SpaceX Falcon Heavy Demo - Discussion and Speculation

[starsilk]

Elon Musk‏Verified account @elonmusk  16m16 minutes ago

 Considering trying to bring upper stage back on Falcon Heavy demo flight for full reusability. Odds of success low, but maybe worth a shot.

[speedevil]

'Bring it back'.

'Reenter the atmosphere substantially intact'.
'Do dummy uncontrolled landing'.
'Attempt controlled landing'.

[whitelancer64]

... we're probably going to fly something really silly ...

Cue the speculation.

Does 'silly' mean something that strikes Musk as humorous or goofy? Or is 'silly' code-speak for something surprising or impressive, as in "I can't tell you now, you wouldn't believe me, this will be awesome."

I would hazard a guess at "silly" like the wheel of cheese on the first Dragon flight "silly."

[dglow]

... we're probably going to fly something really silly ...

Cue the speculation.

Does 'silly' mean something that strikes Musk as humorous or goofy? Or is 'silly' code-speak for something surprising or impressive, as in "I can't tell you now, you wouldn't believe me, this will be awesome."

Elon Musk‏Verified account @elonmusk  16m16 minutes ago

 Considering trying to bring upper stage back on Falcon Heavy demo flight for full reusability. Odds of success low, but maybe worth a shot.

Oh shit, I guess it's the latter. YES!   

https://twitter.com/elonmusk/status/847882289581359104

[NX-0]

cardoso‏
 no chance in hell on telling us what will be the test payload, right?

Elon Musk‏
 Silliest thing we can imagine! Secret payload of 1st Dragon flight was a giant wheel of cheese. Inspired by a friend & Monty Python.

https://twitter.com/elonmusk/status/847882289581359104

[Hauerg]

'Bring it back'.

'Reenter the atmosphere substantially intact'.
'Do dummy uncontrolled landing'.
'Attempt controlled landing'.

'Reenter the atmosphere substantially intact'?? >> CHECK: They could have a LOT of remaining fuel for reentry burn.

'Do dummy uncontrolled landing'?? >>CHECK a final "brown pants type" landing burn with M1D, splash into ocean

'Attempt controlled landing'?? >> NO WAY: You would need to bolt on 4 Superdracos, FUel tanks, and looong landing legs.

And only 5, 6 months to go.

But then again, it's Elon we are talking about.
 

[whitelancer64]

'Bring it back'.

'Reenter the atmosphere substantially intact'.
'Do dummy uncontrolled landing'.
'Attempt controlled landing'.

'Reenter the atmosphere substantially intact'?? >> CHECK: They could have a LOT of remaining fuel for reentry burn.

'Do dummy uncontrolled landing'?? >>CHECK a final "brown pants type" landing burn with M1D, splash into ocean

'Attempt controlled landing'?? >> NO WAY: You would need to bolt on 4 Superdracos, FUel tanks, and looong landing legs.

And only 5, 6 months to go.

But then again, it's Elon we are talking about.

For a first test, I'd do something that requires minimal modifications to the 2nd stage, like put a heat shield on the nose and attempt a controlled re-entry. If it survives reentry, you win, if it doesn't, you really haven't lost much of anything, and if the FH demo payload is a wheel of cheese or something similarly silly, then cutting into the payload margin doesn't matter much. The question really is - how long have they been preparing to attempt 2nd stage reuse? As with everything that SpaceX has done that surprises us, they may be much further along than any of us can guess.

[docmordrid]

Elon Musk ✔ @elonmusk
Considering trying to bring upper stage back on Falcon Heavy demo flight for full reusability. Odds of success low, but maybe worth a shot.
 
 Elon Musk ✔ @elonmusk
Falcon Heavy test flight currently scheduled for late summer
2:46 PM - 31 Mar 2017

[Eagandale4114]

In response to: "serious q: if it fails, what do you have to lose?"

Elon: Good point, odds go from 0% to >0%

[Brovane]

I think someone is leaning forward on Twitter again....

[abaddon]

For a first test, I'd do something that requires minimal modifications to the 2nd stage, like put a heat shield on the nose and attempt a controlled re-entry.

What nose?  The PLF (or Dragon) is the "nose" of the rocket and it's gone.  So you've got the Dragon attachment or Satellite adapter on the front of the 2nd stage now, neither of which seems like a very good place to attach a heat shield...

[wannamoonbase]

For a first test, I'd do something that requires minimal modifications to the 2nd stage, like put a heat shield on the nose and attempt a controlled re-entry.

What nose?  The PLF (or Dragon) is the "nose" of the rocket and it's gone.  So you've got the Dragon attachment or Satellite adapter on the front of the 2nd stage now, neither of which seems like a very good place to attach a heat shield...

Things could be done, but not in 4-5 months.  Unless they have something in work previously.

[brickmack]

What nose?  The PLF (or Dragon) is the "nose" of the rocket and it's gone.  So you've got the Dragon attachment or Satellite adapter on the front of the 2nd stage now, neither of which seems like a very good place to attach a heat shield...

Move the adapter hardware to a new expendable module, attaching to the front of the heat shield (could reuse Dragon trunk separation hardware even). Release payload, deorbit, drop the payload adapter

[Bob Shaw]

The big advantage they have for LEO Second Stage re-entry demos is that they already have a supply of used Pica-X heat shields of the same diameter from Dragon 1s. All they need to do is demonstrate structural integrity until ocean impact, which then allows the same step by step process as with First Stage recovery. Ideally, not on a barge, but at White Sands or their Texas launch site after a couple of orbits. GTO stages are probably too hard at present.

[TomH]

I would prefer to see them send a used Dragon I on a lunar circumnavigation test prior to sending the manned Dragon II.

[robert_d]

Probably a crazy thought but -
Could a set of legs be mounted within the PLF?
Base ring attached to the payload adapter and upper ring holding the ends in position. Actuators replaced by detachable springs. Or possibly an inflatable cross-shaped gas envelope to push them past perpendicular.

Legs and center area between them covered in PICA X. Now you've got a comparatively large cross section to distribute the heat of reentry.

Just trying to think of something "off the shelf" that SpaceX could throw at the 2nd stage recovery problem and still cobble together in 6 months.

[Kaputnik]

Probably a crazy thought but -
Could a set of legs be mounted within the PLF?
Base ring attached to the payload adapter and upper ring holding the ends in position. Actuators replaced by detachable springs. Or possibly an inflatable cross-shaped gas envelope to push them past perpendicular.

Legs and center area between them covered in PICA X. Now you've got a comparatively large cross section to distribute the heat of reentry.

Just trying to think of something "off the shelf" that SpaceX could throw at the 2nd stage recovery problem and still cobble together in 6 months.

Sounds about as easy as making an arrow fly backwards.

[Jcc]

My thought and several others with regards to second stage recovery is to land on its " nose" with the M1Dvac bell pointing up. Can't use it to land anyway because of LOX boil off and kerosene freezing. So would need legs and propulsive landing engines (superdracos) beneath the payload adapter. I would say put parachutes in the back, and have it do an imprecise landing in the desert, to minimize need for fuel.

[Barrie]

Mount a dragon 2 on the payload adaptor upside down.  Just land the Dragon 2 as normal with the 2nd stage on top.

[Kaputnik]

Mount a dragon 2 on the payload adaptor upside down.  Just land the Dragon 2 as normal with the 2nd stage on top.