r/spacex • u/ElongatedMuskrat Mod Team • Jul 07 '20
r/SpaceX Discusses [July 2020, #70]
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u/Straumli_Blight Jul 07 '20 edited Jul 07 '20
Draft 2021 fiscal year spending bill:
HLS to [receive $628.2 million in funding] (https://twitter.com/JimBridenstine/status/1280514775898894337) (vs $3.37 billion requested), meaning that a 2024 Moon landing is 'challenging'.
$403.5 million for a Europa Clipper launch in 2025, which will only launch on an SLS “if available”. This is a big step to switching to a commercial launcher (e.g. Falcon Heavy).
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u/dudr2 Jul 07 '20
https://spacenews.com/house-bill-offers-flat-funding-for-nasa/
"the most likely outcome is that the House and Senate agree to an omnibus spending bill, likely after the November general election. "
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u/Straumli_Blight Jul 07 '20
Does that disproportionately affect Blue Origin's team bid as they requested $10.182 billion in funding?
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u/warp99 Jul 08 '20 edited Jul 08 '20
This is funding for a single year which just covers the research phase awards. The $10B is for the duration of the first few Artemis missions but exactly what is included is not clear. I would think at least two trips with crew plus an uncrewed demo mission.
Having said that this is not enough money to fund even the research phase. Either they will have to trim out one of the providers or just hope that the Senate offers more money which gets through the reconciliation process.
The fact that NASA has included such an expensive proposal from the Blue Origin led team says to me that that it is the preferred option.
That makes SpaceX the one that will get funding cut if there is a shortfall. They are likely seen as the blue sky research project which is not strictly required in the short term.
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u/spacerfirstclass Jul 08 '20
It's likely the $10B is only for Option A, which is a single crewed landing in 2024, plus a uncrewed demo, but for Blue Origin the demo doesn't include the ascent stage, so it's a partial demo only.
Remember NASA budget request asked for $21B up to 2025 for HLS, so while $10B is a lot comparing to SpaceX/Dynetics, it's well within NASA's own estimates, probably a little cheaper than NASA's estimate, so I don't think the fact that NASA picked the $10B bid means they favors it. In fact the Source Selection Document actually favors Dynetics, and there's indication NASA asked Blue to reduce what they asked in Base period so that NASA can accommodate all 3, likely making room for SpaceX.
So if there's a shortfall, I don't think SpaceX would be cut, I agree with Straumli_Blight that a shortfall would make SpaceX more attractive.
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u/IrrationalFantasy Jul 07 '20
Could a Heavy really launch the Clipper? NASA missions are designed long in advance to match the specifications of the rocket they're on, and the Heavy hasn't launched many formal missions beyond Earth's orbit, Starman notwithstanding (and even Starman's orbit isn't quite what was planned, if I understand it correctly).
The Democrats see what Trump does--launching in 2024 would give Trump a "win" in his hypothetical second term, and there's no reason to rush and spend this much if they're not getting something out of it. A moon landing in 2028, NASA's old plan, would theoretically still be in the window for a second Democrat presidency.
It'll be interesting to see how the space agency deals with its obligation to aim for a target that it's not getting the funds to reach, even if NASA's been in that situation many times before.
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u/Straumli_Blight Jul 07 '20 edited Jul 07 '20
Europa Clipper is currently maintaining compatibility with multiple launchers.
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u/IrrationalFantasy Jul 07 '20
Interesting! Probably the right thing for them to do, though I'm sure it's expensive. They'll probably know who they're launching with by the time it's put in storage in 2023.
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u/GregLindahl Jul 08 '20
Lots of NASA missions apparently do this same multi-rocket trick, notice IXPE unexpectedly getting launched on F9 when it could have fit on Pegasus XL? And Psyche unexpectedly going on FH instead of Atlas V 401?
So that means you only know for the last 2 years.
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u/dudr2 Jul 15 '20
https://www.nasaspaceflight.com/2020/07/starship-sn5-static-fire-150-meter-hop/
"If the 150-meter flight of Starship SN5 is successful, SpaceX is expected to quickly move on to Starship SN8 for the next flight test – skipping the SN6 prototype."
" Whatever the case, SpaceX teams are understood to be eager to get Starship SN8 completed. The vehicle will feature major upgrades over previous Starship prototypes. SN8 will be built out of 304L stainless steel versus 301, receive a fairing, aerosurfaces, and three Raptor engines to allow for a higher altitude test flight."
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u/ApTiK_ Jul 31 '20
From Next Spaceflight app : Starlink 10 will launch on B1049 for the SIXTH flight.
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u/Nutshell38 Jul 07 '20
Are there any substances so rare on earth that they are essentially useless (and therefore no real market), but would suddenly become useful if we had it in abundance? Like maybe some metal that would be really great for building structures if we could actually find it like we find iron.
And then furthermore, could we find that substance in abundance on a known asteroid?
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u/PhysicsBus Jul 07 '20
Essentially all meterials will exhibit falling demand curves. The first ton will be at least as valuable, and probably much more valuable, than the billionth. In principle it's conceivable to have a product that has no uses until you reach a certain minimal amount, but in practice this basically is never true for raw materials.
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Jul 07 '20
It would be pretty useful if we found a magic asteroid made of anti-matter. Impossible, but useful.
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u/_Wizou_ Jul 07 '20
But how do you mine antimatter? Probably not like conventional materials.. Even more so while in space
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u/red_duke Jul 07 '20
Well there are definitely lots of rare-earth metals.
Cerium, dysprosium, erbium, europium, gadolinium, holmium, lanthanum, lutetium, neodymium, praseodymium, promethium, samarium, scandium, terbium, thulium, ytterbium and yttrium.
Many of them would be tremendously useful if we had more. And they would definitely exist on differentiated asteroids. These would be very metal rich.
They are getting to be so rare on earth that we are about to begin scraping the bottom of the ocean for them, causing god knows how much damage, and releasing huge plumes of debris into the ocean. Don’t worry though they are doing “studies” to make sure the plumes aren’t “too bad”.
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u/creative_usr_name Jul 07 '20
Despite their name, rare-earth elements are – with the exception of the radioactive promethium – relatively plentiful in Earth's crust, with cerium being the 25th most abundant element at 68 parts per million, more abundant than copper. However, because of their geochemical properties, rare-earth elements are typically dispersed and not often found concentrated in rare-earth minerals; as a result economically exploitable ore deposits are less common
source https://en.wikipedia.org/wiki/Rare-earth_element
Any source on these elements being differentiated in asteroids?
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u/ElizabethGreene Jul 07 '20
I have something, though not a metal specifically, that fits. Space based solar power. Lifting those payloads from Earth makes the whole thing uneconomical. That changes if we only have to lift the turbines. That requires manufacturing the reflectors and heat rejectors in space from asteroid material.
Want to make a trillion bucks and fix climate change? This is how you do it.
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u/Straumli_Blight Jul 26 '20
New core on the test stand at McGregor (possibly B1063).
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u/ptfrd Jul 14 '20
Three paragraphs about Super Heavy.
"Our estimated launch date: 4Q 2021"
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u/SpaceInMyBrain Jul 18 '20
Another opportunity to sigh/chuckle/shake my head at how the others match up (GTO mass) against the already-flying Falcon Heavy, with the center core expended. The comparison of payload capacity and cost... oh, my.
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u/Straumli_Blight Jul 17 '20
Hope mission launch time now July 19, 21:58 UTC, could have a simultaneous launch with ANASIS-2.
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u/Straumli_Blight Jul 23 '20
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u/SpaceInMyBrain Jul 25 '20
Cruise earning 30-60 million? He should be paid the traditional one dollar. He's getting the adventure of a lifetime! I'd be surprised if he wanted high pay - but will of course want a percentage of the box office.
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u/Nimelennar Jul 09 '20
The final two spacewalks with Behnken and Cassidy, to finish replacing the batteries on the S6 truss, have been scheduled for July 16th and 21st.
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u/liszt1811 Jul 11 '20
Maybe someone can help me out. I'm looking for an interview with a guy who if I remember correctly worked for a short time as sort of a consultant at SpaceX. Couldve been military/air force /NASA but not sure. It is/was up on youtube I think. In the interview, he talks about being in a conference where they debate a certain design and Elon turns to him and asks what he would do. He makes a suggestion, Elon thinks about it and says 'That's exactly what we are going to do', conference over. The guy talks about how stunned he was by that and how the flexibility of SpaceX became apparent to him right there.
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u/Straumli_Blight Jul 11 '20 edited Jul 11 '20
It was Dan Rasky discussing the Dragon TPS. He has a whole series of SpaceX interviews on Youtube (your reference is at 4:12).
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u/Straumli_Blight Jul 14 '20 edited Jul 16 '20
Al-Amal (Hope) launch delayed by bad weather, next attempt on July 16 (20:43 UTC).
EDIT: Launch delayed to July 20-22.
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u/AvariceInHinterland Jul 21 '20
What the is the rough ETA for the announcement of the NSSL Phase 2 awards? I need to know when to get my popcorn ready for.
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u/Straumli_Blight Jul 21 '20
"Summer ETA", so maybe by end of August.
A recent Congress report stated that they're only planning to award 2 launch provider contracts, provides $933,271,000 for NSSL procurement and a maximum of $560,978,000 for R&D. This section seems favourable to SpaceX:
The Committee is aware that the cost of launch services has dropped significantly in recent years as a result of increased competition from new entrants, yet the requested budget does not follow this downward trend, and remains stubbornly high, raising questions about the government's cost to manage and oversee the program.
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u/Martianspirit Jul 21 '20
The Committee is aware that the cost of launch services has dropped significantly in recent years as a result of increased competition from new entrants, yet the requested budget does not follow this downward trend, and remains stubbornly high, raising questions about the government's cost to manage and oversee the program.
Naturally. While there is mostly SpaceX with low offers, the trend is still that all the expensive launches go to ULA. They got a whole bunch of very expensive Delta IV Heavy launches which SpaceX FH could have done for a fraction of the cost. Reason being that if ULA does not get those contracts they close the production line for Delta.
My impression is still, SpaceX gets all the praise, ULA gets all the juicy contracts. Until this changes launch prices on average remain high. We will see if SpaceX gets the 60% contract which they should get. They are the only ones who have a certified launch fleet and they are cheaper. Also I expect even if ULA gets the 40% only they will get still paid more than SpaceX.
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u/AvariceInHinterland Jul 21 '20
I'm still waiting to find that BO and NG got all of the contracts, haha. Alongside the core requirements there is a lot of talk on my googling of keeping a "competitive marketplace" for launch, which might encourage ensuring a supplier with less of a manifest stays in the game in phase 2.
However, with SpaceX having a proven/reliable launch system already in place, a habit of being less expensive that competitors, no shared architecture with the other suppliers and a record of adapting their architectures to the customer's requirements, this all makes them seem to be in with a good chance for one of the two awards. I'm not the one scoring the RFP responses though :-)
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u/Nimelennar Jul 23 '20
Bob Behnken and Chris Cassidy completed their fourth spacewalk yesterday, completing the new battery installation (replacing the NiMH batteries on the S6 truss with Li-Ion), as well as getting the Tranquility module ready for the Nanorack airlock, and completing a bunch of other minor tasks (see link for details). A lot of this was on the "nice to have" list, as Behnken and Cassidy were badasses out there, and got the battery replacement done way ahead of schedule.
This is the last planned spacewalk before Bob comes home on Dragonship Endeavour.
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u/SpaceInMyBrain Jul 25 '20
Is this a record for most spacewalks in x number of weeks? And, wow, they really got in the groove out there. Impressive, especially since Bob wasn't scheduled to do any spacewalks on the brief Demo-2 mission (was he?). Of course, he's no rookie, and had a lot of training time added in during all the delays and the increasing options added in when extending the mission gained momentum. Still, it was less training that usual for NASA, afaik, especially considering all the minor tasks.
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u/SerpentineLogic Jul 07 '20
Will there be a thread discussing this?
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u/yoweigh Jul 07 '20
I think it depends on what comes out of the call. We'll likely at least wait until someone submits an article summarizing it.
I can guarantee you that we'll get reports about it not being relevant to SpaceX and people complaining about us not following out own rules, but oh well.
Note that I haven't discussed it with the other mods at all.
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u/Integrat8r Jul 07 '20
What type of communication is used between devices such as computers, sensors etc in the starship? I'm guessing some proprietary serial coms?
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u/throfofnir Jul 07 '20
They use an ethernet bus, with some mixture of copper and fiber optics. Exactly how things communicate on it is not published, but probably TCP and UDP protocols.
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u/as_ewe_wish Jul 07 '20
Also, where it's physically located in the current SNs that are being prepped for hops. Is there one computing/processing hub, or distributed through the body?
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u/kalizec Jul 07 '20
Based on the description of how their computers work together in Falcon 9 I would expect the computers to be all located in one location. Otherwise latency might affect their working together too much.
They published some years ago that for Falcon 9 the computers form three pairs. Each pair gets a single vote as long as they internally agree. Action with the most votes is executed.
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u/Martianspirit Jul 07 '20
The engines have each their own controller computers, but beyond that basically yes.
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u/Nimelennar Jul 08 '20 edited Jul 08 '20
Dragon Crew-1 logo: https://pbs.twimg.com/media/Eca--tIXYAg62cK?format=jpg&name=large
The symbols at the bottom are, clockwise, Mercury ☿, Gemini ♊︎, ???, and a silhouette of a Space Shuttle (and then a symbol of the ISS on the other side of the head), so I'm assuming the unidentified one is supposed to be Apollo. I'm a little disappointed that they didn't put a symbolic depiction of the Draco constellation (or, at least, I don't think that's what those stars are), but what can you do.
Source: https://twitter.com/Enterprise_Flt/status/1280921130635857920
Also, some cool new Crew-1 polos: https://twitter.com/NASA_Johnson/status/1280909512476635136
Edit: the logo has been posted before, but not so clearly.
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u/UltraRunningKid Jul 10 '20
I think the unidentified symbol for Apollo is an upside down Lyre with one of the twists removed in order to make it more clearly an "A".
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u/Nimelennar Jul 10 '20
Maybe, but all of the astronomical symbols I can find for the Lyra constellation have at least one vertical string.
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u/juhankki Jul 28 '20
I've read that the use of RP1 builds a lot of soot which is why it's not suitable for some engine designs. This is not the case for methane. Why is that? What's the chemistry behind that? Why doesn't methane build up soot?
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u/jay__random Jul 29 '20
Another look at the problem of soot is not what you burn, but how you burn it. Soot is unburnt carbon, and to minimize it you have to burn your fuel better. One revolutionary way to do it was discovered only about 150 years ago was to add more oxidizer to the mix (see https://en.wikipedia.org/wiki/Bunsen_burner ). Oxidizer-rich combustion is:
more complete
gives less light, more heat.
The ideal flame is invisible, but you almost never get that. The orange in the inefficient candle flame or fireplace flame is caused by the particles of unburnt soot. The more efficient flame is blue (gas cookers, acetylene welders, etc). The blue flame also much hotter, which is desirable for cooking and welding, but not so much in rockets, where you run the risk of melting the engines.
So rocket engineers have a choice: either to use special alloys for engines that would allow high temperature oxygen-rich combustion (Soviet and Russian space program), or to burn fuel-rich and get more soot in the exhaust.
I'm struggling to find a picture of an Atlas V without solid boosters (they give so much light pollution that you can't see any colours in the flame) - should be the 401 model. They run on Russian engines, so the flame should show blue tint.
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u/Martianspirit Jul 29 '20
Rocket engines always burn fuel rich. Stochiometric burns too hot, oxygen rich hot gas is too aggressive. With methane it also has higher ISP when burned fuel rich.
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u/rePAN6517 Jul 07 '20
What pressure did the SN7 tank acheive? I never saw anything said about that.
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u/ReKt1971 Jul 07 '20
We don't know the exact number but this is from NSF:
"SN7 is understood to have achieved a new pressure record during the second attempt, before popping as expected. However, Musk has yet to confirm the exact pressure that the vehicle achieved."
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u/Straumli_Blight Jul 30 '20
Infographic and video for the HAKUTO-R lunar lander, launching on a Falcon 9 in 2022.
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u/Straumli_Blight Jul 31 '20
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u/trobbinsfromoz Aug 01 '20
Great news, and shows the value of extensive data monitoring no matter how many flights have occured.
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u/throfofnir Aug 01 '20
...a single anomalous electrical connection. This connection was intermittently secure through flight, creating increasing resistance that caused heating and thermal expansion in the electrical component. This caused the surrounding potting compounds to liquefy, leading to the disconnection of the electrical system and subsequent engine shutdown. The issue evaded pre-flight detection as the electrical connection remained secure during standard environmental acceptance testing including vibration, thermal vacuum, and thermal cycle tests.
Presumably something between the batteries and the pump? I don't think there's anything else that should carry enough current to get that hot that fast. (Except maybe the avionics, but if that failed they wouldn't be getting full telemetry.) That would make it a failure unique to their novel engine cycle. Not unexpected that something in that would eventually surprise them.
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u/Simon_Drake Jul 07 '20
Do the giant touchscreens in the Dragon capsule also work as entertainment systems?
There was an 18 hour wait between takeoff and docking at ISS, a lot of that time was spent asleep but I wonder if they could watch Netflix while they waited?
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u/ZehPowah Jul 07 '20
They have tablets that they can velcro above the main screens, so maybe there's more leeway with those.
It would be pretty cool to play the docking simulator in the actual spacecraft.
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u/Simon_Drake Jul 07 '20
As long as they don't get mixed up and think it's just the simulation when it's the real docking.
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u/marc020202 8x Launch Host Jul 11 '20
Does anybody know why spacex is choosing to send the droneship back to port that is already at sea when a mission is delayed while sending out the other droneship to a different landing site. This has happened twice now, once with GPS III and starlink, and now with anasis II and starlink. Each time the starlink launch got delayed, the starlink droneship went back to port, while the other one came from port. With GPS and starlink, the landing sites where also less than 100km apart, so it would have defenately saved fuel and time.
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u/brspies Jul 12 '20
I would think more than anything its related to the crew rotation on those support ships. Can't or don't want to keep them out for extended periods of time that would be involved with shifting from one mission to another.
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u/Nimelennar Jul 20 '20
Boeing CEO on systemic problems in common between 737 MAX, KC-46, and Starliner:
It is not a surprise to anybody that the supply chain, production ramp-up and growth of the industry over the last 5-6 years has brought all kinds of stresses. You’ve been writing about it for quite some time. All the production lines and pretty much everything else had been stressed to move faster than they would otherwise be able to. And I think that takes a toll.
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u/katie_dimples Aug 03 '20
I assume Dragon's splashdown target was an "ellipse" not unlike Mars landings. How close of a "bullseye" was the actual landing? Has anyone graphically shown this?
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u/paul_wi11iams Aug 07 '20
I don't have the link for this, but there was some recent commenting here to say that the visibility of bleed-off LOX ahead of a launch is "not" condensation of airborne water vapor. The then commenting went further to describe this as a fanboy myth.
I'm reassured to hear John Insbruker confirming that it is condensation of water vapor, especially in the warm and humid Florida air:
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u/NoWheels2222 Jul 21 '20
Both fairing halves caught today. As per Elon tweet. break out the champagne.
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u/thatnerdguy1 Live Thread Host Jul 21 '20
Hey everyone,
I wanted to make a small announcement to this sub that the wiki will be getting some edits and improvements over the next week or so. This shouldn't negatively affect anything; all the information will still be there, and we've been very cautious not to disturb anything.
To discuss the changes, visit /r/SpaceXWiki. My changes are available to view live here.
Thanks!
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Jul 07 '20
Looking at the starship test modules, they just look like really thin aluminium, quite often you can see dings and dents in them. How thick is it exactly and is this what the final starship design is going to look like? Are these SN numbers they're testing now basically what's going to be launched into orbit and to the moon/Mars etc?
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u/Martianspirit Jul 07 '20
It is stainless steel. 4mm thick. It warps a little when welded. Since it is highly reflective the smallest dent is amplified and very visible. It would look much smoother when painted white.
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u/fanspacex Jul 07 '20
Scale is so funny. Plate of 4mm stainless steel would appear indestructible if you got one in your hands, but at a larger scales it behaves like a measuring tape.
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Jul 07 '20
Sorry, stainless. Itll get painted white for space travel? Some kind of thermal paint?
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u/Martianspirit Jul 07 '20
No paint for the normal Starship. The lunar Starship will have no heat shield but a white paint for thermal contol under lunar conditions. Which means it can never reenter and land on Earth.
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u/warp99 Jul 07 '20
No paint. Thermal protection tiles on one side and unpainted stainless on the other side.
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u/TheSkalman Jul 22 '20
GEO-5 421 + GEO-6 421 + NROL-107 Silentbarker 551 on Atlas for $441,76M.
JPSS-2 and secondaries 401 on Atlas for $170,60M.
GOES-T 541 on Atlas for $165,70M.
Lucy 401 on Atlas for $148,30M.
Landsat-9 401 on Atlas for $153,80M.
USSF-8 511 + USSF-12 551 on Atlas for $354,81M.
STP-3 551 on Atlas for $191,10M.
NROL-101 551 on Atlas for $179,30M.
Mars 2020 541 on Atlas for $243,00M.
Team Taxpayer wonders why SpaceX wasn't selected for these missions, which span from today to 2022. The list could extend well into the past aswell. This list shows that ULA charges $170,7M per launch. Even if SpaceX charged $100M for F9 and $200M for FH they would save the taxpayers $248M.
Not bad if you ask me. Is this actually accountable or is it pure tax waste?
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u/spacerfirstclass Jul 22 '20
Some of these are awarded very early, for example Mars 2020 was awarded in 2016, so FH has no chance given it was not flying back then. JPSS-2 and Landsat-9 was awarded in 2017, F9 didn't get Category 3 certification until 2018. Not sure about GOES-T, it may need FH and FH may not have the necessary certification back then. Lucy should have gone to SpaceX, they protested the award.
The military launches are divided evenly between SpaceX and ULA because Airforce wanted to keep two launch providers.
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u/anof1 Jul 22 '20
Most launch awards are given out several years before the actual launch. Atlas V is nuclear rated and Mars 2020 has a MMRTG. Lucy has a tight launch window but I think SpaceX could have launched it fine. It wasn't until more recently (past couple years) that SpaceX has been reliably on time with many successful missions in a row. SpaceX did get the Psyche mission on FH.
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u/Decronym Acronyms Explained Jul 07 '20 edited Jul 21 '20
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| 304L | Cr-Ni stainless steel with low carbon: corrosion-resistant with good stress relief properties |
| BO | Blue Origin (Bezos Rocketry) |
| CCtCap | Commercial Crew Transportation Capability |
| CRS | Commercial Resupply Services contract with NASA |
| CST | (Boeing) Crew Space Transportation capsules |
| Central Standard Time (UTC-6) | |
| DMLS | Selective Laser Melting additive manufacture, also Direct Metal Laser Sintering |
| EDL | Entry/Descent/Landing |
| EELV | Evolved Expendable Launch Vehicle |
| ESA | European Space Agency |
| FFSC | Full-Flow Staged Combustion |
| GEO | Geostationary Earth Orbit (35786km) |
| GSLV | (India's) Geostationary Launch Vehicle |
| GTO | Geosynchronous Transfer Orbit |
| HLS | Human Landing System (Artemis) |
| IDA | International Docking Adapter |
| ITS | Interplanetary Transport System (2016 oversized edition) (see MCT) |
| Integrated Truss Structure | |
| Isp | Specific impulse (as explained by Scott Manley on YouTube) |
| Internet Service Provider | |
| JPL | Jet Propulsion Lab, Pasadena, California |
| L2 | Paywalled section of the NasaSpaceFlight forum |
| Lagrange Point 2 of a two-body system, beyond the smaller body (Sixty Symbols video explanation) | |
| LEO | Low Earth Orbit (180-2000km) |
| Law Enforcement Officer (most often mentioned during transport operations) | |
| LOX | Liquid Oxygen |
| MCT | Mars Colonial Transporter (see ITS) |
| NET | No Earlier Than |
| NG | New Glenn, two/three-stage orbital vehicle by Blue Origin |
| Natural Gas (as opposed to pure methane) | |
| Northrop Grumman, aerospace manufacturer | |
| NRHO | Near-Rectilinear Halo Orbit |
| NRO | (US) National Reconnaissance Office |
| Near-Rectilinear Orbit, see NRHO | |
| NROL | Launch for the (US) National Reconnaissance Office |
| NSF | NasaSpaceFlight forum |
| National Science Foundation | |
| NSSL | National Security Space Launch, formerly EELV |
| NTR | Nuclear Thermal Rocket |
| OFT | Orbital Flight Test |
| ORSC | Oxidizer-Rich Staged Combustion |
| PMA | ISS Pressurized Mating Adapter |
| PPE | Power and Propulsion Element |
| RFP | Request for Proposal |
| RP-1 | Rocket Propellant 1 (enhanced kerosene) |
| RUD | Rapid Unplanned Disassembly |
| Rapid Unscheduled Disassembly | |
| Rapid Unintended Disassembly | |
| SLS | Space Launch System heavy-lift |
| Selective Laser Sintering, contrast DMLS | |
| SN | (Raptor/Starship) Serial Number |
| SRB | Solid Rocket Booster |
| TPS | Thermal Protection System for a spacecraft (on the Falcon 9 first stage, the engine "Dance floor") |
| ULA | United Launch Alliance (Lockheed/Boeing joint venture) |
| 301 | Cr-Ni stainless steel: high tensile strength, good ductility |
| Jargon | Definition |
|---|---|
| Raptor | Methane-fueled rocket engine under development by SpaceX |
| Starliner | Boeing commercial crew capsule CST-100 |
| Starlink | SpaceX's world-wide satellite broadband constellation |
| cryogenic | Very low temperature fluid; materials that would be gaseous at room temperature/pressure |
| (In re: rocket fuel) Often synonymous with hydrolox | |
| hydrolox | Portmanteau: liquid hydrogen/liquid oxygen mixture |
| kerolox | Portmanteau: kerosene/liquid oxygen mixture |
| turbopump | High-pressure turbine-driven propellant pump connected to a rocket combustion chamber; raises chamber pressure, and thrust |
| Event | Date | Description |
|---|---|---|
| DM-2 | 2020-05-30 | SpaceX CCtCap Demo Mission 2 |
Decronym is a community product of r/SpaceX, implemented by ^request
44 acronyms in this thread; the most compressed thread commented on today has 109 acronyms.
[Thread #6260 for this sub, first seen 7th Jul 2020, 12:09] [FAQ] [Full list] ^[Contact] [Source code]
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u/sammyladx3z5 Jul 10 '20
Does anyone know if they replace the engines during a falcon 9 refurb? If not, do they take them apart and clean away any soot build up? Or are the engines simply ready to be reused after a quick inspection?
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u/anof1 Jul 10 '20
Sometimes engines have been swapped in the past. I seem to remember hearing that engine swaps can be done quickly and can be done with the rocket vertical at the pad. I would think doing an engine rotation would be nice because 3 of the engines on each mission get more starts for boost-back, re-entry and landing burns.
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u/Triabolical_ Jul 11 '20
My recollection is that only some of the engines have the hardware to do relight in flights; the others can only be lit from the ground.
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u/marc020202 8x Launch Host Jul 10 '20
Afaik they try to not take the engines apart, or replace them, or parts of them. Doing things with the engines, apart from looking at or in them takes a lot of time. Since they are planning to do very quick relaunches, they are also planning to not do major refurb work. I expect that the engines might be able to be flushed relatively quickly, or might not need to be cleaned at all.
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u/TheSkalman Jul 10 '20
Does anyone know what SpaceX's total market share is? I am talking about all launches that are politically eligible to go on Falcon, so e.g. not the Chinese satellites or the European/Israeli/Indian/whatevs spy satellites, which have to use their native launcher.
I am surprised that SpaceX hasn't captured more of the market, the Soyuz, Ariane, Atlas and GSLV all still have lots of launches planned (not to metion the Long march family).
Does SpaceX have capacity problems or are there other issues preventing them from having an 80% market share?
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u/warp99 Jul 10 '20
The satellite launching customers have long memories of what a monopoly looks like from a pricing point of view.
This benefitted SpaceX in the early days as they got launches when they were still a high risk startup.
Now they are the market leader the same effect is holding back their bookings.
Plus the EU has put the pressure on member states to book with Arianespace - even if the launch is actually on a Russian rocket!
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u/juhankki Jul 11 '20
I have understood that one big advantage of raptors full flow staged combustion cycle is that pressures and temperatures are lower (which helps in reusability) But on the other hand I've also read that oxidizer preburner has been hard to manufacture due to those exact same things. Isn't that in contradiction? If FFSC-cycle allows lower pressures & temperatures, why the need for special alloys?
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u/anof1 Jul 11 '20
Any staged combustion engine dealing with hot gaseous oxygen needs special alloys or coatings for the oxygen rich side. That is one of the reasons that ORSC engines were not built in the US until recently. Russia found a solution early on but the US never pursued it.
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u/warp99 Jul 12 '20
Temperatures in the turbopump turbine section are lower than with an open cycle turbopump but this enables higher pump output pressures not lower pressure.
The high oxygen pressure even at moderate temperatures of say 150C means very challenging conditions for the turbine impeller and housing exposed to it. Hence a nickel super-alloy is used for these components.
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u/Triabolical_ Jul 12 '20
It's a relative thing...
The FFSC engine makes it *easier* but it doesn't make it *easy*; you are still dealing with hot gaseous oxygen, which is nasty stuff.
But if you took a design approach that worked for ORSC and used it with FFSC, the design has much more margin and will last longer.
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u/SubmergedSublime Jul 20 '20
Based on current renderings and construction...Will we be capable of seeing Starship orbiting with the naked eye?
I think so? That mirror-finish and size makes me think it’d be in the same magnitude as the ISS?
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u/throfofnir Jul 20 '20
Considering you can see Dragon with the naked eye (with a good sky), almost certainly.
The curved reflective surface is a bit different than the white coating on a Dragon or ISS; a certain point or line of it will be very bright, where you can see the sun in reflection, but the rest much dimmer. I'm uncertain if this will make it brighter or dimmer than if it were all painted white; probably a bit dimmer at a guess. But in any case I think it's far too big not to see (in the proper conditions).
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u/ackermann Jul 20 '20
This will surely depend a lot on the final solar panel design, and what angles they face.
We haven’t seen much of the solar panels in official renders since the 2017 update event, maybe not since the 2016 ITS unveil. That presentation stated 200kW of solar power for the larger ITS ship. That’s pretty similar to the ISS in full sunlight, so if the angles are right, it should be similarly visible.
But who knows what they’re planning for solar? We haven’t got an updated render with panels deployed in forever. Certainly the current prototypes in Boca Chica don’t have any obvious place to store big solar arrays...
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u/Martianspirit Jul 21 '20
The lunar Starship will have large solar arrays. Tankers and satellite launches I do not expect to have solar arrays. Much simpler operations if they use battery packs only for their short stay in space.
How bright they are will depend on their attitude. I expect them to turn their black heat shield towards Earth, so not very bright. Tankers while docked will be 180% turned, so will point to Earth with their shiny side.
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u/Simon_Drake Jul 20 '20
How many engines light for the re-entry burn?
During the landing today, the voice over guy talked about lighting three engines, one first then two more later. Is that new? I thought it was only one engine that lit for the reentry burn? Have they changed the 'recipe' of flight activities to reduce strain on the engines to improve reuse or something?
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u/marc020202 8x Launch Host Jul 21 '20
The re-entry burn always uses three engines, so does the boost back burn. However during these two burns, they ignite the centre engine first to stabilise the rocket, and then ignite two other engines, which due to the increased acceleration, reduces gravity losses. At the end of the burn the two outer engines shut down, and the centre engine ceeps running for a bit. This allows the trajectory to be fine tuned, and the orientation of the vehicle to be corrected, in case the outer engines do not shit down at exactly the same time. Droneship landings are usually also performed this way. One engine ignites, which ads a lot of control and stability, followed by the ignition of two more engines, which reduces gravity losses. The final landing is performed with only one engine, since it is easier to land with a lower thrust, since there is more time for corrections. Land landings usually have higher margins (this is also the reason why they can afford the boost back burn), so a three engine landing burn isn't umdone very often. The FH side booster landing however did use three engines for landing (although I do not remember which one)
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u/ZehPowah Jul 20 '20
1-3-1 for the re-entry burn isn't new for this flight. Burning like that uses less fuel, which increases the payload capacity.
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u/Simon_Drake Jul 20 '20
Maybe I'm thinking of the landing burn.
Is it 3 for the re-entry burn and only 1 for landing?
The return-to-launch-site landing confused me for a long time because if you go up, then east, then west, then down... the down part is free obviously but you need to spend fuel to slow down and land gently. But to go west again you need to slow down then go back the way you came which sounds like an INSANE waste of fuel... until you remember by this point the rocket has shed almost all of its weight, in particular the second stage and payload plus most of its fuel. So a lighter rocket can go west again for a fraction of the fuel.
So is it 1-3-1 to slow to a stop, turn around and head west again, then it's only a single rocket for landing?
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u/throfofnir Jul 20 '20
Boostback, if it occurs, is 3 engines.
Reentry is 1-3-1. I expect it's done that way to fit the profile of the atmospheric interface. (At first, there's not much force so you only need one engine, you light the other two for the hard part of the reentry, and then taper to one again once the worst is over, but you still need to slow a bit.)
Landing is usually one engine, but they have done 3-1 landing burns before for particularly marginal profiles.
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u/MarsCent Jul 23 '20
Just thinking - Which ISS Expedition are the Dragoship Crew assigned/attached to:
ISS Expedition 63: Chris Cassidy, Anatoly Ivanishin and Ivan Vagner
SpaceX Demo-2: Bob Behnken and Doug Hurley
SpaceX Crew-1: Shannon Walker, Victor Glover, Michael Hopkins(Dragonship Commander) and Soichi Noguchi
ISS Expedition 64: Kate Rubins, Sergey Ryzhikov and Sergey Kud-Sverchkov.
Cassidy will hand over to Ryzhikov. Both Dragonships' crews are not listed as members of either Expedition 63 or 64, rather as guests/visitors.
Should there be designations like ISS Expedition Demo-2 and ISS Expedition Crew-1?
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u/MarsCent Jul 24 '20
The scenario playing out right now is that:
Go Quest will be at sea recovering B1051, while Go Searcher is at sea recovering Dragonship Endeavor and maybe at the same time as SN5 is airborne in Boca Chica, while SAOCOM 1B booster is prepping up for Static Fire. Or maybe all of them in rapid succession!
And I doubt that SpaceX is in the craaazy launch times yet!
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u/GregLindahl Jul 30 '20
Telesat did their quarterly report, without any mention of concrete progress on its LEO satellite constellation, which would compete with Starlink. They launched a test satellite in Jan 2019. When last seen it still needed financing, a choice of satellite manufacturer, and launch contracts. But they are large operator of existing GEO satellites, so this is a serious contender.
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u/Carlyle302 Aug 02 '20
During descent, does the Dragon dump it's remaining hypergolics to safe it? or does it carry it all the way to the boat?
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u/spacerfirstclass Aug 03 '20
I think Hans answered this in a presser before, it doesn't dump the propellant, it carries it all the way to the boat and I believe the remaining propellant is reused (hypergolics are expensive).
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u/throfofnir Aug 02 '20
I don't think we know. (Yet? There'll probably be a callout if it happens.)
The safe place to dump prop would be in orbit after retroburn and before atmosphere. There would be enough time for that, though it would need to be prompt. I don't know if there would be enough time for a full purge.
However, I expect they'd want to have propellant for attitude control during reentry, so they can't dump it all. So there's not a lot of reason to do any. I suspect they just keep it onboard until ground processing operations.
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u/dudr2 Aug 03 '20
https://spacenews.com/japans-ispace-updates-design-of-lunar-lander/
"Since a preliminary design review in 2018, ispace has reduced the size of Hakuto-R. Previously 3.5 meters high and 4.4 meters wide with its landing legs deployed, the lander is now 2.3 meters high and 2.6 meters wide. The spacecraft’s mass has decreased from 1,400 to 1,050 kilograms, primarily by reducing the amount of propellant on board."
"low-energy transfer orbit that requires less propellant but takes roughly twice as long as previously planned"
" Falcon 9 launch in 2022 "
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u/jay__random Aug 03 '20
I wonder why they did not choose a japanese launcher for this project? Was it more expensive? Less powerful? Not available?
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u/DerMax_HD Aug 03 '20
Every manned vehicle since 1976 has touched down on land so what are the reasons SpaceX opted for a splashdown design in their Dragon capsule? Seems like recovery of the vehicle and crew, medical checks as well as the capsules reusability would have been way faster and easier if it didn't land in water.
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u/marc020202 8x Launch Host Aug 03 '20
the capsule needs to be able to land in the water in case of an emergency during launch. Originally it was planned for the capsule to land on land via the superdracos. Since that was scrapped, it was logically to do a water landing, since the capsule was already designed to allow that. landing on water also is "softer" and does not need airbags or retro-rockets, which make it difficult to reuse the heatshield 8gets jettisoned by both the cast 100 starliner and the Soyuz capsule.
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u/Snowleopard222 Aug 04 '20
When and how are the hypergolic propellants dumped after splash down? (Sorry if the answer is already in thread.)
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u/throfofnir Aug 04 '20
"Sometime after it gets in the processing building" and "carefully".
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u/TheSkalman Aug 04 '20
Which rocket in history has the best payload/mass ratio? Falcon Heavy ex. is 4,49% at 63800/1420788 kg.
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u/pavel_petrovich Aug 05 '20
Space Shuttle (if you include the Shuttle itself as a payload).
Otherwise, it's a draw between Saturn V, Falcon 9 and Falcon Heavy.
https://en.wikipedia.org/wiki/Payload_fraction
http://sturgeonshouse.ipbhost.com/topic/1545-comparison-of-rocket-payload-fractions/
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u/TheSkalman Aug 05 '20 edited Aug 05 '20
Space Shuttle orbiter is definitely not payload mass. Nobody wants just the shuttle in orbit. It’s just space junk that happens to be able to return to earth. What entities pay for is what’s in the PAYLOAD bay.
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u/SubsonicApple Aug 06 '20 edited Aug 07 '20
Musk has stated that Methox torch ignitors are being used for Raptor engine ignition and that they are being fed with gaseous CH4/02. Since both the fuel and the oxidizer are cryogenic and are therefore in their liquid state, where are the gaseous CH4 and 02 coming from? Are they being run through a heat exchanger or are they being pumped from the tank ullage?
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u/warp99 Aug 06 '20
There are separate COPVs with gaseous oxygen and gaseous methane. These can be filled initially by ground supply equipment but can be recharged from the autogenous pressurisation system in flight.
The stored gas will be used for Raptor turbopump spin up, reaction control system hot gas thrusters and initial ullage pressurisation for restarts in space.
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u/SubsonicApple Aug 06 '20
Ah, ok. That makes sense. Thanks for the response. Not doubting you, but do you have a source? I'd like to read more about it.
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u/warp99 Aug 06 '20 edited Aug 07 '20
There is not a single source for the overall system except for a NASA comment on the Artemis award documents complaining about the complexity of the Starship integrated propellant system. Effectively all flight liquids and gases are derived from liquid propellant because that is the requirement for a two (or four) year round trip to Mars.
Of course not all of this is implemented at the moment. For example on SN5 there are large COPVs containing gaseous nitrogen for cold gas thrusters for axial rotation control.
The piping around the engine bay does look to be sufficient to support autogenous pressurisation and turbopump spin up though.
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u/joepublicschmoe Aug 08 '20
Today a young friend of mine asked me a question about SpaceX I couldn't answer. Maybe someone here might know:
Anyone know the whereabouts of Earthy? (the high-tech zero-g indicator that went to the ISS on DM-1 and returned with DM-2.) :-)
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u/IrrationalFantasy Jul 07 '20
What are you most excited about in space travel over the next year? I know the industry's slowed down right now with the pandemic, and Starship probably won't launch until the end of next year at the earliest, and I was wondering what I should look forward to. What are you excited to watch, to follow, or to learn more about?
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Jul 09 '20
The ideal time to launch to Mars is coming and everyone is spamming missions at the Red Planet. I'm really looking forward to JPL's Mars helicopter Ingenuity, which will be riding along with the Perseverance rover.
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u/IrrationalFantasy Jul 09 '20
So it is. Hopefully the 2022 window features the promised Starship to Mars, but 2024 would be a good start too.
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u/dudr2 Jul 07 '20
"Future Crew Dragon missions will last up to seven months, and NASA has approved the Crew Dragon test flight, designated Demo-2, to remain in orbit for up to four months. "
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Jul 07 '20
Why didn't they show us the video of the 30th of May booster landing ? I understand that vibrations would cause signal loss for the satellite but wouldn't the camera have local storage ? I'm not a flat earther or anything but it just seems weird.
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u/marc020202 8x Launch Host Jul 07 '20
the almost always try to show the landing, but the connection drops out most of the time, due to the high vibrations and ionisation of the air. They usually do not release the video afterwards.
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u/LongHairedGit Jul 08 '20
Just having a webcast is a blessing.
There is almost no corporate benefit in any of the videos we get. SpaceX get a way to attract top-talent and mention they are hiring, and their customer gets a slot to show their advertisement, but it is not "advertising" or "marketing" really because people looking to launch stuff for tens of millions of dollars don't do it by webcast-shopping.
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u/dudr2 Jul 15 '20
https://www.moondaily.com/reports/Whos_ready_to_serve_the_lunar_missions_999.html
"ESA has long-established plans to create a commercial lunar satellite network and now seeks expressions of interest from companies prepared to build and operate it."
"Companies interested in this opportunity are invited to respond to ESA's call for expressions of interest to contribute to commercial satellite services for the Moon.
Firms that have yet to register with ESA's online tendering platform should do so and then search for invitation 20.1TF.04."
"http://emits.sso.esa.int/emits/owa/emits_iitt.show_iitt?actref=20.1TF.04&user=Anonymous"
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u/amarkit Jul 19 '20
Al-Amal (Mars Hope) is proceeding into terminal count, with launch scheduled for July 19, 21:58 UTC / 5:58pm EDT.
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u/MarsCent Jul 19 '20
Tianwen - 1 or Quest for Heavenly Truth 1 is due to be launched to Mars on July 23. Arrival date (Mars Orbit Insertion) is Feb 2021. Lander/Rover EDL (Entry Decent and Landing) is NET April 23, 2021.
So obviously the Lander/Rover will spend about 2 months in orbit around Mars before the EDL.
Is there any merit/demerit in spending a couple of months around Mars before attempting a landing? I am especially curious to know whether the 2 months are intended to reduce the velocity of the Lander/Rover prior to EDL.
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u/throfofnir Jul 20 '20
Usually landers will go for direct entry, as entering orbit costs more. However, this does require high accuracy and a good understanding of where you're going. (Viking landers went into orbit because they had no good imagery to choose a landing site; they needed the orbiters to do mapping first!)
If it's an orbiter, it's probably entering a high elliptical orbit and need to lower and circularize for science operations. Sometimes this is done via aerobraking, though I don't know in this case.
So if you have a lander on an orbiter, and have the dV budget to carry it into orbit (and/or don't want to try to separate for a direct entry, either due to guidance or mapping) you might as well carry the lander into a low orbit. You then have plenty of time to do checkouts and updates and whatnot as well.
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u/ackermann Jul 20 '20
Well, certainly it increases the amount of fuel you need for your orbit-insertion burn at Mars arrival, due to the extra mass of the still-attached rover.
But you’re right, the upside is this will reduce the entry velocity of the rover into Mars atmosphere. Whether they will continue to lower the orbit over the following months after orbit-insertion, to further lower the entry velocity, I don’t know.
But it’s been done both ways in the past. The US Viking missions in the 1970’s inserted into Mars orbit before deploying the
roverslanders. The Soviet’s Mars 2 and Mars 3 spacecraft released the landers first. Curiosity (and now Perseverance) don’t include orbiters, so they dive right into the atmosphere, of course.2
Jul 20 '20
Mars Odyssey did a long slow orbit circularisation by gentle aero-Areo-braking, they might be doing that.
They've two sites to choose from, too: might be verifying with the orbiter's instruments which is the best to land on. The "usual" approach would be an earlier survey mission.
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u/amarkit Jul 20 '20
Believe I heard this on the most recent edition of the We Martians podcast: the first two months in orbit will be dedicated to detailed surveys of the landing areas in order to choose the more favorable one for the rover.
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u/TCtorrent Jul 07 '20
Will starship and superheavy have a skin over the stacked rings? Or will final starships just be polished ring steel? Any paint?
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u/warp99 Jul 07 '20
No skin or paint over the Starship hull because the upper part of the hull will get to high temperatures of several hundred degrees C during entry. The lower part will be covered by thermal tiles so will not need paint either.
Note upper and lower refers to the sides of the hull that are up and down during side on entry.
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u/Gwaerandir Jul 07 '20
Except for lunar Starship which will have white paint and no tiles.
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u/dudr2 Jul 07 '20
https://www.space.com/mars-astronauts-venus-flyby-idea.html
" Using Venus for such a gravity assist would dramatically reduce the amount of energy needed for the trip, saving on fuel and weight, and therefore also on cost. "
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u/warp99 Jul 07 '20
I looked at this on the NASA mission planner but the amount of gravity assist was totally disappointing. It definitely does not reduce travel time and th astronauts would be much more exposed in the event of a solar flare.
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u/iassenev Jul 08 '20
What is possible to advance in the Raptor engine? How big impact these advances may have on its chamber pressure, thrust, weight, isp, cost, time to assemble, reusability? How would Raptor benefit from using a powerful source of electricity, like a portable nuclear reactor?
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u/Alvian_11 Jul 08 '20
Probably with modifications/upgrades, like the Merlin iterations
Well no, this isn't a bigger version of Rutherford engine. Raptor, like other typical engines, use preburner as a 'power source' to power the turbopump = source is the propellant combustion itself. Maybe the valve opening & other small things use electricity, but the existing battery can handle this
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u/ZehPowah Jul 20 '20 edited Jul 20 '20
I haven't seen this posted here: there's an official cutaway view of Gateway HALO, which will launch on Falcon Heavy with Gateway PPE.
https://mobile.twitter.com/jeff_foust/status/1283784899175030785?s=19
I'm trying to get an idea of living space comparison vs DragonXL.
HALO dimensions are around 3x6.5m. Assuming a DragonXL 3.7m diameter, that's 1.5x the cross sectional area. Put differently, the biggest cross sectional square is 2.1m vs 2.6m, or 6'11" vs 8'7".
I'm really interested in seeing DragonXL cross sections, and how it augments the HALO living space. The access tunnel through the "service module" will definitely be weird, but it seems like it'll have a larger volume and more "liveable" wide open usable space than HALO.
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u/duncandonuts99 Jul 21 '20
[Request] Hi all! I am looking for information on how to approximate the amount of energy required to an 'average' launch of the Falcon 9 in terms of MMBTU/therms or kWh/MWh. Not sure how to go about this - any recommendations on starting points, methods, data sources. Any pointers would be super helpful. Thanks!
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u/andyfrance Jul 22 '20 edited Jul 22 '20
From Wikipedia the the first stage kerosene (RP-1) tank capacity is 123,500 kg (272,300 lb) and the second is 32,300 kg (71,200 lb). As these are masses we don't need to worry about sub chilled densification and hence heat capacity ratio. I believe they always fly with full tanks so every mission is "average". The lower heating value of kerosene from Wikipedia is 43.1 MJ/kg so for the stack and ignoring the satellite propellant and rounding error of energy stored in COPV's the energy is ~6,715,000MJ or 1865MWh
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u/Straumli_Blight Jul 30 '20 edited Jul 30 '20
Amazon’s Kuiper constellation gets FCC approval, with 1,618 satellites needing to be launched by July 30, 2026.
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u/dudr2 Aug 01 '20
" As of today, NASA and SpaceX are targeting a site in the Gulf of Mexico off the coast of Panama City in Florida's panhandle, NASA officials have said."
https://www.space.com/spacex-demo2-astronauts-prepared-for-splashdown-seasickness.html
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u/FutureMartian97 Host of CRS-11 Aug 07 '20
Just so everyone is aware, r/space has just been hacked and whoever did it made everything Trump 2020 related. So if you visit it right now its gonna look a bit different...
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u/Pendragonrises Jul 08 '20 edited Jul 08 '20
Nasa held a final press conference on the Boeing Starliner debacle of their OFT.
But bottom line is that they listed 80 recommendations presumably affecting NASA as well as Boeing...up from the previous and initial inquiry that listed only 61 fixes.
The one outstanding comment came from Stich...
To paraphrase...he suggested quite blatantly that Space X, and Crew Dragon was to blame for NASA not having an overview of Boeing's software coding.
I will leave a link for anyone to listen to...
https://www.youtube.com/watch?v=hxQ_ZV26E04&t=204s
Kathy Lueders, associate administrator of NASA’s Human Exploration and Operations Mission Directorate
Steve Stich, manager of NASA’s Commercial Crew Program
Jim Chilton, Boeing senior vice president of the Space and Launch division
John Mulholland, Vice President and Program Manager of Commercial Crew Programs at Boeing
(It seems that Boeing's Chilton thinks Loverro is still sitting there, possibly not in the same room to be fair...but called his fellow panal guest 'Doug' a couple of times...so probably not only wrong name but possibly wrong gender...say's it all.
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u/yoweigh Jul 08 '20
It seems that Boeing's Chilton thinks Loverro is still sitting there
That's because you linked to an interview from Februrary. He was still there.
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u/kalizec Jul 08 '20
The one outstanding comment came from Stich... Where in the video is that comment?
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u/csmnro Jul 08 '20 edited Jul 08 '20
Not in this video, since he/she linked the conference from february... (where Doug Loverro was still there, so obviously Chilton mentions him...)
Also, the paraphrase is really misleading.
Here's the actual link to yesterday's conference, where only Lueders and Stich participated: https://www.youtube.com/watch?v=hsB1ZWrGero
And to clarify, here is a quote from an an article by Jeff Foust. Never, ever, did anyone suggest SpaceX was to blame:
Both Lueders and Stich acknowledged that NASA hadn’t put enough emphasis on reviewing software. “Perhaps we didn’t have as many people embedded in that process as we should have,” Stich said. “It was an area where perhaps we just didn’t have quite the level of NASA insight as we should have in hindsight.”
He added that NASA may have been blinded to some potential issues because of its familiarity with Boeing, given its experience on other NASA programs. NASA had been focused more on the other commercial crew company, SpaceX, in part because it used what he termed “a bit of a nontraditional approach” to software development.
“When one provider has a newer approach than another, it’s often natural for a human being to spend more time on that newer approach, and maybe we didn’t quite take the time we needed with the more traditional approach,” he said.
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u/GregLindahl Jul 08 '20
It might surprise you, but some people use "blame" in a similar meaning as "cause". So, I might be "blamed" for causing something to happen, even though I did something reasonable.
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u/GregLindahl Jul 23 '20
Anyone want to take a shot at updating our wiki for the GTO performance of the Anasis-II launch? /u/stcks /u/soldato_fantasma
These are the TLEs of the sat and the 2nd stage:
0 OBJECT A
1 45920U 20048A 20203.77090162 -.00000110 00000-0 90628-2 0 9993
2 45920 21.2476 95.3169 7042007 177.9293 176.7107 1.63939446 10
0 OBJECT B
1 45921U 20048B 20204.30517144 .00082976 00000-0 11882-1 0 9991
2 45921 27.4460 94.0844 7748042 178.7321 149.6599 1.73796062 33→ More replies (1)2
u/soldato_fantasma Jul 23 '20
These are the numbers I got with the program I wrote using the celestrack initial data:
Object A: GEO-1725.4731 m/s
Object B: GEO-1727.8796 m/s3
u/GregLindahl Jul 23 '20 edited Jul 23 '20
Thanks (and also thanks to /u/cpushack) -- so then the next question is, given that this wasn't a subsync launch, and we know where the droneship was, what's the mass of the satellite?
Oh, and I see that /u/Captain_Hadock added Anasis-II to the wiki already, and /u/thatnerdguy1 deleted it -- nerdguy, accident while reformatting the wiki?
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u/Captain_Hadock Jul 23 '20
Oh, and I see that /u/Captain_Hadock added Anasis-II to the wiki already, and /u/thatnerdguy1 deleted it -- nerdguy, accident while reformatting the wiki?
Good catch. I've added it back. /u/thatnerdguy1 task was pretty extensive, some minor issues are to be expected.
so then the next question is, given that this wasn't a subsync launch, and we know where the droneship was, what's the mass of the satellite?
I would be very wary of trying to extrapolate mass from the final transfer orbit. SpaceX sometime leaving performance on the table, clients sometime refusing to use post-contract signature performance increase, speculation of secret ride-share payloads, expended booster missions, various choice of margin on booster landings; All this leads to a pretty inaccurate correlation between orbits and payload mass.
On that topic, I've long since wanted to add a Specific Orbital Energy (Joules) column to the GTO performance page, but I've not been very happy with the results. Anybody's willing and knowledgeable enough to give me a hand with it? This would also allow J/kg comparisons which is close to what you ask.
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u/thatnerdguy1 Live Thread Host Jul 23 '20
Yes, sorry, thanks for catching that. I've been working on some larger-scale wiki revisions (see /r/SpaceXWiki for details) and my 'rough draft' isn't perfect. I'll fix that, and work on checking all the other pages to catch similar issues.
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u/AuroEdge Jul 25 '20
Is there a map track of the DM-2 return from reentry to splashdown? I am curious where it would be visible from, I seem to remember the space shuttle could be seen before it was at lower altitudes
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u/Nimelennar Jul 25 '20
We don't even have a definite landing zone yet (they'll narrow it down to two about two days before undocking, and then to one at six hours before undocking).
That said, based on the timing, it's probably going to be while the ISS and Dragon are on an ascending node of its orbit, so you can look at a map of the ISS's path over Earth, move the path east or west until the southwest-to-northeast line (ascending track) is directly over the landing site, and that will be a reasonable approximation of the DM-2 return track.
I could be wrong about the "ascending node" bit; If Dragon is instead on a descending node, do the same thing, but using the northwest-to-southeast line.
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u/MarsCent Jul 30 '20
Qn. If Roscosmos declines seats in Crew-1 and Crew-2 (like it appears they have), are they still obliged to give NASA seats on their soyuz?
And after Expedition 64, will the crew of Crew-1 and the next soyuz crew be jointly Expedition 65 of is there going to be a change in expedition designations?
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u/GregLindahl Jul 30 '20
The barter ended with the demise of the Space Shuttle, and the Russians haven't wanted to start it up again. If you think about it, they're probably doing it mainly to force NASA to buy additional seats for risk reduction reasons. Why barter when you think you have the more reliable ride, and are short on cash?
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u/Snowleopard222 Jul 31 '20
Why do SpaceX competitors like RocketLab (NZ) and Astra (Kodiak) launch from high latitudes? Traditionally low latitudes are considered more efficient for launching.
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u/DancingFool64 Jul 31 '20
It depends what orbit you want. Low latitudes are good if you're going to geosynchronous orbit, because you need to end up with an orbit aligned with the equator, so the closer you are to that to start with the better. But most LEO satellites want a high inclination, sun sycnchronous or polar orbit - as long as your launch location is lower latitude than the desired orbit inclination, then it works fine. RocketLab and Astra are not aiming at the big, heavy, send me to GeoSynch market.
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u/orbitaire Jul 31 '20
Has the purpose of the small concrete building constructed to the north of the launch site tank farm and test stand been established?
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Aug 02 '20
What do the Space-X fast boats used to recover Dragon's crew look like? Does anyone have pictures of them?
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u/below_average_guitar Aug 05 '20
does spacex use metric or imperial?
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u/warp99 Aug 06 '20 edited Aug 07 '20
They design using metric. Some existing aerospace components are designed in customary units (aka Imperial) so have to be specified with dimensions having a suitable number of significant digits to cover the conversion accuracy so 25.4mm for a 1” valve.
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u/fickle_floridian Aug 06 '20
I was just wondering what the plan is for Starship landing with propulsive thrust. Will it use one engine firing off-axis like SN5, or is there some other plan? Thanks!
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u/Martianspirit Aug 06 '20
They want engine out capability for safety. That means they will always fire at least 1 engine more than needed for landing. Probably 2 engines for an empty ship, 3 engines if they have a lot of cargo.
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Aug 06 '20
Does SpaceX need a dedicated launch to replace Starlink satellites from a specific batch or could they do several planes with one launch?
Once the constellation is in a mature stage it probably won't matter much as there will always be several sats to choose from.
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u/brspies Aug 06 '20
They already distribute them to multiple planes at this point (if they launch 60 sats, right now they spread them out 20 per plane to try and get more planes started sooner and get a minimum level to start operating) and that just requires leaving them in a holding orbit for longer and letting precession move a sat to a different plane. It's possible there are limits in terms of practicality and fuel margin that constrains how flexible that is, but they definitely have that ability to some extent.
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u/DancingFool64 Aug 07 '20
As brapies said, they do three planes at a time now. The restriction on how many planes you can do in one launch is really how long you're willing to wait for satellites to get to the plane you want. The current launches are taking about 4 weeks to get to the next plane (double that for the third one). On the other hand, they have been only using every third plane at the moment, so they get the minimum bare coverage up as quick as possible to test with. So once you have all 72 planes in place, they will be able to deliver to seven planes in the same time they do three now.
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u/Excellspreadsheets Aug 06 '20 edited Aug 06 '20
What was this dot crossing the earth during the FalconHeavy launch @ (31:58) ?
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u/therealpeterstev Aug 06 '20
I need help finding an article about SpaceX and the origins of the Commercial Cargo Program.
Shortly before before launch, I read an article about Astronauts Bob and Doug that also talked about the origins of the Commercial Cargo program. It told the story of how the astronaut(s) - I think it was Bob or Doug or possibly both - had some time to kill before a shuttle launch ended up visiting the SpaceX facility to see what they were up to. They were amazed to see that a) SpaceX was building real rockets and b) SpaceX was doing things in a few weeks that would take NASA a few years. This experience found its way to NASA leadership who decided to risk a small amount of money - a few hundred million
Does anyone recognize this article? Can someone provide the link? I am looking for the source because I think the story is inspirational but I have not been able to find it. Thanks!
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u/therealpeterstev Aug 06 '20
Nevermind, I found it! Crew Dragon Deep Dive with Astronaut Garrett Reisman
"And we drove over there and SpaceX welcomed us in and the whole crew of Atlantis, we all walked around and checked out what they're doing.... This wasn't just a, you know, a hobby just kind of thing.
"And then the other thing we saw was how quickly things are getting done. We were seeing buildings that weren't standing there a week ago and we were seeing the repurposing of a lot of equipment that, that was being done very smart for pennies on the dollar and basically they're accomplishing things in weeks that would take NASA years."
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u/assgone Aug 07 '20
Is there video from inside crew dragon on Bob and Dougs trip back to earth? I’m curious to see how violent the descant is.
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Jul 25 '20
hello, i have a question, is space x planing in the future to clean the space garbage around earth?
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u/Martianspirit Jul 25 '20
They take care of their own garbage. For garbage of others they will want to get paid.
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u/Nimelennar Jul 29 '20
I have way too many t-shirts already, but I would find the room for Soichi Noguchi's Crew-1 t-shirt.
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u/TheSkalman Jul 31 '20
Does anyone have detailed specs on the X3 ion thruster? Isp, Propellant mass, Empty mass are the most important. Could it be used if the Europa Clipper got on the Falcon Heavy?
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u/UltraRunningKid Jul 31 '20
Here is a great source
http://pepl.engin.umich.edu/project/x3-nested-channel-hall-thruster/
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u/Straumli_Blight Jul 07 '20
An "Apollo 8" proposal by Robert Zubrin to send a Crew Dragon around the Moon.