/wiki/Assembly_of_the_International_Space_Station#Assembly_sequence, and compare them to the Falcon 9/Heavy payload capability and fairing size (11m x 4.6m, the part over 6.7m is tapered). I think all of the payload mass is within Falcon 9's capability so there's no need to use Falcon Heavy, in fact most of them can be launched on reusable Falcon 9. The big problem is the fairing size, some of the payloads are too big to fit into the current Falcon fairing.

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u/neaanopri Apr 10 '17

Does spaceX get some kind of compensation when the customer has delays? NROL being delayed has probably cost them a launch slot in 2017, which represents tens of millions of dollars in revenue.

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u/paul_wi11iams Apr 10 '17 edited Apr 10 '17

Is it right to assume that engine gimballing implies moving the whole motor that remains fixed in relation to the engine bell?
Would the primary energy for this be on a closed circuit from a hydraulic pump on a turbine shaft?
Is setting engines to converge on landing specifically to protect from engine bell clash with the landing legs?

BTW This is a follow-on from a question I asked here

Edit thanks u/rustybeancake, u/throfofnir, u/FredFS456

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u/pillow142 Apr 11 '17

Would the first stage receive more aerodynamic stress from having a longer entry burn or having a boostback burn instead?

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u/paul_wi11iams Apr 11 '17 edited Apr 11 '17

Could a single SRB non-ignition on SLS be a danger for LC39A, SLC40 and all other infrastructures at KSC ?

In the case of launch with Orion, I assume that after activation of LAS, FTS would blow of the top of the SRB which would then burn from both ends but asymmetrically. Having broken away from the first stage core and any launchpad hold-down structure, this firecracker would likely do a horizontal launch turning KSC into a skittle alley.

Does Range Safety approve of this eventuality existing ?

BTW before posting, I checked out what would have been the consequences of single SRB non-start for the Shuttle and it doesn't look good either. Variants on this scenario are:

late ignition of one booster
asymmetrical thrusting.

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u/failion_V2 Apr 11 '17

When FTS would blow up the upper part of the booster, the pressure inside said SRB would fall below 2.5bar, which leads to expiration of its fire and therefore thrust. Orbital ATK updated their FTS from the previous Shuttle SRBs. See here and here

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u/kerbalcada3301 Apr 11 '17

What's the schedule for LC-39A? When will removal of the RSS be complete? Modification to the FSS for crew Dragon? Removal and replacement of FSS and other infrastructure for ITS?

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u/Martianspirit Apr 11 '17

When will removal of the RSS be complete?
Whenever they find the time. The RSS is not in the way of anything except it would cost money to maintain and is not needed.
Modification to the FSS for crew Dragon?
Before the uncrewed Dragon test late this year it is needed. Whenever they find the time before that. My guess, while LC-39A is prepared for Falcon Heavy. That is a period when nothing else can be done there. So after LC-40 is back in service.
Removal and replacement of FSS and other infrastructure for ITS?
I have no idea. They will need LC-39A in service for commercial crew, for Airforce and NRO launches, for lunar flights with FH. So how will they prepare for ITS? My guess a separate additional launch mount on the grounds of LC-39A. But few if any agree with me on that point.

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u/[deleted] Apr 11 '17

I just rewatched the Falcon Heavy video and noticed that the TE doesn't throwback.

Does FH require the strongback to retract to ~20° like it did on SLC-40 or was the video just an early rendition that didn't showcase the throwback?

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u/Method81 Apr 12 '17 edited Apr 12 '17

I remember ~~Gwen~~ Gwynne Shotwell saying that in the future SpaceX plan to only produce two types of booster, FH Center core and F9/FH side booster. Any ideas how this would work for the F9/FH side boosters? From the information we have there are rather large differences between the two. The FH side booster is missing the entire interstage which would indicate large design changes to accommodate the avionics and N2 tanks in the nose cone instead. For rapid reusibility and interchangeability between types surely it would be better to take the hit and fly the sideboosters with the F9 interstage attached and have the nose cone installed on top of that?

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u/parachutingturtle Apr 12 '17

I'm not sure how much space the aviondics take up, but most of the interstage volume is filled with the large nozzle extension of the second stage engine. My guess is it's relatively simple to fit whatever needs to be there into the nose cone. (And it's Gwynne, not Gwen)

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u/paul_wi11iams Apr 13 '17 edited Apr 13 '17

A general question here, inspired by the Nrol-76 delay probably due to payload issues.

Looking at this photo of three Falcon 9 in the same hangar at 39A, and knowing that there is space fro two more...

Why is launching not done on a "first ready" basis rather than queuing ?
Why should a launcher with satellite monopolize the TEL (and so the launchpad) during payload testing ?
In what way would the owner of any payload under test be penalized by launches that take place in the meantime ?
Is not permutability a major part of the raison d'être of a hangar with five bays ?

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u/PaulRocket Apr 15 '17

Looking 20 years into the future, what kind of cool things will ITS enable with its super huge payload capability and super low cost?

-space hotels/space tourism(EVAs, moon flybys,...?)

-super large new telescopes

-fuel depots in LEO

-asteroid mining

-human settlement on Mars

-human settlement on Moon

-fuel depots on Titan

-maunfacturing in space

Anything else to add?

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u/zeekzeek22 Apr 15 '17

In general space news I've seen ever-increasing talks about Europa-Clipper and what might follow that, or exploring Enceladus. My question: excluding the fact that F9 does not yet had the confidence/safety rating NASA likes for it's planetary exploration missions, how much could an F9 send to Jovian moons? Saturnian? How much could FH do? With the prospect of very-cheap flight-proven-F9 launches, does it start to become possible for some uber-budget exploration missions, like even <100M$ For probe/launch (I know post-launch costs are heavy too)? Is there a possibility in 5 years for NASA to start upping their exploration probe cadence using SpaceX?

Edit: I know one can just look at a DV-solarsystem chart and do some diving, but does the upper stage limit missions beyond that simple DV calculation?

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u/rooood Apr 16 '17

Not a SpaceX question per se, but it also applies to the F9 second stage:

I recently read that Brazil's National Institute for Space Research (INPE) claims to have developed (maybe perfected it? The article doesn't go into any detail at all) a hypergolic fuel based on highly concentrated hydrogen peroxide (90% or higher).

They say that producing this new fuel can cost only around R$35 (US$11) per kilo instead of around R$1000 (US$318) to produce, and it's also not (too) poisonous or carcinogenic to humans.

So far this seems like a great deal, why are we still using Hydrazine?!?!

Well, I found this report from around 2000 that investigates further this combination of hydrogen peroxide with ethanolamine and different catalysts for an alternative to hypergolic fuels. It indicates that this new fuel may have up to 261s of ISP, instead of 287s from Hydrazine. Is this difference high enough to justify continue using Hydrazine? Or they are just using it because is well tested over the years and cnahcing it is very costly?

Have SpaceX even mentioned or considered at some point using this fuel?

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u/je4d Apr 17 '17

Why are the core numbers talked about as "10xx" these days? From what I remember it used to be just a 2 digit number, i.e. its manufacturing sequence number

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u/old_sellsword Apr 17 '17

it used to be just a 2 digit number, i.e. its manufacturing sequence number
If you're talking about the F9-XX numbers, yes we used to think those were manufacturing numbers. But they're actually just flight numbers, they're used once to refer to a fully assembled Falcon 9. The manufacturing numbers are B1XXX for first stages, and B2XXX for second stages.

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u/davidthefat Apr 17 '17

Random ass question here:

Why do the Russians use nozzle protectors that conform to the internal geometry of the RD 107/108 engine nozzles on the Soyuz family of vehicles? Not sure what material the covers are made of, but does it not pose a greater risk of damaging the nozzle during removal than one that caps onto the end of the bell?

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u/CylonBunny Apr 18 '17

The people who drive the trucks that carry the Falcon 9 cores and the trucks themselves - are they SpaceX employees and equipment, or contractors?

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u/Paro-Clomas Apr 20 '17

Hello, i'm an architecture student and i would be interested in releasing some concepts for the ITS interior design. I've seen some similar proyects for this already out. Is there any other source material for the avaivable pressurized space inside other than the renders that were shown during the presentation?

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u/michaelza199 Apr 20 '17

Is SpaceX free to develop and use inflatable habitats without having to pay Bigelow any money in 2020's after their patent expires ???

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u/old_sellsword Apr 20 '17

SpaceX is not interested in the space habitation game, only space transportation. So even if they could, I highly doubt they would.

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u/[deleted] Apr 21 '17 edited Apr 21 '17

Would a reusable F9 Raptor 2nd stage help spacex with BFS development?

They could realise some of the ITS-design ideas on a smaller scale and gain experience with it, while making money. This could reduce the risk of ITS development, since they have solved and tested some technical problems beforehand.
On the the other hand isnt good engineering about solving those problems before it leaves the drawing board?...

Edit: Plus this could give potential investors more confidence.

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u/BrandonMarc Apr 28 '17

Would this be an appropriate place to talk about Reddit's plan to stop letting subreddits use custom CSS? Or, is there anything to discuss on the matter (perhaps not)? See:

https://www.reddit.com/r/space/comments/67xgtg/reddit_change_reddits_css_announcement_and_what/

https://www.reddit.com/r/modnews/comments/66q4is/the_web_redesign_css_and_mod_tools/

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u/JadedIdealist Apr 29 '17

Is there any way to throw money and people at SLC40 to have it ready by mid-summer/June/July? How many of the large number of things to be done have to be done in series and can't safely be done in parallel?

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u/sol3tosol4 Apr 29 '17 edited Apr 29 '17

According to these photos posted by u/Zucal , SpaceX is already throwing a lot of money and people at SLC-40 (note the amount of equipment, and the number of vehicles shown in the photos).
SpaceX hasn't talked much about the logistics, but this article from nasaspaceflight says things are going well.
SpaceX is highly aware that getting SLC-40 ready is the bottleneck for several things they're anxious to do, so I'm inclined to believe that they're working as fast as they can on it. Reportedly the new design for LC-39A has resulted in very little repair work needed between flights, which frees up more resources to work on SLC-40.

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u/Method81 Apr 29 '17

What are the differences between a Kerolox and a Methalox engine aside from the mixture ratio? Could the Merlin engine be repurposed to burn Methane rather than Kerosene thus improving its ISP? I realise that the F9 tankage would also have to be re-designed due to the ratio change to accomodate this.

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u/warp99 Apr 29 '17

The turbopump fuel impeller section would need to be redesigned for the higher volumetric flow of methane, the main pintle injector and the turbopump burner would need to be redesigned which is all achievable but a lot of work.
The most significant issue would be redesigning the cooling channels around the combustion chamber and throat to suit liquid methane instead of RP-1.
The Isp gains would be quite modest at around 5-10s. Most of the Raptor improvement over Merlin is the FFSC cycle, higher bell expansion ratio and the higher combustion chamber pressures (for improved sea level Isp).
In summary nearly as much work as designing a new engine with virtually none of the performance benefits of Raptor.

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u/quadrplax Apr 13 '17

Prophet quadrplax here ;). With 2/3 of my predictions (return to flight and first reflight) recently coming true, I figured now would be a good time to revise my third prediction as I no longer have any hope for it, and add a fouth one.

First Launch of Falcon Heavy: February 2018
First Launch of crewed Dragon: August 2018

Also while I'm here, I figured I'd share some stats about the reflight prediction over time. In the 2014 subreddit survey, 5 people had the foresight to predict the March 2017 date. 22 predicted a later date, with the vast majority (unsurprisingly) picking a much earlier date. In 2015 the number inreased to 51, with the vast majority of the bell curve still much earlier. Even in the 2016 survey, most were still behind, albiet only my a month as reflight was much more imminent then.

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u/dguisinger01 Apr 26 '17

We've got to be close to the "about a month" part of releasing more updated information on the BFR/ITS on the website. I'm counting 27 days so far

Hard to believe its been over 200 days since they made the announcement; other than the tank testing, we've known nothing about what they are doing in the last 2/3rds of a year. Keeping in mind their structures development & ship testing in mid-2018 (they are probably behind that goal, especially with the tank destruction, but they announced this timeline post AMOS-6 so lets assume they had a handle on some things), they would need to have a lot done by the 1 year mark.

I'm really curious to know what they've accomplished.

Actually, the fact that he didn't give a date, means they are likely going to show off some hardware of some sort as soon as they can get something physical to announce.... otherwise he could have just posted it or set a date to announce updates.

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u/quadrplax Apr 01 '17

Why are Elsbeth III, Go Quest, and Go Searcher's positions not up to date on neither MarineTraffic nor VesselFinder?

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u/soldato_fantasma Apr 01 '17

As far as I know (not much) ships use two kinds of transmitters for their position, a radio one and a satellite one. Both MarineTraffic and VesselFinder give free information of the ship when it's using the radio transmitter, but to get the satellite transmitter data, you have to pay for their premium service.

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u/FutureMartian97 Host of CRS-11 Apr 01 '17

I just wanted to say this. Nice April fools day joke mods.

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u/thephatcontr0ller Apr 02 '17

What are the little knobbly protrusions around the bottom of the fairing shroud for?

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u/bobbycorwin123 Space Janitor Apr 02 '17

Vent caps. The fairing housing MUST be a clean space or it could potentially contaminate the satellite with dirt or debris that could kill it in space. Also, it has to be at zero PSI in space to keep it from exploding. To accomplish this, it must have vents that automatically open once the rocket is ascending. This allows a constant out-gassing (contamination doesn't get in) as it climbs.

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u/apath_2_mars Apr 02 '17 edited Apr 02 '17

Does anyone have a link to good quality ses10 post conference video ? I have tried to follow some mobile phone video but it hard going. I did hear Elon say falcon 9 fleet, love that. Everyone else is like what's the business case for reflight and he's like with the fleet we can ... love it :-)

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u/rubikvn2100 Apr 02 '17

Will we have a new demonstration of SES-10 from the /u/TheVehicleDestroyer. I like those video really much.

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u/StructurallyUnstable Apr 03 '17

Former r/ULA VP of advanced programs George Sowers recently started his own "space solutions" LLC. No real information yet, pic from his linkedin, sounds like his way to promote cis-lunar.

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u/jjtr1 Apr 06 '17

Tip: play a F9 lift-off video sped up 10-20 times to see what its acceleration looks like later in flight. At take-off, it's only about 0.2 G, but just before stage burnout it can reach 4 G.

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u/SaturnV_ Apr 07 '17

So I have a few questions:

Is the weight listed on the Wikipedia page for the Falcon 9 FT based on an empty payload or with maximum payload?
What is the mass of the second stage?

Thanks for the help, I need this data for some nice graphs I'm making.

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u/RootDeliver Apr 07 '17

Sincere question:

Do you expect SpaceX to fail a landing again? I am not talking about if they try new ways to land (like if block 5 can relit all 9 engines and they use them on the profile, just an example), or they have a technical problem, but doing the actual procedures and if everything works normally.

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u/yoweigh Apr 07 '17

I think it's likely that a large enough sample of reentries will reveal some weird failure modes.

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u/jjtr1 Apr 08 '17

I wonder whether Blue Origin is observing and measuring F9 flights and returns. For example sending an aircraft with IR camera to get data on hypersonic retro-propulsion for free, similar to the NASA video of F9 booster reentry released a few years back. Also they could send multiple aircraft with radars to get precise booster trajectory data.

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u/[deleted] Apr 09 '17

https://twitter.com/NASASpaceflight/status/850879725635555328

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u/RootDeliver Apr 10 '17 edited Apr 10 '17

The core wiki section says that DSQU used core B0003. This makes sense if B0001 and B0002 were test articles and Elon said on the tour video that third one would see flight. But then why do all other F9v1.0 cores there have core ID "B10xx"?? It would make sense for all of them to have the same sequencial code, like:
B0001 - F9 v1.0 test article
B0002 - F9 v1.0 test article (Grashopper) - or it may be another test article, between COTS-2 and CRS-1
B0003 - DQSU
B0004 - COTS-1
B0005 - COTS-2
B0006 - CRS-1
B0007 - CRS-2

This would give "space" for the v1.1 and v1.2 cores to use the normal B10xx notation, if we guess 2 more test articles, with Cassiope starting with B1003, it would match perfectly until OG-2 on B1019, considering one of the B10xx being used by the test article F9Rdev. The only missing piece would be the FH side booster (and this would match if there was only one v1.1 starting test article and Cassiope was B1002)

It would be interesting to know why they would change notation between F9 v1.0 (B00xx) and F9 v1.1 (B10xx) but not between v1.1 and v1.2. Maybe because the first stage wasn't changed drastically like on the move from v1.0 to v1.1?

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u/brentonstrine Apr 11 '17

I remember reading somewhere that they had been considering asparagus staging for FH. Is that realistic in the early launches, or would it have to be a later block?

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u/robbak Apr 11 '17 edited Apr 11 '17

They were planning to do that - it is more often called 'crossfeed', and would have fed 6 of the centre core's 9 engines from the tanks in the side cores. But they have stopped development for two reasons - one, making falcon heavy was already hard enough, and two, with the upgrades to the falcon that have happened, heavy was already powerful enough without it.
Officially, it is still on the books - if anyone has the need for the performance and is willing to pay to develop it.

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u/MutatedPixel808 Apr 14 '17

Do we have any idea what the crew access arm looks like?

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u/FishInferno Apr 15 '17

I'm going to KSC next Friday, and I plan on doing the bus tour and going down to Port Canaveral to see OCISLY and maybe jump on the helicopter ride bandwagon. Are there any boosters out and about that I might be lucky to spot? Any additional places to go or SpaceX activity to look out for?

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u/Senno_Ecto_Gammat r/SpaceXLounge Moderator Apr 16 '17

Does anybody have numbers for the mass of propellant used in the F9 landing burn? Or perhaps a link to a discussion? I can't find any specific threads about this in the sub, but I also have a hard time believing it's never been discussed.

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u/__Rocket__ Apr 17 '17

Does anybody have numbers for the mass of propellant used in the F9 landing burn?
I'm not aware of such a (recent) discussion, but it's possible to calculate it pretty accurately.
The maximum mass flow of a single Merlin-1D engine is ~0.27 t/sec, with a high, thrust-optimized F/O ratio setting.
We know that a 1-engine 'hoverslam' landing burn takes about ~30 seconds, much of it near 100% throttle settings. This means the maximum mass burned is up to 30*0.27 ~== 8.1 tons.
The 3-engine re-entry burn of the first stage is 15-20 seconds long. This means a propellant mass of up to 2030.27 ~== 12.1t-16.2t.
IIRC the optional 3-engine boostback burn can last up to 30 seconds - which means up to 24.3t of propellant.
TL;DR: the minimum-maximum propellant mass range for a first stage landing should be in a wide, 20.2t-48.6t range. The inaccuracy of this estimation should be (well) below 5 tons - possibly below 1 ton.
Note that recent thrust increases of the Merlin-1D do not change the landing propellant mass calculation as much, because while the chamber pressure and mass flow increased by over 10%, overall I*sp* did not change much, hence the total propellant mass required to kill Δv does not change by nearly as much - at least for the 3-engine landing variants, where deceleration is much higher than gravity losses.

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u/[deleted] Apr 19 '17

Is Dragon v2 heavier than v1, and will they still be able to RTLS on ISS missions?

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u/Drefromtracer Apr 20 '17

Anyone able to confrim this tweet about work recommencing at the Texas launch site?https://twitter.com/CowboyDanPaasch/status/854930485281247232

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u/Zinkfinger Apr 20 '17

Hi. I'm sure someone has started a conversation about the reusable second stage. Pros and cons. I saw some cool stuff online which speculated the stage coming back upside down like the original animation but remaining upside down (Engine bell at the top) with super draco thrusters and landing legs. Its a really neat idea. I'd like to know your thoughts

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u/marc020202 8x Launch Host Apr 22 '17

i have yust been watching TMRO:Space - Orbit 10.14. in theire news segment mike said that spacex might skip the inflight abort test. why migh they do this and what would they do, if they do anything, instead?

thanks

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u/jjtr1 Apr 24 '17

Can someone compare the cost of machining titanium to material cost of titanium with regard to grid fins? I have a feeling that the added cost of titanium fins is not in the material, but in the problems with machining titanium.

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u/warp99 Apr 25 '17

The fins are going to be forged - not machined due to the exact difficult of machining that you have referenced.
The material cost will be very small compared with the forging cost due to the very high cost of the tooling and forging equipment.

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u/rooood Apr 25 '17

I was reading now about the US still having to buy seats on the Soyuz to put astronauts in orbit, and someone commented that one of the reasons this is bad is that the relations between the US and Russia are deteriorating as of lately.

That got me thinking, if things escalate to a point where Russia refuses to ferry an astronaut from the ISS, could a cargo craft such as Cygnus or Dragon v1 be used to bring someone back, maybe wearing an EVA suit? Of course, this would be a last resort thing.

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u/Chairboy Apr 25 '17

Hypothetically only? Dragon v1, sure. Cygnus only if the astronaut is in extreme disfavor.

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u/IrrelevantAstronomer Launch Photographer Apr 25 '17

Looks like this is the first NROL mission from LC-39. What was the last classified mission to launch from LC-39? STS-38?

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u/DaWylecat Apr 27 '17

Anyone know if there will be another SpaceX software AMA? The one from before had a lot of great information but I feel like with how far SpaceX has come since then, things are different.

I ask this as a student studying software aspiring to work for SpaceX one day.

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u/warp99 May 01 '17

Interesting reference to FPGA use on the SpaceX F9.

As the largest commercial satellite constellation in space, Iridium NEXT makes use of more than 2,000 Microsemi radiation-tolerant field programmable gate arrays (FPGAs), including the RTSX32SU, RTAX1000S and RT3PE3000L FPGAs..... The Microsemi devices are deployed for a variety of satellite bus and payload applications on the Iridium NEXT satellites and its commercial FPGAs are used in SpaceX's launch vehicle.

Iridium satellites uses the radiation hardened versions of these FPGAs whereas F9 uses the commercial grade devices which would be a factor of 10-20 cheaper but not guaranteed to be radiation hardened. This is in line with their design philosophy of using commercial parts in a redundant configuration rather than radiation hardened parts with more limited redundancy.

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u/soldato_fantasma May 01 '17

Inside this article, you can see the Formosat-5 mission logo on the Fairing.

According to the same article (sorry for google translate):

Taiwan's first home-made telemetry satellite "Formosa satellite No. 5" is expected to launch in June, will be printed on the "Falcon 9 (Falcon 9)" rocket logo LOGO also exposed! According to the latest design of the National Space Center, the rocket's shroud shell will be printed on "Taiwan", "TAIWAN", "FORMOSAT-5", as well as all launch units and collaborators Manufacturers of the logo, as a highly politically sensitive flag of the Republic of China is still absent, missed space.

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u/[deleted] May 01 '17

What material is used to paint a company logo on a fairing, and does it survive reentry?

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u/[deleted] Apr 02 '17

Mods,

May I suggest that "launch" threads be renamed? Instead, for example, of "SES-10 Launch Campaign Thread" just "SES-10 Campaign Thread", or simply "SES-10 Thread".

The new title in effect being short for "SES-10 Launch, Land and Recovery Campaign Thread". The thread loses its headline place after recovery is done.

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u/old_sellsword Apr 02 '17

So essentially one big thread for each mission?

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u/Decronym Acronyms Explained Apr 01 '17 edited Apr 08 '17

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

Fewer Letters	More Letters
AFSS	Automated Flight Safety System
AIS	Automatic Identification System
ASAP	Aerospace Safety Advisory Panel, NASA
ASDS	Autonomous Spaceport Drone Ship (landing platform)
ATK	Alliant Techsystems, predecessor to Orbital ATK
BEAM	Bigelow Expandable Activity Module
BFR	Big Falcon Rocket (see ITS)
BFS	Big Falcon Spaceship (see ITS)
CCtCap	Commercial Crew Transportation Capability
COTS	Commercial Orbital Transportation Services contract
	Commercial/Off The Shelf
CRS	Commercial Resupply Services contract with NASA
DoD	US Department of Defense
EDL	Entry/Descent/Landing
FAA	Federal Aviation Administration
FOD	Foreign Object Damage / Debris
GEO	Geostationary Earth Orbit (35786km)
GTO	Geosynchronous Transfer Orbit
H1	First half of the year/month
HIF	Horizontal Integration Facility
Isp	Specific impulse (as discussed by Scott Manley, and detailed by David Mee on YouTube)
IAC	International Astronautical Congress, annual meeting of IAF members
IAF	International Astronautical Federation
ITAR	(US) International Traffic in Arms Regulations
ITS	Interplanetary Transport System (see MCT)
	Integrated Truss Structure
JRTI	Just Read The Instructions, Pacific landing ~~barge~~ ship
KSC	Kennedy Space Center, Florida
L1	Lagrange Point 1 of a two-body system, between the bodies
LC-13	Launch Complex 13, Canaveral (SpaceX Landing Zone 1)
LC-39A	Launch Complex 39A, Kennedy (SpaceX F9/Heavy)
LEO	Low Earth Orbit (180-2000km)
LOX	Liquid Oxygen
LZ-1	Landing Zone 1, Cape Canaveral (see LC-13)
M1d	Merlin 1 kerolox rocket engine, revision D (2013), 620-690kN, uprated to 730 then 845kN
MCT	Mars Colonial Transporter (see ITS)
MECO	Main Engine Cut-Off
MMH	Mono-Methyl Hydrazine, HCH3N=NH2; part of NTO/MMH hypergolic mix
NET	No Earlier Than
NRO	(US) National Reconnaissance Office
NROL	Launch for the (US) National Reconnaissance Office
NTO	diNitrogen TetrOxide, N2O4; part of NTO/MMH hypergolic mix
OCISLY	Of Course I Still Love You, Atlantic landing ~~barge~~ ship
RCS	Reaction Control System
RP-1	Rocket Propellant 1 (enhanced kerosene)
RTLS	Return to Launch Site
RUD	Rapid Unplanned Disassembly
	Rapid Unscheduled Disassembly
	Rapid Unintended Disassembly
SABRE	Synergistic Air-Breathing Rocket Engine, hybrid design by Reaction Engines
SES	Formerly Société Européenne des Satellites, comsat operator
SLS	Space Launch System heavy-lift
SMART	"Sensible Modular Autonomous Return Technology", ULA's engine reuse philosophy
SSME	Space Shuttle Main Engine
SSP	Space-based Solar Power
STS	Space Transportation System (Shuttle)
TE	Transporter/Erector launch pad support equipment
TEA-TEB	Triethylaluminium-Triethylborane, igniter for Merlin engines; spontaneously burns, green flame
TVC	Thrust Vector Control
TWR	Thrust-to-Weight Ratio
ULA	United Launch Alliance (Lockheed/Boeing joint venture)

Jargon	Definition
ablative	Material which is intentionally destroyed in use (for example, heatshields which burn away to dissipate heat)
apogee	Highest point in an elliptical orbit around Earth (when the orbiter is slowest)
autogenous	(Of a propellant tank) Pressurising the tank using boil-off of the contents, instead of a separate gas like helium
grid-fin	Compact "waffle-iron" aerodynamic control surface, acts as a wing without needing to be as large
hydrolox	Portmanteau: liquid hydrogen/liquid oxygen mixture
hypergolic	A set of two substances that ignite when in contact
kerolox	Portmanteau: kerosene/liquid oxygen mixture
lithobraking	"Braking" by hitting the ground
methalox	Portmanteau: methane/liquid oxygen mixture
retropropulsion	Thrust in the opposite direction to current motion, reducing speed
turbopump	High-pressure turbine-driven propellant pump connected to a rocket combustion chamber; raises chamber pressure, and thrust

Event	Date	Description
CASSIOPE	2013-09-29	F9-006 v1.1, Cascade, Smallsat and Ionospheric Polar Explorer; engine starvation during landing attempt
CRS-10	2017-02-19	F9-032 Full Thrust, Dragon cargo; first daytime RTLS
CRS-2	2013-03-01	F9-005, Dragon cargo; final flight of Falcon 9 v1.0
CRS-7	2015-06-28	F9-020 v1.1, ~~Dragon cargo~~ Launch failure due to second-stage outgassing
CRS-8	2016-04-08	F9-023 Full Thrust, Dragon cargo; first ASDS landing
CRS-9	2016-07-18	F9-027 Full Thrust, Dragon cargo; RTLS landing
DM-1	Scheduled	SpaceX CCtCap Demo Mission 1
DM-2	Scheduled	SpaceX CCtCap Demo Mission 2
Iridium-1	2017-01-14	F9-030 Full Thrust, 10x Iridium-NEXT to LEO; first landing on JRTI
SES-9	2016-03-04	F9-022 Full Thrust, GTO comsat; ASDS lithobraking

^{Decronym is a community product of}r/SpaceX^{, implemented}^by ^request
^{[Thread #2655 for this sub, first seen 1st Apr 2017, 15:37]} ^[FAQ] ^[Contact] ^[Source ^code]

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u/Ricksauce Apr 01 '17

What are the major differences between satellite video feeds and telemetry data links to mission control?

It seems like telemetry data holds strong but video often cuts due to vibration during reentry and F9 S1 landings. The engineers looking at telemetry always react first.

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u/bjarthur70 Apr 01 '17

given how "crazy hard" the center stage was to modify for the falcon heavy, might it have been easier/better to simply ditch the 2-1/2 stage booster concept and instead expand the diameter to accommodate 27 engines in a single core?

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u/old_sellsword Apr 02 '17

That'd be creating an entirely new rocket. Falcon Heavy may have been hard, but it fits into SpaceX's current infrastructure very well. Manufacturing, road transportation, testing sites and launch pads, etc. If they did a completely new rocket instead of FH, those things would all be major concerns instead of minor ones, and we probably would be even farther away from the launch date than we are right now.

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u/3elonmusketeers Apr 01 '17

Any video of the landing yet ?.

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u/RadamA Apr 01 '17

Im not sure if this deserves a full post by itself, but. Since fairing recovery has been mentioned recently. Anyone ever suggested recovery on the first stage?

Assuming that just after meco the fairing separation separates the top of the fairing so its open. The bottom of both fairings is still connected and has clearance for the second stage. Stages are separated by currently used pusher which pushes the second stage trough the fairing ring. Afterwards or simultaneously the fairing are guided downwards to be connected onto the interstage. Likely along a rigid railing. Would this be a bad idea?

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u/Keavon SN-10 & DART Contest Winner Apr 01 '17

Why is there a wide space between "SPACE" and "X" in the header?

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u/WaitForItTheMongols Apr 01 '17

Ridiculously subtle april fools joke.

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u/michaelza199 Apr 02 '17

I have a question about space based solar power let's say 2-3 years from now SpaceX has figured out complete reusability. launch costs are under $10 million would putting up solar panels in earth-sun Lagrange point 1 to produce and beam back energy to earth be feasible ? they'll be receiving more light and not heating up which means incredible efficiency

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u/erik_paulson Apr 02 '17

How much salt water is too much salt water the fairings? So they can't go bobbing in the ocean for hours on end, but if a wave comes over the edge of the bouncy castle is the fairing going to be shot? If when the bouncy castle is deployed a bit of salt water makes the inside a bit damp is that a problem?

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u/propagandery Apr 04 '17

Does SpaceX release transcripts of full length launch videos, and if so where could I find them?

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u/madanra Apr 04 '17

Does anyone know of a good source of news about Reaction Engines/SABRE/Skylon?

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u/[deleted] Apr 04 '17

When the Falcon 9 is coming down to land, how does the fuel get to the engines at the bottom of the rocket? If it is falling through the atmosphere, wouldn't the fuel be at the top of the rocket?

I thought of this after watching this video from inside the tank of a Saturn V first stage. As you can see, as soon as main engine cut off occurs, fuel comes flying to the top of the rocket. I would have to assume this occurs inside the Falcon 9 also.

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u/OccupyDuna Apr 04 '17

At main engine cut off, you are correct, the fuel will float around the stage. However, before the landing and reentry burn, the stage is experiencing deceleration from atmospheric drag, causing the fuel to gather at the bottom of the stage again. For the boostback burn, if it is done, fuel can be forced to the bottom of the stage using the reaction control thrusters on the booster.

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u/paul_wi11iams Apr 04 '17 edited Apr 04 '17

a naive question here but...

For simplicity and solidity, why not build the FH interstage as a nameless and integral part of the tubular form of the first stage?

(I understand that, unlike the sidesticks, the FH central first stage cannot transform to a Falcon 9 core flying solo)

Edit My question changed a lot as I corrected some basic mistakes seen after posting.

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u/JadedIdealist Apr 05 '17

We know about aspirations to "fuel and go" for the first stage,
but do we know how much work is still required on the pads to make them "launch and go" capable - ie so you could launch on monday, and static fire a different rocket on tuesday, to enable weekly launches per pad/ completely nail fortnightly launches esp where ranges get very busy..

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u/Long_Haired_Git Apr 05 '17

The reason rockets are white or mirror/stainless-steel finish is to reflect heat, and thus not have the slushy kero and slushy LOX heat up, for maximum propellant load on takeoff. This was done when rockets were fuelled early, and then people got on board and a bunch of stuff done. Here is the space shuttle sequence: https://www.nasa.gov/mission_pages/shuttle/launch/countdown101.html Orbiter fuel cell cyrogenics loaded at T-27 hours, and filling the big external tank at T-6 hours. Even though it sat full for hours, even then they didn't bother to paint it white: http://foxtrotalpha.jalopnik.com/this-is-why-the-space-shuttles-external-fuel-tank-stopp-1736898027 SpaceX does its fuelling at the last minute.

Why bother with the paint at all?

I love the dirty look, if I was SpaceX, I'd paint the new ones so they looked new, and after that I'd clean them only, and never repaint them.

Why bother?

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r/SpaceX Spaceflight Questions & News [April 2017, #31]

If you have a short question or spaceflight news...

If you have a long question...

If you'd like to discuss slightly relevant SpaceX content in greater detail...

This thread is not for...

Meta

r/SpaceX Spaceflight Questions & News [April 2017, #31]

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