SpaceX And/Or Rocketry In General

Mike Hewson
Mike Hewson
Moderator
Joined: 1 Dec 05
Posts: 6588
Credit: 317816235
RAC: 387688

RE: RE: the question of

Quote:
Quote:
the question of whether they will recover the composite Falcon 9's, land and/or sea ?

I think one of the reasons given for the need for ASDS is that the central third of a Falcon 9 Heavy will naturally end the "useful" part of flight rather farther downrange and faster than the two side packs. So boosting it back would require yet more fuel, and thus a larger loss of oomph than for the side packs.

I'd envision a tiered system, with a "barely heavy" launch landing all three at home, and a "barely anything returned" landing the two side clusters on ASDS far down-range, letting the center fend for itself. Of course the top end would be the "nothing returned" option allowing full lift performance devoted to the payload.

The interesting question that all raises in my mind is whether a landed Falcon 9 core is tough enough to withstand another one landing on the same land pad (just barely conceivable to me) or the same sea platform (not at the current size I think).

So full protection of possibilities for Heavy recoveries seems to call for six ASDS units. There seems no good reason to get on with building them until they are more sure that this works, that they want to do it on Heavy (which is a smallish part of the launches) and that they know just what their desired ASDS design is.

I had not thought this through before now, but I now think a real sign of serious intent to do returns on F9 Heavy launches will be the preparation of additional ASDS units. Landing next to one just landed, with no time for safing or tie-down, sounds really, really sporty to me. Probably it would cheaper to deploy two sized for single-unit recovery than one upsized enough to make two-unit plausible.


Sporty indeed. Elon is on record as saying his company is about space efforts and not just producing interesting video footage. :-)

I guess it is a matter of how much they want to cram in a test. A Falcon Heavy is quite alot of money to throw away all at once in a day, without a payload fee, so my call would be to maximise engineering information return on the launch. Once the components separate then each becomes a sub-mission with it's own timeline. So my crystal ball prediction is a trivial payload to LEO ( which is later deliberately de-orbited ) while attempting return of the rest ! Probably thus the core goes downrange to sea barge and the side packs back to land ....

Cheers, Mike.

( edit ) Side note : at sea level, a Saturn V produced 34 Mega Newtons, the Falcon Heavy is rated at 20.4 Mega Newtons, the Delta IV Heavy is around 15.5 Mega Newton depending ( but has H2/LOX not kero/LOX ).

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Gary Charpentier
Gary Charpentier
Joined: 13 Jun 06
Posts: 2061
Credit: 106506104
RAC: 57092

Hate to break up this chain

Hate to break up this chain of thought, but aren't the side pods solid fuel engines? Hence they are light once burn until empty engines. No relight and no vertical landing. I expect they will come back on a parachute as the shuttle SRB's did. Not fancy, but it gets the job done to reuse them.

Mike Hewson
Mike Hewson
Moderator
Joined: 1 Dec 05
Posts: 6588
Credit: 317816235
RAC: 387688

RE: .... aren't the side

Quote:
.... aren't the side pods solid fuel engines?


Nope, they are Falcon Nine first stages, and have been part of SpaceX mission design for many years now.

Quote:

FIRST STAGE

Three cores make up the first stage of Falcon Heavy. The side cores, or boosters, are connected at the base and at the top of the center core’s liquid oxygen tank. The three cores, with a total of 27 Merlin engines, generate 20,418 kilonewtons (4.59 million pounds) of thrust at liftoff. Shortly after liftoff the center core engines are throttled down. After the side cores separate, the center core engines throttle back up to full thrust.

CORES
3
ENGINES
27
THRUST AT SEA LEVEL
20,418kN4,590,000 lbf
THRUST IN VACUUM
22,279kN5,008,500 lbf
BOOSTERS
Each of Falcon Heavy’s side cores, or boosters, is equivalent to the first stage of a Falcon 9 rocket with nine Merlin engines. At liftoff, the boosters and the center core all operate at full thrust. Shortly after liftoff, the center core engines are throttled down. After the side cores separate, the center core engines throttle back up.

PROPELLANT CROSS-FEED SYSTEM
For missions involving exceptionally heavy payloads—greater than 45,000 kilograms or 100,000 pounds—Falcon Heavy offers a unique cross-feed propellant system. Propellant feeds from the side boosters to the center core so that the center core retains a significant amount of fuel after the boosters separate.

THREE NINE-ENGINE CORES
Inside each of Falcon Heavy’s three cores is a cluster of nine Merlin engines. These same engines power Falcon 9, enabling efficiencies that make Falcon Heavy the most cost-effective heavy-lift launch vehicle in the world. With a total of 27 first-stage engines, Falcon Heavy has engine-out capability that no other launch vehicle can match—under most payload scenarios, it can sustain more than one unplanned engine shutdown at any point in flight and still successfully complete its mission.

Which is why the recovery strategy is (a) interesting, and (b) crucial to the overall future success of the program ie. bringing the price per launch down. That's the entire point of bothering to bring back the hardware to refill and re-use. Propellant per core per launch is under $500K - a minor fraction of outlay.

Gary, have you actually done any research on SpaceX ? :-)

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Variable
Variable
Joined: 6 Oct 13
Posts: 31
Credit: 885775341
RAC: 673340

If they plan on trying to

If they plan on trying to recover future launches from Vandenburg they will have to mitigate the fog/ice issue somehow. It's foggy on the central coast for most of the year.

archae86
archae86
Joined: 6 Dec 05
Posts: 3157
Credit: 7224994931
RAC: 1046211

The barge has been towed back

The barge has been towed back home, bearing remains of this Falcon 9.

Click here to see pics posted at SpaceFlightNow.

The first picture I saw after the event had me thinking the F9 was quite a lot more intact than this pictures demonstrate. On the other hand, had I first seen the kaboom video, I would not have expected the remarkably intact exhaust bells. Others think they see nearly intact engines, but I can't discern that.

Mike Hewson
Mike Hewson
Moderator
Joined: 1 Dec 05
Posts: 6588
Credit: 317816235
RAC: 387688

RE: The barge has been

Quote:

The barge has been towed back home, bearing remains of this Falcon 9.

Click here to see pics posted at SpaceFlightNow.

The first picture I saw after the event had me thinking the F9 was quite a lot more intact than this pictures demonstrate. On the other hand, had I first seen the kaboom video, I would not have expected the remarkably intact exhaust bells. Others think they see nearly intact engines, but I can't discern that.


I think it is clear onto which side it fell. There are bell shaped objects .... no doubt to be recycled back into new ones. The Niobium alloy is incredibly expensive.

Cheers, Mike.

( edit ) Counter-intuitive point : the rockets are designed to resist violence from within, not without ! :-)

( edit ) Of interest : there is a actually a Falcon 9 User's Guide, which has been recently updated.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Anonymous

RE: ( edit ) Of interest :

Quote:

( edit ) Of interest : there is a actually a Falcon 9 User's Guide, which has been recently updated.

So, Mike have you downloaded the guide in preparation for your new purchase?

Gary Roberts
Gary Roberts
Moderator
Joined: 9 Feb 05
Posts: 5872
Credit: 117663802703
RAC: 35172580

Of course he has!! They

Of course he has!! They don't call him Dr RTFM for nothing, you know! :-).

Cheers,
Gary.

AgentB
AgentB
Joined: 17 Mar 12
Posts: 915
Credit: 513211304
RAC: 0

RE: I think it is clear

Quote:

I think it is clear onto which side it fell. There are bell shaped objects .... no doubt to be recycled back into new ones. The Niobium alloy is incredibly expensive.

It would be intersting to know how they were manufactured, i would imaging the machining costs to be astronomical (pun intended)

Quote:

a Falcon 9 User's Guide, which has been recently updated.

Fantastic find,so i searched for the recycling section... but found.

Quote:
8.6.5
Disposal
SpaceX makes every effort to mitigate space debris by responsibly passivating and disposing of hardware on orbit.

Passivating... there's a new word.

Mike Hewson
Mike Hewson
Moderator
Joined: 1 Dec 05
Posts: 6588
Credit: 317816235
RAC: 387688

RE: RE: ( edit ) Of

Quote:
Quote:

( edit ) Of interest : there is a actually a Falcon 9 User's Guide, which has been recently updated.

So, Mike have you downloaded the guide in preparation for your new purchase?


Yes, I have. I've already firmed up a mission slot and I'm paying it off on a lay-buy plan ( my first born son has been pledged but don't let on as the bank already has him for the house mortgage ). For now :

Quote:
The user’s guide is not intended for detailed design use. Data for detailed design purposes will be exchanged directly between a SpaceX customer and a SpaceX mission manager.


So I need to whack down my first $10M on the table before I get to see the real specifications. However once my mind control ray is in orbit I'll get repaid. You have to have a good business plan these days, and I thank the large green fizzy monster I met on my last LSD trip for this one. Credit where credit is due I say.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.