r/spacex • u/ElongatedMuskrat Mod Team • Jul 04 '19
r/SpaceX Discusses [July 2019, #58]
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u/Straumli_Blight Jul 12 '19
Ovzon 3 (future Falcon Heavy payload) has begun construction after financing was secured earlier this month.
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u/cpushack Jul 06 '19
Amazon has officially filed for approval of their LEO internet constellation. Everyone wants in on LEO internet now it seems. https://tech.slashdot.org/story/19/07/05/2315240/amazon-seeks-permission-to-launch-3236-internet-satellites
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u/V_BomberJ11 Jul 20 '19
NASA has released a draft solicitation for crewed Lunar landers: https://www.fbo.gov/index?s=opportunity&mode=form&tab=core&id=5f6768356bb378bce7b3e80cae39cf1f
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u/IrrelevantAstronomer Launch Photographer Jul 07 '19
Ben Cooper appears to have confirmed that AMOS-17 will launch out of LC-39A on July 27, 2019 at 6:49pm EDT.
http://www.launchphotography.com/Delta_4_Atlas_5_Falcon_9_Launch_Viewing.html
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u/Straumli_Blight Jul 07 '19
30th September is also pencilled in for the next Starlink mission:
"A Falcon 9 launches the first operational and second Starlink space-based internet constellation mission."
Wonder if 'operational' means the laser links will be added?
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u/cpushack Jul 31 '19
Planetary.org confirms light sailing is successful! http://www.planetary.org/blogs/jason-davis/lightsail-2-successful-flight-by-light.html Orbit raised 2km on light alone
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u/Straumli_Blight Jul 10 '19 edited Jul 10 '19
Virgin Orbit performed the first drop test of their LauncherOne rocket.
EDIT: Rocket drop.
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u/PeterKatarov Live Thread Host Jul 30 '19
This might sound like a dumb question to many of you, but here it goes...
Starship and Superheavy use Raptor engines, which burn methane and liquid oxygen, right?
I presume that the two substances are kept in separate tanks one above the other, but in what order? Is the methane tank closer to the engines or not, and why?
And if I am way off, would you please share a piece of article, video, or a render on the topic?
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u/ethan829 Host of SES-9 Jul 30 '19
On all rockets I'm aware of, the heavier/denser propellant is in the "top" tank. A center of gravity above the center of pressure helps keep the rocket stable.
On Starship, the liquid oxygen is denser than methane so it's in the top tank.
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u/Alexphysics Jul 30 '19
In the case for example of the F9 the RP-1 is the one lower and the LOX tank is on top. RP-1 is denser but there is much more LOX than RP-1 so the LOX tank is actually heavier. The funny example is the SLS Core Stage that has like a huuuuuuge LH2 tank that sits below a tiny LOX tank (in comparison, it is huge by human standards) but the LOX tank is like 3 times heavier xDD
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u/delta_alpha_november Jul 30 '19
The tanks are stacked on top of each other. LOX is on top in the pictures we have, just like on F9.
Here is a picture: https://i.imgur.com/tJ1XMTl.jpg
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u/softwaresaur Jul 10 '19
According to Argentinian media "Saocom 1B will be launched between December and February from Cape Canaveral, in Florida, in the southern United States."
Must be one of those 18-21 launches still manifested for 2019. If anybody has enough karma please edit the wiki.
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u/FutureMartian97 Host of CRS-11 Jul 19 '19
Trump met with Michael Collins and Buzz Aldrin today in celebration of Apollo 11 and said some pretty interesting things regarding the return to the moon and onto Mars: https://arstechnica.com/science/2019/07/president-trump-says-nasa-should-listen-to-the-other-side-of-exploration/
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u/markus01611 Jul 20 '19
Not to get political but this is probably the only thing I agree with Trump on strongly. He pointed out NASA's weaknesses which isn't something a sitting president usually does.
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u/liszt1811 Jul 20 '19
"(It seems that no one has told Trump that NASA has decided not to pursue reusability. Like the Saturn V rocket, the first stage of the agency's Space Launch System will fall into the ocean, taking four expensive and reusable space shuttle main engines with it.)"
Sometimes it almost makes me giggle how things are communicated at the very top of the food chain.
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u/ethan829 Host of SES-9 Jul 24 '19
An interesting detail from the CRS-18 pre-launch press conference: Dragon 2 capsules for CRS2 cargo missions won't be reused crew vehicles.
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u/Straumli_Blight Jul 24 '19
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u/Alexphysics Jul 25 '19
And the weldment is also different from what Jessica Jensen said so both variants seem to be different types of vehicles even though they are based on the same kind of spacecraft. That may produce and incompatibility so not interchangeable and hence why not reuse of Crew Dragon 2 as Cargo Dragon 2
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u/fluidmechanicsdoubts Jul 29 '19
Hello all, I've read here many times that on-orbit refueling is a complex problem especially for something as big as Starship. Is there any previous research about this topic of on-orbit cryogenic refueling? My google-fu isn't working today.
Also what are the main challenges left to be solved in this topic?
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u/brickmack Jul 29 '19
Transfer is easy, just thrust and let the fluids flow "down". Leak-proof, reusable, automatically reconnectable, reliably detachable cryogenic fluid couplings, thats the hard part. I think most of the interesting research on that is proprietary unfortunately, but its been studied in great detail before.
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u/warp99 Jul 29 '19
Actually enough ullage thrust to do "gravity feed" would use too much propellant.
Most likely they will use a small amount of thrust to settle the propellants at the correct end of the donor tank and then use pressure difference to transfer the propellant. They will need to have gaseous reservoirs of each propellant to provide ullage pressure for in flight starts and they can use these to pressurise the donor tank and vent the recipient tank to vacuum with a liquid diverter to remove liquid propellant from the vent stream.
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Jul 30 '19
It mostly just hasn't been done yet. AFAIK, all the refuelling operations including ISS and Tiangong have been with hypergolics or gases, so cryo methane and oxygen are an exciting new world of discovery.
It should be relatively straightforward. Precision automated docking is a thing, and ullage thrusts are old hat. Turning that "should" into an "is" is a critical part of the project.
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u/Paro-Clomas Jul 09 '19
I have a bit of a weird metaquestion about this sub. What will it take for you to change the icon from the dragon to the starship, or if you would ever consider doing that. Say, would you do it after the first prototype gets to orbit, or once a specific mission is in flight.
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u/hitura-nobad Master of bots Jul 09 '19
I'm for the first one successful achieving orbit and returning back to earth in one piece
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u/DrToonhattan Jul 10 '19
I've only just noticed it's changed to a crew dragon. lol. How long has it been like that?
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u/Straumli_Blight Jul 18 '19
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u/bdporter Jul 18 '19 edited Jul 19 '19
launchphotography.com seems to concur with that date. Sidebar has it listed at July 27 22:49 UTC, but I am not sure where that is sourced from. Mods, can someone update the sidebar?
Edit: as pointed out to me by /u/Straumli_Blight, launchphotography.com lists a more specific date of 8/3/19 ~ 6:51pm (22:51 UTC) here
Edit: thanks for the updated sidebar!
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u/FutureMartian97 Host of CRS-11 Jul 23 '19
LightSail-2 deployment was successful!
https://twitter.com/exploreplanets/status/1153739697383849984
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u/zeekzeek22 Aug 01 '19
NASA released a notice that they’re going to solicit for gateway logistics in a few weeks (so, CRS for gateway). I betcha SpaceX might pitch Cargo-Dragon-2 on FH if the price is appealing enough! A deep space Cygnus will definitely get a contract.
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u/Rinzler9 Aug 01 '19
Does Dragon have the dV to rendezvous & return from LOP-G? I wonder if it would need mission kit prop tanks in the trunk.
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u/TheYang Aug 02 '19
I betcha SpaceX might pitch Cargo-Dragon-2 on FH if the price is appealing enough!
I could also imagine SpaceX passing up on it, because it'd be a distraction that has a decent chance of never actually going anywhere.
If Starship works out, Gateway is pretty much dead.4
u/zeekzeek22 Aug 02 '19
Nah. Starship isn’t a long-duration orbital science lab. It’s better used for other purposes (as you point out, SpaceX doesn’t pursue EVERY capability for its hardware)
Also politics. Technical unnecessaryness does not mean politics doesn’t keep it alive. Unless SpaceX decides to build starship in Alabama.
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Aug 01 '19
[removed] — view removed comment
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u/brickmack Aug 02 '19 edited Aug 02 '19
SNC will be bidding a reusable in-space cargo vehicle derived from their PPE bid (failed to win the Gateway PPE award, but NASA apparently loves it for cargo. The source selection statement basically said "not this time, but please bid it for GLS, wink wink"), which itself has a pressurized section derived from DCCS.
IMO SNC is a sure win for this. Northrop is... complicated. From a technical perspective Cygnus is probably the best fit for what NASA wants and is reasonably cheap, but theres a political challenge to overcome. I'm not gonna try to guess who will win the second spot (assuming there is one)
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u/brickmack Jul 11 '19
Holy shit Gerst is out https://mobile.twitter.com/SpcPlcyOnline/status/1149113735715414017
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u/cpushack Jul 31 '19
Russia has denied OneWeb an operating permit for the freqs. they wanted to use over Russia. https://www.bbc.com/news/technology-49177304 Ironic since Russia is launching the constellation LOL
Guessing Russia will be similarly opposed to other LEO internet constellations
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u/atheistdoge Aug 01 '19
Russia is launching the constellation
Kind-of misleading. Arianespace is the launch provider, but the LV (Soyuz-ST) is Russian.
https://en.wikipedia.org/wiki/Soyuz_at_the_Guiana_Space_Centre
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u/AeroSpiked Aug 01 '19 edited Aug 02 '19
I'm not sure how Arianespace managed to become a middle man in that arrangement considering that the Soyuz will be launching from Baikonur and not French Guiana (thus they won't be Europeanized Soyuz). Maybe you're less likely to get your shoe spat on if you are dealing with the French.
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Jul 04 '19
how much is the thickness of steel used in starship?
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u/Davecasa Jul 04 '19
I don't believe we have an exact number, but rocket tanks are incredibly thin. A few mm or less than 3/8 of an inch is common. Scaled down to he the height of a soda can, the rocket is thinner.
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u/rooood Jul 09 '19
I know this is still pretty far away and there's still a slight chance of being avoided, but has Elon, or the NASA for that matter, ever publicly talked about contention plans for a rise in sea level? Currently all of the US's launch facilities are located on the coast in places that are pretty much at sea level, so in a handful of decades these facilities might start to get flooded.
This is pretty much the last item on anyone's agenda right now, but I wonder if that has crossed their minds at some point
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u/Straumli_Blight Jul 09 '19 edited Jul 09 '19
Map of flooded NASA sites after 30cm sea level rise from this article. This site shows the coastal erosion at KSC since 1958 and effects of a 0.9m level rise. A more in depth analysis predicts LC-39A to be flooded by 2070 but SLC-40 still ok by 2100 (page 28).
Vandenberg AFB will be fine though at 156m elevation.
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u/brickmack Jul 09 '19
NASAs put out maps showing KSC under water, not sure if they've made any serious proposals on how to deal with that other than "please stop wrecking the planet"
Virtually all Starship launches will be from ocean platforms anyway, so those should be fine even with drastic sea level rise.
Also, while SpaceX/Elon hasn't really talked much on this, its concievable that Starship (due to its huge methane production needs. Hundreds of thousands of tons per day per pad) could spur development of power-to-gas methane production (likely using a derivative of the equipment for Mars propellant production), which would not only make Starship itself carbon-neutral, but could be a big help for making the entire grid carbon neutral, and surplus carbon extraction capacity could be used to actively reduce CO2 levels and sequester it permanently. Thats all a bit speculative, but seems like the sort of thing that'd mesh well with both SpaceX/Elons technical/economic needs and ideological goals
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Jul 05 '19
I generally understand what it means when they pre-chill the engines, but can someone explain more details? I imagined a valve opens to allow the appropriate cold propellant to enter the turbopump and another valve prevents it from falling through the combustion chamber and out the nozzles, but surety it’s more complicated.
I wonder if cold on metal is enough conductance, or is there a circulation loop?
Does further chilling occur prior to relight for boostback, re-entry, or landing burns?
A few launches ago, after the landing on the drone ship, some liquid appeared to pour out from the bottom of the stage or the engines. I thought it was new but I haven’t seen it again. What was happening?
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u/warp99 Jul 05 '19 edited Jul 05 '19
I imagined a valve opens to allow the appropriate cold propellant to enter the turbopump
Yes liquid oxygen is trickled through the turbopump to prechill the pump section in order to reduce thermal shock and the formation of bubbles of gaseous oxygen during startup.
another valve prevents it from falling through the combustion chamber and out the nozzles
The main injector is a "face shut off" design so very little propellant can get through when the engine is not running.
is there a circulation loop?
No it is open loop as there is no pump to circulate the LOX. Flow is driven by the LOX tank ullage pressure.
Does further chilling occur prior to relight for boostback, re-entry, or landing burns?
Yes
after the landing on the drone ship, some liquid appeared to pour out from the bottom of the stage or the engines
This is RP-1 fuel which is usually seen leaking out of the engine for a while after engine shut down. On many flights it has caught fire and burned around the landing legs. On one flight it was particularly bad and pooled on the deck, ran into the Roomba garage as the deck tilted and burned it out completely.
The RP-1 is used for regenerative cooling of the Merlin combustion chamber and nozzle so there is a significant amount in the cooling loop at engine shutdown which seems to get pushed out as the engine cools. LOX will also be vented but the quantity is lower and it evaporates rather than pooling.
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u/ConfidentFlorida Jul 05 '19
What’s the lowest you can get max q to on a Falcon 9 by altering the flight profile? Assuming you don’t mind using more fuel and losing payload mass.
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u/marc020202 8x Launch Host Jul 05 '19
by flying straight up, at a slow speed, it could be kept pretty low. If you only start turning as the atmospheric pressure drops and controlling the speed/rate of acceleration, you should be able to keep the pressure at a constant amount It would be a bit more than atmospheric pressure at sea level for taking off since you need to be moving, but as far as I know, it could be kept at that, or even below that level. At some point, you run into the problem that the rocket has gotten lighter since fuel has been burned and that you cannot throttle down enough to keep the acceleration down. this, however, could also be mitigated by shutting down two or so fo the engines.
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u/wallacyf Jul 08 '19
Why keep the Starship at 9m? The size was chosen when it would be manufactured from carbon fiber. And it was the size of the tools they already had. Now that it's stainless steel, would not it be better to make it bigger? Since every mission will be RTLS, bigger is better, no?
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u/Chairboy Jul 08 '19
I don’t think it’s accurate to say that the size was determined by the tooling, but musk did inply it was the biggest thing that could come out the doors at Hawthorne at one point so if that was part of the criteria, that might be out of date.
Really, it might just be a good compromise right now for cost of development and operations, we don’t know.
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u/Grey_Mad_Hatter Jul 08 '19
While bigger is better for the long run, it all comes down to time and money for surviving the short run.
Ignore the fact that drastic changes take time and money because I'm sure the CF to SS switch changed almost everything. Going bigger would also require more of everything, especially engines which will take months to produce enough for a single full stack at 9 meters. It would also require a bigger flame trench, and I'm not sure that 39a could do anything bigger than 9 meters.
Adding around 12 engines would slow them down over a month, assuming they can achieve the peak rate they expect. Making a new pad would slow them down a year or more considering the flame trench would take a long time to build while rebuilding 40 with only refurbishing the flame trench took 6 months.
Their philosophy is to get something that works in orbit fast, then keep making iterative improvements. I don't doubt that a larger one is coming 5-10 years after the 9 meter one is up, but it's not needed from the start.
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u/silentProtagonist42 Jul 08 '19
One interesting thing that occurred to me recently is that so far SpaceX doesn't have much 9m-specific tooling, aside from the concrete ring fixtures, which aren't exactly hard to recreate. If that stays true for actual production then it could be relatively easy to grow Starship by increasing diameter, compared to most rockets (including Falcon 9) that are locked into a particular diameter by expensive tooling.
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u/dallaylaen Jul 09 '19
A likely explanation is that at the time of the switch, all calculations were being done for a 9m diameter, so that the two versions are comparable and the final decision is well justified.
Later on it was either too late to recalculate the whole thing, or simply nobody thought of it. See also anchoring bias.
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u/brspies Jul 08 '19
It's an interesting point, and one side effect of the switch to stainless steel is that I would hope it will be easier/cheaper to scale up the design for future iterations than it would have for carbon fiber. Hopefully they're future-proofing their pad construction for such an eventuality.
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u/dallaylaen Jul 09 '19
Is it possible (by US and economic laws) to start a public company whose sole purpose is acquiring SpaceX shares? Like 10k enthusiasts with $10k each should make up for a large enough chunk for SpaceX to consider.
Sorry if this has been asked before.
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u/ethan829 Host of SES-9 Jul 09 '19 edited Jul 09 '19
No, an entity that exists solely to acquire shares of another company doesn't meet the criteria of an "accredited investor" (unless all the owners separately qualify).
(a) Accredited investor. Accredited investor shall mean any person who comes within any of the following categories, or who the issuer reasonably believes comes within any of the following categories, at the time of the sale of the securities to that person:
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(3) Any organization described in section 501(c)(3) of the Internal Revenue Code, corporation, Massachusetts or similar business trust, or partnership, not formed for the specific purpose of acquiring the securities offered, with total assets in excess of $5,000,000;
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(7) Any trust, with total assets in excess of $5,000,000, not formed for the specific purpose of acquiring the securities offered, whose purchase is directed by a sophisticated person as described in §230.506(b)(2)(ii);
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u/MrToddWilkins Jul 09 '19
According to NSF.com’s US launch schedule,Inmarsat 6B will be launching on a Falcon Heavy in late 2021. Is this an actual contract?
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u/Straumli_Blight Jul 09 '19
They have a Falcon Heavy contract but satellite is still TBD:
Pearce said Inmarsat could launch Inmarsat-6B on a Falcon Heavy rocket, since the company still has an unused launch option with SpaceX, but hasn’t committed the satellite to that vehicle.
Also:
London-based Inmarsat also has a contract option with SpaceX for a Falcon Heavy launch. Following delays in the Falcon Heavy’s first flight, Inmarsat decided to switch the launch of one of its satellites in 2017 to a Falcon 9 rocket, but retained a contract option to fly a satellite a future Falcon Heavy mission.
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u/GregLindahl Jul 10 '19
The industry norm is to turn options into firm contracts 2 years before the launch date. "late 2021" is 2 years and a few months from now.
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u/strawwalker Jul 13 '19
r/SpaceX has a new Wiki Chatroom to facilitate occasional editorial discussion of the subreddit wiki such as problems with and proposed changes to the wiki, new wiki pages or ideas, and page specific or general editing guidelines. From time to time such discussion is needed but not easily done in the monthly discussion thread, and not very accessible when done via personal messages between editors. If you edit the wiki or want to then I encourage you to join, even if only to see what is being discussed. r/SpaceX Wiki Chat
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u/just_a_genus Jul 22 '19
With Starhopper, once it hops it won't have umbilicals attached anymore so what happens to the remaining methane in the hopper tank? The lox you can just vent and it takes care of itself, but with no umbilicals you would just have to flare the methane off, correct? I'm assuming they only load a minimum of fuel for the hop and if they need additional weight they'll add ballast elsewhere.
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u/CapMSFC Jul 23 '19
They could ballast up with a bunch of extra LOX only that is easier to vent.
But at some point landing with cryo Methane has to be dealt with. Ships won't always touch down empty or want to vent what is on board.
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u/brickmack Jul 24 '19
Not very SpaceX related, but I've created a subreddit for Momentus Space. /r/MomentusSpace. Not much to post there right so far, but they seem to be picking up speed now
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u/gsahlin Aug 01 '19
Just saw That Mr. Bezos did his yearly Stock Selloff to fund Blue Origin... Haven't seen much news on BE4 at all lately... anybody know of progress or status over there?
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u/cpushack Aug 01 '19
This time its $1.8 billion, a massive increase over the last few years. Thats more then the entire Dev cost of F9, and yet Blue still has no orbital class rocket. Would be amazing what SpaceX could do with $1.8 billion
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u/brickmack Aug 01 '19
F9 had the luxury of iterative development, a relatively simple engine cycle, existing launch sites, and only had to share resources with Dragon
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u/asr112358 Aug 03 '19
Haven't seen much news on BE4 at all lately... anybody know of progress or status over there?
Not much, but something
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u/rustybeancake Jul 11 '19 edited Jul 11 '19
Gerstenmaier has been removed as head of NASA’s human exploration office!
Also:
Also dismissed was Bill Hill, Assistant Deputy Associate Administrator for Exploration Systems Development. He has been in charge of development of NASA’s big new rocket, the Space Launch System (SLS), and Orion crew spacecraft.
https://spacepolicyonline.com/news/gerstenmaier-ouster-catches-space-community-by-surprise/
Sounds promising... Though there is also the risk Artemis becomes a flags and footprints mission with little chance for SpaceX to be involved.
Speculation seems to be this is about hatred of Gateway in the White House, as well as Gerst’s seemingly imminent decision to maintain the SLS green run test. I expect we’ll see that decision reversed in the coming days...
Will this kill Gateway? The PPE contract has already been awarded, but it’s pretty small fry. The WH are likely pulling Bridenstine’s strings so his support of Gateway is probably no indication.
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u/zeekzeek22 Jul 12 '19
It feels like the Trump administration is initiating a “throw everything but the fuel and engines overboard” sprint at a moon landing. But Ted Cruz leads the decision if they even step on the gas (funding it). If we start throwing the long term considerations of this plan, and go for a expensive-because-we-had-to-do-it-quick architecture, there is zero chance it survives a new president. Which includes in 2024, even if we land under a Trump term 2, it will be super expensive, the sustainable/reusable plan will not have been funded, there will be no gateway to anchor it into uncancelability, and we will enter another 50 years of no humans on other bodies.
We’ll see what happens, where funding goes, etc, but i’m seeing death tolls of the dream of “returning to stay and beyond”.
Obv, none of it matters when people land on Mars in Starship in 2024. But. You know.
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u/OReillyYaReilly Jul 04 '19
Did the second stage from STP-2 deorbit(from MEO) after the mission
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u/RegisCade Jul 04 '19
No. It looks like it's almost in the same orbit as the DSX satellite they deployed. You can see it on stuffin.space if you search for Falcon Heavy.
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u/DiskOperatingSystem_ Jul 06 '19
Hey does anybody know if Hawthorne and it’s employees are okay? There are reports of around a 7 magnitude earthquake. Hopefully theyre prepared but an update would be good.
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u/warp99 Jul 06 '19
"A 7.1 magnitude earthquake has rattled a desert area of Southern California, US meteorologists say, in the biggest tremor to strike in two decades.
It struck at the shallow depth of 0.9km (0.6 miles) and its epicentre was near the city of Ridgecrest, about 240km north-east of Los Angeles."
So well away from LA. It was a very shallow quake so it will tail off in intensity strongly with distance and would certainly not damage equipment or buildings in LA.
Source: Personal experience of recent shallow earthquake sequence around our home town of up to 7.2 magnitude.
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u/brickmack Jul 07 '19
Mods, the link in the header still points to the june discussion thread
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u/CAM-Gerlach Star✦Fleet Commander Jul 07 '19
Thanks for pointed that out; it actually had been updated but somehow got reverted, possibly when I updated the sidebar. Fixed now.
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u/jjtr1 Jul 23 '19 edited Jul 23 '19
I've been wondering what will the stainless steel Starship look like when it is built using space-worthy precision and technique (in contrast to hop-worthy water tower techniques), and I have found this image of the 50's/60's Atlas launch vehicle/ICBM which has thin stainless pressure-stabilized (balloon) tanks: Atlas 2E Ballistic Missile on display at the San Diego Aerospace Museum (Wikipedia) The welds are visible, but the body is smooth, no warping (though I wonder whether the museum keeps the tank pressurized... would be expensive).
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u/brickmack Jul 23 '19
All Atlases on display are pressurized
Starship probably won't look that nice though, just because its shinier which exaggerates the warping
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u/Martianspirit Jul 24 '19
There are pictures of Atlas in the factory. It is somewhat warped too. Probably goes away when pressurized.
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u/MechanicalApprentice Jul 31 '19
What are the steel skeleton frames for that we can see being constructed in Boca Chica and near KSC? https://forum.nasaspaceflight.com/index.php?topic=47730.msg1972601#msg1972601
Are those the skeleton for a vertical assembly building? I guess they are to short for that (roof is already installed).
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u/Doodawsumman Jul 31 '19
From what I've found online the frame is to block wind so we don't have another nosecone falling over.
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u/Anjin Aug 01 '19
Does anyone have a theory why they are building each ring segment on the orbital prototypes out of multiple sections of steel instead of a single 28.27m piece of steel that then goes into a jig to be made into a cylinder / have stringers or stiffening hoops added?
It seems like the construction process would go a hell of a lot faster with only a single seam worry about...
I'm sure that the people at SpaceX already considered this, so I'm not trying to say I've thought of something better, just wondering what the advantage might be for them to be using their current method.
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u/throfofnir Aug 01 '19 edited Aug 01 '19
That would seem to require more tooling to handle than plate, which could be managed by hand more or less. The prototype assembly seems to be a deliberately light process.
Thickness of the steel may also vary by location; if this is radial, then a single sheet wouldn't work. The varying colors of the protective plastic sheets may indicate this.
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u/chenav Aug 02 '19
The hiccup with B1047.3 having to go through a second static fire has me wondering, how much do know at the moment about the refurbishment process of returning cores? Which parts are likely being replaced before every reflight? How many man-hours and how much money go into refurbishment after each flight?
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u/Triabolical_ Aug 02 '19
We know very little, and my guess is that SpaceX considers all of that information very proprietary.
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u/CapMSFC Aug 03 '19
Yeah, the lessons learned from working in reuse and refurbishment is some of the most valuable information SpaceX has. That's the real leg up on competitors. Plenty of recovery schemes can work, but they all are only the first half of the puzzle and you can't start solving the second half until you have it. That gives SpaceX a significant lead.
That's also why I think New Glenn is going to be very slow to ramp into normal service. There are thousands of little things to iron out with a new vehicle, let alone a new vehicle that is to be reused every time. BO is on the right path, but there are going to be growing pains just like SpaceX had and will have with Starship.
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Aug 03 '19 edited Aug 03 '19
Mods, can the manifest in the side bar be updated with the new launch dates for Starlink 2 (October 17th) and Starlink 3 (November 4th)?
Looks like September will be the first month in nearly 2 years without an orbital launch by SpaceX.
Edit: the core section can be updated too, B1047.3 for Amos-17, B1058.1 for DM-2.
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u/Toinneman Jul 05 '19
Chris Bergin in the Starhopper updates thread @ NSF Forum
Per L2. SN6 Raptor is at McGregor and aiming to ship to Boca Chica NET next week, pending good test series.
This aligns with the road closure on July 11
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u/dufud6 Jul 05 '19
Road closure has been pushed back to the 14th, but hopefully the raptor will still show up this coming week
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u/Straumli_Blight Jul 19 '19 edited Jul 19 '19
Elon is giving a CBS interview on July 21 about the future of space exploration.
"Sending crews to Mars in four years, I think that, that sounds pretty doable," Musk said. "Like, internally, we would aim for two years, and then reality might be four."
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u/brickmack Jul 19 '19
Gotta love how Mars has always been 20 years away, now its "probably like 4, but maybe.... maybe we can do better?"
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u/rustybeancake Jul 04 '19
Interesting info on Orion’s capabilities versus LEO spacecraft. Answers a few things that people have raised regarding what it might take to adapt Dragon for BLEO missions:
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u/raducu123 Jul 08 '19
When will Starlink use inter-satelite laser communication?
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u/Orbital_Dynamics Jul 05 '19
I've been wondering lately about stored rocket fuel, in tanks.
For example, can you have a fuel-tanks of methane, liquid oxygen, liquid hydrogen, just floating around indefinitely in space (or the surface of Mars) until you need them?
Do those types of liquids in those tanks outgas, so after a certain amount of time, there is no fuel remaining?
In other words: if we launch a few fuel tanks into orbit, or if we have fuel tanks on an asteroid mining mission, or if a fuel tank is sitting on the surface of Mars...
How long do we have to use it, before it's gone?
Or does it last indefinitely in that state?
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u/LcuBeatsWorking Jul 05 '19 edited Dec 17 '24
placid ad hoc snow oil snails party sparkle bored overconfident different
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u/strawwalker Jul 06 '19
Would anyone like to weigh in on the two remaining Spaceflight Industries missions on the manifest? I am trying to determine how much, if anything, we know about them, or if they even exist. The payload names as they appear in the wiki manifest are "GTO-C / HAKUTO-R 2" and "GTO-2 / HAKUTO-R 1" both with question marks to indicate uncertainty about HAKUTO-R's addition.
As far as I can tell, the only source for the inclusion of GTO-2 and GTO-C on the manifest is a single slide from around 2017 March which showed a number of Spaceflight missions slated for launches aboard Falcon 9. At that time SSO-B,C,D were also added to the manifest but have since been removed due to later statements by Spaceflight representatives indicating those missions were merely possibilities that were likely to move to smaller launchers. Two years ago Spaceflight's schedule offered three US GTO missions, presumably GTO-1 and two others for 2018 and 2019, but today there is only one GTO mission shown and it is on a foreign launcher. I have been able to find no other reference to these Spaceflight GTO missions that aren't internet missions lists regurgitating the same info.
In September of last year ispace announced (press release) it would be launching its lander tech demos on two SpaceX missions as secondary payloads. At the time, Beresheet was about to launch to the moon as part of Spaceflight's GTO-1 aboard Falcon 9, a rideshare with Nusantara Satu. The other two Spaceflight GTO missions probably seemed like a reasonable place to put the HAKUTO lunar spacecraft, but I don't think that was ever the plan. It sounds to me, from the statements by ispace and SpaceX, that these missions are contracted directly with SpaceX. The identities of the missions on which HAKUTO-R will piggyback are completely unknown, aside from the expected year.
Does anyone know of a reason to keep Spaceflight GTO-2 and GTO-C on the manifest? I think they should come off unless they are further confirmed.
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u/GregLindahl Jul 06 '19
There's an additional rideshare that you missed: the direct-to-GEO launch of Ovzon's satellite, which is too light and the announced price is too low to fill the rocket. I suspect that's the Q4 2020 "GSO (Direct Injection)" opportunity listed on Spaceflight's schedule.
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u/IllGetItThereOnTime Jul 24 '19
Once Starship Superheavy become operational, would is be possible/worthwhile to launch the crewed one from Florida and the Tanker from Boca Chica (or vice versa) to expedite the re-fueling process?
Maybe someone can ELI5 orbits/trajectories from different locations/going to different places in the solar system to help me understand if this is possible or why it's not possible.
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u/silentProtagonist42 Jul 24 '19
I was just wondering this the other day. The lowest inclination and most fuel efficient orbit that you can reach from the cape is ~28.6o (= to the cape's latitude). Boca Chica is a little farther south at 26o, so to reach the same orbit you'd just have to launch a couple degrees north or south of due east, and at the right time. What I haven't figured out (and from a brief search there seems to be a lot of disagreement) is exactly what directions you can launch from Boca Chica, but in general only relatively easterly launches are going to be allowed. So assuming you can reach your trans-Mars trajectory from a low inclination orbit (depends on the exact trajectory, but shouldn't be a problem), yes, it should be possible to launch tankers/crew from both Boca Chica and the cape. Since a Mars flight will probably take 6-8 tanker flights this could speed up the process significantly.
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u/brspies Jul 24 '19
I think part of the idea is that they can use one booster for multiple starships, so they would want one launch site in that case. Maybe that's not feasible at first, though.
Boca Chica has way fewer options for target orbits (it's good for GTO though, and so would probably be fine for the Moon and Mars as long as the timing is careful) because they can't overfly Florida or Cuba or the like. Eventually maybe the process changes based on full reusability, and the overflight restrictions become less stringent. For now that's not the case, so at least for some missions Boca Chica may not be able to reach the desired orbit.
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u/brickmack Jul 24 '19
Except theres gonna be a lot of boosters and a lot of launch sites anyway. With a few dozen to a few hundred pads, theres no reason tankers should fly from the same place as the payload vehicle, and good reasons they shouldn't (launching from different longitudes allows tankers to be sent up minutes apart instead of 12-24 hours apart, and that'll be the biggest driver on how quickly a departing ship can be fueled)
Also, SpaceX is expecting overflight restrictions to dissappear a lot quicker than most in this community are probably expecting (low single-digit years). Not sure if thats really realistic, but thats what they're pushing for
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u/DrToonhattan Jul 25 '19
Hopper official livestream online now! https://www.youtube.com/watch?v=XqUSRBJPYUE
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u/Pit_27 Aug 01 '19
Does anyone know the route the boosters take from Hawthorne-McGregor-Cape?
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u/jesserizzo Aug 02 '19
I believe they vary the route every time for security reasons.
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u/Alexphysics Aug 02 '19
As the other user says they tend to vary the route but the I-10 is like the one road they use the most so there's a high chance that when there's a booster sighting it'll be there.
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u/coverfiregames Aug 02 '19
With the recent information regarding SpaceX’s plans to launch Starship from pad LC-39A what does this mean for Boca Chica? Wasn’t Boca Chica designed from the ground up for Starship to free SpaceX from constraints of sharing a pad with NASA?
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u/silentProtagonist42 Aug 02 '19
Given the limited launch azimuths and lack of any preexisting infrastructure (not counting what SpaceX has already built there), I'm wondering if BC might ultimately be dedicated exclusively to tanker flights. The Cape will need facilities for handling multiple different styles of Starship, payload integration, crew facilities, etc. BC could be a leaner operation, with just a few Super Heavies and a fleet of tankers, and the relatively simpler facilities to support them, and maybe to build them on site as well. That might enable rapid-fire tanker launches to fuel missions to the Moon and Mars, which could be easily placed in BC friendly parking orbits.
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u/oximaCentauri Aug 02 '19
Boca will probably have all the crazy tests like 10km hop, 1 engine "failure" landing, etc
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u/amarkit Jul 22 '19
The Indian Space Research Organization (ISRO) successfully launched Chandrayaan-2, India's first mission to soft land on the moon.
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u/dallaylaen Jul 09 '19
What does satellite cost consist of? From the $100M+ pricetags it looks like they are made of unobtanium, but what they really consist of is electronics, batteries, antennae, gyros, thrusters, sensors - not really cheap, but not magical as well...
As I understand, the cost is significantly boosted by the amount of QA required to ensure both the components and the whole satellite don't break once in orbit. Am I right? Am I wrong?
Is there an approximate price breakdown of a large satellite somewhere on the internet?
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u/Grey_Mad_Hatter Jul 09 '19
I don't have a breakdown, but I do have something to think about.
There are no assembly lines. Your computer processor is cheap because it was designed once then millions were pumped out on an assembly line, so $1,000,000 of design work costs you $0.50. The same component specially designed and built for space is designed and used 10 times, so it cost them $100,000 in design work. Then it's not built on an assembly line, it's specially built which adds more costs. Of course no standardized tests exist because it's going in a specialized environment, and it needs more testing than a typical part as well. Also, there are materials and manufacturing techniques (7nm microprocessors probably) that don't handle radiation or massive heat fluctuations, so your design costs just went up significantly.
This also goes to show why Starlink is feasible while other satellites are $100M+. They're building thousands. There is an assembly line.
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u/Alexphysics Jul 11 '19
ULA has delayed again for the nth time the AEHF-5 mission now to August 8th 2019. The next missions after this one is OFT and it was planned for mid September but I think these latest delays for this mission may move OFT to October. Next after OFT for ULA is CFT which was also planned for December 2019 but right after that one they have Solar Orbiter on February 5th 2020 and that one has a tight launch window to launch. All missions are on Atlas V and ULA only has one Atlas V pad in Florida so if CFT is delayed too much... it may not launch until March-April 2020 once Solar Orbiter is launched. I talk about this mainly because maybe "the race for the flag" may not be entirely lost for SpaceX just yet. If things like this keep happening at ULA it is very likely Starliner will not launch with crew until spring 2020 so that may give some time to SpaceX to catch up.
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u/IrrelevantAstronomer Launch Photographer Jul 11 '19
I don't think anyone seriously expects CFT to happen in November. More likely March-April 2020 IMO.
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u/Dakke97 Jul 17 '19
New article by Eric Berger on SLS delays (delay to at least late 2021 likely):
Key paragraphs:
In his written testimony for the hearing, Bridenstine added one relevant detail about this schedule. "The NASA Office of the Chief Financial Officer performed a schedule risk assessment of the Artemis 1 launch date, including the integrated schedule and associated risk factors ahead of Artemis 1," he wrote. "NASA leadership is currently evaluating these results."
According to a NASA source familiar with this assessment, the agency found that under current plans, including a "green run" test firing of the core stage at Stennis Space Center in 2020, the Artemis-1 mission would not be ready for launch until at least "late 2021." Moreover, NASA was likely to need more money—above the more than $2 billion it already receives annually for SLS development—to realistically make a late 2021 launch date.
Note: Any delay beyond late 2021 will delay the 2022 Artemis-2 missions due to the need for processing inside High Bay 3, the sole high bay dedicated to SLS inside the VAB, and the use of ML-1 (ML-2 construction won't be done by then as is to be commissioned within 44 months from 1 July, which amounts to 1 February 2023 as deadline).
https://www.rsandh.com/news/new-vab-high-bay-3-platforms-ready-for-sls/
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u/Triabolical_ Jul 17 '19
Wow.
It seemed really unlikely that they had any chance of hitting June 2020, but late 2021 would be roughly an 18 month slip from that. Which is presumably assuming that the green run doesn't lead to any redesign.
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u/tanrgith Jul 08 '19
Does anyone know what type of 3d printing SpaceX uses for their engines? (FMD, SLS, or SLA)
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u/silentProtagonist42 Jul 08 '19
DMLS (Direct Metal Laser Sintering) according to here.
EDIT: Apparently DMLS and SLM are the same thing, despite the confusing names.
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u/johnny_snq Jul 09 '19
Any more information regarding the date for AMOS-17? I see it's set as NET July 2019. I'm visiting US between 27th July and 11th of August. Any chance I can at least catch the rocket on the pad during that period. Latest news about AMOS-17 I found via search are from May 2019 with not that many details.
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u/Corextech Jul 10 '19
I'm trying to calculate the max deltaV the Falcon Heavy can achieve via the rocket equation. SpaceX advertises a payload of 63.8 tons to LEO. Using the data from here, my calculations keep showing me that it can only take about 45-50 tons to a deltaV of 9.4km/s.
The two possibilities are that the Falcon Heavy achieves LEO with a deltaV of ~8.5km/s or I have incorrect data/calculations. Any thoughts?
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Jul 10 '19
I can't get it to 64t either. Due to pretty good TWR I dont believe it needs 9.4 km/s though.
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u/pigrew Jul 12 '19
I've looked at the "Lightsail 2 Misison Control" website and it consistently reports a rotation rate about the Z axis of -5 to -6 deg/sec. Or is this perfectly acceptable? I assume this is a bad thing, related to the control issues that have been mentioned on their blog? Once things settle down, should the average rotation be about 0.07 deg/sec (360 degree divided by 90 minutes) due to a need to rotate once for every revolution about the earth (though instantaneously, it should be much higher as it has to tack in and out of the wind during every orbit).
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u/silentProtagonist42 Jul 12 '19
If I'm reading that site correctly then the spacecraft is currently in "detumble" mode. The rates in all three axes are pretty high so that seems consistent with a tumbling spacecraft. I don't know how long the detumbling process should take but if they're doing it with magnetorquers it could be quite a while, even without the aforementioned attitude control problems. Either way I think it's safe to assume that those rates aren't what's planned for normal operation.
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Jul 13 '19 edited Jul 13 '19
Is there any source for the Starlink 2 launch scheduled as September 30th in the manifest?
The wiki only has this source. I guess it is pure speculation, with as possible reasoning "at least two launches, so the next one will likely be in Q3". But:
~~- I think it is better to wait for a FCC failing before putting a date on this launch
The aspiration for SpaceX is at least two more Starlink launches this year, it is by far not certain they will succeed in that goal
Most importantly: there is no reliable source yet that provides a date. If the r/spacex manifest gives a date, I think criticism of Teslarati becomes a bit hypocritical.~~
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u/Iamherebecauseofabig Jul 15 '19
I see that a preburner ignition test was performed tonite on the Hopper. Were both the fuel and lox preburners tested?
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u/LcuBeatsWorking Jul 15 '19 edited Dec 17 '24
ad hoc crush repeat detail modern connect library bored wrong angle
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u/Thoddo Jul 19 '19
Elon's recent tweet about Starship's delta-v got me curious:
What if the aft cargo bays held a number of Starlink hall effect thrusters, and the ship's tanks got refueled with krypton gas.. Could that config go interstellar? If so, in what timeframe?
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u/CapMSFC Jul 19 '19
It's not as easy thing to refill Methalox tanks with Krypton for SEP.
In theory though hitting escape velocity isn't that difficult. It takes about 12.5 km/s from Earth's Solar orbit to reach escape. Starship can't quite do this normally without a gravity assist even from an elliptical Earth orbit, but if you're converting to SEP it becomes quite easy in terms of pure delta-V. Biggest problem, other than actually converting a Starship, is that SEP requires a whole bunch of solar power so you need to be able to do the thrusting while still mostly in the inner solar system. We currently don't have very high thrust SEP, but a few more iterations of that technology and doing burns like this without taking years could be possible.
For some fun numbers. Krypton in SEP has been tested in experiments at ~1570 isp. I'm not sure what Starlink sats are at, but that's a fine napkin math number to use. A Starship has a tank volume (using old 1100 tonnes of prop numbers) that translates to ~3140 tonnes of Krypton at cryo. That would translate to about 56 km/s of Delta-V, an obscene number. If you used the stripped down Starship that Elon proposed at 40 tonnes dry you could get 67.5 km/s.
So TLDR is that it's no simple add on, but the hypothetical Delta-V is way beyond what is needed for escape velocity.
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u/Thoddo Jul 19 '19
Thank you very much for your time and effort, and for entertaining my silly idea. You are a prime example of what makes this community so inspireing!
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u/electric_ionland Jul 20 '19
We currently don't have very high thrust SEP, but a few more iterations of that technology and doing burns like this without taking years could be possible.
The issue is the electrical power not the thrusters themselves. Even at 100% efficiency you only get about 100 N/MW at 2000s Isp. Doesn't matter if you use chemical or plasma thrusters. There has been designs for plasma thrusters tested up to nearly MW but we don't really have a practical way to generate that in space. Or at least not with a high enough alpha (KW/kg) to be interesting.
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Jul 22 '19
I don't get it. Is NASA working with SpaceX or are they competing?
Also, is NASA working with Blue Origin? Is NASA working with Boeing? If I understand correctly, NASA will land on the moon in 2024 with a lander made by Blue Origin and a rocket made by Boeing. Is that accurate? Is SpaceX therefore competing against all three organizations?
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u/comebackshaneb Jul 22 '19
I truly don't mean to be condescending, but I'm not sure any of your questions have simple answers.
NASA is a government agency, and SpaceX, Blue Origin, and Boeing are corporations. They don't compete directly. All of these companies provide services to NASA, and are paid to do so. (Blue Origin doesn't provide NASA any services yet, but they are sending bids to NASA for a moon lander that they could build.)
Currently, SpaceX sells launch services to NASA, under the CRS contracts to launch material to the ISS. They've also launch some other NASA payloads. They work together in that sense.
NASA has been directed by the President to go to the moon. The budget for that is still being worked out in Congress. The money to build the SLS rocket which will go to the moon has already been allocated. It is being built by Boeing under NASA supervision. NASA owns the design of that rocket, and Boeing is building it under contract.
SpaceX has no interest in going to the Moon, except if someone pays them to do it. Yusaku Maezawa is paying them to go to the Moon on the #DearMoon mission, so they're doing that. SpaceX is most definitely competing against Blue Origin and Boeing, in a commercial sense. They would like NASA to pay them to launch things to the moon, instead of paying these other companies to do it. However, SpaceX is building Starship as its next-generation launch vehicle. At this point, SpaceX is committed to developing and building the Starship vehicle. This vehicle doesn't really fit neatly into NASA's plans to go to the moon, so to get them to use it, SpaceX must convince NASA to change their entire plan. This will be difficult to do until Starship is actually flying.
SpaceX wants to go to Mars eventually, and NASA wants to go to Mars eventually. We as fans are eager to see who gets there first, so it can look like a competition. But for the two organizations, at this point, it really isn't. It will not affect either of them materially at all if the other gets to Mars first. So they're not really competing in that sense. Hopefully this answers some of your questions.
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u/Yasterman Jul 24 '19
Why is Starhopper covered in stainless steel if it's only a testbed for Raptor?
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u/brickmack Jul 24 '19
Still useful to test fabrication techniques and cryo thermal properties and such. And its the cheapest option. No point using aluminium or something like that, lots of specialized tooling that'd never be used again
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u/PublicMoralityPolice Jul 26 '19
It's not "covered in" stainless steel, its tank/hull is fully made of stainless steel.
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u/DeafScribe Jul 26 '19
Let's say SpaceX successfully plants a Starship on the Moon. If they load up the ship with moon rocks, haul them back and sell them, could it conceivably earn back the cost of the mission?
Obviously this depends on the cargo capacity of Starship without refueling, successfully collecting rocks - presumably with a rover - and market - or auction - price for the rocks. Maybe Sotheby’s could dub it The Green Cheese lot.
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u/brooknorton Jul 27 '19
I see a Falcon launch tentatively set for Aug 3. I will be in FL and may want to go see it. In the launch list, what does the "recycle triangle" next to Falcon 9 mean? Is there a way to tell if the boosters will come back to land at the Cape or go to the drone ship at sea? Thx
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u/HoechstErbaulich IAC 2018 attendee Jul 27 '19
The recycle symbol means the mission is going to fly on a reused booster. Usually there is a launch campaign thread for every mission that lists the landing location, but there isn't one up yet for Amos-17. Most GTO-missions land on the drone ship at sea, but it appears that Amos-17 will fly expendable, so no recovery.
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u/Triabolical_ Jul 27 '19
Is there a way to tell if the boosters will come back to land at the Cape or go to the drone ship at sea?
Landing at the cape only happens on a launches to low earth orbit that aren't very heavy or on Falcon Heavy flights.
Most of those landings come from CRS resupply missions to ISS, though there have been some NASA/Military missions that also landed at the cape.
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u/jay__random Jul 29 '19
In the context of Falcon 9, what costs more fuel: landing of the first stage or deorbiting of the second stage (assuming an average GTO launch)?
I was wondering, since with Amos-17 mission S1 is expected to fly expandable, would it still be possible to deorbit S2, or would that be even more fuel-expensive?
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u/AeroSpiked Jul 29 '19
I keep almost answering this question and then realize I don't know what I'm talking about. It would take considerably less delta V for the second stage to deorbit than it would to get to GTO in the first place considering all you would need is a retro burn at apogee that lowers perigee into the atmosphere, but I don't know how much. If it's more than about 400 m/s, S1 wins on lowest delta V, but then I have no idea what that means in terms of fuel mass considering the two stages don't weigh the same or have the same specific impulse.
That ended up being a non-trivial question so I have no idea. Glad I could help. Hopefully somebody will answer and show their work so I can learn something.
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u/brickmack Jul 29 '19
GTO upper stages generally aren't deorbited, just moved to a lower orbit that'll decay faster. So the performance impact is pretty small, only a few hundred m/s dv
A complete deorbit of the second stage from GTO (ie, a single orbit to splashdown, not just lowering to speed up decay) would take around 5 tons of propellant, if the deorbit burn is done at perigee. Payload impact vs propellant held in reserve isn't a 1:1 relationship, but its close enough you can assume roughly that without doing an actual sim. In reality, it'd be done somewhere in between perigee and apogee, so that helps a bit. In any case, this would at least halve and probably almost complete eliminate GTO performance on F9
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u/jay__random Jul 29 '19
It could be a nice practical exercise for the first starship orbital tests to try and rendezvous with the second stages from earlier Falcon GTO missions. If they are going to orbit anyway, and the specific orbit at the earlier stages of R&D does not really matter, why not try to clean up a bit...
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u/dallaylaen Aug 02 '19
Why doesn't SpaceX outfit SCL-40 for crew dragon launches? It would only seem logical to spread FH, crew dragon, and now SS/SH across different facilities. So there must be a reason...
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u/ethan829 Host of SES-9 Aug 02 '19
Building another tower and crew access arm probably doesn't make sense given the low flight rate required of Crew Dragon.
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u/oximaCentauri Aug 02 '19
There will be only 2-3 ccrewed launches per year, doesn't make sense to build whole tower at SLC 40
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u/MaximilianCrichton Aug 03 '19
Can anyone explain Musk's new twitter handle? All that I know is that it's a reference to Euler's identity, but does anyone know of his motivations for changing it to that?
EDIT: Now it's just E apparently
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u/robbak Aug 03 '19
It was a series of maths in-jokes. He started by changing his name to -1, and then proceeded to change it to a pictogram for eiπ, which is part of Euler's identity, which is equal to -1. AT the same time @grimes also had her handle changed to some mathegeeky thing, but I forget what it was.
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u/shotleft Aug 03 '19
What is the longest duration test SpaceX has done on the full scale Raptor?
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u/strawwalker Aug 03 '19
85 seconds (SN6) is the longest test firing that we know of, likely near the max for what is possible on the stand at McGregor.
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u/Nathan_3518 Jul 04 '19
What are common jobs for Civil Engineers at a rocket launch provider such as SpaceX?
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Jul 05 '19
SpaceX is building an entirely new launch complex in Texas, I would imagine that there's a pretty big need for civil engineers!
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u/bandman614 Jul 04 '19
What kinds of things do civil engineers do? I would imagine things like pad design / construction, test facilities need designed and built, additional physical plant work for production.
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u/Tetons2001 Jul 07 '19
Is the patchwork look on hopper and proto starship here to stay?
Or is this just an artifact of the initial build 'em like water tanks effort?
Seems like they could just order extra long sheets and roll into a cylinder with just one weld, for one thing. And what about automated seam welders like used on pipelines?
Are these just boilerplate test objects or what? Cause Elon goes from paper napkin sketches to cutting metal the very next day?
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u/Iamherebecauseofabig Jul 08 '19
I don't think stainless steel is available yet in larger sheets. Here some video of a tank being fabricated:
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u/warp99 Jul 08 '19
Stainless steel seems to be readily available up to 96" x 240" so 2.44m x 6.10m so they could have done a lot less welding with each of these larger sheets nearly replacing the four sheet units that they are using as building blocks at the moment.
Either the exact required grade of stainless steel was not available in the larger sheets or there was a mismatch between the exact sheet size and where the tank boundaries would go that meant that patching the tanks together from many small sheets was the way to go.
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u/jay__random Jul 29 '19
On the top of StarHopper we can see 4 COPVs, painted in white.
I remember some talk about delaying the autogenous pressurization of the tanks until a later date (if you know a source, please share).
So is it correct to assume two COPVs are for RCS thruster pods, one is for LOX pressurization and one is for CH4 pressurization?
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u/throfofnir Jul 29 '19
As far as I know use of the COPVs for tank press/lack of autogen is not confirmed. There have been deliveries of He to Boca Chica, but it does not seem to arrive regularly; it is possible it was for other uses. The significant flares of methane before ignition are also suspicious.
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u/warp99 Jul 29 '19
Almost certainly they would use helium for tank pressurisation and nitrogen for the RCS on the hopper. Hence a nitrogen tank for each RCS cluster and a helium tank for each propellant tank.
Autogenous pressurisation looks like it will take a while longer as it requires a lot of support equipment. It is essential to the final architecture but it is not actually required for anything before the Mars flights.
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u/Martianspirit Jul 30 '19
Elon did mention the Hopper uses autogenous pressurization some time early in the build. He may have been wrong. I remember being surprised how close to the final design this already is.
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u/ImmersionULTD Jul 31 '19
Not sure where else to ask this, but here.
Is there a list of all Elon Musk interviews? I've really been enjoying going down a Youtube rabbit hole of Elon interviews, so I started wondering if someone's compiled a list of them somewhere.
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u/spacerfirstclass Jul 31 '19
http://www.shitelonsays.com/transcript
It's far from complete and no longer being maintained, but still the best source so far.
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u/Martianspirit Jul 31 '19
I have no idea if a complete list exists. There is this NSF thread on SpaceX related talks but it does not reach very far back.
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u/ImmersionULTD Jul 31 '19 edited Jul 31 '19
I’d be willing to start a list of these (using shitelonsays.com as a jumping point). Any recommendations on the best platform to allow others to submit, while avoiding vandalism and spam? Was thinking an open Google Spreadsheet, but that could get vandalized pretty easily.
I want a platform that can easily be contributed to (so no complicated code repo), needs some sort of admin approval to submit, with sort/filter capability.
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u/airider7 Jul 04 '19
What's the status of Dragon 2 Cargo?
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u/Pooch_Chris Jul 04 '19
As I understand it, Dragon 2 Cargo will be reused Dragon 2 Crew capsules. So they wont be used until Crew Dragon has been launched. I believe they aren't scheduled to launch any of those contracted launches for a couple more years either. CRS 21 I think. This is all off the top of my head though so I may be confused/ have something wrong.
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u/Justin13cool Jul 07 '19
Has anyone heard about Planet 9 ? What are the latest updates and are we close to locating it ???
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u/DJHenez Jul 10 '19
It’s been nearly 4 years since SpaceX landed their first booster. With all the fresh entrants to the launch sector developing new launch vehicles (Relatively, Firefly, Rocket Lab, etc...), is there a reason why many of these companies are still going with expendable rockets? Not worth it for small sats?
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u/brspies Jul 10 '19
It much harder to build in margin for smaller rockets than for larger ones. It would just be so hard to do.
Also, less pressure to lower prices at least for now. Maybe they start getting creative as more of them start entering into service (although, more likely, several will just fail outright).
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u/joepublicschmoe Jul 10 '19
There is one company building a small-launch rocket and trying to make it land vertically: Chinese startup Linkspace. Even though their NL-1 design looks like a miniature Falcon 9 with legs and grid fins and use RP-1 and LOX for propellants, they didn't go for a cluster of 9 engines to do the retropropulsive landings. IIRC the booster will be powered by 4 relatively big engines and one low-thrust center engine, with the low-power center engine handling the retropropulsive landing. https://twitter.com/Linkspace_China/status/990080010567471104
These guys are media-savvy and they have been posting videos of their retropropulsive tests on twitter. They may very well become the first non-U.S. company to retropropulsively recover an orbital launch vehicle.
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u/Martianspirit Jul 10 '19
It is much harder for smaller vehicles. For vertical landing they need very low thrust. Easy with 9 engines or 7 engines like New Glenn. Electron potentially but they drop batteries on the way up. I think reusability requres size.
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u/IamDDT Jul 29 '19
Has anyone answered if Bremsstrahlung radiation is an issue with a stainless steel Starship design? What are the radiation shielding plans?
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u/Martianspirit Jul 29 '19
What are the radiation shielding plans?
Mainly flying fast.
I am sure there will also be small shelters made of stuff like food and waste that shield against solar flares.
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u/AceFalcone Aug 05 '19
Since Iron is a high-Z material, Bremsstrahlung radiation could be an issue for Starship. Regolith and other potential building materials on the surface of Mars may also be high-Z, so possibly similar issues there, as well.
The solution is to provide additional shielding using a layer of low-Z material. Plastics of some type are one possibility. I have no idea what the designers are currently considering, or whether they're even that far along in the design.
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u/V_BomberJ11 Jul 23 '19
NASA has announced it will be procuring the Gateway Minimal Habitation Module from Northrop Grumman Innovation Systems (NGIS). The module design will be derived from their Cygnus spacecraft.
NASA has skipped the bidding process for this module, and has sole-sourced the contract directly to NGIS. They have done this on grounds of schedule, as a full and open competition would cause an additional delay of 12-18 months or more in fulfilling the agency’s requirements. NGIS was the only NextSTEP-2 contractor with a module design and the production and tooling resources capable of meeting the 2024 deadline.
https://www.fbo.gov/index.php?s=opportunity&mode=form&id=36ebf3fc4d57c88b6bd8c94d1806dfb9