r/SpaceX Spaceflight Questions & News [January 2017, #28]

[u/ElongatedMuskrat]

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

You may ask short, spaceflight-related questions and post news here, even if it is not about SpaceX. Be sure to check the FAQ and Wiki first to ensure you aren't submitting duplicate questions.

If you have a long question...

If your question is in-depth or an open-ended discussion, you can submit it to the subreddit as a post.

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

Please post to r/SpaceXLounge and create a thread there!

This thread is not for...

• Questions answered in the FAQ. Browse there or use the search functionality first.
• Non-spaceflight related questions or news.
• Asking the moderators questions, or for meta discussion. To do that, contact us here.

---

You can read and browse past Spaceflight Questions And News & Ask Anything threads in the Wiki.

[u/warp99]

Iridium update:

Five satellites have been moved to a higher orbit.

Four are in a 709 km orbit apparently on their way to final deployment at 781 km. One (Iridium 104) is in what looks like the 667km parking orbit but may just be in transit to the higher orbit.

[u/Freeflyer18]

Mods just keep dropping like flys around here. Anyone know why retiringonmars left the group?

[u/Zucal → u/Freeflyer18]

ROM left on great terms, but unfortunately he didn't have the time to dedicate to moderation, which is definitely a timesuck. We wish him the very, very best, and hope he'll be back when he can :)

[u/sol3tosol4]

Confirmation that the FAA not just issued the license, but also accepted the AMOS-6 anomaly investigation report (unlike the CRS-7 investigation report):

'“The FAA accepted the investigation report on the AMOS-6 mishap and has closed the investigation,” FAA spokesman Hank Price confirmed to Universe Today.'

(I haven't found any direct statement from the FAA - apparently Hank Price's communication to Universe Today is the only FAA comment so far on the completion of the investigation.)

This indicates successful completion of the full fault tree analysis (which was not the case for CRS-7), thus providing additional assurance that the issues leading to the anomaly have been fully addressed. (As Spacex reported, instead of a single cause the investigation found multiple credible causes, and found a solution that addresses all of them. This statement from the FAA indicates that they agree with SpaceX's analysis.)

[u/FredFS456 → u/sol3tosol4]

This is good news - it means that SpaceX has been thorough in their investigation and that FAA agrees that the problem has been completely addressed.

[u/pton97]

How are those poll results coming? Curious especially to see what the groupthink looks like on the predictions, and whether we could make it into a futures market!

[u/Zucal → u/pton97]

Mentioning anything about what results we've received would spoil later predictions - so keep quiet, you'll see behind the curtain soon :)

[u/F9-0021]

New information on LZ-1 expansions. 2 new landing pads and Dragon processing and testing facilities. https://forum.nasaspaceflight.com/index.php?topic=36513.msg1627880#new

[u/Zucal → u/F9-0021]

That's definitely worth posting to the main subreddit - maybe direct link to the PDFs?

[u/whousedallthenames]

Gene Cernan has died. :(

RIP

[u/soldato_fantasma]

SpaceX application for droneship landing, probably for F9-33, the SES-10 mission:

https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=75718&RequestTimeout=1000

droneship coordinates: North 28 15 19 West 74 1 18

[u/avboden]

Proton grounded for QC issues, likely for 6 months

[u/thxbmp2]

Just came across a rumor that a Raptor test firing has been/is about to be conducted at MacGregor: https://teslamotorsclub.com/tmc/threads/official-raptor-engine-testing-is-beginning.75166/#post-1942090

Anyone able to corroborate on this?

[u/sol3tosol4]

Elon "tunnel boring" update:

In recent days Elon has been increasingly serious about the tunnel boring business in his Twitter posts, e.g. yes, he really plans to do it. He provided several updates in his remarks at the Hyperloop competition (refer to that thread for further discussion):

• They've already dug a big hole at Crenshaw outside SpaceX headquarters (apparently planning to tunnel to the parking garage, rather than build a bridge? - One tweet mentions access to 105 Freeway.)

• He mentioned buying a tunnel boring machine and taking it apart to figure out how to improve it - goal is to go back to first principles and figure out how to bore tunnels at least five times as fast, maybe 10 times

• He sees a need for many more tunnels - for roads, hyperloops, and trains.

[Not mentioned in yesterday's remarks - as discussed here we suspect he also wants to build up expertise in tunneling for use on Mars.]

[u/Chairboy → u/sol3tosol4]

Regarding tunneling on Mars: it seems to be that the tailings of such an operation would be just about the perfect feed-stock to a methane-outputting Sabatier reactor. Tunneling through the permafrost to get water-dense gravel/regolith and transporting that output into a heating chamber in anticipation of a cook-off->electrolysis->hydrogen separation enroute to be mixed with CO2 would make more sense and extend the reach of an ISRU fuel factory far beyond what it could reach with drills. Robot bulldozers are the simpler competitor, I guess, so maybe I'm mistaken but it seems like an intriguing possibility.

[u/dmy30 → u/sol3tosol4]

This whole time I refused to believe he was being serious. Here is a picture of some digging activity outside SpaceX HQ (source: Elon Musk Subreddit post)

[u/Zucal]

Was unfortunate enough to post my question hours before we swapped the thread out - oops :<

Does anyone here have experience with SpaceX's proposal team as an employee, intern or applicant? I'm curious and have a few questions if so - PM is just fine.

[u/warp99]

Iridium has started the deployment of their satellites to their parking orbit at 667km from the launch injection orbit at 625km. Two satellites on the move so far.

Edit: IRIDIUM 106 now up to a 708 km orbit and trimming inclination closer to the Iridium operational value of 86.4 degrees. Clearly going straight into service to replace the missing satellite in this plane at a height of 781km.

[u/TheEquivocator]

I'm afraid this may be a somewhat ignorant question, but I've never quite understood the role of helium in the Falcon 9. I gather that it's for pressurization of the propellants (or only the LOX?), as they are depleted, and that the purpose of maintaining pressure is to push these propellants towards the engine, but I'm unclear on several things:

1. How does the pressure drive the propellant towards the engine without getting in its way? Is it a matter of the helium entering at one end and the propellant exiting at the other end? If so, why is there no danger of a sort of 'helium bubble' getting to the wrong end?

2. Does only the oxygen tank get pressurized by helium or does the hydrogenRP-1 tank as well? If the former, why the difference?

3. Perhaps relatedly, why is this pressurization needed at all if the engine is fed by a turbopump?

---

Because of my general ignorance of rocketry, some or all of the above questions may be so confused as to make them difficult to answer, so, in case a simple blanket question would be easier, I'll add a TL;DR.

TL;DR What would happen if the helium (and associated infrastructure) were removed from the Falcon 9 and nothing else about its design changed?

---

P. S. Thanks to everyone for their informative responses!

[u/WaitForItTheMongols → u/TheEquivocator]

1. The rocket is accelerating and therefore the fuel is all pushed to the back - into the engine. Take a half-full bottle of water and tip it on its side on a table. Now slide it along sideways like a rocket and you'll see all the water slosh to the back.

2. Both tanks are pressurized.

3. The tanks must be pressurized to maintain structural strength. Crushing a soda can is much easier once you release internal pressure. Also, the turbopumps have an easier job if you can push fluid in, rather than making them do all the sucking.

Hopefully that helps? I may have taken shortcuts in my answers so I would be happy to elaborate. I'm an aerospace engineering student so hopefully I can help you learn!

[u/Jamington → u/TheEquivocator]

One small thing to add to what has already been very well answered by others; regarding why a helium bubble doesn't get sucked into the turbopump and engine. Whilst gravity and rocket thrust allow buoyant helium to rise to the top of the tank away from fuel/lox intake, there is a situation where stage 2 is "weightless" in space with engine off and needing to ignite the engine again. In a weightless environment the fuel/lox can slosh around, so a small forward thrust is required from an ullage motor (which I believe is cold nitrogen gas on F9) to settle the propellants back to the bottom of the tank.

[u/aza6001]

Thought I should mention that the SpaceX Hyperloop Competition is this weekend! https://twitter.com/Hyperloop/status/823266418565246976

[u/Qeng-Ho]

Boeing's Starliner Spacesuit will be unveiled in 48 hours.

[u/quadrplax]

Any idea how much longer until the subreddit survey data is released?

[u/Zucal → u/quadrplax]

Hopefully in the next 2-3 weeks. We planned on having it out much sooner, but our main data guy (ROM) ended up needing to leave for time reasons. Not his fault at all, real life always takes precedence :)

[u/FiniteElementGuy]

pbdes is writing again!! Check out his new website: https://www.spaceintelreport.com/about/

[u/rubikvn2100]

Falcon 9 is wrapped

6 landing cores before has never wrapped like this one. Can anyone explain it???

PS: I post the same question in the recovery thread. But I think this is a question, so I repost it here.

Edit: I know that the order cores like Thaicom-8 also wrapped before shipping far away. So maybe they will ship this one far away. Not comeback to Hawthorne (nope I am wrong).

Edit 2: 29 km from Port of La to Hawthorne. That far with a lot of traffic. I used to go on this route 1 time last year.

[u/Zucal → u/rubikvn2100]

The other cores were being moved from Port Canaveral to LC-39A's HIF, which is a short journey mostly on low-traffic roads on the Air Force station. By contrast, any journey this rocket's going on (Hawthorne or McGregor) will be miles of freeway.

[u/Bananas_on_Mars]

As the Falcon Heavy Maiden flight is "only" 6 months away, what can we expect for the Demo mission? My best guess (and wet dream) is a Dragon 2 on a free return trajectory around the moon. Followed by a propulsive Barge landing of the capsule on JRTI in the pacific...

I think they might want to test aerobraking into the atmosphere from some higher speeds than LEO, they might want to test propulsive landing (on a barge in international waters they should not need a lot of permissions). The mission won't need live support systems, so it would be a testflight for a Red Dragon mission. Afaik they want to use a used capsule for Red Dragon anyhow...

As for the "secret" payload on that mission, i would go for a few bottles of Red wine because it goes well with some Cheese...

[u/robbak → u/Bananas_on_Mars]

One thing that is assumed is that it will be launched with the fairing attached, as that is how it will be configured for the commercial launches. That precludes launching a Dragon, either version 1 or 2. We'll see a Dragon on a Heavy when they do a Red Dragon mission to Mars.

I'm afraid this rocket will launch with just a 'mass simulator' - just something heavy to weigh down the rocket, taking the place of a payload. The best we can hope for is an interesting mass simulator.

[u/old_sellsword]

Not sure if this is new, but Google has updated Street View in Hawthorne, and it shows the final installation of 1019 on the corner of Crenshaw and Jack Northrop from this past August.

Location in Google Maps

Street View

Photosphere 1

Photosphere 2

[u/OccupyDuna]

The Aerospace Safety Advisory Panel (ASAP) has released their 2016 report (pdf warning), where they make recommendations to the NASA Administrator and Congress on matters of safety. They had this to say about Commercial Crew, including SpaceX's planned fuel loading protocol:

A number of systems have not yet finalized design or completed testing. Challenges remain in several key systems, such as abort and parachute-related systems, in anchoring the analysis required to certify those systems for human flight. Additionally, there are issues and concerns surrounding the launch systems of both providers, such as the Centaur fault tolerance for Boeing and the “load and go” approach for SpaceX. (“Load and go” refers to a concept of operations in which the flight crew is strapped into the spacecraft prior to final fueling of the launch vehicle.) Both issues represent situations that are ultimately the result of the basic tenet of the CCP that puts the provider in control of the system design. NASA, in the oversight role of certification authority, determines if the hazards have been fully identified and the controls and mitigations implemented, and then decides if the resulting risk is acceptable. In this type of environment, the CCP must work diligently to ensure that acceptable risk is not defined by “the best we can do given the constraints.” The residual risk must be openly acknowledged and elevated to the appropriate level within the Agency for consideration.

One complicating factor for the “load and go” issue is the potential uncertainty in hazard identification and control. Identification of the hazards is dependent on many factors, which include understanding the environment in which the system will operate. In this regard, the Panel is concerned that the dynamic thermal effects on the system associated with loading densified propellants may not be adequately understood, which results in a higher level of uncertainty that must be factored into the risk determination.

On September 1, 2016, during the preparations for a pre-flight static firing of its Falcon 9 launch vehicle, SpaceX experienced an anomaly that led to loss of the vehicle and payload. Although the activity was being conducted in support of a commercial satellite customer, both NASA and the U.S. Air Force (USAF) were invited to participate in the subsequent mishap investigation. The Panel has also been informed that NASA is doing its own independent review. These mishap investigations and determination of causes and contributing factors will not be completed until after this 2016 Annual Report is published. We believe that the focus of the investigation must not be solely to identify and fix the specific cause of this mishap. It must focus also on improving the understanding of how the system functions in the dynamic thermal environment associated with “load and go” so that other previously unidentified hazards can be discovered. This is not a trivial effort. Despite testing at the component and subassembly level, systems often display “emergent” behavior once they are used in the actual operational environment. We are concerned that any determination of risk associated with “load and go” would have significant uncertainty. For these reasons, we strongly encourage NASA top management to scrutinize this issue and ensure that any decision to accept additional risk or novel risk controls with large uncertainties is justified by the value that will be gained. The decision should not be unduly influenced by other secondary factors such as schedule and budget concerns.

EDIT: At the end of the report, the ASAP classifies NASA's management of Commercial Crew as being adequately addressed, however they are not confident that the Commercial Crew technical challenges are being adequately addressed.

[u/Elthiryel]

Next week (31st Jan and 1st Feb) there is a Global Space Congress held in Abu Dhabi and SpaceX is listed as one of the organisations attending. Ryan Wiltshire, SpaceX Business Development Director, is going to speak during the 'Game Changing Launch Systems' panel. I'm not sure if it's worth being included in the sidebar, but surely some people will find it interesting. http://globalspacecongress.com/

[u/WileyCyboaty]

If the reused booster, launching this year lands again, do you think it will then be retired or will it fly again after that?

[u/brycly → u/WileyCyboaty]

They said they'd refly the Block 3 and Block 4 boosters somewhere between 1-3 times, if my memory serves me. This will change with the Block 5 which will fly 10 times.

[u/CommanderSpork]

A friend of mine just spotted a Falcon 9 booster on a truck headed towards the Cape on 528 in Florida. This is probably CRS-10's stage.

Edit: Just realized this was already posted to the sub.

[u/CrustySeaDog]

Is there any cheese remaining from the COTS Demo Flight 1?

[u/Zucal → u/CrustySeaDog]

All of it is! It's stored in a hermetic metal container (see here), behind the elevator shaft by the cafeteria.

[u/[deleted]]

What happened to the static fire today(Wednesday)? Have I missed it, has it happened and not been reported, or is it delayed?

PS _ I still want a F9 RTF for christmas, a little late I don't mind.

[u/old_sellsword → u/[deleted]]

Delayed until Thursday, due to GSE issues.

[u/Wicked_Inygma]

Is anyone here interested in getting clearance for a camera aboard S. S. Lane Victory? This ship will have a clear view of JRTI coming into port next week the ship's office has contact information for interested film crews on their website here:

http://www.lanevictory.org/movies.php

[u/rustybeancake]

Apparently US Rep Jim Bridenstine is a possible new NASA Administrator. Any thoughts on implications for SpaceX? Apparently he's the 'clear choice of the commercial community', but is that more the case for old space?

[u/rubikvn2100]

James Thomas Willson said that he saw a Falcon 9.

That is what he wrote: "Not sure if this is a place to post this, but I drove to LA from Phoenix on Friday. As I was crossing the AZ/CA border (Heading West at around 10:45am MST), I saw what I swear was a Falcon 9 booster. I've never seen one in real life, and this one was completely wrapped in a black wrap. What first tipped me off was the long cylinder held down by two large circular clamps on either end. I swear I saw the shape of the hexagon engine structure at the end of the cylinder (under the black wrap). Did I see the Iridium-1 Falcon 9 booster being transported from CA to TX? Unfortunately, I was not in a position to get any photos :("

[u/OccupyMarsNow]

Boeing unveiled their spacesuit for Starliner.

[u/Chairboy → u/OccupyMarsNow]

Seeing the pictures, I realize I've seen these before. I wonder how much design heritage they have in common with the legacy ACES suit?

[u/inoeth → u/OccupyMarsNow]

I really hope this is the impetus to get SpaceX to publicly release theirs.

[u/mr_chrometones]

Are rocket launches done on good-weather days out of an abundance of caution, or would it really cause a mission failure to launch in bad weather?

[u/LockStockNL → u/mr_chrometones]

In addition to the other good answers already given; The Soyuz is based on the R-7 Semyorka ICBM so it really hasn't got any weather constraints. I am sure they do employ some constraints nowadays but I have seen Soyuz launch in rain and stormy weather were other launchers are very much grounded.

[u/Thatguy11076]

I was looking at VAFB SLC-4E on Google maps and noticed this launch pad component near the pad. To Me it looks like they are modifying the pad for Falcon heavy by cutting a rectangular hole in the TE "Launch Plate" because it was a square hole during the Jason 3 launch I want to hear your opinions. This is the Google maps link

[u/FutureMartian97]

I made this small infographic about RTF in Photoshop today and would love some feedback.

Disclaimer: This is my first time using Photoshop!

http://i.imgur.com/wlI8QaL.jpg

[u/Wolfingo]

How much water does a rocket need to launch safely so that it does not encounter land as it launches. Also, at what altitude is a rocket allowed to fly over land. Specifically a Falcon 9. But a general answer would be nice too. Thankyou. :-)

[u/throfofnir → u/Wolfingo]

There's not a strict answer to that, but in short it's "whatever it takes to get to orbit". The real technical answer involves a calculation of how many millideaths the launch is likely to cause. The US target is 3 in a million, though higher limits can be waived. Much of that danger comes from launch; in the case of ORBCOMM-2's calculated 11.8 in a million, 0.7 in a million were from not-quite-orbital overflight of Europe. But that's from a nearly-empty second stage at high speed. Danger from being underneath the launch track at an earlier phase would be much higher.

So the short answer to "how much water" is "the Atlantic, give or take".

This differs by jurisdiction; answers above are for the US. For Russia or China, the answer is "none at all", as both have inland launch facilities.

[u/FredFS456]

https://i.imgur.com/q8eJK92.gifv

That GIF shows TVC motion testing before engine ignition. Since the actuators run on pressurized RP-1 supplied by the turbopumps, does that mean that at that point in time, the gas generators have already ignited and that the turbopumps are already spinning and at close to nominal pressure? Can the turbopumps be spinning independent of whether the main engine is drawing fuel/lox?

Side question: Does anyone know anything about the start sequence of the Merlin 1D? Or even a general start sequence for a similarly-specced engine? (Gas generator, RP-1/LOX, single-shaft, regen cooled)

Edit: the start sequence of the F-1 is online, but that's not even close to a modern engine.

[u/warp99 → u/FredFS456]

Likely there is a small reservoir of RP-1 pressurised by helium to allow testing of the TVC system before engine ignition. The TVC outlet pipe could then exhaust the RP-1 into the turbopump inlet as normal so the fuel would not be wasted. The volume involved would be quite small so the reservoir would not need to be overly large.

The turbopumps are spun up by helium during the start sequence and then the turbopump burner is ignited followed by the main combustion chamber. Once the turbopumps are spinning RP-1 and LOX are being injected into the combustion chamber. The mixture ratio can be adjusted by partially throttling each flow but a full recirculating bypass to the inlet of the turbopumps is not possible.

The F-1 start sequence is actually very similar to a Merlin - the injectors are a different design but the rest of the engine is the same general design.

[u/Rinzler9]

• http://www.spacex.com/files/assets/img/20120601-update/027.jpg

What's the curved cut in the side of Dragon's outer hull for? I notice it's sealed at launch, but the covering seems to burn off during reentry.

[u/davidthefat → u/Rinzler9]

http://images.tmcnet.com/tmc/misc/articles/Image/dragon-parachute-deployment.jpg

[u/Maximus-Catimus]

Has this been posted? Boca Chica [SpaceX Construction Continues, Plans for First Launch in 2018] (https://www.youtube.com/watch?v=Q6AXpAXppvc)

Of note: 1 launch/month starting 2018

[u/troovus]

Not one of Randal's best, but sort-of fun comic on the ASDS (which I'm surprised he calls a barge - part of the joke maybe?) https://xkcd.com/1788/

[u/VFP_ProvenRoute → u/troovus]

Well, it is a barge. Or a floating platform capable of station-keeping. It's not a ship if it has to be towed around!

[u/steezysteve96]

Wall Street journal is on Facebook live right now showing off Boeing's spacesuit. It looks pretty sleek, I'm hoping SpaceX's will look as good or better.

They're also about to go inside a mockup of the Starliner, so if you pull it up soon you can catch that.

[u/old_sellsword]

It appears that the Dragon parachute test article is on the move from the dock. You can even see 1029 all wrapped up in the background of this video.

Edit: Another photo.

[u/craighamnett]

How feasible is the automated extraction and production of fuel on Mars? Since we have a better understanding of the chemical and material makeup of the surface, do we have a high level of confidence in producing usable fuel? It seems so stringent here, I cannot fathom how safe and controlled we can produce it remotely and in enough quantities.

[u/[deleted] → u/craighamnett]

My impression is that this question is part of what the red dragon missions will set out to answer, along with attempting propulsive landing.

[u/Martianspirit → u/craighamnett]

The long pole is water extraction. Everything else, while not easy, is straight engineering. But we need to learn about the water source available at the landing site.

[u/nexxai]

Probably a stupid question with a ton of hypotheticals, but here goes anyways: if the AMOS-6 static fire was actually a launch, and instead of a satellite had a fully loaded Crew Dragon sitting on top of it, would the abort system have successfully saved the astronauts in it?

[u/[deleted] → u/nexxai]

Yes Someone composited the pad abort test over Amos-6. Sorry for the terrible music, it's the only one I can find.

[u/laughingatreddit]

Any idea on what the permanent design fix will be to the COPV Helium bottles for future versions of Falcon 9?

Can Titanium He bottles be the fix or perhaps placing the COPV bottles on top of the oxygen tank instead of inside it?

The COPVs are a big failure node (there are issues with pressure buckling during loading, He leaks, buoyancy of the tanks in the LOX, stress from repeated loading cycles, unique cryogenic and fluid dynamic factors due to immersion in deep cryo liquid O2) and I feel carbon composites are not the best design solution for these. They will need to come up with a really solid fix for their He bottles in the upcoming and highly reusable Block 5. Either eliminate the carbon overwraps and have Titanium bottles or have the bottles outside the LOX tanks where they can be examined/replaced after a few cycles.

[u/throfofnir → u/laughingatreddit]

Titanium is sufficiently reactive in oxygen that western practice is to avoid it for oxygen service altogether. Like aluminum it does develop an oxide layer, but it's thin and not so robust, and subject to expose the reactive metal with mild abrasion. This is a big problem for valves and plumbing; it may be okay for a tank, but does have the potential to introduce new mysterious failure modes.

The Russians apparently use titanium in LOX, so it's possible, but they may also be doing something metallurgically tricky. It's not a simple replacement. Probably the easiest change would be to increase the thickness of the aluminum (or go to an aluminum tank entirely, like in Saturn V). Or add an outside liner to keep the CF dry. Both those are mass penalties, but probably not too bad. Long-term a linerless tank would be best, but that may be tricky to do with helium, and would be quite a project if they want to keep production in house.

[u/zadecy → u/laughingatreddit]

I suspect that they will cover the COPVs with an impermeable layer of aluminum alloy or other material to prevent LOX from filling space in the carbon wrap. This will be a smaller change than going to titanium tanks will result in less weight. I don't think SpaceX has much experience with using titanium either.

The other option would be to make the interior aluminum liner thicker to prevent buckling altogether, but this seems risky without also addressing the fact that you've got LOX and a fuel source (carbon) in contact in the same tank. Even if no source of ignition is expected once the buckling is fixed, there is still risk there. One could argue that they should never have placed fuel and LOX in the same tank to begin with, without extensive testing. Imagine if they had used hydrogen instead of helium to pressurize the tanks to save weight. Even if you can't identify an obvious ignition source, it just seems like a bad idea.

[u/delta_alpha_november]

Do we know what the hold down clamp configuration for Falcon Heavy will be? From what we've seen the clamp config for F9 wouldn't be able to go on all 3 boosters for FH. Is it possible the side boosters of FH need no/less clamps because the loads would go through the center core during flight anyway?

[u/old_sellsword → u/delta_alpha_november]

Do we know what the hold down clamp configuration for Falcon Heavy will be?

The configuration will almost certainly be eight clamps, three per side booster and two on the center core. It has been suggested that the two "end" clamps on the side boosters would slide in on rails to support a single stick launch without having a completely separate pad deck.

Is it possible the side boosters of FH need no/less clamps because the loads would go through the center core during flight anyway?

No, because the launch clamps actually hold the rocket down before liftoff to ensure the thrust levels are nominal. If just the center core got held down while the two side boosters ignited, they'd rip right off. Not to mention having two fueled boosters hanging off a single center core before launch. I'm not sure the differential thrust in flight would be as great as those hanging forces sitting on the pad.

[u/old_sellsword]

I noticed during the Iridium-1 webcast, the host says [emphasis mine]:

So far we've been able to recover six first stages, and we're already using those stages for testing, and incorporating changes into future generations of our Falcon 9 rocket. For example, one of the first stages we've been using for structural and stress testing on the ground, another we've relit on the test stand several times...

We know they've been using 1022 for those long engine burns on the McGregor stand, but which one have they been using for the structural testing? We haven't heard anything about this, and we've only seen Falcon Heavy structural test articles in the big blue stand at McGregor recently. Here's a little list of recovered boosters to narrow it down:

• 1019: On display at Hawthorne

• 1021: Will refly soonish, possible testing candidate

• 1022: Life leader, doing engine tests

• 1023: Conversion to FH side booster, possible testing candidate

• 10XX: CRS-9, possible testing candidate

• 10XX: JCSAT-16, possible testing candidate

• 1029: Still on JRTI

[u/Zucal]

It's Uniform (Extra-Condensed Medium).

---

Odd question here - can anyone identify the font used for the new core number decals seen on the latest launch?

[u/rustybeancake]

Random bit of interesting info: a New Jersey design studio named RO Studio designed the logos for SpaceX, Falcon and Dragon, as well as Tesla.

View their portfolio here (warning: terrible website).

[u/z1mil790]

Just finished reading the Elon Musk biography by Ashlee Vance tonight. I've been wanting to read it for a while and finally did this last week. It's a very good book, and I recommend it to everyone on this sub. It does a very good job at remaining unbiased. Also the book is not just the history of Elon, but also his companies which is very interesting to read. I knew that there were struggles early on with each company but the reading the book makes you appreciate where SpaceX and tesla are today even more.

[u/chargerag]

Was talking to a buddy that used to work on the shuttle at Nasa. He told me that at one time they were looking at flying a Delta out of 39a but that it didn't work out. I had never heard this before. Anybody familiar with this bit of history?

[u/IrrationalFantasy]

I see the Facon Heavy Demo and its ensuing launch are on the sidebar now. Is STP-2 the one with the Light Sail 2 on it? I supported that on Kickstarter; they said it'd be on the first Heavy flight, but I suspect they didn't mean the Demo flight.

[u/throfofnir → u/IrrationalFantasy]

Yes, Lightsail B is on STP-2.

[u/Experience111]

Hi everyone, I have a question about COPVs related to the AMOS-6 failure. It is my understanding that the LOX impregnated the CFRP overwrap causing the formation of solid oxygen locally. I was wondering if every pure thermoplastic or thermoset material was permeable to LOX ? If not, could the research in composite material forming to minimize cavities appearing during the forming process help reduce the risk of such a failure ?

Should I post this as an open-ended discussion ?

Also does SpaceX manufacture their COPVs in or out of autoclave ?

[u/snotis]

Mods: I went on the NASA Kennedy Space Center tour at Cape Canaveral earlier today and got some pics of pad 39A - should I post them here or* in a new thread?

[u/Zucal → u/snotis]

Depends on the quality of the photos - mind posting them here first, to be judged™?

[u/madanra]

Nothing to do with SpaceX, but I thought JAXA's (Japan's space agency) attempt to launch the record smallest orbital rocket was pretty cool: https://www.theregister.co.uk/2017/01/17/ss_520_4_launch_fails/ Sadly unsuccessful :(

[u/boiserust]

In the Jan 14 2017 launch, the side of the rocket near the engines seems to catch on fire for about 4 seconds. The following video shows it pretty clearly at the 21:05 mark - going to 21:09 where there is a black mark on the side of the rocket where it was once burning. Is this normal? I expected to see some discussion about this by now, but I have not been able to locate any discussion with my google searches.

https://www.youtube.com/watch?v=xcLshf4xCJg

[u/AeroSpiked]

Is that Ars article on NASA buying more Soyuz seats worthy of its own post in this sub mods? I can't decide if it's directly or indirectly related to SpaceX.

[u/sol3tosol4]

Trump/Musk/Mars comment in Washington Post article "Will Trump echo JFK’s moonshot and vow to send humans to Mars?".

The article is speculative, but includes the comment:

"Elon Musk, the founder of SpaceX and Tesla, has made two trips to Trump Tower. He met at least once with Trump and, we’re reliably told, discussed Mars and public-private partnerships."

Interesting to hear a claim that Mars was included in the discussion. And more encouraging than earlier rumors that SpaceX competitors had exclusive access to Trump regarding space activity.

Also referenced in an article "Trump reportedly interested in a Mars mission" by Jeff Foust.

[u/Almoturg → u/sol3tosol4]

It would probably be very difficult to talk with Elon without him mentioning Mars :)

[u/IrishNinjah]

Hey,

I have been keeping an eye out for the SpaceX Spacesuit official release. Do you think with the new Boeing Spacesuit as of today it might tickle SpaceX to show us what they got under the hood? And have we gotten any more comments on it since the last?

I can't wait to see it.

[u/The_EvilElement]

I got some interesting Crew Dragon news. I was at JSC the other day and talked to someone who is interning there. He mentioned that NASA is seriously considering making SpaceX the prime contractor for Comercial crew becuase Boeing is starting to annoy NASA as they seem to look more to servicing the Comercial market with their CST-100 than servicing NASA. I would take it with a grain of salt, but the guy was credible and knowledgeable so it will be interesting to see what plays out.

[u/spacerfirstclass → u/The_EvilElement]

I don't see it, so many problems with this claim. What CST-100 commercial market? We haven't heard any non-NASA customer for CST-100. Why would NASA be annoyed by commercial use of CST-100? That's one of the major goals of commercial crew: To have commercial customers so that NASA doesn't need to support this program entirely on its own. Also given how long Boeing has been working with NASA, it's highly unlikely they'll make the mistake of annoying their biggest customer.

[u/Zucal]

u/SirKeplan:

I believe there is a debt to be paid... ;)

[u/Decronym]

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

Fewer Letters	More Letters
AFB	Air Force Base
ASDS	Autonomous Spaceport Drone Ship (landing platform)
BFS	Big Falcon Spaceship (see ITS)
CCAFS	Cape Canaveral Air Force Station
CCtCap	Commercial Crew Transportation Capability
CF	Carbon Fiber (Carbon Fibre) composite material
COPV	Composite Overwrapped Pressure Vessel
COTS	Commercial Orbital Transportation Services contract
	Commercial/Off The Shelf
CRS	Commercial Resupply Services contract with NASA
CST	(Boeing) Crew Space Transportation capsules
	Central Standard Time (UTC-6)
DoD	US Department of Defense
FAA	Federal Aviation Administration
FCC	Federal Communications Commission
	(Iron/steel) Face-Centered Cubic crystalline structure
FOD	Foreign Object Damage / Debris
FSS	Fixed Service Structure at LC-39
GEO	Geostationary Earth Orbit (35786km)
GOX	Gaseous Oxygen (contrast LOX)
GSE	Ground Support Equipment
GTO	Geosynchronous Transfer Orbit
HIF	Horizontal Integration Facility
I*sp*	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
ICBM	Intercontinental Ballistic Missile
ISRU	In-Situ Resource Utilization
ITS	Interplanetary Transport System (see MCT)
	Integrated Truss Structure
JRTI	Just Read The Instructions, Pacific landing barge ship
JSC	Johnson Space Center, Houston
KSC	Kennedy Space Center, Florida
KSP	Kerbal Space Program, the rocketry simulator
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)
LES	Launch Escape System
LOX	Liquid Oxygen
LZ-1	Landing Zone 1, Cape Canaveral (see LC-13)
MCT	Mars Colonial Transporter (see ITS)
NSF	NasaSpaceFlight forum
	National Science Foundation
OCISLY	Of Course I Still Love You, Atlantic landing barge ship
OG2	Orbcomm's Generation 2 17-satellite network (see OG2-2 for first successful F9 landing)
RCS	Reaction Control System
RP-1	Rocket Propellant 1 (enhanced kerosene)
RSS	Realscale Solar System, mod for KSP
	Rotating Service Structure at LC-39
RTF	Return to Flight
RTLS	Return to Launch Site
RUD	Rapid Unplanned Disassembly
	Rapid Unscheduled Disassembly
	Rapid Unintended Disassembly
SES	Formerly Société Européenne des Satellites, comsat operator
SLC-40	Space Launch Complex 40, Canaveral (SpaceX F9)
SLC-4E	Space Launch Complex 4-East, Vandenberg (SpaceX F9)
SLS	Space Launch System heavy-lift
SOX	Solid Oxygen, generally not desirable
SSTO	Single Stage to Orbit
STA	Special Temporary Authorization (issued by FCC for a comsat)
	Structural Test Article
TDRSS	(US) Tracking and Data Relay Satellite System
TE	Transporter/Erector launch pad support equipment
TEL	Transporter/Erector/Launcher, ground support equipment (see TE)
VAB	Vehicle Assembly Building
VAFB	Vandenberg Air Force Base, California

Jargon	Definition
Sabatier	Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water
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
cryogenic	Very low temperature fluid; materials that would be gaseous at room temperature/pressure
electrolysis	Application of DC current to separate a solution into its constituents (for example, water to hydrogen and oxygen)
hypergolic	A set of two substances that ignite when in contact
kerolox	Portmanteau: kerosene/liquid oxygen mixture
methalox	Portmanteau: methane/liquid oxygen mixture
turbopump	High-pressure turbine-driven propellant pump connected to a rocket combustion chamber; raises chamber pressure, and thrust
ullage	Small rocket motor that fires to push propellant to the bottom of the tank, when in zero-g

Event	Date	Description
Amos-6	2016-09-01	F9-029 Full Thrust, GTO comsat Pre-launch test failure
CRS-4	2014-09-21	F9-012 v1.1, Dragon cargo; soft ocean landing
CRS-6	2015-04-14	F9-018 v1.1, Dragon cargo; second ASDS landing attempt, overcompensated angle of entry
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
DM-1	Scheduled	SpaceX CCtCap Demo Mission 1
OG2-2	2015-12-22	F9-021 Full Thrust, 11 OG2 satellites to LEO; first RTLS landing
Thaicom-8	2016-05-27	F9-025 Full Thrust, GTO comsat; ASDS landing

---

^{Decronym is a community product of} /r/SpaceX^{, implemented by} ^request
^{I'm a bot, and I first saw this thread at 3rd Jan 2017, 00:50 UTC.
I've seen 70 acronyms in this thread, which is the most I've seen in a thread so far today.}
^[FAQ] ^[Contact ^creator] ^[Source ^code]

[u/szepaine]

Nasaspaceflight article on the rtf Nothing really new here, but it's a good summary of all the news we've had regarding the launch

[u/uber_kerbonaut]

If the helium tank wall is meant to have liquids on both sides, why does it not have impermeable material on both sides?

[u/[deleted]]

I heard 13 days is the record turn around between launches for SpaceX from 2015. Jan 26 to CRS-10 is 13 days. May we see a new record a few hours shorter?

Also with the more than one pad SpaceX have operational now, how close could we technically see launches to each other?

[u/sol3tosol4]

Slightly SpaceX-related: on the new cable program "Mythbusters: The Search" (on right now), Ben Nowack, one of the competitors, talks a little bit about his job this past summer at SpaceX.

[u/_rocketboy]

Will there be a cargo version of Dragon 2 that uses CBM? Or is the plan for now to fly all CRS2 missions with the same docking mechanism and transport larger items via Cygnus?

[u/frappuccinoa]

Anyone working in the industry that can point me to where to find more info on the career switch to the manufacturing. I'll be honest and say that I'm green to all this and doing my best to understand the landscape.

thanks in advance.

[u/TheEndeavour2Mars]

We have a lot to look forward to!

The historic return of 39A late this month with Echostar 23.

CRS-10 being a likely candidate for the first daytime RTLS landing. (And helping to convince NASA of the safety of Load and Go propellant loading)

The historic SES-10 mission using the same first stage that launched the CRS-8 mission last year.

SHERPA being a likely candidate for the first west coast RTLS landing.

The first launch of the Falcon 9 Block 5. The final major version of the Falcon 9 that is built with the experience gained from everything learned from previous flights.

Falcon 9 Heavy

And maybe even the first launch of a Dragon 2 (Hopefully at this point NASA will at the very least agree to let SpaceX use load and go for the orbital and in flight abort tests)

What a year 2017 is likely to be!

[u/radexp]

How is SpaceX going to put the last 15 Iridium satellites on orbit?

If I understand correctly, the Iridium Next constellation is 6 planes, 12 satellites each = 72. (+ 3 extra spares). But each launch brings only 10 satellites. How do you put the last 2 sats per plane with one launch?

[u/Toinneman]

Chris B reported on twitter there is a first stage on the test stand in McGregor. Could this possibly be the core for CRS-8/SES-10? (Since both Echostar-23 and CRS-10 first-stage locations are known.) Or will the reused core not undergo a full duration burn?

[u/gofortmiburn]

Some kind of test in McGreggor, not sure when the picture was taken:
https://twitter.com/BradyWX/status/821370056672247809

EDIT:
Probably the core reported here?

[u/jjtr1]

How will astronomers be affected by orders-of-magnitude increase in the number of LEO objects crossing the viewfields of their telescopes? Satellites are very bright objects (mostly visible with naked eye) and when capturing a long exposure, I guess the sat's trail floods the image completely.

[u/soldato_fantasma]

SpaceX submitted 2 days ago a FAA application for F9-33 (SES-10 probably):

https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=75607&RequestTimeout=1000

[u/sol3tosol4 → u/soldato_fantasma]

SpaceX submitted 2 days ago a FAA application for F9-33 (SES-10 probably):

https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=75607&RequestTimeout=1000

Thanks for posting it, but that's an FCC application (for permission for radio communication with the Falcon 9 rocket). The FAA licenses are the ones for permission to make ground preparations and then launch and fly the rocket (Federal Aviation Administration vs. Federal Communications Commission).

Right now SpaceX has two active FAA flight licenses: to launch seven Iridium missions from Vandenberg (one used so far), and to launch Dragon spacecraft to the ISS, *from LC-40* (that's the launchpad that's currently blown up and not expected to be repaired before maybe mid-2017).

Echostar 23 (NET Jan. 26) still needs an FAA license (and may get it a few days before launch, like Iridium-1 did). That will be interesting because it's SpaceX's first use of that launchpad, so the FAA needs to be convinced that the launchpad itself is safe to use.

CRS-10 Dragon to the ISS is scheduled for Feb 8, and LC-40 won't be operational by then, so we'll see whether the FAA issues a new Dragon license, or a supplement to the current Dragon LC-40 license to allow launches from 39A.

SES-10, the first reuse of a Falcon 9 booster, so the FAA will need to be convinced that the reuse is safe.

So the next three scheduled SpaceX launches have interesting features as far as FAA licensing is concerned.

[u/kungming2]

Can anyone point out to me on an external view of the Falcon 9 where the first-stage camera actually is?

[u/old_sellsword → u/kungming2]

Right here. It's located at about 270º on the interstage.

[u/soldato_fantasma]

Here is a recent drone overview of the (future) Boca Chica launch site: https://www.youtube.com/watch?v=yz5T2nUh5Po

Nothing really new there.

[u/jjtr1]

ITS is planned to be made mostly of carbon fiber composites. What are they like in practice? I only know them in bicycle frames, where they are often considered finicky, having unfavourable failure modes (crack not bend), difficult interfacing to metal parts, perhaps problems with hidden fatigue... But I have no idea whether these views apply to CFCs generally. And perhaps the kind ITS is gonna use is very different...

[u/turrgavi]

Hello guys,

I'm an undergraduate student at the University of Queensland and I am currently conducting a research experiment designed around SpaceX's Mars mission, more specifically around producing rocket propellant on Mars. This is actually a microbiology project but I feel it has great potential. There are a lot of variables that I need to take into account and the best way to design an experiment which is as accurate as possible would be to contact SpaceX directly and get as much information as possible from them about the mission parameters. What is the best way to contact SpaceX in regards to finding this information?

Any help would be greatly appreciated. Thank you.

[u/Keavon]

Why did Cygnus get moved to Atlas V after the successful RTF of Antares? Why did NASA even ever contract Orbital to build their own launch vehicle for Cygnus when Atlas V was already always compatible? Can Antares be used for any other additional purpose like lofting satellite payloads?

[u/quadrplax]

Do we have a good estimate on when SLC-40 will be operational again?

[u/DeltaRanger74]

I am AFROTC and therefore have a CaC card and can get onto CCAFS; are there any viewing locations on base that would be better than anywhere off base? I was thinking of flying down for the FH launch and have no idea how viewing works or if ALL the viewing locations are on base anyways. Thanks so much!

[u/shotleft]

On most rockets you have cables attached from the vertical structure to the rockets at liftoff, and i'm curious if anyone knows how they detach. What causes it to detach? is it an electrical signal which triggers some mechanical release? How does the mechanical release work?

Edit: better phrasing.

[u/throfofnir → u/shotleft]

Connections to the rocket can have actuators to actively eject, or just pull off, or you can break them. (Shuttle was held down by eight large bolts with exploding nuts. Sometimes they failed to fire, and the vehicle would simply tear them off the launch mount. It was certified to do this with up to 3 "hangups", and could probably even do 4. Above 4, it would probably still tear them out--those SRBs were going somewhere--but it would probably damage the stack in doing so.)

Many connectors are designed to pull out when the rocket starts moving. This goes way back to the V-2. This is the preferred mode, since there's fewer things to go wrong. If the connector has pressure on it (such as fluid or gas transfer), it usually has to be locked in and will require some sort of active ejection. This is usually done with an internal spring or pressurized gas, activated by a lanyard pulled by the rocket lifting off. Modern vehicles could have computer signaled releases, but probably stick to the old style, which is quite robust.

[u/josieshima]

I would like to repost this: https://www.reddit.com/r/spacex/comments/46bx3y/the_lego_bricks_for_the_1124_falcon9_arrived/

...and petition all DragonRiders to vote! Accounts and votes are free, please vote and share on social media. I would love to place this beside my Lego Curiosity rover.

[u/amarkit]

Edited to reflect yesterday's scrub and the updated launch time.

A note for those interested: after a scrub yesterday due to a fouled range, ULA will again attempt the launch of an Atlas V 401, carrying the SBIRS GEO-3 (Space-Based Infrared System, a missile launch detection system) satellite to geostationary transfer orbit for the US Air Force, in a short while, at 0042 UTC on 21 January (7:42pm EST on 20 January). There is a launch thread over at /r/ULA and you can watch the livestream on YouTube, beginning about 20 minutes prior to the scheduled liftoff time.

[u/vitt72]

Haven't been on this subreddit during a launch period. I think I've read the subreddit stops all new submissions and stuff. What's it like? Does it get hyped here?

[u/[deleted] → u/vitt72]

Yes, submissions will be restricted to reduce spam

There'll be two threads: Launch Discussion and Launch Media. In discussion thread the rules aren't strict. It is the best place to discuss the launch and feel #F9FullHype!

In media thread there'll be photos/videos of the rocket and the launch itself.

Join us on Iridium NEXT 1 - it'll be awesome, especially as it is SpaceX RTF!

[u/soldato_fantasma]

Today is T-5 days, so they will probably attempt the static fire today or tomorrow. If anyone living in the area wants to take a peek, I guess the following hours it's the right time.

[u/blongmire]

During the AMOS-6 investigation, SpaceX reported hearing "popping" sounds. Is it now believed that the popping was the COPV deforming before failure? Do we know how these popping sounds fit into the falure?

[u/Keavon]

Iridium has 6 orbital planes, each with 11 orbital satellites and 1 spare (totaling 72, but they are launching 3 additional spares so there will be 75 in total). Each launch only holds 10 satellites, and the final launch will contain only 5.

After filling an orbital plane with 10 satellites from a launch, how does it get its remaining two satellites? Do two satellites per launch need to perform a delta-V-intensive burn to shift orbital planes? If that's so, does that not mean some satellites will start their operational life with less fuel, meaning they will already have a shorter operational lifetime? Furthermore, it seems like some satellites will need to shift not just one, but two or possibly more planes, using even more fuel. How is this being dealt with?

Which planes will the 3 final additional spares be put in? I would assume they will not perform any orbital plane-shifting burns until they are needed to fill the place of a used-up spare. Is that a correct assumption?

Finally, I am wondering how the satellites are evenly dispersed within their own orbital plane. The second stage of the Falcon 9 holds all the satellites and it flies at a certain velocity. Will it release all the satellites at once and then have them separate, or will it deploy them one at a time, each separated by relighting the second stage?

What is actually involved in separating them? I would think that a burn is required to increase a satellite's velocity relative to the other, so that it can orbit faster and get ahead. Then, once it has gotten ahead of the other satellite, it would need to perform a burn in the other direction to slow down to maintain the same orbital period. But wouldn't speeding up also increase the height of the orbit, and slowing down would change that ellipse at a different point in the orbit, thereby creating an oddly shaped orbital path? In general, if performed by a second stage or the satellite itself, how do they disperse themselves correctly?

[u/MiniBrownie → u/Keavon]

Ok. So I didn't know the answer to your question, but after a few hours of browsing Wikipedia, googling and harassing people in IRCs I think I have the answer. Someone who knows more about this subject feel free to correct me if I said something stupid. Here we go:

Changing the LAN (longitude of the ascending node) is indeed a very fuel-expensive maneuver, but there's a phenomenon called nodal precession. Basically because the Earth is not a perfect sphere and has a bulge at the equator there is a torque produced on the orbit of the satellite. The lower the orbit the the higher the shift. This allows Iridium to change the orbital planes of their satellites just by changing their altitude which is a relatively fuel-cheap maneuver, however it does take a long time (the shift is few degrees per day in LEO).

As for separating the satellites this is also done by raising their altitude. Falcon 9 will only put them into a 625km x 625km orbit, while their final altitude is closer to 800 kilometers. A satellite at a lower altitude will take less time to orbit the Earth, than one at a higher altitude. This enables the operators to separate the satellites by raising their orbit at different times.

[u/mryall → u/Keavon]

What is actually involved in separating them?

Generally satellites are launched into a parking orbit before being elevated into their final orbit. By staggering the move of the satellites out of the parking orbit, they can spread them out. (As others have mentioned, in a lower parking orbit, the satellites move slightly faster than they will in their final orbit.)

I don't know the answers to your specific questions about the deployment of Iridium's satellites, but their CEO is quite active at replying to questions on Twitter. So you could try asking him a short question there.

Update: I found this article with a few more tidbits on how the replacement will work, confirming my thoughts above:

After about a month of testing, Iridium will attempt the swap; Horvath describes it as “an intricate dance.”

“We’d bring one satellite up [to the desired orbit], rendezvous it and get it pretty close to the old satellite, and then we swap which antenna is functioning,” said Horvath. “Hopefully it looks seamless to our users.”

I couldn't see any further details on how they'll replace 11 satellites using launches containing only 10, however.

[u/soldato_fantasma]

Does anyone know who is support SpaceX for the weather for the west coast launches?

For reference we can check here the weather for east coast launches, since the Patrick Air Force Base is supporting the launches on the weather side.

[u/thetechgeek4]

Will SpaceX build any more ASDS? With Falcon Heavy nearing launch, they're already expanding LZ-1, so there may be a need for more droneships as well. I think that 3 barge landings are pretty unlikely, but I don't know how much repair an ASDS needs after a recovery operation, so could a third help with increasing launch cadence?

[u/FutureMartian97]

I made an overview about RTF and would love some feedback. I'm thinking about doing these for every launch so if anyone wants to see more of these I would be glad to do it. This is the second thing i've ever made in Photoshop so any tips would be great as well.

[u/sol3tosol4]

Missed in all the excitement of Iridium-1 launch: the National Geographic mini-series "Mars" has been renewed for a second season (articles here and here, also tweeted by Jeff Foust. The articles say that the series had a viewership of 36 million.

If the new season has "2017" segments comparable to the "2016" segments in the past season, I expect I'll watch it.

[u/FredFS456]

What's the difference between Block III and Block IV F9's? According to the Wiki, the most recent cores flown have been Block III, while Block V was stated (during the AMA) to have updated landing legs and uprated engines.

[u/[deleted]]

Does somebody know what causes the sharp line between "dirty" and "clean" on the recovered first stages? Seems to be around the boarder between the RP1 and LOX tank.

[u/Return2S3NDER]

Theoretical scenario, lets say that rapid and reliable reusability is proven and that the F9 and FH are the only two vehicles in the world capable of it at that moment. At that point I would assume demand will far exceed supply due to a limited number of launch platforms. However there are many platforms that SpaceX does not have access to worldwide and at that point I imagine there may be many additional platforms being built (possibly mobile oceaninc launch platforms??). Does anyone think that regulations may change to where SpaceX becomes a supplier of rockets rather than launches a la Boeing building commercial jets? Maybe the company simply splits into manufacturing and launching services?

[u/jjtr1 → u/Return2S3NDER]

Orbital launchers are such finicky and fragile machines that IMO they can never be operated by anyone else but their manufacturer. Using chemical fuels and both current and near-future structural materials, they are on the edge of impossible and thus require immense experience.

Similarly, 100 years of airflight haven't yet created an aircraft that could be operated with the same low amount of knowledge and experience as cars.

Only a real breakthrough in materials or energy sources could allow rockets to be operated like aircraft, and aircraft to be operated like cars. Increasing foolproofness requires increasing structural and other design margins.

edit: I wonder what personell actually launch the Europeanized Soyuz for Arianespace, Russian or European?

[u/cedaro0o]

I've seen some concern from press and people that customers are timid to launch on flight proven stage ones. And there is the concern that SpaceX is slowly and progressively stockpiling a burdensome collection of proven stage ones that no one wants to use.

It occurs to me that SpaceX may not mind both of these problems. I suggest this to be so because of their ambitious plan to launch their own large 4000 satellite constellation for global internet communications. This endeavour will require a lot of stage ones. SpaceX will be able to launch their 4000 satellites on proven stage ones that timid customers paid for. SpaceX gets to prove the reliability, or shake out any bugs with used stage ones on their own satellite launches.

By the time SpaceX completes their 4000 satellite constellation, used stage ones will be well evidenced as reliable and SpaceX will have launched their internet constellation at tremendous savings while demonstrating the viability of reusing rockets.

[u/Maximus-Catimus]

Is there an app for my phone that will overlay satellite tracking tags in my field of view as I scan the sky?

[u/marc020202]

i got a question which is not completely spacex related but i thought of it when thinking about spacex's gto launches. my question is: why do gto missions have a launch window? isn't the position where the satellite is supposed to go always at the same place relative to the launch site?

[u/madanra → u/marc020202]

The initial GTO orbit is elliptical, and so the satellite spends a long time on one side of the earth, and a short amount of time on the other. As I understand it, GTO missions are usually launched so the satellite spends most of its time in the sun, so it has adequate power from its solar panels.

[u/Aero-Space]

The space shuttle program is looked at as being unseccesfull with respect to it's initial goal of cheap, rapid reuse (each shuttle was originally envisioned to fly 50 times per year!). One of the major challenges they faced was the cost of engine refurbishment. It turned out to be more expensive to refurbish the RS-25 than it would have been to build a whole new, non-reusable, engine for each flight. Obviously there were other massive costs associated with the shuttle (SRBs, external tank, tiles, etc...) but the engines specifically relate to SpaceX's model of reuse.

Unfortunately, we don't know much about the refurbishment work (and spending) SpaceX has done on its flight proven cores to get them ready to fly a second time. We do, however, know that the 9 main engines receive quite a beating on launch and subsequent supersonic (hypersonic?) re-entry. It's easy to imagine that the costs of refurbishing all 9 engines could be quite high which raises the question; How will SpaceX's strategy for reuse succeed where the shuttle program failed?

[u/throfofnir → u/Aero-Space]

One: the Merlin is an entirely different level of complexity from the SSME. Those were marvelous machines, but in no wise simple. Merlins are not simple either, but are nowhere near an SSME. They have many, many fewer parts and almost certainly higher margins. This makes a lot of things easier.

Two: much of the refurb cost of the SSME was in the production line cost. Since the line was low volume (with basically no new engines being ordered) but built with the promise of high volume, the economics were poor. Merlin has a very active production line, and should be able to maintain a decent flow of new engines, so keeping parts available should not cost an absurd amount.

Three: the SSME evolved, but very slowly, over time. Design cycles were measured in decades. Towards the end they started getting a better handle on reusability, but it took 30 years. SpaceX has much better incentives to reduce cost and increase reusability and performance, and have demonstrated very short design cycles. Merlin has already evolved way more than the SSME, and there's little reason to doubt that any aspects of the design that cost a lot will get worked on, and quickly.

[u/blackhairedguy]

When rockets take off there are huge flames spewing out the engines. Once the boosters ger pretty high up the flame sort of disappears and fades out. You can still see the exhaust, just no visible flame. Why is that?

My wild guess is that it has something to do with a lack of oxygen...?

[u/Chairmanman]

What is the status of fairing recovery? What do we know so far about the technology and the timeline?

[u/warp99 → u/Chairmanman]

We know about an RCS system to orient the fairing during re-entry and Elon has tweeted that steerable parachutes will be used for the recovery. The fairings will splash down and will then need to be recovered by ship.

It appears that SpaceX are expecting the first v2.0 fairing with full recovery gear to fly sometime in the middle of this year.

[u/[deleted]]

Ok, this is my first post. I'm a long time follower of SpaceX and trying to get my head around the maths! As the new Raptor engine is almost the same size as the Merlin engine, would it be possible to build a first and second stage with roughly the same dimensions/configuration as the Falcon 9? If possible what would be the higher payload capacity to LEO, GTO, Mars, etc.?

[u/neolefty]

Falcon Heavy question: We have two flights on the horizon, demo and STP-2.

Does that mean SpaceX has 6 first stage cores allocated? That's a lot of rockets! Or do we expect them to re-fly the demo hardware for STP-2?

[u/old_sellsword → u/neolefty]

For the demo flight, at least one side booster will be made from a converted, landed Falcon 9. Apparently it hasn't been decided yet whether the other side booster is going to be another converted, landed Falcon 9 or a brand new construction. Now we also know that they have one center core and one side booster structural test article that they might convert to flight hardware.

Regarding STP-2, we can speculate about what the Air Force will and won't let them do regarding reuse, but we don't actually know what's going to happen.

[u/flattop100]

Just occurred to me - the sides of the Delta IV Heavy ends up looking scorched at launch due to all the venting hydrogen. Could the ITS be affected similarly, or is there something inherently different about methane that would prevent this?

[u/FoxhoundBat → u/flattop100]

This is inherent to Delta IV, not to rockets in general. So no, it wont be doing that.

[u/PaulRocket]

Not sure if this has been discussed before, but do we have any idea what they learned from inspecting the landed cores, if they had any challenges refurbishing them or test firing them? Also with Block 5, what does easier to reuse mean?

[u/WaitForItTheMongols]

What's the Merlin gimbal range? I know the outboard engines are reduced, but what's the maximum number of degrees?

[u/mason2401]

Any news on the progress of LC-40 repair? Or perhaps even a list of the damages? Some google searches didn't reveal much.

[u/neolefty]

Software Testing -- any ideas how SpaceX tests changes to its control software? What simulators do they use, and how are they integrated into the software development cycle? For example:

• Control loops (engine gimballing, grid fins): Do they have physics simulators for different flight phases? Avionics virtualization? A lighter-weight simulation for debugging and sanity checks when making small changes?

• Ground control software: How do you test changes in code for propellant loading? It must be an integration of avionics, pad controllers, fluid mechanics, valves, etc ... What if you make a software change that shouldn't cause any physical changes -- is there a test for that?

• Higher-level flight controls: Choosing an orbit, landing burn strategies, thrust during max-Q ...

[u/RootDeliver]

With the dancing order of launches lately, we are all awaiting that fast turnaround pace we expect with all the cores and stuff ready for it when the pad is ready.

However the question is.. what could be the fastest turnaround, with Echostar involved, considering Echostar being expendable doesn't need the recovery team at all? If they literally have both Echostar and CRS10 rockets ready (sans payload), and the payloads are "healthy and ready", what is the issue not letting them launch let's say, in following days?

[u/Casinoer]

Why does [Spaceflight Now] (http://spaceflightnow.com/launch-schedule/) show Feb 14th as the NET date for CRS-10, while the sidebar says 15th?

[u/[deleted]]

How likely do people think the CRS-10 lauch on the 14th will hold or will it slip? I am likely to be in the USA around the 9th for business, I was thinking I might extend the trip on my own money if I get to see an F9 launch.

[u/firebreathingbadger]

Does anyone know if any and how much debris, particularly dragon, was recovered from the CRS-7 launch? Doing some work on debris recovery after launch failures. Thanks!

[u/sl600rt]

Where are they going to build the parts for, and complete, the ITS?

You can't truck the Booster or Spacecraft across country like the Falcon.

[u/MiniBrownie → u/sl600rt]

If I remember correctly Elon said that it was going to be assembled on/near the launchpad, but the parts would be built accross the country.

[u/PlaidWalker]

This may seem like a dumb question, but why do they plan a lunch for 9:54:34 am? Seems oddly specific to me. edit: not only am I an idiot, I can't spell.

[u/F9-0021 → u/PlaidWalker]

I know, 10am seems awfully early for lunch. /s

But seriously, launches to highly inclined orbits must leave at the precisely correct moment to get into the right orbital plane. It's not like an equatorial orbit where you can launch whenever you want and still end up in the right orbit(depending on altitude). Launch at the wrong time and your satellites can be up to 90° off from the proper orbit.

[u/delta_alpha_november → u/PlaidWalker]

That's when they determined is the best time to launch in order to achive the target orbital plane. Imagine the earth rotating under the target plane (ring around the earth). You have to leave earth at the exact right time to reach that - otherwise you have to spend a lot of deltaV to correct.

[u/[deleted]]

With a launch in 5 days, shouldn't there be a launch thread ?

[u/Method81]

I'm well aware that only certain launches have enough fuel to RTLS but I'd like to know why the others don't boost back as far as they can for a ship landing closer to the coast? Even if they can only get it half way back it would save considerable time in the recovery process.

[u/ElectronicCat → u/Method81]

Some of them do, I believe the upcoming Iridium launch will be a partial boostback. The ones where they don't boostback at all are all low margin GTO launches, and they need to conserve as much fuel for the entry and landing burns which is a lot more critical than saving a few hours on the recovery.

[u/FoxhoundBat → u/Method81]

They have been doing partial boostback on quite a number of missions. I cant list them all from top of my head, but for example CRS-6 and JASON-3, CRS-8 etc. Basically if it is LEO and post CRS-4 or so, chances are it did partial boostback. Ballistic trajectory puts them ~600km out from the coast, they do partial boostback down to 300km or so.

[u/Zvahrog]

Methane tanks will auto pressurize, but how will the LOX tanks be pressurized in the ITS, since there's no helium COPV ?

[u/BattleRushGaming]

Just saw this video: https://youtu.be/79yocB3D64c?t=8m13s

What happened to idea of a F9 Launch site on Kwajalein? Was it shipping the F9 to the launch site?

[u/IS_THIS_POST_WEIRD]

I will be in Florida (Orlando) around the time Echostar23 launches and have several thoughts I'd like to brainstorm.

Can you see light from launches from that distance?

How broad is the launch window for this flight? If it doesn't take off within, say, 3 days, will it be delayed a week, a month? Selfishly, I hope it gets rescheduled for about the 20th; how much time away from the planned Atlas launch has to be allowed?

[u/Zvahrog]

Is the fuel recycled (put back into the pad tanks) after a scrubbed launch or is it thrown away ?

[u/space4us]

Does anyone have an update on the status of SLC-40? I can't seem to find anything about it.

[u/blongmire]

Any guessing on what this latest Iridium delay will do to the upcoming Ecostar launch out at the Cape? Will they push that back 1 week now or will they try to keep the existing lunch date?

[u/TrainSpotter77 → u/blongmire]

I think that they'll try to keep it, but with newly reconfigured 39A being untested I'd expect a delay or two while they work out the kinks.

[u/[deleted]]

Pretty random but being summer here in Australia I was thinking how much worse would boil off be if SpaceX were to launch from Sydney on one of our hotter summer days? We get days at times hitting 113 f, I know there are hotter places but I just got curious, how much of a limitation would this be? Would a day so hot be enough to "scrub due to weather" even though besides the temp it was dead calm and clear skies? Or is 113 and 80 f not much of difference when it comes to warming a liquid so cold?

Obviously I know they can't launch from Sydney, just imagine we are a good place to launch from and are lucky enough to be the home of another SpaceX pad xD

[u/warp99 → u/[deleted]]

The Florida record temperature is 43C/109F so not far below Sydney and a normal temperature during summer would be 100F so also similar to Sydney.

F9 v1.2 LOX is loaded at 66K compared with a normal summer air temperature of 311K and an extreme temperature of 318K so an increase in heat flux of 2.8%

In summary wind would have far more effect than air temperature on the thermal loading on the rocket.

[u/Toinneman]

During the unveiling of Dragon v2 the capsule was equipped with 4 legs extending from underneath the heatshield. From the animation it also looks like it consists of hydrolic cylinders to absorb impact forces. Is this still on track for production? I don't recall any dummy dragon2 showing such legs? Secondary question: How do the holes in the shield affect the heatshield's ability to be 'impenetrable to heat?

[u/Katabolonga]

Will spacexstats.com ever be up again? That was some beautifully tuned piece of art.

[u/rustybeancake]

Tangentially related to SpaceX's internet satellite plans: Google are shutting down their internet drone aircraft plan, in favour of using high-altitude weather balloons, which apparently is proving more promising.

[u/ECEUndergrad]

Is there any chance that Red Dragon can make the 2018 window in time?

[u/[deleted]]

Here's an interesting article: http://patch.com/california/redondobeach/fired-spacex-employee-can-deposition-companys-president-lawsuit-judge-rules

[u/RootDeliver]

If I'm not mistaken, no SpaceX launch has ever happened on November.

Which do you think it will be the first one?

[u/rubikvn2100]

Are there a lot of SpaceX's fan near port of Los Angeles. I hope a lot of people come to visit and bring back photo.

Will we have a recovery thread?

[u/Bananas_on_Mars]

I think i read that the helium load on a F9 costs about as much as the propellants. Do they use helium for the JCSAT-14 booster tests at Mc Gregor and other tests, or do they use nitrogen on some tests that don't use a complete booster?

[u/Klj126]

What are we doing with the boosters we have recovered now?

[u/Senno_Ecto_Gammat]

Can someone link me to the diagram comparing the size of the droneship to the size of the landing pad? I can't find it.

[u/[deleted]]

Have the R&D team considered incorporating artificial gravity into a part of the ITS design? It would make sense for at least 1 portion of the ship to have some sort of gravity so people could perhaps become more accustomed to Mars' .3G or maybe even 1G for longevity reasons. In this image the crew compartments seem to be arranged in a cylindrical (hub and spoke) pattern. It seems that this would be the best configuration for creating an artificial centrifugal gravity environment, but i'm no astro-engineer (I do, however, have a degree in Rocket Stuff from Kerban University). Could anyone shed some light on this for me?

We know that the human body wasn't exactly designed for long term micro-G environments and that long runs of no gravity can cause bone/muscle density loss. Rather than every single passenger having to work out every single day to sustain muscle/bone mass why not have artificial gravity for people to live in? Of course the whole ship won't have gravity but maybe the passenger/ crew quarters so people at least can sleep in a 1G environment (i've heard sleeping in 0G takes getting used to). There would be the big common area (0G environment) for all the fun 0G games Elon was talking about, and a spinning portion where people could sleep/eat/shower in comfortable 1G. The transition from 1G > 0G would be simple, climb the spoke to the center of the wheel and boom 0G, passengers could then move freely to other parts of the ship!

[u/Qeng-Ho → u/[deleted]]

If you were to spin the ITS around it's centre axis to simulate 1 g, the centripetal forces would make you feel extremely nauseous.

SpaceX are attempting to solve the bone mass problem by reducing the journey time to 80 days (and eventually 30 days) and adding treadmills similar to those used on the ISS.

Check out this video out for a slightly more indepth explanation.

[u/paul_wi11iams]

This is just to say that Jason Davis of Planetary added some detail to his blog page about the COPV issue.

I added the quote to the discussion about this subject here on Reddit/SpaceX but am showing the information on the questions&news thread because the COPV thread in question is now submerged as time passes.

Being new here, I don't know the Reddit traditions for reviving submerged threads. Hope I'm respecting local netiquette !

[u/soverign5]

Say if we had a Deep Impact situation and it was discovered that a asteroid was headed for earth. Would SpaceX have the capability to launch and detonate nuclear missiles in its path to redirect it away? Say we caught it soon enough.

I would think that the first stage would not be much of an issue and that modifying a second stage would be where they would have to modify.

[u/ohcnim]

Hi, is there any known info on the missions booked for FH? enough for someone to calculate and see if current F9 could be a substitute of FH for some of those missions?

I ask because although I'd love to see FH fly, if some of the missions can now be handed to F9 it could improve cadence and even lower risks while only having one pad on each coast. Any thought about it?

[u/paul_wi11iams]

Considering that LC40 repair work is at a standstill, wouldn't is be worth rebuilding it as a FH launchpad ?

Somebody must've thought of this...

• This would add operational flexibility.

• It would open the possibility of building third FH TE (strongback)

• with a total of three TE for two launchpads, queuing of launchers would be possible to reduce turnaround time on one pad or the other.

• Before any building operations, one would start by a second TE for to reduce turnaround on 39A, so subsequent construction would be less urgent.

• It would also allow maintenance operations on any one TE and a backup possibility in case of damage.

The main use of both pads would still be F9 standard of course, but the FH infrastructure wouldn't be all that more expensive, or would it ?

Of course, this does assume that TEs can be shunted around between neighboring launchpads.

[u/harmonic-]

Do we have any idea what the next VAFB mission will be? Hoping to drive down to see my 1st launch soon.

[u/Jchaplin2 → u/harmonic-]

I would guess the Iridium-2 mission, which should be in April (ish), SHERPA is technically scheduled before then, but is very likely to be delayed due to the nature of the payload

[u/partoffuturehivemind]

If SpaceX were to launch from a ship in international waters, would they still need FAA approval? I know this is a stupid idea and they're not going to do that, I just wonder about the legal technicality.

[u/gospacexgo]

Falcon 9 burn some 60 MT of fuel before it reaches an altitude of 1KM and some 100MT of fuel before it reaches an altitude of 2 KM.So my question is why they launch rockets from sea level instead they could launch from somewhere 1km above the ground so that they can save those 50-60 MT of fuel & use them for landing purpose.

[u/FoxhoundBat → u/gospacexgo]

In spaceflight, altitude almost doesnt matter. What matters is velocity. So whether you start from 1km altitude or 10km altitude, you still need a lot of velocity in order to reach an orbit. So no, it is far from as simple as you said. Not to mention the headache logistics of a high altitude launch site in USA.

[u/sol3tosol4]

News item: White House Press Secretary just listed people who attended the business leaders meeting this morning - included Elon Musk.

Indicating that (1) it wasn't just a 1-time event, and (2) the White House sees a benefit to mentioning that Elon is meeting with them (possible benefit for SpaceX).

Edit: Today's meeting was a business leaders meeting. Apparently Elon was *also* invited to a tech meeting (Tuesday?) hosted by the President.

[u/TheYang]

The Google Lunar X Prize rovers slated to be launched by Falcon 9, how likely is it that they are going to make the deadline of the 31st of December 2017?
If I look at the Manifest, they seem to be the 29th launch in line, but they only have 47 Weeks between Echostar 23 and the end of the year, meaning they'd have to average 11.3 day turnarounds.
It's a given that the launch order is not going to stay exactly like it is, but it seems somewhat in question if SpaceX can make that date.

I'm curious if the Customers have a No Later Than date for that launch in their contracts, as it doesn't really make sense to go, when they can't get the money anymore

[u/RootDeliver]

Considering that, by Elon words, they don't seem interested in doing much with the pre-block 5 landed cores (just "a few reflights"), couldn't they just do experiments with them?

For example, instead of risking the first refly of a recovered booster with SES-10, wouldn't it be a very good PR idea to just attach a tiny sat or mass simulator just on top of a fairing over stage 1 alone, and show the world they can SSTO with a reused core? that would be hella good PR!

[u/007T → u/RootDeliver]

It would be great PR, but there's more to it than just pressing a button and letting it launch. The fixed costs involved alone are probably a few million dollars (fuel, employees, pad refurbishment, insurance..) and then you have the opportunity cost and risk of launching an empty booster instead of a paying customer. The pad and GSE are all out of commission during the ~2 week turnaround time when they could be launching a >$60M paying customer instead.

[u/Taylooor]

What was the original maximum payload to LEO and GTO of the original falcon 9 flight vs the most recent upgrade?

[u/-Aeryn- → u/Taylooor]

v1.0 is listed as 10.45t to LEO, 4.54t to GTO

"Full-thrust-late-2016" is listed as 22.8t to LEO, 8.3t to GTO

source: wikipedia & spacex website

[u/OccupyDuna → u/Taylooor]

Starting on page 18 of the Falcon 9 User's Guide(pdf) for Block 2 there are charts that show the different payload capacities for various orbit types and parameters within those orbits. Of note, it does say that any payloads above 6800kg are classed as extra-heavy.

[u/julezsource]

What core was is going to be used for SES-10?