SpaceX Falcon Heavy Discussion (Thread 6)

[Mader Levap]

Not everyone requires tens of billions of dollars to build a launch vehicle.  Recall the study that showed it would have taken $4B to build F9 using NASA's approach, but it actually took $390m (1/10th the estimate)?  Tens of billions becomes a few billion... and the builders have so much relevant experience and applicable technology now.

I could argue in same vein that creating ITS equivalent would take 50B$ for NASA, so it would be 5B$ for SpaceX. I won't, because it is silly argument.

$1-2B seems reasonable; tens of billions sounds like wishful thinking (a.k.a., denial).

You are projecting.

[gospacex]

Well, but let’s not forget that SpaceX also needs FH to fly a whole class of payloads that is well in existence and currently flies on /...skip.../, Proton

No, for competing with Proton SpaceX does not need FH. Last F9 launch lofted a payload with the mass equal to the maximum Proton payload.

Maybe its me, but do you think that SpaceX is designing capability against a 50+ year old launcher that Russia is trying to replace?

You are reading too much into my post. I just corrected a notion that SpaceX needs FH to compete with Proton. I'm not implying anything except what I said there.
(As a side note, "trying to replace" thing for Proton is not going well - the replacement costs *more*).

[Scylla]

elonmuskFalcon Heavy maiden launch this November

https://www.instagram.com/p/BXEkGKlgJDK/

[The_Ronin]

elonmuskFalcon Heavy maiden launch this November

https://www.instagram.com/p/BXEkGKlgJDK/

Need some dates to book some AirBnB space!  Come on, Elon!!!! Work with me!

[Req]

Elon Musk‏
@elonmusk
Side booster rockets return to Cape Canaveral. Center lands on droneship.

https://twitter.com/elonmusk/status/890774088104370176

I think most of us guessed that, but here it is confirmed.

[NuclearFan]

I know that the center core will throttle down its engines to increase payload, but on future versions could they shut off a significant number of the engines (like 4) and throttle the rest, then restart them shortly before booster separation to gain more payload or save more fuel to reduce heating during reentry?  I know this would require modifying those additional engines to be restartable.  Even in the event the engines fail to restart, the core should still be able to limp into orbit by burning landing fuel to counter gravity losses from lower thrust with only five engines.

[wannamoonbase]

BRING IT!!

I can't wait, this will be the most exciting space event since the final Shuttle launch.

I'm looking forward to the whole transition and testing of the FH leading up to the launch.

[yokem55]

I know that the center core will throttle down its engines to increase payload, but on future versions could they shut off a significant number of the engines (like 4) and throttle the rest, then restart them shortly before booster separation to gain more payload or save more fuel to reduce heating during reentry?  I know this would require modifying those additional engines to be restartable.  Even in the event the engines fail to restart, the core should still be able to limp into orbit by burning landing fuel to counter gravity losses from lower thrust with only five engines.

It's been discussed before and it's generally considered too risky for what it's worth. It would greatly complicate engine out scenarios and would make the booster sep process more complicated.

[su27k]

I don't remember where I saw this, but someone mentioned a idea that if SpaceX did implement cross-feed on FH, then they may not need to strengthen the center core so much. Basically if they have cross-feed, then the side boosters do not need to lift the center core (like Delta IV heavy), instead they would just be providing propellant to the center core engines. All three cores will be flying in formation without significant force between them, and the side boosters would be like giant flying fuel tanks. Would this work?

[Proponent]

I suppose that with cross-feed, you could in principle throttle down the boosters so that they accelerated themselves and exerted little or no axial force on the core.  But then the boosters become essentially just weightless propellant tanks, and I'm sure that would quite substantially reduce LEO payload capability.

[octavo]

I suppose that with cross-feed, you could in principle throttle down the boosters so that they accelerated themselves and exerted little or no axial force on the core.  But then the boosters become essentially just weightless propellant tanks, and I'm sure that would quite substantially reduce LEO payload capability.

It would probably make rtls of the side boosters challenging, given how much later they would stage.

[Herb Schaltegger]

I don't remember where I saw this, but someone mentioned a idea that if SpaceX did implement cross-feed on FH, then they may not need to strengthen the center core so much. Basically if they have cross-feed, then the side boosters do not need to lift the center core (like Delta IV heavy), instead they would just be providing propellant to the center core engines. All three cores will be flying in formation without significant force between them, and the side boosters would be like giant flying fuel tanks. Would this work?

Not really. The boosters would show a net rate of fuel consumption of 50% greater than the core and therefore they would tend to accelerate faster than the core. Thus the boosters would still in effect be lifting the core, unless you throttled the boosters down to compensate. Throttling down that deeply on ascent means staging much further downrange and makes recovery much more difficult.

[MP99]

I know that the center core will throttle down its engines to increase payload, but on future versions could they shut off a significant number of the engines (like 4) and throttle the rest, then restart them shortly before booster separation to gain more payload or save more fuel to reduce heating during reentry?  I know this would require modifying those additional engines to be restartable.  Even in the event the engines fail to restart, the core should still be able to limp into orbit by burning landing fuel to counter gravity losses from lower thrust with only five engines.

It's been discussed before and it's generally considered too risky for what it's worth. It would greatly complicate engine out scenarios and would make the booster sep process more complicated.

If one or more engines fails to restart, the centre core would have a performance shortfall which would risk the mission.

However, by abandoning recovery of the centre core, the recovery prop can make up the shortfall.

It might be something worth them doing (if there's a possible payload that would warrant it) once FH operations become routine, if the extra cost risk to SpaceX is priced into the contract.

Cheers, Martin

Sent from my Nexus 6 using Tapatalk

[JAFO]

I saw this image on Space X's website  http://www.spacex.com/falcon-heavy




Question: it shows FH as being able to put 63,800 kg to LEO, that boggles my mind compared to the ones next to it, (STS, Delta IV, Proton, etc). Is this just Elon being Elon, a future variant, or are they for real?

TIA

[Herb Schaltegger]

I saw this image on Space X's website  http://www.spacex.com/falcon-heavy




Question: it shows FH as being able to put 63,800 kg to LEO, that boggles my mind compared to the ones next to it, (STS, Delta IV, Proton, etc). Is this just Elon being Elon, a future variant, or are they for real?

TIA

It's a little disingenuous to compare to STS - the orbiter itself was part of the payload mass (e.g., deploying a satellite was not the only thing a typical 5 - 14 days mission was sent to accomplish). That adds another 200,000lb to the "payload" more or less (just spitballing - don't wanna go look up mission masses in the Green Book).

[AncientU]

I saw this image on Space X's website  http://www.spacex.com/falcon-heavy




Question: it shows FH as being able to put 63,800 kg to LEO, that boggles my mind compared to the ones next to it, (STS, Delta IV, Proton, etc). Is this just Elon being Elon, a future variant, or are they for real?

TIA

That comparison has existed for five years or more.  Only the FH numbers have been (repeatedly) updated; the other vehicles are as they were 5-6 years ago AFAIK. 

FH will now be born with reusable boosters which accounts for about 90% of the vehicle cost -- the payload will be somewhere around 40,000kg (40 metric tonnes) in the reusable mode.  The 63t number is expendable which is fair for comparison purposes, since all the others are expendable (only) except Shuttle.  (SpaceX has also repeatedly sandbagged the numbers on this page -- Elon being Elon.)

A heavier variant of Delta IV Heavy is now available lifting around 28t.  The Shuttle, Titan, and Ariane ES are retired or never built (ES version), Delta Heavy/Atlas V and Ariane 5 are being replaced by lower cost versions Vulcan/Vulcan ACES and Ariane 6 respectively in the early 2020s, Proton M possibly by Angara, and Japan and China have follow-on vehicles, too.

Basically, though, the comparison is for real.

[Owlon]

I saw this image on Space X's website  http://www.spacex.com/falcon-heavy




Question: it shows FH as being able to put 63,800 kg to LEO, that boggles my mind compared to the ones next to it, (STS, Delta IV, Proton, etc). Is this just Elon being Elon, a future variant, or are they for real?

TIA

Maybe not quite on the test launch, as that is cobbled together from a couple of older recovered cores. Any operational launches will probably be flying on Block 5 cores from the start, which should have the stated performance when flying with no recovery hardware.

I'm fairly sure the Falcon 9 as currently flying has the highest payload fraction (payload mass/liftoff mass) of any rocket in history, and that Falcon Heavy will do slightly better.

[hkultala]

I saw this image on Space X's website  http://www.spacex.com/falcon-heavy




Question: it shows FH as being able to put 63,800 kg to LEO, that boggles my mind compared to the ones next to it, (STS, Delta IV, Proton, etc). Is this just Elon being Elon, a future variant, or are they for real?

TIA

That comparison has existed for five years or more.  Only the FH numbers have been (repeatedly) updated; the other vehicles are as they were 5-6 years ago AFAIK. 

FH will now be born with reusable boosters which accounts for about 90% of the vehicle cost -- the payload will be somewhere around 40,000kg (40 metric tonnes) in the reusable mode.  The 63t number is expendable which is fair for comparison purposes, since all the others are expendable (only) except Shuttle.  (SpaceX has also repeatedly sandbagged the numbers on this page -- Elon being Elon.)

A heavier variant of Delta IV Heavy is now available lifting around 28t.  The Shuttle, Titan, and Ariane ES are retired or never built (ES version), Delta Heavy/Atlas V and Ariane 5 are being replaced by lower cost versions Vulcan/Vulcan ACES and Ariane 6 respectively in the early 2020s, Proton M possibly by Angara, and Japan and China have follow-on vehicles, too.

Basically, though, the comparison is for real.

Yep.

And this comparison is only for LEO.

For higher orbits, the difference between DIVH and FH would be much smaller, as FH is a LEO-optimized launcher, but DIVH is BLEO-optimized launcher whose LEO-capasity is badly limited by the thrust of the single RL-10 of the upper stage.

[Ike17055]

It is still hard to beat the "wow" factor of a Delta IV Heavy launch. I imagine Falcon Heavy as envisioned will be as impressive or more. That Orion/Delta Heavy launch was worth the wait. Still love watching the footage.

[JAFO]

I saw this image on Space X's website  http://www.spacex.com/falcon-heavy




Question: it shows FH as being able to put 63,800 kg to LEO, that boggles my mind compared to the ones next to it, (STS, Delta IV, Proton, etc). Is this just Elon being Elon, a future variant, or are they for real?

TIA

That comparison has existed for five years or more.  Only the FH numbers have been (repeatedly) updated; the other vehicles are as they were 5-6 years ago AFAIK. 

FH will now be born with reusable boosters which accounts for about 90% of the vehicle cost -- the payload will be somewhere around 40,000kg (40 metric tonnes) in the reusable mode.  The 63t number is expendable which is fair for comparison purposes, since all the others are expendable (only) except Shuttle.  (SpaceX has also repeatedly sandbagged the numbers on this page -- Elon being Elon.)

A heavier variant of Delta IV Heavy is now available lifting around 28t.  The Shuttle, Titan, and Ariane ES are retired or never built (ES version), Delta Heavy/Atlas V and Ariane 5 are being replaced by lower cost versions Vulcan/Vulcan ACES and Ariane 6 respectively in the early 2020s, Proton M possibly by Angara, and Japan and China have follow-on vehicles, too.

Basically, though, the comparison is for real.

Yep.

And this comparison is only for LEO.

For higher orbits, the difference between DIVH and FH would be much smaller, as FH is a LEO-optimized launcher, but DIVH is BLEO-optimized launcher whose LEO-capasity is badly limited by the thrust of the single RL-10 of the upper stage.

That's a very important point I had not considered. (Rockets aren't Legos     )

Still, an impressive payload capability. I better start planning my sick call to work so I can go.