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Space X CR6 First stage landing
- trurl 12y ago"Just Read the Instructions"? Sounds very Culturey.
- TeMPOraL 12y agoThat's straight from Banks. As is the other barge, that is to be named "Of Course I Still Love You". http://www.tor.com/blogs/2015/01/elon-musk-iain-m-banks-just-read-the-instructions http://www.tor.com/blogs/2015/01/elon-musk-iain-m-banks-just...
- dperfect 12y agoAs if this weren't impressive enough already, according to a comment made by Scott Manley[1] it sounds like the final maneuver (where it appears the rocket is making a fairly strong lateral correction) is entirely intentional. Not sure if anyone here can confirm or deny the claim, but apparently the trajectory prior to landing is not supposed to be exactly above the barge as one would expect - I understand it may be an attempt to limit exposure/damage to the barge in case of failure. [1] https://www.youtube.com/watch?v=C9I55o8hQgs https://www.youtube.com/watch?v=C9I55o8hQgs
- zaroth 12y agoI was wondering about that too! I guess it does make sense if the final burn fails to not have a fairly large bomb dropping at terminal velocity directly onto the barge! On land I guess less of a difference though...
- andygates 12y agoNot terminal velocity, just fairly fast: there's a deceleration burn earlier in the descent plan. If that doesn't work, the big red abort button can be used to blow it up at high altitude.
- Shivetya 12y agojust the fact they can hit a barge after falling back from space impresses me. I wonder if there are any islands they could use instead, surely they had to have looked for one. Would a stationary oil platform work better?
- noselasd 12y agoThey do launches with different trajectories, so you'll run out of fuel if the landing site is fixed and you're launching the rocket in another direction. Besides, you'll anyway need something to transport it back to mainland. If all this goes well though, the intention is to eventually fly it back and land it on the mainland.
- vidarh 12y agoA volcano base if one is to judge by Elon's tweets.
- spectrum1234 12y agoThis is pretty fascinating and makes a lot of sense. You obv want to land very slowly, but going slow means less control to keep it vertical. So the clever work around is use thrust at the last second which will allow it to also be vertical and stable. And that means coming in from a non vertical angle beforehand which is exactly what they do.
- transfire 12y agoIts tail is wagging way to much. Landing will always be a crap shoot if they don't get that stabilized.
- TeMPOraL 12y agoYou mean thrust vectoring? It's intentional, it's how the rocket steers itself.
- natarius4k 12y agoMakes me wonder if they just leave them on the ground of the ocean or recover them? ...I bet otherwise the Russians or Chinese would love to get their hands one of them :)
- 31reasons 12y agoChinese are just waiting until it succeeds. Their hackers are probably on stand-by to download the blueprints and the code. lol
- jordanthoms 12y agoIt's interesting to think that if you are building rockets, up til now you've never really gotten to take the rocket apart _after_ flying it - it's burnt up in the atmosphere or at the bottom of the ocean somewhere. I imagine there will be lots of interesting insights that come out of recovering, undamaged, a flown first stage and taking it apart to see what's experienced wear etc.
- vinkelhake 12y agoNASA has been recovering their rockets from ocean landings for some time. See: https://www.youtube.com/watch?v=Gbtulv0mnlU https://www.youtube.com/watch?v=Gbtulv0mnlU
- TeMPOraL 12y agoBut only after getting them totally messed up by salt water. Also, those were solid-fuel rockets, which are significantly simpler than liquid-fuel ones. There's probably a lot to learn from an undamaged liquid-fuel first stage that went to space.
- agumonkey 12y agoSomeone on ArsTechnica said it was a sticky valve causing thrust lag and trajectory swing.. anyone thought the same ?
- mladenkovacevic 12y agoIt must be amazing working in a field where failure is almost as exciting as success. What's the main obstacle to slowing down and stabilizing the rocket on its descent to the platform? Is it just a matter of speed or also the shape of the rocket and its center of gravity? Would a set of 3 parachutes might slow it down a little bit or at the very least straighten it before the rockets need to kick in saving some fuel?
- jccooper 12y agoSpaceX seems to be able to stabilize fine with RCS and/or their grid fins. The rocket design must be reasonably stable--even tail-first. I don't think incoming velocity is much of a problem. Terminal velocity is gonna be no more than 90 m/s. The engines on that stage are more than capable of slowing it down--and fast. In fact, they're too powerful--it can't hover.
- mladenkovacevic 12y agoIf it's a matter of control then all it needs is just a bit more fine tuning. My money is on success next time they try it.
- zaroth 12y agoIt was jaw dropping as-is, but when they finally do stick a landing I imagine the engineers will be running around like little kids screaming with the pure joy and exhilaration of it all. I hope they share the video at mission control as well when the day does come! The sheer drama of how fast it comes down, the awesome power of the Merlin engine just blasting away delta-v... I wonder how many g's it takes on that final burn? Would a drougue have simply added too much weight or too much complexity to deploy? I guess slowing down the freefall velocity before the burn just doesn't really help all that much? Amazing that Falcon Heavy will have 27 Merlins on board.
- jccooper 12y agoA drogue would seem unnecessary; a Merlin can scrub off plenty of m/s real fast, and if it can't do it fast enough, they have more of them. In fact, it might be easier if the thing is coming in faster, because you get to run the engine a bit longer and have more time to adjust your aim with the engine's greater control authority. Anyway, they don't seem to have any problem managing the vertical velocity. It's been the horizontal each time. And this time, only a tiny bit off.
- frakkingcylons 12y agoA drogue chute strong enough to avoid shredding at these speeds would be too heavy.
- justin66 12y ago> Would a drougue have simply added too much weight or too much complexity to deploy? Never mind the weight: the problem sited with this landing was excessive lateral velocity. A drogue chute would have the potential to make that problem worse rather than better.
- atroyn 12y agoI can't help but feel bad for that one poor little RCS thruster doing its level best to keep the first stage upright, but ultimately running out of fuel.
- hyperbovine 12y agoJudging from the ensuing explosion there was still fuel left over.
- sfeng 12y agoThe RCS thrusters are powered by compressed nitrogen, not the rocket fuel that powers the main engines.
- acadien 12y agoMusk commented himself on twitter something to the effect that the explosion is from the pressure difference of the fuel canister when it is breached. Also the fuel mostly burned at high heat and didn't explode per say.
- darkmighty 12y agoMaking it a little puzzling ask to why the engines didn't try harder to lower the vertical velocity on approach. Perhaps there are improvements to be made in the control systems.
- fleitz 12y agoI have a feeling their engineers may have considered this. This is after all rocket science.
- darkmighty 12y agoI also have this feeling, but from my limited experience with control systems you might want to try the simplest first. There is a tremendous amount of variables to consider, and the analysis of how to take each into account is non trivial -- if you don't measure some variable precisely enough it might make the whole system less stable, the solution might get worse due to increased computational load, the conditioning might degrade, etc. So with the number of controls they have and the predictive models available, I'm sure they're actually scrambling to refine their systems right now.
- filvdg 12y agothis footage give a real sense of how close they are to getting it right
- NDizzle 12y agoWatching this footage made me immediately go to SpaceX's website and look at job openings.
- mrep 12y agoI agree. I feel like if they had a larger area to land on they would be able to get it. That way, they could focus less on pinpointing the exact position, and more on keeping it upright and stable.
- waterlesscloud 12y agoWatching it made me realize I only had an abstract idea of how difficult it was to even attempt this. It's insanely hard, and they're so close!
- 31reasons 12y agoYes its a very hard problem but what makes it hard ? Is it engineering of the components, algorithms or expensive tests and economics of it ? Maybe people before Elon Musk were not interested in solving this problem not because its technically hard problem but because their existing business model is much more lucrative.
- imaginenore 12y agoYou have to deal with real physics and the real physical world - turbulence, friction, lag, wind, waves, none of which are predictable.
- InclinedPlane 12y agoIt's hard not because the engineering is fundamentally difficult (it's challenging but compared to a lot of engineering problems not terribly so) but rather because it's very unforgiving and it takes a great deal of foresight and risk management / business savvy to do what SpaceX has done efficiently and cost effectively. Look at a couple of the issues they've faced and managed to deftly conquer. Take vehicle design, for example. If you design a purely expendable launcher you tend to want to minimize engine count and concentrate on 2nd stage performance, which leads to a design with an expensive 2nd stage and a cheaper 1st stage with very little throttle authority (due to using a small number of engines). That makes reuse very difficult and not very worthwhile because you'd need to either try to reuse the 2nd stage (a much more challenging task) or to heavily modify the 1st stage, which would then only save the cheapest component of the launcher. So if you want to concentrate on reuse you need a vehicle like the F9, with lots of 1st stage engines, and most of the cost in the 1st stage. But even then you need to figure out how to run your business. It would be easier to envision the launcher with reuse an integral part of the design from day 1, which would lead you towards testing the reusability aspects of the design prior to the first launch. But that would be tremendously expensive and would make it more difficult to keep a company running while that was going on. SpaceX has been able to provide numerous orbital launches with their rocket and earn a tremendous amount of revenue before it is capable of actually being operated in a reusable fashion. A common engineering dictum is "you ain't gonna need it", to avoid introducing unnecessary design elements that aren't strictly immediately necessary. But without designing the Falcon 9 with reuse in mind from day 1 they would have had a much more difficult time in developing the reusable aspects. Note that SpaceX has made use of hundreds of millions of dollars of flight hardware in their various landing tests, all of which they not only didn't have to pay for out of pocket but actually earned a profit for. That's smart business. Meanwhile, for all of the launches where they haven't attempted landings they've added operational experience and real-world testing of their overall vehicle design and components. Big, bureaucratic companies that are bringing in billions a year in revenues (like ULA or Arianespace) don't tend to engage in behavior like this, because they don't have the hunger, they don't have the boldness, they don't have the coherent foresight. What SpaceX has done is something that a lot of other companies are going to replicate, likely fairly successfully, once it's been proven. But getting to that point has required not just engineering acumen but enormous risk management skills and business savvy. They'll have a significant market advantage due to their head start for quite some time, and hopefully they will retain enough boldness and savvy to continue moving ahead even as others attempt to catch up.
- shiftpgdn 12y agoWhy did it explode in such a dramatic fashion? I thought the booster was almost entirely empty when it returns to the barge.
- richeb 12y agoIf you think that was dramatic, look up on YouTube some rocket explosions on the launchpad when the tanks are full.
- benihana 12y agoYep, it's almost empty. It shows how much stored energy rockets deal with and how hard it is to get out of this gravity well we call home.
- revelation 12y agoIt's hard to appreciate the energy density of the fuel they're using, but this makes for a good example.
- nickff 12y agoThere is always some extra fuel and oxidizer, as it is used to slow the vehicle, and is needed until touchdown. If the vehicle were to run out of propellant before landing, it would crash. In addition, the LOX makes any combustion spectacular.
- melling 12y agoComplete destruction is obviously expensive. Finding a way to prevent an explosion if it falls over after landing seems worthwhile. If it hovered for 5 seconds at .5 meters, for example, could it burn off enough extra fuel?
- cryptoz 12y ago> If it hovered for 5 seconds at .5 meters, for example, could it burn off enough extra fuel? The Falcon 9 cannot hover. The thrust of the single landing engine, even when throttled down to minimum, will provide significant lift to the empty rocket. That's part of what makes this maneuver so difficult and so awesome: it's called the hoverslam, where you achieve 0m altitude and 0m/s velocity at time = 0. For reference, though, the Grasshopper/F9R-dev1, could hover due to it only having 3 engines, not 9, and because they could ballast it with additional fuel.
- corywright 12y agoThis is an "unpublished video" on a non-SpaceX YouTube channel. Who uploaded this?
- stevesearer 12y agoAlso somewhat interesting that it appears to be the same angle as the official video posted to Vine [1], only in drastically higher quality. [1] https://vine.co/v/euEpIVegiIx https://vine.co/v/euEpIVegiIx
- smackfu 12y agoAnd the vine stops before the explosion.
- atroyn 12y agoThe video appears to be a leak from inside Space X.
- palebluedot 12y agoFrom reading the comments over on /r/spacex, this looks to originally have been an unlisted video in SpaceX's youtube channel, and shortly after appearing on reddit it was made private. Not before several people had made copies, however, and re-uploaded it (one of those people has the same reddit username as the youtube channel linked here). That said, impressive video. This shows how close they are truly getting. Unfortunately, it doesn't stop clickbait headlines that imply that this was a setback (for a while, drudgereport was running a story with the headline akin to "SpaceX rocket fails to land on landing pad"). Maybe that is why the video was made private, out of fear of appearing like a failure. Of course, now that the cat is out of the bag they are better off embracing the video.
- hydrogen18 12y agoOne great thing about being a government contractor: Public opinion isn't something you need to worry about.
- 12y ago
- swamp40 12y agoWhat happens once it lands successfully? Won't one stray wave tip it right over into the ocean? Those landing struts are only 1/10 the length of the rocket. If this wasn't so tall, it wouldn't be nearly the problem that it is. Are they perhaps really trying to develop a Dragon landing system? And using this extra tall rocket as a worst-case scenario?
- atroyn 12y agoSpace X would like to return Falcon to dry land, but given the high chance of failure, they're first trying to do it on the drone ship "Just Read the Instructions" at sea. That way when things go wrong, it's not such a big deal.
- stevesearer 12y agoThe goal of the barge landings is to prove they can land precisely in a targeted position repeatedly to prove they are able to touchdown on land without accidentally hitting populated places.
- smackfu 12y agoSince it's empty of fuel, and has big metal engines at the very bottom, the center of gravity is surprisingly low. So it should be fairly stable immediately after landing. And then they plan to secure it so it stays upright.
- Osmium 12y agoI'm not an expert, but here's my understanding: > What happens once it lands successfully? It becomes a lot easier to get permission to attempt a landing on dry land. But, as I understand it, they will always need to land some rockets at sea. In the long run, they hope that they can then re-use the rocket, which will drastically reduce the cost of launches. > Are they perhaps really trying to develop a Dragon landing system? They almost certainly are, but this is unrelated to that, I believe. > And using this extra tall rocket as a worst-case scenario? No. The length of the rocket is ultimately determined by the amount of fuel it needs to carry. The first stage will always be very long like this. Note that this rocket came from a successful mission which launched a Dragon capsule to the ISS on a re-supply/science mission.
- DannoHung 12y agoSuch a bummer! So close. Keep it up guys, you'll get it soon!
- atroyn 12y agoThat's two for two for getting to the ship, definitely not a bummer!
- rebootthesystem 12y agoNon-engineers see this as a failure. Engineers and scientists see this as an awe-inspiring success from which to learn, iterate and try again. I don't fault reporters for exagerated headlined focusing on failure. They don't know any better. That is not what their lives are about and most might be challenged to understand that nothing in that video constitutes failure in the context of evolving a design. In fact, failure is absolutely necessary in order to better understand the problem you are trying to solve.
- _Adam 12y agoI don't agree that failure is absolutely necessary. I think success is generally more informative, because it gives you data about something that works end to end. If your rocket blows up on the launch pad, you just learned that you shouldn't overpressure your fuel tank (or w/e). But if your rocket lifts off, goes to space, and lands, you learn thousands of things that work that you can use again.
- deeviant 12y agoI strongly disagree. I have seen a company be destroyed because they got things almost right, from the beginning. This "success" informed their every decision and created an enormous resistance to trying anything new and in the end it turned out almost simply wasn't good enough. The initial success destroyed them.
- hga 12y agoThat destroyed two Space Shuttles and killed their crews. Both the failing field joints ("O-rings") and detaching external tank insulation weren't quite bad enough to kill a Shuttle, were all but ignored, until of course they couldn't be ignored.
- robryan 12y agoI agree, this video makes it look like there was a strong chance that it could have been a success if the random variables on the way down aligned better. If it had of been they may not have learned and iterated based on this possibility and may have had a failure down the track.
- ufmace 12y agoAnybody know anything about the tech they're using to guide the stage to the barge? Since the flight is so short, I suppose they could get a GPS position on the barge at liftoff and pre-program that as the initial target, but I'd think they need some kind of terminal guidance actually tracking the barge to hit it reliably. Maybe visual or radar, or a radio beacon or something?
- mark-r 12y agoI've always imagined that the big bulls-eye wasn't painted on the barge just for decoration. I don't have any hard info though. Come to think of it, it would be hard to get video through the rocket exhaust.
- grecy 12y agoOn the live feed, just after +1:30 I heard "Recovery platform has acquisition signal"
- magic5227 12y agoI almost think it would be easier to let it do what this video shows, and build a giant metal net to just prevent it from sinking. Or is that harder than landing on a small platform?
- Throwaway90283 12y agoIt looks small in the video, but that first stage is the height of a 20 story building. It can't tip over without destroying itself, and it's not something you want to get wet.
- mb_72 12y agoMy thoughts too, but I guess any ingress of sea water makes it necessary to junk the engines. Also, once you've solved the 'landing problem' once, presumably the method can be reused on each and every subsequent landing; if you are looking at many such landings it becomes worth doing it 'once' and properly.
- TeMPOraL 12y ago> if you are looking at many such landings it becomes worth doing it 'once' and properly. Yup; the point is, SpaceX is not trying to just recover the first stage, they're trying to solve the vertical-landing of rockets for rapid reusability - which is vital not only for cost reduction, but for their plans to go to Mars. Because if they solve landing here, they can use the very same technique to land on Moon, Mars and other planets.
- ansible 12y agoThe goal is not to recover the stage per-se, but to land successfully. If they get a the 1st stage down on the drone ship, with all four legs touching, the main engine shut off, and it stays upright for even a few seconds, there will be much celebration. They would, of course, want to then actually examine the rocket afterwards, but that is a bonus.
- solve 12y agoSeems that the control system only tries to guide it on the X & Y axis, but if I was controlling it and saw it coming in at that steep angle, I'd fire hard on the Z axis to try to raise it up, fix the angle, and then lower it down again. Is it correct to say that this landing control system never tries raising the craft vertically?
- grecy 12y agoIt's tricky because it can't hover, one engine on minimum provides too much thrust. So if you do raise it up, you'd have to stop the engine, then wait a little and re-light it again.. which I think is tricky to do, and the engines only have so many "re-light" cycles in them, so you don't want to use up too many , else you can't re-use the thing for another real flight.
- pjc50 12y agoThey can't turn it off and on. They can restart it once and it has too much minimum thrust to hover.
- grecy 12y agoWe know it does three separate burns while coming back down (Boostback, entry burn, landing burn). I wonder if each burn starts with the RCS thrusters to turn the stage "nose up". i.e. when it's free falling, does it always roll around and fall nose down, requiring RCS to get it back to nose up? It would be awesome to see footage from the entire return trip. Do they have cameras mounted on stage 1?
- rdoherty 12y agoFrom what I've seen there are vanes on the top that guide it down, keeping it upright during reentry and descent. http://images.gizmag.com/inline/crs-5-crash-5.jpg http://images.gizmag.com/inline/crs-5-crash-5.jpg
- cfreeman 12y agoThey're called grid fins: http://en.wikipedia.org/wiki/Grid_fin http://en.wikipedia.org/wiki/Grid_fin I believe they are less to "keep it upright", but for better accuracy. The rocket doesn't really having a hard time staying upright because all of the weight is on the bottom where the engines are.
- hurin 12y agoQuestion: Why don't they land into the water instead of a hard surface? (Wouldn't this give them more leeway in terms of impulse?) Edit: i.e. landing on a net stretched (under the lake/ocean-surface) by 3 or 4 ships - reel the net it in to raise stage out of the water, I'm pretty sure seawater is not significantly corrosive from 2-3 hours of exposure.
- hydrogen18 12y agoThis how NASA recovered the SRBs. They landed upright, much like SpaceX's rocket. They were bouyant and floated vertically. The tender would approach the SRB, hook onto it, pump more water into it so it would sink. It would then carry it horizontally back to land. Seawater is incredibly corrosive and as it evaporates it leaves behind a fine layer of sea salt. Since these were SRBs, they had few moving parts. They were completely disassembled and the individual components were inspected and recertified prior to the next launch. Also, just to give you some scale of how crazy the Space Shuttle program was: the SRBs are the largest lift platform that was ever in use. ICBMs are fireworks compared to them. To land in the water, the SRBs needed not one but 3 of the largest parachutes ever produced.
- TeMPOraL 12y agoCorrect me if I'm wrong, but AFAIR SRBs weren't really reused, it was cheaper to make new ones than refurbish those they fished out.
- hydrogen18 12y agohttps://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Booster#Descent_and_recovery https://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Boo... Some of the parts from the first missions were re used on the last. The SRBs weren't disposable, but they were essentially refurbished after each launch.
- rdoherty 12y agoThey have landed it in the water once as a proof of concept. Seawater is very corrosive and would require cleaning & inspection of nearly all the components. Landing on a dry surface means they can eventually reuse rockets soon after landing (a few days I believe).
- lotsofmangos 12y agoI wonder if you could put thrust deflectors on the legs, then vary the fold out to help stabilise it just before landing.
- grecy 12y agoElon says it's in slow motion too "High resolution, color corrected, slow motion rocket landing video https://youtu.be/BhMSzC1crr0" https://youtu.be/BhMSzC1crr0" https://twitter.com/elonmusk/status/588463193070022656 https://twitter.com/elonmusk/status/588463193070022656
- monk_e_boy 12y agoHow high did it get? Does it burn the whole way down (I assume it uses those little X-wings to 'fly down?) When does it start the descent burn? How fast is it going at this point? How much does it weigh, what sort of forces are we talking about? How hard is landing this puppy in terms of human achievement? Top 10% of tricky things humans have so far achieved? [edit] wouldn't it be easier to hover it a few meters above land and grab it with some big robot arms?
- sfeng 12y agoIt burns three times after the second stage detaches. The first is to get the landing zone closer to the takeoff, the second slows it down from 1300 m/s to about 250 m/s, the third slows it to (hopefully) 0 m/s on the landing pad. Here's a diagram: http://media2.s-nbcnews.com/i/newscms/2014_51/812491/141217-launchprofile_f4fcb1ed474952c078a75c07a96cae6f.jpg http://media2.s-nbcnews.com/i/newscms/2014_51/812491/141217-... If the 'x-wings' are what I think you're referring to, they're the landing legs. They are shaped like that to have as minimal impact on the air resistance of the ascending rocket as is possible. They open just before landing. It can't hover. Even just using a single one of the nine engines, the engine can't be throttled down enough for the rocket to hover. The landing method relies on what they call a 'hover-slam', where they fire the engine during landing to slow it down just before it touches. Landing this is extremely impressive. It is going four times faster than the speed of sound, and they are landing it on a pad smaller than a football field. Vertical landing of a returning rocket has never been done. It's also the key step in the process of dramatically lowering the cost of spaceflight which could usher in a new era of technology around earth, and on other planets.
- monk_e_boy 12y ago
- staunch 12y agoThe best part of their reusable rocket project is how incremental the progress has been. I'm not sure I would have appreciated the difficulty of what they're doing as much without these failures.
- bane 12y agoEven cooler is how they're pulling off these tests on production flights.
- jozzas 12y agoGetting paid to develop product features is the best way to do it!
- calinet6 12y agoA ton of lessons here. If you deliver your primary objectives well and keep improving at everything else in the process, your customers will keep on loving you for it.
- trose 12y agoTHE best part in my opinion is that they live stream every mission and are very transparent about failures. I think they realize how many geeks and engineers are watching and that we understand that failure !== defeat.
- Rapzid 12y agoI wonder what happened there. Looks at 4 seconds the guidance system figured it needed to pull an ultra manoeuvre to slow the the horizontal speed(was drifting left) but ended up with a solution putting the rocket upright again at nearly 0m. If it would have left some altitude for stabilizing I think they would have had it. Arm chair rocket science is fun.
- TeMPOraL 12y agoAccording to Elon's tweet that seems to have disappeared by now, they had static friction in bipropellant valves introduce a lag that the control system couldn't handle.
- Rapzid 12y agoIt made a solid effort.
- TeMPOraL 12y agoThat it did, and it almost succeeded.
- shostack 12y agoCan you or someone else please explain what that means in slightly less technical terms without dumbing it down too much?
- jffry 12y agoSo presumably this is a valve controlling fuel flow to the engine. The valve is hooked up to some form of motor/actuator, and the rocket's control system needs to open/close the valve to control some aspect of the thrust. Since valves cannot open instantaneously, the control system has to know how long the valve takes to open/close, and start that process a little bit early so the valve is open when it needs to be open. If something goes wrong with the valve, it doesn't open as quickly, and so the computer model thinks it should be open and isn't, which could easily go off into an unstable state.
- dude3 12y agoIt looks like the main engines didn't cut quick enough.
- socialist_coder 12y agoIs there a reason you couldn't have things on the side of the landing pad that "grab" onto it and secure it? It could be as simple as a huge ring of cable that just closes around the top of the rocket, then pulls it tight on all sides- like the guidelines on a tower to keep it stable. Maybe they don't want to do that because they think they can do it without it?
- iyn 12y agoI was thinking the same, seems that it would be the easiest way to stabilize the rocket. I'm curious what were the reasons for not using this idea - for sure they though about it, but concluded that the current way is better.
- TeMPOraL 12y ago> Maybe they don't want to do that because they think they can do it without it? If they master vertical landing without external support equipment, they can pull it off on Mars as well. I think that's their other goal here.
- NamTaf 12y agoThat's certainly the case. It has to be entirely self-contained to the rocket.
- polemic 12y agoIt might also be that the structural changes required to handle a grabbing force would be too extreme. At that point it's basically a thin shell, so a grabber or cable might just slice it. I like the 'but then it can't land on mars' answer too though.
- Lorento 12y agoIf you want a more intuitive mechanical system, see the Boeing/somebody 1st stage engine recovery plan that uses a heat shield and parachute to land just the engine, not the whole stage body. Don't forget the barge is also actively controlled to keep it stable. If you have sufficient control systems, you don't need mechanical aids. Just like humans can walk on two legs every day our whole lives using our brains, so we don't need four for "extra safety".
- bane 12y agoPretty inspiring after all this time that the problem is not so much getting stuff up, but landing it successfully. I kind of feel like this is where we should have been in the 70s.
- jfoutz 12y agoPretty sure the original plan was mars after the moon. The cold war shifted away from the space race, and we built skylab instead. Some of the mars plans were pretty crazy. send 3 rockets. 1 with crew and supplies, 2 for the return trip. 2 just in case something went wrong.
- paulddraper 12y agoThat's tricky stuff. What was the intention behind not doing a water landing, like with the Space Shuttle boosters/tank?
- scott_karana 12y agoI think the plan is to eventually land it somewhere that it can be checked, refueled, and sent straight back to space. The barge, I suspect, is simply for safety/liability at this point ;) (Even if I'm dead wrong, and they want to land it on a barge forever: seawater is some nasty, corrosive shit that I wouldn't want my rocket dunked into! :)
- pixie_ 12y agoMars doesn't have water.
- ezegolub 12y agoAny info on how much damage the barge took from that explosion?
- sheerun 12y ago"Droneship is fine. No hull breach and repairs are minor. Impact overpressure is closer to a fast fire than an explosion." https://twitter.com/elonmusk/status/588490238936240129 https://twitter.com/elonmusk/status/588490238936240129
- Udik 12y agoCome on people, have a go at it yourselves: http://moonlander.seb.ly/ http://moonlander.seb.ly/
- will_hughes 12y agoSomeone needs to make a version of this for a Falcon9.
- Veratyr 12y agoOr even better: https://kerbalspaceprogram.com/ https://kerbalspaceprogram.com/
- obituary_latte 12y agoWas this filmed from a drone? I couldn't find any info.
- tommoor 12y agoIn the middle of the ocean It seems doubtful... I'm also intrigued by the angle - maybe a helicopter?
- obituary_latte 12y agoPlausible it could be launched from the landing platform prior to the attempt. Although, you'd think a drone could have a closer viewpoint. Anyway, very cool to see.
- sesutton 12y agoThe only thing I could find describes it as a "chase plane". I know one time they used Musk's private jet but I think that was an emergency replacement.
- mikeyouse 12y agoSpaceX has a chase plane that films the landings from afar; https://twitter.com/elonmusk/status/588142879245238273 https://twitter.com/elonmusk/status/588142879245238273 I can't seem to find what type of plane it is though.
- ezegolub 12y agoIf any of the engines has a TWR above one when landing, even at it's lowest setting, i can't help but wonder why don't they use a smaller engine which can be more effectively used to land. I'm sure theres a perfectly good reason for this, there's a reason SpaceX has its reputation, but i'm curious as to why.
- dlgeek 12y agoBecause the primary job of the engine is to get as massive a payload as they can to orbit, not to land. That's just a bonus.
- sfeng 12y agoFor one, developing reliable rocket engines takes a long time, you can't just whip up a new one. The current Merlin has a very large throttling range already when compared to existing engines. The size of the engines they use now is defined by the need to get payload's to space, the landing has to be secondary.
- simonh 12y agoGrasshopper was able to hover, or even perform a powered descent and was probably lighter than an F9 first stage, so I don't think this can't be it. They likely do have an engine configuration capable fo a lower minimum thrust, but they're choosing not to use it presumably because it's not optimal for the primary mission, and they believe it's not necessary for the landing.
- jccooper 12y agoMostly, I think, because they'd prefer to avoid having several types of engine involved. SpaceX is big on cost savings through commonality. The development and tooling and testing etc. for creating a smaller landing-only engine would probably cost darn near as much as for the main engines, so if you can get it done with them, it makes sense to do so. If they can't get them on the ground reliably with just the Merlins after trying enough, then maybe they'll do something like that. But if it's a simple matter of software and a handful of tests, as it seems may be the case, then they've saved a lot of effort and cost. The other answer is that the F9 architecture was designed (and flying) before this mode of recovery was "the one". And they'd prefer to not redesign the thing if it can work as-is. So they'll try it and see before spending gobs of money on a re-design. Rockets aren't software (except to the extent they are) and changing things about them is dangerous and expensive.
- rtpg 12y agothis might be a silly question but why can't they use parachutes? wouldn't a mostly empty rocket float? or is there an issue with the salt water and whatnot
- MrSourz 12y agoThey intend for it to land on land in the future, not out at sea. For that they cannot use parachutes.
- peeters 12y agoAnyone know how fast the engine's gimbal is? The video makes it look like the gimbal lags significantly behind the angle of the rocket, so even when you're rotating one way, you end up burning more toward that angle as the engine slowly gimbals to the other side. Granted, this is in slow motion. I just would've expected the engine to be gimballing to the other side even before there was a noticeable rotation.