SpaceX Falcon Heavy Discussion (Thread 6)

[Rocket Science]

NASA could just fund an "American mission" with investors/donors and the astronauts could take a "leave of absence" so this would be on their own personal time avoiding all the "legal government civil servant BS"...

[woods170]

General FAA commercial spaceflight regulations do come into play, however, including those directed toward human crew and passengers. Those regulations are rather ambiguous and subject to a great degree of further interpretation and development as befits an industry segment that’s not yet well established.

But the point is that the FAA would still have to issue a launch license, and for a mission carrying human beings, the process will be a somewhat more than simple paperwork.

Agreed. But FAA requirements are not nearly as intrusive as NASA's.

[envy887]

So.... the Falcon Heavy center booster has COPV's in the RP-1 tank?

https://twitter.com/spacecoast_stve/status/1118766512079298560

[Alexphysics]

All boosters have COPV's on their RP-1 tanks, I don't know why that's a surprise.

[envy887]

All boosters have COPV's on their RP-1 tanks, I don't know why that's a surprise.

I presume you mean "all Falcon boosters", and not all boosters in general?

I can't recall seeing this publicly stated or depicted by SpaceX, and I haven't seen any other public pictures of the inside of a completed RP-1 tank (at least that can be positively identified as a RP-1 tank).

[Alexphysics]

All boosters have COPV's on their RP-1 tanks, I don't know why that's a surprise.

I presume you mean "all Falcon boosters", and not all boosters in general?

I can't recall seeing this publicly stated or depicted by SpaceX, and I haven't seen any other public pictures of the inside of a completed RP-1 tank (at least that can be positively identified as a RP-1 tank).

Yes, I meant Falcon boosters, of course. There are multiple reasons why there are COPV's on the RP-1 tank...

[Slarty1080]

Even though SpaceX only wants to reuse the side boosters for STP-2, given that the center core had a slim chance of landing safely, why would they not reuse the center core once it comes back to port?

I don't think SpaceX has ever said they would not reuse the ArabSat center core.  They just can't contractually use it on STP-2, as they are only allowed to reuse the side boosters through a contract change.

I fully expect they'll reuse the center core for some other mission unless the stress was beyond limits.

Sadly they won't be able to reuse the center core now as it has been lost at sea:
https://www.space.com/spacex-loses-falcon-heavy-core-booster-at-sea.html
 
Octograber was not configured for the center core - but should be for the next mission.

[lonestriker]

Even though SpaceX only wants to reuse the side boosters for STP-2, given that the center core had a slim chance of landing safely, why would they not reuse the center core once it comes back to port?

I don't think SpaceX has ever said they would not reuse the ArabSat center core.  They just can't contractually use it on STP-2, as they are only allowed to reuse the side boosters through a contract change.

I fully expect they'll reuse the center core for some other mission unless the stress was beyond limits.

Sadly they won't be able to reuse the center core now as it has been lost at sea:
https://www.space.com/spacex-loses-falcon-heavy-core-booster-at-sea.html
 
Octograber was not configured for the center core - but should be for the next mission.

Funny how reality has a way of invalidating all of your predictions and assumptions 

I hope they got back enough to at least learn something of value for a hot, GTO reentry that they can apply to future center cores.  They'll at least know to expedite Octograbber for FH now.  As they say, if you learned something, it wasn't a total failure...

[Herb Schaltegger]

Even though SpaceX only wants to reuse the side boosters for STP-2, given that the center core had a slim chance of landing safely, why would they not reuse the center core once it comes back to port?

I don't think SpaceX has ever said they would not reuse the ArabSat center core.  They just can't contractually use it on STP-2, as they are only allowed to reuse the side boosters through a contract change.

I fully expect they'll reuse the center core for some other mission unless the stress was beyond limits.

Sadly they won't be able to reuse the center core now as it has been lost at sea:
https://www.space.com/spacex-loses-falcon-heavy-core-booster-at-sea.html
 
Octograber was not configured for the center core - but should be for the next mission.

Um, that article is several days old. Scroll up just a few posts before your own. The remains (the RP1 tank, engines, octoweb and legs) have been in Port Canaveral for a couple days now.

No need to pose old (incomplete) news as if it was some new information.

[Rondaz]

Falcon Heavy-Drag Coefficient..

Made by: Jonathan Hellberg

https://docs.google.com/document/d/1x3lzi2FTutseTfd4_a7UwSMZ_ExbANuRHa0Hz1uMpy8/edit

[gongora]

[Space News] Air Force certified Falcon Heavy for national security launch but more work needed to meet required orbits

What that means is that Falcon Heavy has been certified “for certain orbits,” said Thompson. “It’s not certified for all of our most stressing national security space orbits,” he said. “We continue to work with SpaceX to mature their design and I think that’s going well.”
...
A spokesman for the Air Force Space and Missile Systems Center said the Falcon Heavy is certified for two Phase 1A reference orbits.

The two reference orbits are for the missions that Falcon Heavy was awarded by the Air Force under Phase 1A of the Evolved Expendable Launch Vehicle program

[sevenperforce]

I was looking at edge-case performance of Falcon Heavy and did some math specifically around the quoted Pluto delivery....

Came up with a whopping 81+ tonnes of propellant residuals if launched without payload to use as a space tug.

Really blew my mind. I keep checking my math to see if I missed something.

[S.Paulissen]

Isn't that essentially an almost full second stage ?

[spacenut]

Why can't they just launch a 2nd stage with only docking equipment attached.  Then launch a Lunar Stack of a capsule, service module, and a lunar lander.  The 2nd stage would dock with them and shoot them to the moon. 

[MATTBLAK]

Isn't that essentially an almost full second stage ?

About 80% percent full.

[woods170]

Why can't they just launch a 2nd stage with only docking equipment attached.  Then launch a Lunar Stack of a capsule, service module, and a lunar lander.  The 2nd stage would dock with them and shoot them to the moon. 

What lunar lander?
And that lunar stack would be launched on what?

[MATTBLAK]

Another Falcon Heavy and/or Vulcan, presumably. If SLS goes away that's what we'll be looking at.

[sevenperforce]

Why can't they just launch a 2nd stage with only docking equipment attached.  Then launch a Lunar Stack of a capsule, service module, and a lunar lander.  The 2nd stage would dock with them and shoot them to the moon.

This was exactly the use case we were considering. Although I would presume we'd launch the lunar stack first, since it has storables, and then launch the "naked" Falcon Heavy to a matching orbit. The lunar stack would complete the rendezvous and docking while the FHUS merely held position with cold-gas thrusters. Saturn V threw 44 tonnes onto TLI; by my math, a naked Falcon Heavy upper stage could throw upwards of 47 tonnes.

Of course Orion is too heavy to be the capsule in such a situation. Fitting the whole thing into a LOP-G architecture would have SLS sending crew to LOP-G on Orion independently and using distributed launch to deliver the lunar lander to LOP-G. Boeing's monolithic two-stage lander, which they propose launching on SLS, must necessarily be less than SLS's 37-tonne throw capacity. It could be launched to TLI by a naked FHUS along with a ten-tonne logistics module just for fun, or delivered directly to LOP-G with capacity to spare. No refill missions required.

Isn't that essentially an almost full second stage ?

About 80% percent full.

Yeah. The only way I can make "3.5 tonnes direct to Pluto" work is if core booster burnout occurs at 1000-1100 under LEO.

[spacenut]

A deep space Dragon capsule with Superdracos added for more maneuverability.  Then for a lunar lander add a stripped Dragon capsule with no heat shield and Superdracos for landing and return to orbit.  Both of these would be launched by a Falcon Heavy.  The almost fully fueled upper stage of a Falcon Heavy would dock at the rear of the stack and launch them to the moon like Saturn V upper stage.  If it takes 3 launches to get the whole stack, maybe two Falcon 9's could launch the Dracon capsule and the lander.  Join, then dock with the upper stage, and you have a lunar program for less than half the cost of an SLS> 

[sevenperforce]

A deep space Dragon capsule with Superdracos added for more maneuverability.  Then for a lunar lander add a stripped Dragon capsule with no heat shield and Superdracos for landing and return to orbit.  Both of these would be launched by a Falcon Heavy.  The almost fully fueled upper stage of a Falcon Heavy would dock at the rear of the stack and launch them to the moon like Saturn V upper stage.  If it takes 3 launches to get the whole stack, maybe two Falcon 9's could launch the Dracon capsule and the lander.  Join, then dock with the upper stage, and you have a lunar program for less than half the cost of an SLS>

Cons: would only allow for flags and footprints unless you pre-landed surface assets. Would be better to have a standard delivery module (using either SuperDracos or meth-gox thrusters) and use that both for delivering surface assets and as the descent module.

Deep space Dragon 2 doesn't need more SuperDracos; it needs more propellant. And you can't put more propellant in the trunk without running prop lines into the capsule, which hoses the current design. Better to put an independent propulsion unit in the trunk. Trouble is engines. SuperDraco is too large and too thrusty; Dracos are not thrusty enough. You could use something like a Rutherford if you could find a way to solve kerolox boil-off.