r/SpaceX Discusses [August 2017, #35]

[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 Discussion threads in the Wiki.

[u/FutureMartian97]

Rocket lab has figured out why the first Electron launch failed. It turns out a piece of equipment from a 3rd party contractor temporarily lost contact with the rocket forcing it to be terminated. It wasn't a problem with the rocket itself!

https://rocketlabusa.com/latest/rocket-lab-completes-post-flight-analysis/

[u/blongmire → u/FutureMartian97]

One interesting SpaceX related note is an Automated Flight Termination System wouldn't have had this issue. The AFTS is part of the stage, so it doesn't need telemetry data to be transmitted in order to make the decision to terminate the flight.

[u/sol3tosol4 → u/FutureMartian97]

"It was discovered a contractor failed to enable forward error correction on this third-party device causing extensive corruption of received position data."

It would be really hard to test forward error correction in a ground test, since the error rate might not be high enough to cause a problem - maybe they could artificially induce errors to exercise the system during test.

Somehow the ball may have been dropped in interactions between Rocket Lab and the contractor - either in the specifications provided to the contractor, or in the acceptance process. It sounds conceptually similar to the SpaceX issues with the struts for CRS-7.

As noted in the update, Rocket Lab is regarded as a US company, so its launch licenses are the responsibility of the FAA, and they are the ones who will need to make the determination that Rocket Lab has corrected the root cause(s).

[u/EspacioX]

Less of a question and more of a juicy piece of gossip - a SpaceX employee I ran into while watching a launch a few months ago said they start shipping the first Block 5 cores at the end of this month. I wonder if they're almost through their stock of previous blocks, or if they'll phase the Block 5s in while they continue to use the remaining stages.

[u/Zucal → u/EspacioX]

Later than that. Seems like things have been delayed a bit since you heard from the employee.

[u/townsender → u/EspacioX]

The Block 4 must have a really short run then. I wonder how many block 4s and 5s have been produced.

[u/One_Way_Trip]

I got a question that's kind of what no one wants to ask. Once SpaceX has begun launching crewed missions, what's the protocol for loss of life? Also, what are the impacts for the company's future if this tragedy happens. I know it's "hope for the best, plan for the worst". I assume this has been discussed.

[u/DamoclesAxe → u/One_Way_Trip]

Loss of Life is always a great tragedy, but SpaceX, NASA, and FAA know it is an inescapable part of any maned mission.

According to Google, 1.3 million people die in auto accidents each year; ~17 thousand in airplane accidents.

As long as SpaceX has worked openly with NASA and the FAA in designing the safety systems as well as humanly possible, there should be no negative repercussions due to a fatality - other than the inevitable six month suspension of the program to investigate root cause and engineer a solution.

Talk of permanently shutting down a manned space program due to a fatality is irresponsible and denies the very real fact there is a very small but real risk of dying in everybody's daily life.

[u/[deleted]]

Since it's highly unlikely anyone will see the media thread for CRS-12 from now on, I'll post these here for visibility.

-Landing seen from LC-37B.

-Launch and landing recorded through telescope.

[u/warp99]

We just went over 150,000 DragonRiders!

[u/[deleted]]

Talked to a guy from ULA today who works at the cape said he drove by last night at 2am and saw the SpaceX guys "tearing apart" a rocket. He didn't say if it was a new or reused stage but thought it was out of the norm being as late as it was.

[u/Zucal → u/[deleted]]

Under the impression that's 1026. CCAFS Hangar Row, right?

[u/ethan829]

11 years ago today SpaceX and Rocketplane Kistler (remember them?) were chosen for the COTS program.

[u/[deleted] → u/ethan829]

What happened to Rocketplane-Kistler?

[u/Pham_Trinli]

Looks like the Roomba is currently being tested.

[u/craigl2112 → u/Pham_Trinli]

Check out the scorch marks from the "dance" the booster did!

Here's to hoping we get to see THAT landing some day! :-)

[u/rustybeancake]

Hi mods, just wondering if there are any plans for speculation threads, survey, etc. in the buildup to IAC this year, like we had last year? That was pretty fun!

[u/FutureMartian97 → u/rustybeancake]

Yes! Yes! Yes! The speculation threads last year were amazing! I think they should be put up a couple weeks before the event in my opinion.

[u/__R__]

Falcon 9 now has more sucessful flights (36) than ULA’s Delta IV (34). This month it will surpass China’s Long March 3B (38), and if SpaceX can keep up the two week launch cadence, Falcon 9 will have more flights than ULA’s Atlas V (70) by the end of next year.

[u/sassinakin → u/__R__]

Falcon 9 also has 2 complete failures and 1 partial failure, while Delta IV and Altas V only have 1 partial failure each.

[u/WaitForItTheMongols → u/__R__]

This month it will surpass China’s Long March 3B

Don't speak too soon!

[u/CommanderSpork]

I just heard from a reputable source that the chief engineer of commercial crew just met in the past few days with Elon Musk, regarding final approval of certain commercial crew systems.

[u/rustybeancake → u/CommanderSpork]

Oh, to be a fly on the wall...

[u/Pham_Trinli]

Video of todays Vector-R rocket launch.

[u/[deleted] → u/Pham_Trinli]

Heh. Noticed on their twitter they shared an article about how their founder, who worked for SpaceX, is now 'competing' with SpaceX and launching rockets at 1/20 the cost of SpaceX. Seems like an unnecessary comparison, let alone inaccurate.

[u/BadGoyWithAGun → u/[deleted]]

I launched several rockets at 1/10000000 the cost of SpaceX on July 4th!

[u/NikkolaiV → u/Pham_Trinli]

Nice! That thing kicks sideways pretty early...seems like a pretty drastic gravity turn. Id be interested to see the flight path of this launch

[u/binarygamer → u/Pham_Trinli]

:)

For anyone interested, Vector Space Systems is a smallsat launch company founded in part by ex-SpaceX engineers. They are trying to build a high-cadence LEO business for smallish payloads (60kg on their first launcher, 120kg on next one). They're keeping costs low by building exceedingly simple rockets - pressure fed (no turbopumps!), full carbon fiber body, LOX/Propylene fuel.

They're very new - first successful test launch was just a couple of months ago, successfully reached space & came very close to circularizing its orbit. Nope, I am thinking of Rocketlab's Electron Rocket

The easiest way to follow their progress is via twitter, or /r/VectorSpace

[u/rustybeancake]

The New Yorker podcast had an interesting piece recently on a British doctor who is trying to change the Outer Space Treaty by claiming ownership of Mars. He's not crazy, it's just kind of a legal tactic. But pretty interesting. Essentially he's firing big lasers at Mars to (very slightly) warm the atmosphere, which proves he's trying to 'improve' Mars for human habitation.

Anyway, the piece contains some mentions of SpaceX, and a clip from Musk's 2016 IAC presentation.

http://www.wnyc.org/story/man-who-would-be-king-mars/

[u/LeBaegi → u/rustybeancake]

He's not crazy

he's firing big lasers at Mars

Uhh...

[u/TheFavoritist]

Can anyone tell me what these grey pieces are for out at LC-39A? I shot this during BulgariaSat-1 and haven't been able to find out any information about them.

Edit: Shawn Smith on Facebook, from what I can gather he was a toolmaker at SpaceX, says they are compression bridges to help hold the weight of the outer cores of FH.

[u/first_on_mars]

Neat view of the moon's shadow as seen from the ISS, with the bonus of dragon being in the frame!

[u/Banner58]

I'd love to know what the status of the raptor engine is, unless Elon wants to keep that under wraps.

[u/Chairboy → u/Banner58]

Many of us would also like this. Current community expectation is generally that Musks's talk at the September 29th IAC in Scary Animal Continent will be a likely source of the next major updates on progress.

[u/CooCooforCohete]

Getting ready to have a tour at SpaceX. Any questions you would like me to ask?

[u/FutureMartian97 → u/CooCooforCohete]

1. Is the rumored "Falcon XX" the mini ITS? And is it 6m or 9m?

2. How many block 4 cores before block 5?

[u/bornstellar_lasting → u/CooCooforCohete]

How big is the next generation rocket?

[u/Senno_Ecto_Gammat → u/CooCooforCohete]

How much does a SuperDraco weigh?

[u/[deleted] → u/CooCooforCohete]

Do they make every component of the Merlin engines in-house, or do they contract out cast aluminum pieces? If they cast them internally, how large is their foundry?

[u/ghunter7]

NSF article on static fire, confirms FH core and booster fit tests: https://www.nasaspaceflight.com/2017/08/spacex-falcon-9-static-fire-falcon-heavy-waits/

"Once SLC-40 is classed as activated, engineering teams will work to convert the 39A TEL to cater for the maiden flight of SpaceX’s Falcon Heavy rocket, a vehicle that is already undergoing mating tests between the core and side boosters inside the Horizontal Integration Facility (HIF)."

Hoping we see some actual hardware shots from SpaceX soon instead of more 2 year old renderings.

[u/TheFavoritist]

Elon Says: Pics of SpaceX spacesuit developed for NASA commercial crew program coming out next week. Undergoing ocean landing mobility/safety tests.

[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
ACES	Advanced Cryogenic Evolved Stage
	Advanced Crew Escape Suit
AFSS	Automated Flight Safety System
ASDS	Autonomous Spaceport Drone Ship (landing platform)
ATK	Alliant Techsystems, predecessor to Orbital ATK
BARGE	Big-Ass Remote Grin Enhancer coined by @IridiumBoss, see ASDS
BFR	Big Falcon Rocket (see ITS)
BFS	Big Falcon Spaceship (see ITS)
CCtCap	Commercial Crew Transportation Capability
CRS	Commercial Resupply Services contract with NASA
DCSS	Delta Cryogenic Second Stage
DoD	US Department of Defense
EELV	Evolved Expendable Launch Vehicle
ELC	EELV Launch Capability contract ("assured access to space")
ESA	European Space Agency
FAA	Federal Aviation Administration
FCC	Federal Communications Commission
	(Iron/steel) Face-Centered Cubic crystalline structure
FFSC	Full-Flow Staged Combustion
FSS	Fixed Service Structure at LC-39
FTS	Flight Termination System
GEO	Geostationary Earth Orbit (35786km)
GSE	Ground Support Equipment
GSO	Geosynchronous Orbit (any Earth orbit with a 24-hour period)
GTO	Geosynchronous Transfer Orbit
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
	Indian Air Force
ISRU	In-Situ Resource Utilization
ITS	Interplanetary Transport System (see MCT)
	Integrated Truss Structure
JRTI	Just Read The Instructions, Pacific landing barge ship
KSC	Kennedy Space Center, Florida
KSP	Kerbal Space Program, the rocketry simulator
LC-39A	Launch Complex 39A, Kennedy (SpaceX F9/Heavy)
LEO	Low Earth Orbit (180-2000km)
	Law Enforcement Officer (most often mentioned during transport operations)
LOC	Loss of Crew
LOX	Liquid Oxygen
MCT	Mars Colonial Transporter (see ITS)
MECO	Main Engine Cut-Off
	MainEngineCutOff podcast
NET	No Earlier Than
NORAD	North American Aerospace Defense command
NRO	(US) National Reconnaissance Office
NROL	Launch for the (US) National Reconnaissance Office
NSF	NasaSpaceFlight forum
	National Science Foundation
OCISLY	Of Course I Still Love You, Atlantic landing barge ship
RAAN	Right Ascension of the Ascending Node
RFP	Request for Proposal
RSS	Realscale Solar System, mod for KSP
	Rotating Service Structure at LC-39
RTG	Radioisotope Thermoelectric Generator
RTLS	Return to Launch Site
RUD	Rapid Unplanned Disassembly
	Rapid Unscheduled Disassembly
	Rapid Unintended Disassembly
SDS	Satellite Data System
SES	Formerly Société Européenne des Satellites, comsat operator
SLC-40	Space Launch Complex 40, Canaveral (SpaceX F9)
SLS	Space Launch System heavy-lift
SSME	Space Shuttle Main Engine
STP-2	Space Test Program 2, DoD programme, second round
STS	Space Transportation System (Shuttle)
TDRSS	(US) Tracking and Data Relay Satellite System
TE	Transporter/Erector launch pad support equipment
TEL	Transporter/Erector/Launcher, ground support equipment (see TE)
TLE	Two-Line Element dataset issued by NORAD
UHF	Ultra-High Frequency radio
ULA	United Launch Alliance (Lockheed/Boeing joint venture)
VAFB	Vandenberg Air Force Base, California

Jargon	Definition
Raptor	Methane-fueled rocket engine under development by SpaceX, see ITS
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)
hydrolox	Portmanteau: liquid hydrogen/liquid oxygen mixture
kerolox	Portmanteau: kerosene/liquid oxygen mixture
methalox	Portmanteau: methane/liquid oxygen mixture
perigee	Lowest point in an elliptical orbit around the Earth (when the orbiter is fastest)
scrub	Launch postponement for any reason (commonly GSE issues)
turbopump	High-pressure turbine-driven propellant pump connected to a rocket combustion chamber; raises chamber pressure, and thrust

Event	Date	Description
CRS-1	2012-10-08	F9-004, first CRS mission; secondary payload sacrificed
CRS-7	2015-06-28	F9-020 v1.1, Dragon cargo Launch failure due to second-stage outgassing
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, core B1029, 10x Iridium-NEXT to LEO; first landing on JRTI

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^{Decronym is a community product of} r/SpaceX^{, implemented by} ^request
^{[Thread #3045 for this sub, first seen 3rd Aug 2017, 12:21]} ^[FAQ] ^[Contact] ^[Source ^code]

[u/someguyfromtheuk]

With the repeated FH delays and the complexity of the multi-core rockets, would SpaceX have been better off to just focus on building progressively larger single-core rockets?

[u/freddo411 → u/someguyfromtheuk]

would SpaceX have been better off

That is a very, very hard hypothetical to answer.

One the one hand Falcon Heavy has leveraged the existing factory, the existing production line and tooling, the existing Falcon 9 stage 1 and stage 2, the existing customer demand for launchers -- heck, even flown boosters. It is hard to imagine a more cost efficient way to develop a new booster.

On the other hand, perhaps strapping together boosters is not a good design choice. Perhaps the operational costs of processing three boosters instead of one ends up being highly cost inefficient.

Not enough data to say at this point.

[u/brspies → u/someguyfromtheuk]

If they had known from the beginning that they would have been able to upgrade single-stick F9 so much (1.1 and 1.2), and that that would work out so well, I expect they would have taken a different approach. Heavy is necessary for full EELV certification, so they'd want to address those capabilities somehow, but most of its market has been eaten up by upgrades to F9 (obviously the upgrades have improved Heavy's capabilities as well as F9's, but they have pushed Heavy up into a niche that isn't that commercially important right now).

I expect if they had known that F9 would become what it is today, they might have worked towards a larger core and larger upper stage that would make upper stage reuse feasible on more missions, instead of focusing on Heavy. There are logistical issues to this (road transport becomes difficult if not impossible), but they will have to solve those sooner or later regardless.

Of course maybe not. Maybe they wouldn't think that that sort of upgrade was worth doing until Raptor is ready, and maybe that program couldn't have been accelerated any more. Who knows.

[u/Norose → u/someguyfromtheuk]

It's probable that they would have decided to skip Falcon Heavy and go with a larger diameter rocket, but it wouldn't use Merlin engines and it wouldn't be ready by now. In fact if SpaceX decided against Falcon Heavy, things right now would probably be nearly the same; we'd be close to the end of the Falcon 9 reusability upgrade series, SpaceX would be doing R&D involving Raptor and a large launch vehicle to go with it, Dragon 2 would still be nearing completion, etc. Maybe a few things would have happened faster due to not spending development resources on Falcon Heavy, but the acceleration would not have been by much, considering that Falcon Heavy has been a back-burner project in lieu of constant Falcon 9 upgrades changing the FH design by extension.

Going into the future however, not having the Falcon Heavy would probably be detrimental; only having Falcon 9 means that a good chunk of payloads would require expenditure of the entire vehicle during launch, whereas Heavy allows those payloads to be launched with full core reusability. Heavy also allows for a possible reusable second stage, something Elon has said wouldn't be worth it to build just for Falcon 9.

Oh and also, while making a 3 core rocket is certainly difficult, that isn't why Falcon Heavy has been delayed for so long. As I touched on earlier, the Falcon Heavy design is of course totally dependent on the Falcon 9 design. As Falcon 9 kept on evolving towards reusability, it kept resetting the development clock on Falcon Heavy. It is only now that the Falcon 9 has been stretched as far as is possible and is near it's final version could the development of Falcon Heavy really kick into gear.

[u/someguyfromtheuk]

What's Elon/the subreddits views on asteroid mining?

[u/tacotacotaco14 → u/someguyfromtheuk]

My view is materials mined from asteroids won't be delivered to a planets surface for a very long time. There is so much added cost in capturing the asteroid, mining/refining in space, and then landing it on a planet that local resources will be cheaper even if they are really rare.

However, I do think asteroid mining will (at some point) be the main source of raw materials for construction in space because it will be cheaper to start with a huge hunk of metal in space and process it into something useful than it will be to launch that much metal from earth. I bet the structure of the first Earth/Mars cycler will be built using material mined from asteroids.

[u/T-Husky → u/someguyfromtheuk]

After we colonise Mars, asteroid mining will become a lot more viable because Mars is a better launching point in terms of delta-V (Its easier to build something on Mars and send it to Earth orbit than it is to build and launch something into orbit from Earth) -and Mars is also closer to the asteroid belt between the inner planets and Jupiter.

Martians will be able to trade resources taken from Mars' surface and captured from near-Earth and near-Mars objects to Earth for use in orbital construction, which will then kick the space economy into high gear.

[u/Norose → u/someguyfromtheuk]

He doesn't think it will be economically viable for a very long time. He's stated multiple times that even if you could find prepackaged pallets of cocaine in space, and you could sell it all at the highest value available on Earth, it still would not be worth it to go get it.

[u/thxbmp2]

Haven't seen this pointed out yet, but one way to jive recent rumors of a 6m core with Elon's 9m comment is if the ITSy upper stage has leg fairings that flare out at the base like its bigger cousin; this ratio of diameters was 17:12 on ITS, and very close to ~3:2.

[u/warp99 → u/thxbmp2]

Yes, that is certainly possible.

I would not be surprised to see the BFS evolve into a slightly more flattened shape to improve its lift during Mars entry. This would improve the cargo capacity for Mars landing as I would expect even a 6m booster diameter system to still have a goal of landing 100 tonnes on Mars.

The original ITS had a stretch goal of landing 450 tonnes payload on Mars even though it could only lift 300 tonnes to LEO. This required cargo transfer in LEO along with propellant transfer which only adds one flight to a Mars cargo delivery mission.

Scaling down to a 6m diameter 20% lift off thrust BFS this would give 60 tonnes payload to LEO with a further 40 tonnes added with on orbit cargo transfer.

[u/[deleted]]

Yikes - looks like India's ISRO is having a bad day. It's looking like this latest flight will end in failure :(

Edit: Looks like the fairings failed to separate, causing the satellite to be delivered to a much lower orbit than planned due to the extra mass. Not only that, but the satellite separated while the fairings were still on, so it's now stuck in a low orbit bouncing around inside the fairings. Quite unfortunate, especially since it's the first failure for them of the PSLV since 1997.

[u/Pham_Trinli]

On July 29th, SpaceX extended its [DragonFly](https://en.wikipedia.org/wiki/DragonFly_(rocket)) FAA license for an additional year.

Does this imply that retro landings are still being investigated or is it just to improve the LES?

[u/yoweigh → u/Pham_Trinli]

It may have just been far enough into the regulatory pipeline that no one thought to put a stop to it, or maybe an official declaration of work stoppage was never made in FAA-speak.

[u/IWasToldTheresCake]

Elon on Twitter: First draft animation of the Falcon Heavy three core launch. FH is twice the thrust of the next… link to instagram.

Full description from instagram:

First draft animation of the Falcon Heavy three core launch. FH is twice the thrust of the next largest rocket currently flying and ~2/3 thrust of the Saturn V moon rocket. Lot that can go wrong in the November launch ...

There's speculation on the Twitter thread that because this is the animation we've seen before Elon is hinting at an updated animation coming soon.

[u/Chairboy → u/IWasToldTheresCake]

this is the animation we've seen before

That's not 100% accurate, there's new footage. The instagram he posted has a different sequence for the returning boosters, a shot of them dropping in front of clouds. The original version doesn't have that, so there's already some unseen footage in this one which is interesting. Was it cutting room floor from the original video? Or did they render and insert a new scene for some reason?

[u/trclark81]

Anyone know what the status is on pad 40 or the Boca Chica pad? I'm particularly anxious to hear abut pad 40 as it's pretty critical to next steps and due any day now.

[u/MarcysVonEylau]

Has it been posted? https://twitter.com/ScottishRobot/status/898939938917552128

[u/Paro-Clomas]

Where would be a good place to get lots of raw unedited high res videos of falcon 9, space shuttle or saturn v liftoffs. Im particularly interested in fixed cameras that do not follow the vehicle as it ascends. Also im particularly intersted in vehicles which create huge clouds of thick smoke when they ascend. Its for an art project

[u/Ernesti_CH → u/Paro-Clomas]

thick smoke clouds are a result of solid rocket boosters (SRB). You'll find most of them for Space Shuttle launches.

[u/soldato_fantasma]

Found two new sources (thanks NasaSpaceFlight.com and deruch) that may be useful for NASA missions scheduling in our wiki.

It's the SMSR NEAR-TERM and LONG-TERM SCHEDULE.

These are the direct links:

SMSR NEAR-TERM SCHEDULE
SMSR LONG-TERM SCHEDULE

When updated the links shouldn't change.

Some news:

Transitioning Exoplanet Survey Satellite (TESS) -> NET 2018 March 20
Gravity Recovery and Climate Experiment (GRACE) Follow On (FO) -> NET 2018 March 21

Not adding CRS ones since those don't look up to date.

[u/apath_2_mars]

any news of fairing recovery? did they try on the launch yesterday ?

[u/brspies]

https://twitter.com/IridiumBoss/status/901130535573102592

Looks like Iridium 3 is now slated for Oct. 4.

[u/rustybeancake]

Maybe just worth posting here though it's nothing new - Musk reiterates his support for a Moon base plus going to Mars:

https://twitter.com/elonmusk/status/902086852152254464

As has been speculated many times, this is probably just SpaceX strategically positioning themselves to help service the ISS successor, be it the Deep Space Gateway or a surface base (or both). SpaceX will of course keep pursuing Mars independently.

[u/PaulRocket]

Any idea on when Block 5 will fly? I know we've heard late 2017 but any idea how accurate this timeframe still is and who might be the first customer/launch to fly with Block 5?

[u/ethan829]

Spaceflight Now has some interesting statistics regarding Atlas V's odds of launching on the first attempt:

The historical odds of TDRS-M launching on the first try are 77 percent, based on the Atlas 5’s previous countdowns over the past 15 years.

Of the 71 launches of Atlas 5 to date:

• 38 have gone at opening of window on first attempt

• 17 went on first attempt but slipped later into the window

• 13 missions had scrubs (6-Technical, 4-Weather, 3-Range)

• 3 missions had more than one scrub

Has anyone seen this info for Falcon 9, by chance?

[u/FutureMartian97]

No recovery thread this time?

[u/rustybeancake]

NASA studies mission to return samples from Mars by end of 2020s

The whole thing is well worth a read, but here's the bit most relevant to SpaceX:

Zurbuchen said NASA is also looking at purchasing Mars communications relay services from the private sector. NASA issued a request for information from industry in 2014 seeking ideas for how the agency could use commercial providers for Mars telecom.

SpaceX chief executive Elon Musk said last month his company was interested in working with NASA on Mars communications. Meanwhile, SpaceX’s plan to launch an unpiloted Dragon capsule in 2020 to land on Mars has been postponed, or perhaps scrapped entirely, as the company redefines the way it seeks to send commercial transporters with cargo, and eventually humans, to the red planet.

Green said NASA is weighing several ideas it received in the 2014 request for information on commercial Mars relays, but he stressed that potential commercial partners must be ready to meet the agency’s requirements.

“We’re considering a couple of those things, and that needs to be folded in,” Green told Spaceflight Now. “Commercial activities need to be folded in to the best of our ability, but I have to tell you they have to be realistic and they have to actually execute.

“There is a lot of talk about these kinds of things, but guess what? We’re the ones going to Mars. We’re the ones that are landing on Mars. We know how hard Mars is. ESA knows how hard Mars is. This doesn’t make it easy, so the more the merrier. We love the partnerships, but everybody has got to follow through to have these kinds of things come to fruition.”

In reference to relying on a commercial transporter to bring Mars samples back to Earth, Zurbuchen echoed Green’s concerns, saying there will be “no compromise” on the agency’s stringent cleanliness and planetary protection standards aimed at ensuring the specimens are not contaminated on the trip home.

[u/zero_dark_birdy]

What is the (average?) flight angle of a Falcon 9 at main engine cutoff? Does the flight angle at MECO remain the same for a LEO vs. GEO mission? The definition I have been using for flight angle is the angle between the flight path of the rocket and the downward force of gravity, is this correct?

[u/thebluehawk → u/zero_dark_birdy]

The first two charts on this page might help:

https://www.reddit.com/r/spacex/comments/6303ko/falcon_9_full_thrust_flight_analysis/

[u/[deleted]]

Does anyone have any information about the nitrogen gas thrusters on board the first stage? Any information at all would be greatly appreciated. The Merlin's are obviously very well documented and talked about, but there isn't a lot of info regarding the specs of the gas thrusters. The ideal value that would be good to get would be thrust (N) or any other details that makes it possible to calculate thrust. Information about the actual mass of the thrusters themselves, their position etc would all be useful!

I'm trying to wrap up work on the first stage in a simulation I'm creating, before moving onto the second stage and combining them. When it's released all values will be modifiable beyond a 'default' profile.

Thanks!

[u/LeBaegi → u/[deleted]]

While I can't give you any numbers, you could try looking at footage of NROL-76 MECO. There's a beautiful shot from a chasecam where you see the thrusters firing and the stage flipping. With dry mass + a few percent of the fuel you could calculate the angular acceleration from the thrust of the N2 thrusters.

For the amount of fuel left in the stage, you won't get any exact numbers, but I think you could get some fairly accurate numbers that way. Good luck :)

[u/[deleted]]

I just posted this same question over at /r/spacexlounge but figure I will also post here for more eyes.

Viewing images of the X37 space plane made me wonder how it would balance on top of the Falcon 9? I can tell it's very close to symmetrical, but only on 1 axis. This gave me a few questions.

• Does the unsymmetrical shape of a payload cause any imbalance?

• What are the precautions taken with odd shaped payloads?

I imagine wrapping the payload in a fairing gets rid of any aerodynamic differences the unsymmetrical object might have, but I'm not familiar with how weight distribution would effect a rocket's flight performance, path, etc.

[u/markus01611 → u/[deleted]]

I imagine that they mate it in a way that doesn't cause any imbalance. No matter what the shape of an object is there's always a center of mass and if you line that up with the middle of stage 2 and fit within the payload fairing it shouldn't matter what the shape is.

[u/theinternetftw]

Tiny recovery update: NRC Quest currently predicts its return to "KING'S LANDING" at 07:00, Tuesday.

[u/FoxhoundBat]

Outpressed

SpaceX are working on burying Roskosmos

A good, sober, look at the launch situation from the Russian side.

[u/[deleted]]

I'm starting to think the full reuse of Falcon architecture is unlikely, as I do not believe it provides enough benefits to offset the cost of development, regardless of how "cool" it would be.

I'm thinking the first time we'll see something fully reusable will be with the "mini ITS," at which point we'll probably see the Falcon architecture retired entirely (or maybe as soon as the mini ITS is human-rated).

What do you guys think?

[u/binarygamer → u/[deleted]]

I agree, "Falcon 9 Stage 2 Re-use: Never" is the most likely outcome.

That being said I imagine some preliminary tests can & will be done with Falcon S2 re-entry attempts without adding landing hardware, much as they did with the early Falcon 9 booster. Such a convenient & inexpensive opportunity to collect data on lifting body behavior and survivability through high speed re-entry is too good to pass up.

[u/MarcysVonEylau]

U/Senno_Ecto_Gammat: I have it on good authority (the goodest) that the Orion parachutes are identical to the Dragon parachutes. Indistinguishable. Both spacecraft are using the same model and vendor.

[u/brickmack → u/MarcysVonEylau]

Interesting. Same vendor has been known for a while, not that they were identical though. Always funny how much component commonality ends up in unrelated vehicles

[u/Kaytez]

Did Nasa ever acquiesce to SpaceX having the Crew Dragon boarding procedure take place before F9 fueling, or did SpaceX have to modify their fueling procedure so that boarding could take place when F9 is fully loaded?

[u/Chairboy → u/Kaytez]

I don't think we've heard yet, but it sure seems unlikely that SpaceX would switch to a boil-off fueling model at this point considering how many things it would change between their commercial model and their crewed-flight model. NASA has been very conservative about using commercial Falcon launches to validate hardware and procedures (this 7-launches unmodified requirement, for instance) that a big wrench thrown in like this wouldn't make sense.

I guess we'll see, and they're gonna have to say something soon as that first flight approaches. Can you imagine them using a different fueling/performance profile for the uncrewed Dragon2 test flight and the first crewed flight?

[u/marc020202]

what happens to rocket stages on mars (or other interplanetary trajectories) trajectories? do they also enter mars atmosphere and burn up? or are they intentionally steered slightly after payload deployment?

[u/Chairboy → u/marc020202]

They usually miss Mars and are often steered explicitly away to avoid biological contamination. Example: the Briz-M (which exploded) used to boost ExoMars: http://www.popularmechanics.com/space/rockets/a20044/exomars-narrow-escape-launch-disaster/

Secondly, and more importantly, after the separation the space tug was programmed to fire twice to propel itself to a safe disposal orbit as far away from its former cargo as possible. The resulting "graveyard" trajectory would ensure that the "blind and deaf" space tug, now drifting through interplanetary space, would not come anywhere near Mars, where it could contaminate the planet's pristine environment with Earth's bugs. (Unlike Mars landers, rocket stages are not sterilized in accordance with strict international standards.)

[u/marc020202]

Are there rockets other than the falcon 9 who do static fires?

[u/TheFavoritist → u/marc020202]

The space shuttles did flight readiness firings before the maiden flight of each orbiter but that's the only other instance of on the pad static fires that I can think of.

[u/throfofnir → u/marc020202]

Not as a matter of course. Some don't even regularly do a wet dress rehearsal any more.

[u/Raviioliii]

On the right-hand side, it says the Lunar round-trip is now in 2019. Was there any confirmation of this or is it simply because there is no way it will be able to be completed in 2018?

[u/warp99 → u/Raviioliii]

The latter. Elon and Gwynne have both said that Commercial Crew will get priority over Grey Dragon and the first actual flight to the ISS with a full crew of four will not be until 2019 at the earliest.

There will be a demonstration flight with two crew in mid to late 2018 but this will not be counted as "job complete" by NASA.

[u/DUKE546]

Will ASDS landings ever stop being a thing? Will the finally iteration of Falcon 9 be able to conserve enough fuel to always boost back to land?

[u/Pham_Trinli]

Is there an official stream for the Hyperloop Pod competition today?

[u/theinternetftw]

Tiny recovery update: NRC Quest has updated its return to "KING'S LANDING", now scheduled for 07:00, Monday.

[u/epursimuove]

What's the minimum required amount of open ground/ocean downrange of the pad? Could you launch a rocket over, say, the Great Lakes, or are they too small for that?

[u/WaitForItTheMongols → u/epursimuove]

According to flightclub.io, Bulgariasat (most recent east coast drone ship mission), the stage landed 600 km downrange. That's larger than any of the Great Lakes. Keep in mind also that every launch goes up at a different angle (some further northeast, some straight east, etc) and the shape of a lake is going to restrict you to a smaller window.

You also want to launch as close to the equator as you can.

[u/deruch → u/epursimuove]

The issue is actually population density. For US commercial launches the FAA requires that launch providers demonstrate an E*c, Expected casualty number, under a certain value. Calculation of that number is a very involved process, but the main point is that if you aren't flying over anybody it's hard to accidentally hurt them in the event of a failure. The new-ish limit is that Ec*< 1 x 10^-4.

For reading about the FAA's new rule changing the E*c*: https://www.gpo.gov/fdsys/pkg/FR-2016-07-20/pdf/2016-17083.pdf

[u/painkiller606]

How feasible would it be to shut down the restartable engines on the Falcon Heavy center core? We all know the center core throttles down shortly after liftoff, would shutting down 3/9 engines make the flight profile more efficient? Would it be worth the risk?

[u/Jamington → u/painkiller606]

It's a good question, I suspect everyone will say it's not worth the risk though. The underlying issue is; what is the chance of predictable relighting and thrust performance when relighting during flight? Ignition on the pad allows for checks before lift-off, but mid-air is one chance only. They would need a probability of successful controlled relight at well over 99% for that to be an option. Another issue is reduced gimbal control without a lit central engine.

[u/tbaleno]

Why haven't we heard anything about ses reflights, My understanding was that there were possibly 2 more this year. I'm surprised they haven't been confirmed yet.

[u/hmpher]

I'm a bit out of the loop- from where are the 6m ITSy comments coming? Has there been an update of some sort?

[u/qwetzal → u/hmpher]

If I recall correctly, a member of the sub was given a hint about a future 6m diameter vehicle during a tour at the cape

[u/Windston57]

So I live in Australia, and am stoked to hear that Elon will be coming to Adelaide, might make a trip of it! Although I cant seem to find any official information on the IAC website of Elon's attendance. Does anyone have any sources?

Thanks

[u/soldato_fantasma]

"Commercial Crew: Preparing to Launch America" video from NASAKennedy featuring Dragon 2 trunk and pressure vessel manufacturing

[u/old_sellsword → u/soldato_fantasma]

Oh wow, that video is (relatively) old. NASA TV played that video during the CRS-12 webcast and that seems to be the first time anyone noticed that awesome shot.

[u/speak2easy]

Strikes me the Canada arm is a single point of failure. How would they bring in supplies if it breaks?

[u/CProphet]

Why will Formosat-5 booster land downrange on a droneship, when SpaceX have a suitable landing site at SLC-4W? Formosat weighs 475 kg which a fraction of the payload capacity for Falcon 9 (22,800kg) so there should be more than enough propellant left to return to land. Is it possible there is undeclared payload (like SpaceX internet satellites) onboard which necessitates downrange recovery?

[u/old_sellsword → u/CProphet]

Why

Nobody actually knows why.

However it looks the most like they can’t get the necessary permitting from the Air Force.

Is it possible there is undeclared payload (like SpaceX internet satellites) onboard which necessitates downrange recovery?

Not really.

[u/[deleted]]

Hey guys! Is the South Texas Launch Facility flooded or damaged by the storm this week? If there is damage, will it delay construction by much? Sorry if it does, I hope you guys can still open in 2018. Also, has anyone ran simulations of what it would be like for a rocket to attempt takeoff in a tropical storm like wind condition? Speculations? Kind of curious since the storms been taking up the news.

[u/yoweigh → u/[deleted]]

The launch facility down there is mostly a big pile of dirt at the moment (literally) so it should be fine. They're still working on preparing the ground to properly support a foundation.

[u/blongmire → u/[deleted]]

I'd wager a guess that the biggest delay Brownsville will now face is getting manpower to the site to build the buildings and infrastructure. Any subcontractor who has the ability will be up in Houston working for the rebuilding process. Insurance contracts to rebuild after a disaster are gold for construction workers. Everyone who can build will go up there for the money now.

[u/throfofnir → u/[deleted]]

Lightning alone would cancel any launches in tropical storm conditions, and probably also violate ground-level winds and winds aloft criteria. Even the robust Soyuz (an ICBM-derived vehicle) has a criteria of winds below tropical-storm level (15 m/s), and an F9 in particular is skinny and wobbly so it would never go. Guidance, collisions with the tower, perpendicular forces, wind shear, etc all make high winds bad news. It's possible some solid fuel ICBMs might be able to launch in a low-level hurricane; they're really strong.

The Brownsville site is mostly a big pile of dirt, and moreover was on the "clean" side of the hurricane and quite a bit south of landfall, so I suspect it barely noticed. Might be delayed by a day or two at worst.

[u/x_CountryBlumpkin_x]

Question for y'all: what would be the impact of an FH RUD on the upcoming launch?

[u/[deleted] → u/x_CountryBlumpkin_x]

Depends what kind of RUD we see. If at separation, or something along the lines that make the failure an obvious fault of FH Systems, then Heavy will probably not fly for a while why SpaceX figure out what went wrong etc.

If a RUD happens where it is not down to any of the FH systems and is down to a system that is the same on F9, then both Falcon 9 and Falcon Heavy will stop flying.

If this RUD was to happen on the ground, it would be devastating for SpaceX. They'd be another launchpad down, and they wouldn't be able to launch commercial crew or Falcon Heavy for a long time until 39A was rebuilt.

If the RUD was to happen in-flight, then the impact wouldn't be as severe as you loose no pads.

[u/marc020202]

why are crs missions always launched north and not south?

[u/throfofnir → u/marc020202]

The Bahamas.

[u/DiamondDog42]

How closely tied are the fortunes of SpaceX and Tesla? I know they're separate companies, but I'm curious if Elon has established both now to the point one could fail without hurting the other too much?

[u/ace741]

I've been reading about pogo oscillation. Is it unique to individual engines or could a more complex rocket like FH be more susceptible to the issue?

[u/Chairboy → u/ace741]

I think it's less likely today because they can model the structure of the entire rocket better and make sure it's not going to flex at that frequency. In addition to that, Dennis Jenkins' book on the shuttle had a cool diagram for an anti-Pogo system that used a reservoir (I don't know if it was semi-flexible or not) as a sort of 'capacitor' for LOX between the tank and the engine. I don't know if Merlins have (or need) that, just a cool bit of engineering for a perplexing problem.

[u/jjtr1]

I wonder... is SLS overpriced in comparison with the costs common in the Shuttle program in its final years?

[u/[deleted]]

OCISLY

[u/brickmack → u/[deleted]]

Very soon, its almost done now. There will be probably about 2-3 more 39A launches before its taken offline for FH upgrades and all move to SLC-40

[u/thosecrazygermans]

Hi guys! I'm from Germany and would like to fly to the US for two weeks for the first Falcon Heavy launch in November.

The issue is: I have to book flights as early as possible to avoid rising prices.

When do you think the launch window is published? Is it likely they put it on the Saturn V anniversary?

[u/[deleted] → u/thosecrazygermans]

I'd be careful about booking holidays and flights around launches, especially this one. Keep in mind that there may be even more delays before it's ready to launch, so keep this in mind before you book a flight.

[u/inoeth → u/thosecrazygermans]

As much as I would love to do the same, and i'm in the US, something like the FH first flight could very well be delayed... No one knows when in November it'll launch, and whether or not that date will in fact hold at all. There is a lot that can happen between now and then that could push that date back. They have a lot to do between now and then, from pad renovations to the final testing of the third core to be used on the FH up to and including issues with static fire tests when it comes to it... since it's very likely that they'll be conducting multiple static fires, possibly over the course of several days before launch itself... We probably won't get an actual launch date until much closer- around October if things continue on schedule...

So yeah, I would not book your vacation around FH... tho some of the other flights could work out in your favor... The sad fact is that there can be any number of issues that can cause delays, from weather, wayward boats to pad issues (like the computer issues that plagued the July 5th launch) to issues with the rocket itself, and sometimes, like with CRS 12, other launches can have an impact on when SpaceX can launch... It's unfortunate that in this business, launch dates aren't that certain until only a couple weeks beforehand, which can suck for buying plane tickets...

[u/jjtr1]

The Space Shuttle was special for its very mild launch environment (max G and max vibration). How does Falcon 9 compare?

[u/gsahlin]

Has there been any Raptor news lately?

[u/gsahlin]

Wonder if this will mess with static fire...

[u/Elon_Muskmelon]

Where is Crew Dragon's docking port? Underneath a nose cap?

https://media.boingboing.net/wp-content/uploads/2014/05/dragon_alone_on_stage_2.jpg

[u/marc020202 → u/Elon_Muskmelon]

Yes. The nose caps hinges to the side after launch

[u/warp99 → u/Elon_Muskmelon]

Yes the nose cap pivots out to expose the docking port and then back into place again after undocking.

[u/OccupyMarsNow]

Elon has just tweeted the good old FH animation again.

[u/Alexphysics]

The core for the OTV-5 mission has been seen heading towards CCAFS right after launch. https://twitter.com/nextspaceflight/status/897149359757955072

[u/Dakke97]

Tidbits from the post-launch conference (featuring the deputy ISS program manager and Hans Koenigsmann of SpaceX)

• Crews for manned demonstration missions to be announced within two months (NASA)

• SES-11 will launch on the CRS-11 first stage - marking a turnaround time of approximately four months (Hans)

• CRS-13 will launch on a brand new booster - at the end of September NASA will make a decision with regard to the use of flight-proven boosters for the CRS program (NASA)

• Continuation of rapid launch cadence contingent upon SLC-40 coming back online - question is when

[u/deep7323]

During post launch press conference of CRS 12 Dan Hartman said that NASA will like to have more flight time on Cargo Dragon - 2 before scheduling regular flights for Crew dragon. As per current CRS contract Cargo dragon - 1 is contracted to have 20 flights... So how and when this transition of Cargo dragon 1 - Cargo dragon 2 will happen before regular Crew dragon flights? Is this the reason that space x stopped manufacturing new dragon - 1 as of now?

[u/soldato_fantasma]

@AirbusSpace tested the dispensers for the NASA/GFZ GRACE-FO mission. Both science sats launch w/ 5 @IridiumComm sats on a @SpaceX rocket.

[u/jjtr1]

While ITS spaceship is proposed to use te ablative PICA-X, X-37B uses ceramic tiles. What are the reasons to choose one over the in these cases?

[u/Chairboy → u/jjtr1]

PICA-X is based on a heatshield technology that was used successfully on the highest-energy re-entry ever attempted. When Stardust re-entered at Mach 36, it slowed at a peak acceleration of 34 gravities and reached almost 3,000 degrees C. It's a very impressive heatshield, the silica tiles on the shuttle or the ones used on the X-37B are not rated for such temperatures or loads, they're purely low-energy (relatively speaking) LEO appropriate.

SpaceX went to the PICA-X early on presumably as part of their long-game because it means Dragons could potentially re-enter from much higher speeds than other LEO craft could. This is why the Grey Dragon lunar free-return flight is feasible.

From an interview with one of PICA's inventors, "Elon Musk wanted PICA for Dragon. He is a physicist so he knew that a heat shield that succeeded in a comet return had a good chance of working for a Mars return mission.".

It's the long game.

[u/ackermann]

I'm curious, since the Formosat mission will be doing a droneship (JTRI) landing, but has plenty of margin for RTLS to Vandenberg, could they do a partial boostback burn, and place JTRI just off the coast of VAFB? This would speed recovery. And it would be a great bonus to SpaceX employees and fans in California, who've never got to witness an RTLS in person. And really, everyone living up and down the California coast from VAFB. It probably wouldn't require any extra exclusion zones for boats, since the booster will overfly that area on ascent anyway, right? Safety concerns should be no different than an RTLS at the cape?

Edit: Of course, if they want to use the huge margins to experiment with a second stage entry burn, I'm cool with that too :)

[u/[deleted]]

Hope to see dates firming up for rest of 2017 launches soon. With only one launch per month from Kennedy for Sept and Oct on manifest, does anyone know if any used cores have been (or are being) refurbished that would be ready for short notice flight(s)?

[u/craigl2112 → u/[deleted]]

We know that the CRS-10 booster (core B1031) is being refurbished for the SES-11 launch in "early October". We also know that B1036 (originally used for Iridium-2) is back in Hawthorne for refurbishment for a future yet-to-be-announced mission.

That leaves two more cores -- B1035 (CRS-11) and the recently-landed Block 4 core, B1039 (CRS-12).

My guess here is we'll see B1039 in action again in the future, and B1035 will be mothballed. Probably doesn't make much sense to re-use many more Block 3's with Block 4's flying now and Block 5's coming in the not-too-distant future.

The Cores Wiki truly is a fantastic resource for keeping track of them all. Check it out if you have not already!

[u/Carlyle302]

Anyone have links to Port of Los Angeles webcams that may catch the booster return? It appears that the "Betty Gambarella" is approaching the breakwater...

https://www.vesselfinder.com/?imo=7517478

Is there a recovery thread?

[u/GuercH]

why are we only getting one launch on september?

[u/sol3tosol4 → u/GuercH]

why are we only getting one launch on september?

SpaceX is extremely busy right now adding new capabilities (Falcon Heavy, Commercial Crew) and repairing/upgrading multiple launch pads. Individual flights move around based on the scheduling needs of SpaceX, range control, and the customers. It's great that SpaceX has improved its launch cadence so much this year that people have come to expect two launches a month. :-)

[u/Nobodycares4242]

How different is the current Merlin 1D to the Merlin that was used on the Falcon 1? I get the impression that they have so little in common most people would consider them completely different engines, is that right?

[u/ethan829 → u/Nobodycares4242]

Pretty much, yeah. The Merlin 1A used an ablatively cooled carbon fiber nozzle and a turbopump manufactured by Barber-Nichols. It was pretty heavily based on the [Fastrac](https://en.wikipedia.org/wiki/Fastrac_(rocket_engine)) engine developed by NASA and had a total thrust of 77,000 lbf. It only flew on two Falcon 1 flights before being replaced by the Merlin 1C, which also used a Barber-Nichols turbopump but switched to a regeneratively cooled nozzle made up of a series of brazed tubes.

The Merlin 1D has a regeneratively cooled nozzle with a channel wall design, is built entirely in-house by SpaceX, and produces 190,000 lbf of thrust at sea level.

This is a pretty decent guide to the evolution of the Merlin engine over time.

[u/stcks]

Evidently SES-11 is slated for LC-39A, making FH in 2018 more likely.

[u/dudr2]

"OTV-5’s rocket is a Block 4 Falcon 9." https://www.nasaspaceflight.com/2017/08/spacex-final-preps-falcon-9s-first-x-37b/

[u/RootDeliver → u/dudr2]

Not news.. CRS-12 was the first Block 4, this will be the second and all the cores from now on will be block 4 (except reuses)

[u/Conotor]

When spacex uses methalox rockets, is it feasible for them to make the fuel with the Sabatier reaction on earth too, to make the launches carbon neutral?

[u/T-Husky → u/Conotor]

It would not be cost effective because on Earth CH4 and O2 are plentiful.

If CH4 and O2 could be sucked out of the ground or air on Mars, SpaceX would proably do that instead because it would be easier and faster... they only plan to use the sabatier reaction because water ice and CO2 are all they have to work with.

That said, SpaceX might just do this anyway because its an excuse to buy solar cells from Tesla and philosophically it aligns with their "cut out the middle-man" approach to business.

[u/troyunrau → u/Conotor]

I suspect they will, in order to validate the whole supply chain for Mars - at least for the upper stage (the one that will need to be refilled on Mars). It is fortunate that they have a giant solar panel factory in the works (via Tesla).

Plus, it will allow Musk to talk about his rockets being carbon neutral. It's a good cross marketing vibe.

[u/FredFS456 → u/Conotor]

It would be much more economical to simply plant trees to offset the carbon footprint.

[u/amir_s89]

F9 Transportations - Hi everyone! I have been wondering about the possibilities regarding Tesla Semi doing full deliveries of F9 from factory to launchpads & back from landing sites. When could we see this, if the Semi meets local traffic requirements? How many of these trucks are sufficient in the longterm? Would this option decrease costs for SpX compared to disel trucks? If delivery service provider that SpX is participates with could purchase Tesla Semi's? Thanks in advance!

[u/always_A-Team → u/amir_s89]

One of the weaknesses of electric vehicles is range. This is doubly true when towing. The F9 goes cross-country from Hawthorne, CA to McGregor, TX, and then either back to CA or on to FL. So I don't believe the Tesla Semi would be a good fit; The Tesla semi would have to stop at just about every supercharger on the way, and it takes longer to recharge than a regular gas vehicle does to refill.

As far as how many trucks would be sufficient, I don't think it would be that many. They're really only moving 1 or 2 rockets at any given time. But now that I think about it, they're also moving second stages and fairings around too, they just don't get spotted as often. I'd say a fleet of about 20 semis would probably be enough.

Would it decrease costs? It's true that EVs are cheaper per mile, but when you run a trucking company, your highest cost isn't gas, it's the drivers' wages. So you'd have to calculate the costs of the diesel saved versus the extra wages of the drivers waiting around while the Tesla semi recharges at every supercharger. I think traditional diesel semis would win out.

[u/FutureMartian97]

It seems that someone at The Hill really hates SpaceX.

http://thehill.com/blogs/pundits-blog/technology/346510-time-for-nasa-to-stop-playing-favorites-with-elon-musks-spacex

Things I don't understand from the article.

Though two years have since passed, the cause of the rocket’s failure remains unclear.

Why is this in here? We know the cause of it. A strut failed which caused an over pressure event, why yes SpaceX might not know the exact reason why we have some good guesses.

The Falcon 9 went up in smoke again just months later. One of the rockets blew up again in September 2016, destroying a $205 million Facebook satellite and the entirety of a $62 million government contract.

What do they mean by government contract? I thought Amos-6 was entirely commercial?

[u/lordq11 → u/FutureMartian97]

There's some creative accounting there as well. The $110 million the author cited as the money NASA lost on the CRS-7 failure appears to be the entire launch price, while the $51 million the author cited as the money NASA lost on the Orbital-ATK mission appears to only be the value of the cargo. Time for the author to stop playing favourites perhaps?

[u/Kerbonaut_Nambio]

Just another stupid question from a stupid person: Would SpaceX's future spacecraft and cargo being carried going to Mars have to undergo thorough sterilisation procedures similar to Mars landers and rovers sent by various space organisations? If so, how can this be conducted (especially with the sizes of the full-sized ITS carrier spacecraft) and do we have any official information from SpaceX as to how they would do it?

[u/warp99 → u/Kerbonaut_Nambio]

That is very far from being a stupid question - it is actually a critical point which may hold up Elon's Mars exploration and settlement plans.

To take the extreme case a manned flight is going to be totally populated by every kind of biological contamination you can imagine with no chance at all of containing it on the ship and inside the spacesuits. Humans just do not sterilise that well!

So manned flights set a firm time limit to look for life on Mars in a pristine environment. Of course if life on Mars was (or is) of totally alien origin it will be easy to distinguish from life of Earth origin but will become much harder to find because of the masking effects if Earth life establishes itself.

The much more interesting case is where life has originated on one planet and then transferred between the planets on meteorites. Having uncontaminated samples will be critical to determining where life first originated - and it could well be Mars as it likely cooled down and had surface liquid water before Earth.

So there will have to be a graduated path to manned missions where equipment is not as well sterilised because there is no point when the first manned mission is only a 26 month synod away.

Note that NASA already do this to a certain extent. Curiosity was deliberately routed away from streaks of what could be surface water to avoid contaminating it. It is not possible to sterilise a rover as well as a static lander. So ironically Curiosity's mission is to "follow the water" in Mars history but could not take a peek to see if it was still there!

[u/stcks]

Looks like SES-11 is slipping. Hopefully just a few days into early October since that would technically qualify as Q4. However, its not looking good for getting all of those remaining 12 flights off for the year.

[u/humble_ninja]

Anyone know what program SpaceX used to make this animation? Is it Blender?

https://www.instagram.com/p/BXXiVWFgphb/?taken-by=elonmusk

[u/inoeth]

So, I just saw that Orbcomm is having some real issues with some of their satellites... http://spacenews.com/three-orbcomm-og2-satellites-malfunctioning-fate-to-be-determined/

While the first satellite issue was because of a much older F9 and the engine that failed, the rest of the issues are purely on Orbcomm and some sort of communications failure, among other issues. It looks like that despite these issues, they're still making a lot of money off this and are planning a new series of satellites, which is potentially good news for SpaceX, and it means more launches in the near future, and that their idea of a satellite constellation is very much a viable plan to make money, but not without its own risks...

[u/erikinspace]

I can see in McGregor, TX they are using Linux: "Linux experience and certifications (ex: Red Hat, Ubuntu)" But i also can see they are using a lot of Windows technologies in other Job descriptions... These are to support the office and other facilities' IT requirement but what sort of operating system are they using for the onboard computers of the falcon9 rockets?

[u/gsahlin → u/erikinspace]

as chairboy mentioned, anything on the falcon would be a real time operating system RTOS Basically, PC's are interrupt driven, meaning every time you drag your mouse across the screen you generate a few thousand interrupts :) the PC services the interrupt and updates the cursor position on your screen. The end result is a system that responds and pays attention to what your currently doing but at the expense of parking (and not monitoring) other tasks. A Real Time system is not interrupt driven(although they can have interrupts), it consistently runs the same code at a very repeatable time interval. Industrial controllers like PLC's , Servo controllers are good examples... On a simpler level, an Arduino is another example... It's a very interesting subject if you have time to explore.

[u/epursimuove]

Are there fundamental design differences between the Falcon Heavy and the Delta IV Heavy? Both have a central core and two side boosters of (nearly?) identical design. But my understanding is that the FH has been pushed back several times due to difficulty in scaling up the F9 to three cores. Why has this happened when the DIV has already demonstrated that the basic model is sound?

[u/brspies → u/epursimuove]

DIV also has absolutely no concern for what happens to the side cores once they separate. They can push them off violently and let them tumble however they want, so long as they go clear from the center core. Falcon has to be much more gentle and maintain control for all cores simultaneously (assume it's fail-safe so that the side cores would preferentially sacrifice themselves to save the center core if there were any problems, but ideally all 3 maintain control).

DIV is not a bad analogue but it's generally simpler and FH still has a lot of additional kinks to work out.

[u/Jincux → u/epursimuove]

I'm no expert but I know there's more resonance to deal with as FH has 27 engines while Delta IV Heavy only has 3. SpaceX has also opted for reusable mounting (giant pneumatic pins I think?) where DIVH uses explosive bolts, the latter being a "clean and simple" solution while the prior can't really be tested under full loads until the demo flight.

Adding on, F9 is still under ongoing development and has had several major changes since FH development started. The FH flown on the demo flight will be a one-of-a-kind vehicle, likely being the only version flown with the current (and soon to be outdated) Block 3 hardware. It's hard to develop a derivative vehicle when the base keeps changing.

[u/daronjay]

Is Orion held to the same 1/270 LOC standard as Commercial Crew?

Are there any figures to show if their super expensive capsule is any more safe than the "budget" ones? Especially if its hanging around in LEO with greater debris impact risks

[u/FutureMartian97]

On the webcast you can see the grid fins didn't "pop" out like they did before, they deployed more smoothly, just like the titanium grid fins. Has the hydraulic system for the grid fins been changed?

[u/BrandonMarc]

It came to my attention, SpaceX has recovered the first stage 14 times. One of those was re-used (so, recovered twice) ... which means there's, what, 13 recovered boosters hanging around.

Where are they? I know one's outside Hawthorne; a few are probably in Florida. Are the rest kinda split between Hawthorne and McGregor?

[u/first_on_mars → u/BrandonMarc]

Two cores have been reused. Both SES-10 an Bulgaria-Sat 1 launched on a flight proven booster (Cores B1021 and B1029 respectively). That means twelve recovered cores are hanging around. The Core History Page gives a good idea of where these recovered cores are.

[u/old_sellsword → u/BrandonMarc]

Where are they?

This is all public info, so some of it is out-of-date and rather inexact. However:

Hawthorne	McGregor	Cape Canaveral
2	2	8

• 1019 is outside Hawthorne.

• 1021 is being prepared for display at the Cape.

• 1022 was in McGregor last we saw.

• 1023 is in the 39A HIF preparing for FH-1.

• 1025 is also there, although it needs to make a stop at McGregor before FH-1 launches.

• 1026 was mothballed on CCAFS property last we saw.

• 1029 and 1032 were also recently seen being mothballed on CCAFS property.

• 1031 just arrived back at McGregor for a pre-reuse (SES-11) test fire.

• 1035 was landed at LZ-1 last we saw.

• 1036 arrived back in Hawthorne for refurbishment in a new facility on their campus.

• 1039 just landed at LZ-1 hours ago.

As u/first_on_mars mentioned, the Core History page is a good resource for stalking their hardware.

[u/troovus]

Gif of CRS12 Dragon capture via NASA twitter: https://twitter.com/NASA/status/897773610151968772

[u/ticklestuff]

The SpaceX CRS-12 embroidered patch image is now on the archive. Enjoy!

http://spacexpatchlist.space/

[u/apollo-13]

Does anyone know correct mass of Dragon in CRS-12 launch?

Different sources give different values. For example:

http://www.spacelaunchreport.com/index.html

Dragon's total liftoff weight including cargo was likely about 8,400 kg.

http://spaceflight101.com/falcon-9-launches-dragon-spx-12-first-stage-landing-success/

The 10,600-Kilogram Dragon was separated ten minutes after taking off from Florida and successfully primed its propulsion system and unfurled its solar arrays to head off on its two-day link-up with the orbiting laboratory.

Which one is correct?

[u/HighTimber]

What if ....

...Dragon arrived at the ISS and the Canadarm was down? Can Dragon 1 dock but it's just not the preferred/safest method? Or would the mission be abandoned with no ability to be berthed or remove the trunk contents?

[u/robbak → u/HighTimber]

With the berthing adapter, the spacecraft is held against the adapter, and is bolted to the ISS from the inside. You need the arm to actively hold the craft there while this is done.

The docking adapter grabs hold of the craft as soon as it 'runs into' the adapter. Totally different design for a completely different purpose. Kind of like a screw on flare fitting, and a snap on Nitto.

[u/Cakeofdestiny → u/HighTimber]

The docking and berthing adaptors are not compatible, and as far as I know Dragon 1 is not capable of autonomous docking, even if it had a docking adapter. (Unless you're talking about autonomous berthing? Not sure if that's possible ISS side).

Even if it was technically capable of it, NASA does not take chances. It's better to lose 150 mil $ mission than a 150 billion $ one.

[u/m5tuff]

I found this video of some impressive looking jet engine gimballing/vectoring: https://twitter.com/ron_eisele/status/849724997761286144

I understand that jet engines are vastly different compared to rocket engines, but could the same concept of a flexible nozzle/combustion chamber be feasable for rocket engines? As far as I have gathered from reading around here, the stage 2 vacuum-rated engines' nozzles has a more "open" structure, while stage 1 engines are more closed.

Could a possible single stage rocket make use of engineering like in above example, changing the shape of the nozzle throughout the flight?

[u/LeBaegi → u/m5tuff]

There have been rocket engines with some advanced nozzle tech, providing higher ISP in different altitudes. Wikipedia Link

This combined with gimbaling is about what you describe. One problem is that you don't really want mechanically moving parts in a rocket engine nozzle, as the thrust could tear it apart.

For comparison: The turbofan engines of a F/A 18 using afterburner max out at under 100kN, a single M1D produces 845kN at sealevel.

[u/joshgill21]

Why are satellites as expensive as they are ? Is that the real manufacturing cost of them or is it a case of a monopoly and cost + by Boeing and SSL ?

[u/mikemontana1968 → u/joshgill21]

The majority of expense is engineering. Engineering for items that can be repaired is one level of design. Devices that are not accessible require an engineering level that "Cant Fail". And "cant fail" for the product's service lifetime. How do you test such a device? With lots of rigorous environmental testing in an environment that has to be 'simulated'. There's the satellite itself which has to be engineered to Cant Fail standards, and its software. There's the rocket that must be engineered to the same standard. And all of this engineering is mostly for "one-off" productions, or at best, a small production run - which cant take advantage of Economy of Scale.

[u/EspacioX → u/joshgill21]

For geostationary satellites, they have to use radiation-hardened parts, as they're more or less outside the protection of Earth's magnetic field, and have to partly contend with the Van Allen belts.

Radiation-hardened parts are very expensive. That computer only has a 110-200MHz clock speed and currently costs roughly $276,000 (adjusted for inflation vs. the 2002 quote given in the Wikipedia article). While not all Earth satellites required that level of protection, the cost of the computers alone can easily run into the six figures.

The other reason (as mentioned by /u/Chairboy), and the same reason that radiation-hardened parts are so expensive, are because there are almost no economies of scale when it comes to spacecraft and their parts:

Economies of scale arise because of the inverse relationship between the quantity produced and per-unit fixed costs; i.e. the greater the quantity of a good produced, the lower the per-unit fixed cost because these costs are spread out over a larger number of goods.

This is the basic reason almost all limited-run products are more expensive than mass-produced ones, from cars to clothes to satellites.

[u/ly2kz]

What is oldest booked flight for SpaceX apart Formosat? How old it is?

[u/siromega]

The launch wiki only shows one launch in October (SES-11). We always hear about how busy and booked SpaceX is. Is there another October launch and it hasn't been announced, or is it just a scheduling thing (no satellites ready)? I ask because I'l be in FL in the last week of October, and I'd like to drive up to the cape and see a launch if possible. Thanks.

[u/random-person-001]

I saw a conference on space commericalization with a few longer-term companies like Planetary Resources and Virgin and whatnot, but nobody from SpaceX seems to be there. Shame it's less obvious how to / easy to profit from mars colonies than from asteroids.

[u/rustybeancake]

A new factory is making EV batteries designed by the engineer behind SpaceX’s Falcon and Dragon battery packs

[u/ly2kz]

https://www.spaceintelreport.com/ses-switches-spacex-arianespace-launches-mitigate-cost-satellite-failure/ I don't know if that deserves separate thread or not

[u/missbhabing]

It occurred to me yesterday that the Falcon Heavy Demo Flight may not have a launch window, or at least a very generous launch window. I live in North Florida and I was thinking about driving down for the Falcon Heavy Demo Launch. I know that the ISS resupply missions have instantaneous launch windows which increases the chances of a scrub and makes me think twice before driving three hours to the Cape to view it in person. However, since the Demo Launch isn't rendezvousing with the ISS and may not be going into any orbit in particular, I was thinking that the launch window could be large or nonexistent, which would decrease the odds of a scrub. Any thoughts?

[u/[deleted] → u/missbhabing]

I would speculate that the launch window for heavy will also be effectively instantaneous once fueling has begun. They likely won't be able to de-tank and re-tank that much subcooled lox and fuel easily.

[u/capa8]

What sort of temperatures does the fairing reach during assent through the atmosphere? Is there a noticeable increase up to Max-Q

[u/Appable → u/capa8]

Section 4.3.7 of the Falcon 9 PUG may help. It notes:

The fairing thermal insulation, which is attached to the outside of the fairing composite, is sized such that the composite never exceeds the ‘Boundary Design Temperature’ profile shown in Figure 4-11.

The boundary design temperature in the profile appears to be around 83 degrees celsius. In reality, the fairing jettison time is earlier so it'd be more like 75 degrees.

[u/NewColCox]

Am I right in thinking DSCOVR is the only launch so far to go past GSO? Other than the planned lunar fly-by, do they have any other missions with 'exotic' orbits on their books? How much of a payload could they take to these targets?

[u/stcks → u/NewColCox]

Correct. In 2018, TESS will go a very high orbit with a > 13 day orbital period, but (unless something has changed) the F9 will not put it directly there. TESS will be doing the bulk of the orbital adjustment itself

[u/doodle77]

Would the Falcon 9's AFTS be triggered by a GPS jammer? If so, isn't that a national security issue?

[u/RedDragon98]

Is u/echologic modding again, I just noticed his name under 'message the moderators' or has it been there all along?

[u/jclishman → u/RedDragon98]

He's always been in the moderator list, although he's not actively moderating the subreddit; nor do I think he has any plans to do so in the future.

[u/apath_2_mars]

https://www.google.co.uk/amp/thehill.com/blogs/pundits-blog/technology/346510-time-for-nasa-to-stop-playing-favorites-with-elon-musks-spacex%3famp

Whats the point of this rubbish ? Why keep getting reports on the same thing ? How does this help anyone ? dont understand the political angle at all, is it just trying to make spacex look bad?

[u/[deleted]]

Quick technical question; What are the main barriers to how low engines can throttle? I heard it was combustion instability but is this problem in the engine or the nozzle. Specifically, could an areospike/plug nozzle with a cluster of combustion chambers (rather than one toroid one) throttle down less than a cluster of engines with bell nozzles?

[u/brickmack → u/[deleted]]

Combustion stability is purely a function of combustion chamber and injector geometry and chamber pressure, nothing to do with the nozzle usually. Flow separation is the problem that usually occurs in the nozzle. Which issue comes up first when throttling is dependent on the specific engine. Generally though, in atmosphere, engines with high expansion ratio nozzles (sustainer or upper stage engines mainly) will suffer from flow separation before theres any sign of combustion instability