Gywnne says that the next landing attempt may be on land.
20 thoughts on “SpaceX News”
Huh?
The only way I can interpret this is there must be major damage to the drone ship. They’d been taking about the first land landing being the Jason 3 launch out of Vandenburg, BUT, CRX-7 out of Canaveral is scheduled before then. They’ve got a launch scheduled before that, but without enough margin to try recovery.
So, my first guess is there’s enough damage to the drone ship that they don’t expect it to be ready for CRX-7, so the next recovery attempt will be Jason 3. Or, a longer shot, they think they can land CRX-7 on land.
Perhaps the demonstrated accuracy has been enough for them to get range approval to land at Canaveral?
Surely the only reason for using the barge at this point is because they haven’t got permission to land on land? Land is a significantly easier target, because it’s larger and not moving.
Eventually they may want to land Falcon Heavy centre stages on the barge, or others when they need as much fuel as possible to reach orbit… but they can work on that harder problem once they’ve solved the simple one.
There are plenty of reasons to use the drone ship for *some* flights, not just FH cores; there are launches where there’s sufficient margin for droneship landing, but not for RTLS, which takes more delta/v.
Land is a significantly easier target, because it’s larger and not moving.
Yes, but it’s a significantly harder target, in that it’s a lot farther away from where the stages separate…
True. But haven’t they already been doing a boost-back burn for these tests? I remember seeing a diagram showing that in one of the news articles I read about the last one… though it’s quite possible a journalist didn’t know what they were writing about.
Yes, they have done some boostback burns (including one on this flight), but, only enough to shorten the trajectory, not enough to get enough Delta/V to reach land. You’d need a longer (by about 3x) boostback burn for that, and unless you have enough remaining prop to do it, you aren’t doing it. (and one some launches, due to performance demands, you do have enough remaining prop to land on a drone ship, but not enough for RTLS)
The only way I can interpret this is there must be major damage to the drone ship.
Droneship is fine. No hull breach and repairs are minor. Impact overpressure is closer to a fast fire than an explosion.
Someone should collect all the ludicrous Rube Goldberg solutions to “how to catch a falling booster” that people have “helpfully” been suggesting, and compile them into an illustrated book…
Didn’t ULA just do that?
ULA’s idea is fine. I am kind of doubtful of how they can disconnect the engine from the plumbing safely but the idea itself is ok. Reusing the whole stage like SpaceX is doing makes a lot more sense in the long term as unlike ULA I think the tank isn’t THAT cheap. Once you start using Al-Li or composites the costs start going up and you still require some manufacturing time which you wouldn’t need if you could reuse the whole thing.
I agree, that’d be one heck of a book!
My own helpful suggestion regarding drone ship landing is to simplify things for the F9. Currently, it has a lot to deal with, what with course corrections, transonic buffeting, etc. All this could be solved if the ASDS simply met the F9 earlier in the trajectory, such as before the atmospheric entry interface.
Problem solved.
🙂
Are they going to have Landing Complex 1 (the former Launch Complex 13) ready by then?
Shouldn’t any landing, by definition, require the use of land? What they’ve been doing so far should be called “barging”.
You’re not even going to recognize the language once I’ve finished straightening it out.
Naval aviators call them carrier landings (or traps), so no.
IMHO they will attempt to land the 3 engined first stage which will be used for Dragon 2 in flight abort tests. At Vandenberg.
Some months ago there was speculation here about why the development vehicle lost in Texas had 3 engines. I said at the time maybe it was a special vehicle that would be used for Dragon in flight abort tests and as they are testing fueling of another one at Vandenberg at present it all makes sense. This gets a test of recovery in an expanded envelope from that used in Texas, recovers a stage which may need re-use if the first abort test doesn’t go well and a land recovery of the most critical parts of the recovery sequence significantly more realistic than the Texas tests.
As for the barge attempt the other day it sure looks to me like the stage encountered wind shear *twice* in the last few hundred feet
and the timing was such that the control loop/vehicle response frequency had difficulty. Nevertheless it almost worked even so. Over the water the air is often warmer than the sea surface resulting in low level temperature inversions which allow large wind shears to exist and persist. I wonder if they do a quick sounding balloon flight just before the stage arrives?
“I wonder if they do a quick sounding balloon flight just before the stage arrives?”
If they did, what are you thinking they’d use the data for? In flight parameter modification? Post landing attempt analysis? Both?
Makes sense to me. Question is where? Those islands off the coast that SpaceX has been in negotiation with the US Navy over, or back in Vandenberg? To me make it would seem a Vandenberg site would make more sense for the abort test flight profile. However I thought site prep was still a ways out?
If sea stability is an issue, how getting an offshore drilling rig converted to a super stable barge?
Because it needs to be in different locations for different missions.
Use a rig similar to the one used by Sea Launch. It’s very stable and movable.
Huh?
The only way I can interpret this is there must be major damage to the drone ship. They’d been taking about the first land landing being the Jason 3 launch out of Vandenburg, BUT, CRX-7 out of Canaveral is scheduled before then. They’ve got a launch scheduled before that, but without enough margin to try recovery.
So, my first guess is there’s enough damage to the drone ship that they don’t expect it to be ready for CRX-7, so the next recovery attempt will be Jason 3. Or, a longer shot, they think they can land CRX-7 on land.
Perhaps the demonstrated accuracy has been enough for them to get range approval to land at Canaveral?
Surely the only reason for using the barge at this point is because they haven’t got permission to land on land? Land is a significantly easier target, because it’s larger and not moving.
Eventually they may want to land Falcon Heavy centre stages on the barge, or others when they need as much fuel as possible to reach orbit… but they can work on that harder problem once they’ve solved the simple one.
There are plenty of reasons to use the drone ship for *some* flights, not just FH cores; there are launches where there’s sufficient margin for droneship landing, but not for RTLS, which takes more delta/v.
Land is a significantly easier target, because it’s larger and not moving.
Yes, but it’s a significantly harder target, in that it’s a lot farther away from where the stages separate…
True. But haven’t they already been doing a boost-back burn for these tests? I remember seeing a diagram showing that in one of the news articles I read about the last one… though it’s quite possible a journalist didn’t know what they were writing about.
Yes, they have done some boostback burns (including one on this flight), but, only enough to shorten the trajectory, not enough to get enough Delta/V to reach land. You’d need a longer (by about 3x) boostback burn for that, and unless you have enough remaining prop to do it, you aren’t doing it. (and one some launches, due to performance demands, you do have enough remaining prop to land on a drone ship, but not enough for RTLS)
Elon says otherwise. https://twitter.com/elonmusk/status/588490238936240129
Droneship is fine. No hull breach and repairs are minor. Impact overpressure is closer to a fast fire than an explosion.
Someone should collect all the ludicrous Rube Goldberg solutions to “how to catch a falling booster” that people have “helpfully” been suggesting, and compile them into an illustrated book…
Didn’t ULA just do that?
ULA’s idea is fine. I am kind of doubtful of how they can disconnect the engine from the plumbing safely but the idea itself is ok. Reusing the whole stage like SpaceX is doing makes a lot more sense in the long term as unlike ULA I think the tank isn’t THAT cheap. Once you start using Al-Li or composites the costs start going up and you still require some manufacturing time which you wouldn’t need if you could reuse the whole thing.
I agree, that’d be one heck of a book!
My own helpful suggestion regarding drone ship landing is to simplify things for the F9. Currently, it has a lot to deal with, what with course corrections, transonic buffeting, etc. All this could be solved if the ASDS simply met the F9 earlier in the trajectory, such as before the atmospheric entry interface.
Problem solved.
🙂
Are they going to have Landing Complex 1 (the former Launch Complex 13) ready by then?
https://en.wikipedia.org/wiki/Cape_Canaveral_Air_Force_Station_Launch_Complex_13
They have the sign up, anyway. That’s a start.
Shouldn’t any landing, by definition, require the use of land? What they’ve been doing so far should be called “barging”.
You’re not even going to recognize the language once I’ve finished straightening it out.
Naval aviators call them carrier landings (or traps), so no.
IMHO they will attempt to land the 3 engined first stage which will be used for Dragon 2 in flight abort tests. At Vandenberg.
Some months ago there was speculation here about why the development vehicle lost in Texas had 3 engines. I said at the time maybe it was a special vehicle that would be used for Dragon in flight abort tests and as they are testing fueling of another one at Vandenberg at present it all makes sense. This gets a test of recovery in an expanded envelope from that used in Texas, recovers a stage which may need re-use if the first abort test doesn’t go well and a land recovery of the most critical parts of the recovery sequence significantly more realistic than the Texas tests.
As for the barge attempt the other day it sure looks to me like the stage encountered wind shear *twice* in the last few hundred feet
and the timing was such that the control loop/vehicle response frequency had difficulty. Nevertheless it almost worked even so. Over the water the air is often warmer than the sea surface resulting in low level temperature inversions which allow large wind shears to exist and persist. I wonder if they do a quick sounding balloon flight just before the stage arrives?
“I wonder if they do a quick sounding balloon flight just before the stage arrives?”
If they did, what are you thinking they’d use the data for? In flight parameter modification? Post landing attempt analysis? Both?
Makes sense to me. Question is where? Those islands off the coast that SpaceX has been in negotiation with the US Navy over, or back in Vandenberg? To me make it would seem a Vandenberg site would make more sense for the abort test flight profile. However I thought site prep was still a ways out?
If sea stability is an issue, how getting an offshore drilling rig converted to a super stable barge?
Because it needs to be in different locations for different missions.
Use a rig similar to the one used by Sea Launch. It’s very stable and movable.
Way too expensive for what they’re doing.