"Musk's video shows, when these things fail it's fairly spectacular, and he'd rather that was done safely out to sea."
Perfectly safe, except for the barge crew.
SpaceX boss Elon Musk has released video footage of the catastrophic attempt to land one of his multimillion-dollar Falcon 9 rockets on a floating ocean spaceport – revealing why the landing barge looked quite so toasted. This was the first attempt to land and secure the reusable stage of a Falcon 9 rocket after it had …
Maybe it wasn't very soft, but it was right on target. I figure the lack of fluid at the end led to the approach being just a stone's throw out of line. The auto-controller had been tasked to try to land the rocket on the barge, and not just wherever it happened to be when the surface was reached. When it became clear that the barge was not going to end up directly below the rocket, the controller did its best to make it so.
Pretty good placement, under difficult conditions too. Those low-angle rocket approaches are a bitch. But hey, at least some of the rocket landed (and stayed) on the barge, right?
If you can make it work reliably on water when the station keeping isn't necessarily exact and the waves will move the platform up and down to some extent, it adds an extra level of assurance that doing it on land will be problem free.
Still, hopefully when it is done on land that is very near a large body of water, or at least an uninhabited area like a desert, so there's a convenient place to abort to if problems are encountered on the descent.
Plenty of room at the Kennedy Space Center, and it's near the sea. By the time it's too late for Range Safety to blow it up over the ocean, it must surely be clear where it would hit the ground.
I don't see why landing a first stage should be any more dangerous than the actual launch.
I am afraid this is the difference between being financed by an engineering entrepreneur (REAL ONE, not a fake produced by a business school) and financed by grants.
Unfortunately, engineering entrepreneurship in UK is practically extinct. We have a country run by public school humanity graduates - top to bottom. Starting with a government without a single technically literate person in it and finishing with most companies down to ~ 200 people having no real engineers in their management. Disclaimer - real means having actually built something themselves instead of degenerating into PHBs from the first day of their career.
The very exemptions (Arm, etc) just go to emphasize the overall point.
I remember Musk explaining the "running out" part somewhere else- the equipment to recirculate the hydraulic-essential-media would have added more weight to the rocket than simply making the tank large enough, and hoping to estimate the correct amount of media they'd need. Guess what part of that went wrong.
It is not a closed system, it is an open system and yes it did "run out" of fluid. A recirculating pump for a small-tank closed system would have added more weight than having a big tank and a pumpless open system. Unfortunately the tank was not big enough by 10%, so next time's tank will be 50% bigger.
Get it within a few hundred feet of the ground, shut down all the rockets and catch it in a big net!
Seriously, more power to these guys for attempting this. They'll get it right eventually and in 50 years it'll be as every day as hover boards, flying cars and flux capacitors are now.
I read to just before your post so I could be sure all the children had had their say and that we could get on with a discussion.
Pity you were so slow to catch on. Maybe next time eh?
What is it about ramjets and paraffin that puts people off that sort of thing for re-entry vehicles?
I would have thought all the said fuel could be used up outbound and through docking/releasing cargo all the way maybe to re-entry then a switch over to said paraffin low cost cruising?
Whilst I agree that catching it in a big, rocket-proof net would be easier to an extent, it wouldn't be nearly as cool as a 1950s-sci-fi esque vertical landing.
And if there's one thing Musk and his companies seem to be a fan of, it's the Rule Of Cool.
Upvote delivered though...
By the time it's needed the vertical velocity is so low that the drogue would have no effect.
Also, landing on land - where? As someone else pointed out on another thread, the stage has
considerable velocity eastwards due to the rocket thrust. The next land is in Europe or Africa somewhere depending on the launch angle for the desired orbital inclination, and at least a couple of thousand miles away. It's probably a lot more economical on fuel to come down forward & bleeding off the forward speed on the way down rather than trying to send it back to Cape Canaveral. A sea platform recovery is probably going to be used, and be a (weather, sea state) constraint for some time to come.
Well the barge is being used for testing only at the moment. Once the (FAA) are happy with their accuracy they will land back at the cape.
Where the barge comes in long term is for their next rocket - the Falcon Heavy. This has additional cores (think 3 Falcon 9's strapped together) which they want to return, but having them all come back to the cape would need too much fuel ( and therefore less payload can be lifted) so they will recover these to the barge. They are also thinking of refueling the stage after it lands on the barge and then lifting off again and back to the cape (just a mere hop away).
Cool stuff if they can make it work.
I recall Musk stating that a fly back to the cape is very fuel heavy and the sea barge is the way to go for the foreseeable future unless the payload is very small. By the time of 1st stage separation they are over 220km downrange with ~4.5 mach worth of velocity. This would have to be eliminated, the stage turned around, fly back to the cape and have enough fuel to land. Very high fuel penalty even though its not a 1:1 ratio of payload to fuel on the first stage.
rapid unscheduled disassembly.... Yeah, happened to us last night in the pub with a high-amp speaker. We also had a failure with one of the hydraulic fluid containers to stop it from rapidly combusting the ceiling, but one working container was enough thankfully.
Kudos to Musk's team though. They were darn close and I stand in awe of the engineers who designed and build this.
Turns out in tests the parachutes are about the same weight as fins and/or engines in combination. So you'd have extra weight for little to no extra control at the low descent. A chute for slowing down in the higher atmosphere can help when returning orbital craft I think (though I've got that idea from computer games so may be wrong!).
The fuel is lighter and the engines can be controlled better than a parachute. It's just getting the control there in the first place I guess. A but like a helicopter. We could land all the helis with parachutes, but by the time the technology is perfected, we can do powered landings.
Hydraulic fluid ran out about a minute from landing, it's an open system, so fluid is lost during use. Tanks wasn't big enough (or carrying enough fluid). Grid fins locked hard over when they ran out.
Parachutes have already been tried by SpaceX and sucked, hence they are trying this hoverslam landing approach. Parachutes also add unnecessary weight . Stage already has grid fins and thrusters for maneuvering, plus gimballed engine nozzle, but is incapable of hovering (cannot throttle engine low enough)
tbh, the phrase catastrophic is also wrong. A catastrophic result would mean no data was received in this test flight, meaning it was wasted, whereas there is a clearly a lot of data and in many ways this was a successful TEST.
Next test in three weeks.
Adding a 'landing engine' will add weight, also where would you put it? The base is taken up by the 9 Merlins. The Merlin can throttle back to 70%, they may have a few more % in the back pocket so to speak as they gain experience. Deeper you throttle the engine, the greater chance it will become unstable. It is easier to twig the control software on when to restart the engine than to mess with the engine to get deeper throttling.
The LEM decent stage engine could throttle back to 10%, but that was a very special engine!
The idea of floating platforms like this isn't new - sort out the rock'n'roll and tow the thing anywhere.
What with Google and their waterborne server farm (or whatever it is/was) it seems that some people are looking ahead as regards the rise in sea level.
Mr Costner will have to re-do the movie - we will still have sharks with frikkin' lasers!
For those who, for whatever reasons, never seem to to get a working non-YouTube embedded video link in Firefox on Ubuntu.
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