Just 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.
It's not that they have been "unsuccessfully trying". They were not expecting to recover the previous launch vehicles. Instead, the past re-entry attempts have been entirely successful in that they have provided exactly what they expected to get out of the tests. Data.
The data from the last launch provided a lot of really crucial information that has informed design decisions made for this and following launches.
It's actually better if the next recovery fails too, at least if it happens in a way that provides really important data. This would then let them work out the engineering and science required to improve the design further.
"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.
Do 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.
Assuming "re-entry" means "to decelerate from (near) orbital velocity" and not "to pass from vacuum-to-atmosphere", isn't this a solved problem for fast high-altitude jets (e.g. SR-71 Blackbird, 3,529.6 km/h). Wait, I see the problem:
These 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.
If 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.
The 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.
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).
This 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).
Yes, 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.
I 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.
Remember the stage being retrieved to ground level weighs a lot less than the stage sitting on the launch pad, because it's empty. Grasshopper took off and landed on the same (permanently extended) legs, so its legs, like the undercarriage of an aircraft, had to be able to support not only the engine and big hollow tank, but a fuel load.
But the landing legs on the Falcon 9 first stage don't have to carry the weight of fuel fuel, never mind the weight of the second stage and payload and their fuel -- it launches from a pad and the legs only carry the dry stage at landing.
The empty first stage is bulky, but relatively light.
The real question in my mind is how much extra fuel it takes to re-light the first stage motor after separation and decelerate it to the point where it can land vertically. There's got to be quite a weight penalty in there. (Which AIUI is why the second-gen Falcon 9 first stage tankage is 30% bigger than the original. Fuel is cheap compared to precision engineering.)
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.
Even once they get the landing perfected, my concern would be the wear-and-tear of even a single launch of the rocket. It has to reduce the success probability of the next launch by some percentage.
No, 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).
Not 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.
KSP 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.
Just 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.
You 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.
[+] [-] gedmark|12 years ago|reply
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.
[+] [-] lholden|12 years ago|reply
The data from the last launch provided a lot of really crucial information that has informed design decisions made for this and following launches.
It's actually better if the next recovery fails too, at least if it happens in a way that provides really important data. This would then let them work out the engineering and science required to improve the design further.
[+] [-] aray|12 years ago|reply
This test isn't expected to be successful, either.
[+] [-] lutorm|12 years ago|reply
[+] [-] jessriedel|12 years ago|reply
https://www.youtube.com/watch?v=kJrFwxE3lzI
Is this video incomplete? Will both the 1st and 2nd stages will actually require re-entry shielding?
[+] [-] hyp0|12 years ago|reply
[+] [-] unknown|12 years ago|reply
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[+] [-] unknown|12 years ago|reply
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[+] [-] haswell|12 years ago|reply
http://new.livestream.com/spacex/events/2833937/statuses/480...
Next attempt will be April 18th.
[+] [-] pothibo|12 years ago|reply
[+] [-] Gravityloss|12 years ago|reply
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|12 years ago|reply
[+] [-] geerlingguy|12 years ago|reply
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).
[+] [-] rbanffy|12 years ago|reply
[+] [-] wolf550e|12 years ago|reply
http://www.spaceflightnow.com/falcon9/009/status.html
NASA live stream (higher resolution than above):
http://www.ustream.tv/nasahdtv
SpaceX live stream:
http://www.spacex.com/webcast/
[+] [-] coreymgilmore|12 years ago|reply
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|12 years ago|reply
[+] [-] troymc|12 years ago|reply
[+] [-] simonh|12 years ago|reply
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.
[+] [-] cstross|12 years ago|reply
But the landing legs on the Falcon 9 first stage don't have to carry the weight of fuel fuel, never mind the weight of the second stage and payload and their fuel -- it launches from a pad and the legs only carry the dry stage at landing.
The empty first stage is bulky, but relatively light.
The real question in my mind is how much extra fuel it takes to re-light the first stage motor after separation and decelerate it to the point where it can land vertically. There's got to be quite a weight penalty in there. (Which AIUI is why the second-gen Falcon 9 first stage tankage is 30% bigger than the original. Fuel is cheap compared to precision engineering.)
[+] [-] andymoe|12 years ago|reply
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.
[+] [-] Crito|12 years ago|reply
We have photographs of the actual production legs (folded away) on this current F9.
https://pbs.twimg.com/media/BlIDkwYCUAAiWXz.jpg:large https://pbs.twimg.com/media/BlL4V42IYAAgZ1J.jpg:large
[+] [-] jobu|12 years ago|reply
[+] [-] unreal37|12 years ago|reply
[+] [-] unknown|12 years ago|reply
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[+] [-] dm2|12 years ago|reply
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-...
[+] [-] InclinedPlane|12 years ago|reply
[+] [-] fit2rule|12 years ago|reply
http://www.space.com/23193-spacex-grasshopper-rocket-highest...
[+] [-] unknown|12 years ago|reply
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[+] [-] hyp0|12 years ago|reply
This is an incredibly significant step, and crucial for the long-term vision of cheap space-travel through reusable vehicles.
[+] [-] rkarachinsky|12 years ago|reply
[+] [-] nawitus|12 years ago|reply
[+] [-] callesgg|12 years ago|reply
[+] [-] JshWright|12 years ago|reply
[+] [-] yaur|12 years ago|reply
[+] [-] astrodust|12 years ago|reply
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.
[+] [-] unknown|12 years ago|reply
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[+] [-] api|12 years ago|reply
[+] [-] tensenki|12 years ago|reply
[+] [-] Crito|12 years ago|reply