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SpaceX CRS-3 launch scrubbed due to helium leak
- unreal37 13y agoInteresting, it's going to land vertically in water as if it was on land. Low chance of success (30-40%)
- deleted 13y ago[deleted]
- rkarachinsky 13y agoFYI, the launch itself will be at 4:58pm ET.
- nawitus 13y agoApparently that's 4:58pm in EDT, or 16:58 in EDT, or 20:58 in GMT (nearly UTC).
- IneffablePigeon 13y agoIf you're in the UK, remember we're on BST currently, so it'll be 21:58 here.
- aninhumer 13y agoThe difference between UTC and GMT is that GMT used to also refer to astronomical time (UTC-12), so UTC is preferred for clarity. They are otherwise identical, so "nearly" is just confusing here.
- nawitus 13y agoWikipedia states that GMT doesn't have a precise definition: "The term Greenwich Mean Time (GMT) does not have a precise definition at the sub-second level, but it is often considered equivalent to UTC or UT1. Saying "GMT" often implies either UTC or UT1 when used within informal or casual contexts. In technical contexts, usage of "GMT" is avoided; the unambiguous terminology "UTC" or "UT1" is preferred."
- aninhumer 13y agoYou are correct, and I should have been more precise in my criticism. Nonetheless I think describing GMT as "nearly UTC" isn't particularly helpful, since it's not defined accurately enough to be wrong. Furthermore, EDT is defined in terms of UTC, so there's no reason to mention GMT at all.
- nawitus 13y agoI think I mentioned GMT for it's familiarity. I think "nearly UTC" is fitting, as it's close to UTC even though it's not precisely defined.
- geerlingguy 13y agoThere's also a good thread with links, updates and commentary over on Reddit: http://www.reddit.com/r/spacex/comments/22zo8c/spacex_crs3_launch_updates_and_discussion/ http://www.reddit.com/r/spacex/comments/22zo8c/spacex_crs3_l... Launch time is 20:58:44 UTC (16:58:44 EDT), and of note, this launch will be deploying over a hundred femtosats, and will be SpaceX's first attempt at first stage vertical landing (over water).
- dm2 13y agoIs this one of their Grasshopper rockets? Apparently the name Grasshopper was just the name of the rocket during the tests, because I can't find that term used anywhere. http://www.nasaspaceflight.com/2014/02/spacex-crs-3-landing-legs-plan-first-stage-recovery-ambitions/ http://www.nasaspaceflight.com/2014/02/spacex-crs-3-landing-...
- fit2rule 13y agoI think you're referring to this rocket: http://www.space.com/23193-spacex-grasshopper-rocket-highest-hop-video.html http://www.space.com/23193-spacex-grasshopper-rocket-highest...
- deleted 13y ago[deleted]
- InclinedPlane 13y agoNo, this is a fully operational regular launch which will deliver cargo to the ISS. But it will have sufficient extra payload capacity to allow for this test (which will test some but not all of a reusable flight profile of the first stage including a controlled deceleration and hover burn but only over the ocean).
- dm2 13y agoSo this rocket is fully capable for vertical landing, they're just doing it over the ocean for safety reasons? That's awesome. Such a short time from initial testing to actual use. I wonder if they have a buoy or something for it to target.
- mscarborough 13y agoNot fully capable, they say 30-40% chance of success, but that it in any case, it will provide good data for future work.
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- coreymgilmore 13y agoThis is like "guess and check" method, just on steroids for rocket scientists. 30-40% sounds like a good enough percentage to me. If I remember correctly, it wasn't until the space shuttle solid rocket boosters that NASA managed to recover a 1st stage. SpaceX is a lot younger.
- JshWright 13y agoThis is a _completely_ different sort of recovery though. The Shuttle SRBs just fell into the ocean under parachutes. The F9 first stage will be 'landing' under its own power (after decelerating itself to reduce aerodynamic stresses).
- wolf550e 13y agoAlso, the SRBs were not "rapidly reusable", they were not simply refueled or merely refurbished. They went in sections back to Utah for essentially re-manufacturing. It was more expensive to reuse the SRBs than to buy new ones, but the decision was made to reuse because of prestige.
- Retric 13y agoI suspect it had less to do with prestige than jobs. A large chunk of the initial SRB cost was raw materials, more of the refurbishing costs was manpower. Congress critters dislike direct welfare but but put a fig leaf on it an call it a middle class job and there practically in love.
- troymc 13y agoYes, NASA did recover the shuttle's solid rocket boosters, but for a different definition of "recover." They fell into the ocean and required an expensive overhaul.
- coreymgilmore 13y agoMakes it that much more interesting that a private company is attempting to recover/reuse at a reasonable price. The cost saving should be substantial, but until the IPO we won't know! Also of note, the space shuttle missions were the first "reusable" systems. SpaceX is just starting out and they are already attempting it. Very cool!
- hyp0 13y agoThis would be awesome! Can you imagine seeing that thing land! Like the numerous very cool test flghts, up-down, but for real... This is an incredibly significant step, and crucial for the long-term vision of cheap space-travel through reusable vehicles.
- simonh 13y agoI obviously don't know what I'm talking about, but my main concern is the landing legs. Building deploy-able landing legs strong enough to handle a landing but light enough to make the concept viable isn't going to be easy. The leg frame on Grasshopper looks massively over-engineered, which is fine for a test vehicle but would be far too heavy for an actual launch vehicle. We have still to see the final leg design, and the ones in the CGI mockup video look, to my untrained eyes, very skinny. Grasshopper has proved the basics of the maneuvering and landing capability, but there's still a fair way to go.
- andymoe 13y agoHere is a close up of one of the legs: http://www.redorbit.com/news/space/1113080151/spacex-adds-landing-legs-falcon-9-rocket-022514/ http://www.redorbit.com/news/space/1113080151/spacex-adds-la... I'm pretty sure the landing legs will be fine if they can pull off the controlled burn and keep the rocket spin under control. The last time they tried this (without legs) the falcon 9 spun too fast in the atmosphere damaging the in tank baffles so that the fuel centrifuged causing the engines to go out on the second burn.
- simonh 13y agoNice picture, butI believe that article is inaccurate and misleading. The powered descents over the ocean were not intended to actually recover the stage, but just systems tests. To date Spacex has never actually attempted a recovery of any of their vehicles, but the article says they have tried an failed and are now trying an alternative method using legs, where in fact this was the plan all along.
- andymoe 13y agoI really just wanted to show you a pic of the legs. That article was the first thing that came up and you are correct.. I think the article is a bit off. SpaceX has, however, attempted the 2x engine restart on the first stage during decent once before per my previous comment. I've been following this extremely closely.
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- Gravityloss 13y agoIf the first stage reusability works fine and cost per flight goes down a lot, then it starts making sense to optimize the upper stage and spacecraft for lower cost per flight as well. (Because now, even if the first stage flight was free, the launch would still cost a huge amount of money.) In manned flights to low earth orbit, since the spacecraft reenters, at least that part could be reused. The second stage is hard to reuse because it flies so far downrange horizontally and reenters at very high speed. The engine also can't run low in the atmosphere, meaning somehow different recovery than for the first stage. The parts of the spacecraft that are not heat shielded (service module) will be sacrificed, but in the future the whole spacecraft might be a monolithic entity or even part of the second stage and do its mission and reenter and land as a whole.
- jcampbell1 13y agoThe first stage has 9 motors, and the second stage has 1. Recovering the 2nd stage seems incredibly difficult involving lots of compromises for a relatively small benefit. I'd invest engineering effort into making the first stage motors not require much re-manufacturing between flights. The cost savings are going to come from a first stage that is re-fill and go, vs completely disassemble the motors and rebuild and replace parts.
- Crito 13y agoAlso, although the first stage is quite large and has 9 engines, when it finally touches down it uses only the center engine, throttled down. Even using just that one engine, it produces too much thrust to hover (grasshopper can hover, but grasshopper is heavier than a returning F9 first stage). The second stage is meant for use in a vacuum so it's expansion nozzle is much larger, so perhaps that extra weight would balance things out a bit, but I suspect that the second stage would have a massive thrust/weight ratio when reentering almost empty. Makes things more challenging, even if the engine does work in atmosphere correctly.
- Gravityloss 13y agoAFAIK the second stage merlin with the big nozzle would have flow separation and would shake itself apart if fired at low altitude. IIRC The concept videos have shown separate smaller DRACO landing engines. Also used with Dragon for soft touchdown?
- wolf550e 13y agolive updates with video: http://www.spaceflightnow.com/falcon9/009/status.html http://www.spaceflightnow.com/falcon9/009/status.html NASA live stream (higher resolution than above): http://www.ustream.tv/nasahdtv http://www.ustream.tv/nasahdtv SpaceX live stream: http://www.spacex.com/webcast/ http://www.spacex.com/webcast/
- api 13y agoThis is IMHO bigger than Apollo. The moon missions were an expensive one-shot, while this has the potential to truly open the frontier.
- Crito 13y agoI'd save the "bigger than Apollo" language for the MCT/BFR. Those should be actually bigger than Apollo. ;)
- tensenki 13y agoYou think that recovering a rocket is bigger than landing on another planet? I've actually re-written this comment a couple times because I'm honestly not trying to say your opinion is stupid, but I cannot fathom how you have come to this conclusion.
- avar 13y agoHaving cheap & sustainable launch capabilities is going to be a much bigger deal in the long term than brute forcing your way to the Moon as a one-off by spending 1/20th of the US GDP over the period of a few years. After we have cheap & reusable rockets we'll have much larger leaps in space travel in the next 40 years than we have since the 40 years since Apollo.
- toufka 13y agoThey are very different in nature; first vs productive. In terms of literal impact on the future, this particular event is likely greater. In terms of name recognition, the Apollo missions certainly were greater. You probably know of the Model T, but don't know the first combustion engined car. Choose the MPMan, or the iPod for history? Who had more direct impact on the American Continent, the Spaniard, Columbus or the British Mayflower? Not saying I'd agree, but there's at least a reasonable rationale.
- syncsynchalt 13y ago(To put some words in the commenter's mouth) he's saying that a 90% cut in launch costs would be bigger than Apollo. In those terms, it's a defensible argument.
- gedmark 13y agoJust to set expectations, SpaceX has tried to recover the 1st stage of almost all of its launches to date. (Using just parachutes for most of them). They've yet to successfully recover a first stage. Their most recent test went pretty well all things considered. For the first time they tried a "death swoop" maneuver, turning the 1st stage 180 degrees around as it was starting to re-enter and refire some of the engines to slow it down. It picked up a nasty roll though and centrifuged the propellant, cutting the engines prematurely. They recovered some debris but that's about it. It's hard to overstate how big a deal it will be if they pull this off. But the odds of success are very low, given the propensity of these things to tumble and roll on reentry.
- aray 13y ago"This test is not a primary mission objective and has a low probability of success (30-40%), but we hope to gather as much data as possible to support future testing." This test isn't expected to be successful, either.
- jessriedel 13y agoDo you know how fast the Falcon 9 1st stage gets? Judging by the video animation of their long term re-usability plan, the 1st state separates before it achieves a velocity necessitating re-entry. https://www.youtube.com/watch?v=kJrFwxE3lzI https://www.youtube.com/watch?v=kJrFwxE3lzI Is this video incomplete? Will both the 1st and 2nd stages will actually require re-entry shielding?
- gedmark 13y agoJust from what I've read - At 1st stage separation the F9 is going Mach 10 at an altitude of 80km. There's no hard and fast definition of how high/fast you need to be going for it to count as a "re-entry", but that certainly qualifies.
- jessriedel 13y agoHey, thanks much. That's useful. For everyone else's information, low-earth orbit is ~8km/s, or Mach 24. According to Wikipedia, "Thermal control becomes a dominant design consideration" above Mach 10. https://en.wikipedia.org/wiki/Mach_number https://en.wikipedia.org/wiki/Mach_number If anyone knows anything about the how the first stage is shielded, I'd be very interested to know. In the artistic video, you can see a quick peak of the nose of the first stage. It's colored tan/yellow like the heat shield on the second stage, but there aren't many details. (Presumably, this was purposefully vague.)
- callesgg 13y agoSeams to me that a braking parachute could help enormously with the fuel economy of the landing.
- JshWright 13y agoNot really... you'd still have to do the earlier burns to slow the stage down enough that it doesn't break up in the atmosphere, and the burn to boost it back to the launch site. The parachutes would just save the final 'hover slam' burn, but the terminal velocity of a practically empty first stage is already pretty low, and the complexity of a parachute system wouldn't be offset by the minimal savings in speed reduction.
- bronson 13y agoPlus, if you're aiming for a target on the ground, the atmospheric effects (wind) on a parachute would be severe. You'd probably burn as much fuel recovering from the parachute's meandering miles off target as you would just slowing the ballistic final leg. (not sure though, -ENOMATH)
- rbanffy 13y agoIIRC, they actually considered it, but the parachute, plus its pyros and extra equipment were heavier than the extra fuel for braking. Parachutes are very useful when you don't have engines powerful enough to slow you down, but the whole purpose of this is the controlled landing of nine very powerful engines.
- astrodust 13y agoJust as realistic would be having a giant butterfly net that could catch it. It doesn't have to be a gentle landing, there's never going to be any people on board. It just has to not come apart in the process. A very high-g hard-stop could be cheaper in terms of weight than a giant parachute.
- yaur 13y agoKSP knowledge is both a plus and a minus here. If you have played it you know that once the chutes open you are going to land pretty much wherever they take you. OTOH in real Earth there are winds that are going to make it difficult to predict exactly where that is and there aren't hundreds of miles of open space where you can just oopsy your landing.
- haswell 13y agoSadly, the launch has been scrubbed due to a helium leak. http://new.livestream.com/spacex/events/2833937/statuses/48058415 http://new.livestream.com/spacex/events/2833937/statuses/480... Next attempt will be April 18th.
- pothibo 13y agoThese kind of things seem to happen often. I know helium is very hard to keep in containment due to it's atom size. Nonetheless, I wonder if there's technologies being developed right now that could fix that once and for all.
- Gravityloss 13y agoIf launches were more frequent, all these things would be ironed out.
- astrodust 13y agoDo you mean it's hard to contain because you have a gas comprised of tiny noble atoms versus hydrogen which is generally found in pairs?
- rbanffy 13y agoHelium atoms are also smaller than Hydrongen atoms and that makes it even easier for Helium to find its way around the smallest joints and seals.
- krasin 13y ago>Helium atoms are also smaller than Hydrogen atoms How is that? Hydrogen atom is one proton + one electron [1], and "Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with either one or two neutrons, depending on the isotope" [2] [1] http://en.wikipedia.org/wiki/Hydrogen_atom http://en.wikipedia.org/wiki/Hydrogen_atom [2] http://en.wikipedia.org/wiki/Helium_atom http://en.wikipedia.org/wiki/Helium_atom
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- rbanffy 13y agoI imagined the launch control announcing the abort with a chipmunk voice...