SpaceX Falcon Heavy

[CalculusWarrior]

SpaceX just posted a new animation of what the Falcon Heavy's flight profile could look like, it's pretty cool!

What's the forum's thoughts on Falcon Heavy? Will it fly? Do you think it will it be one of the most popular heavy lift rockets in the future?

[DeepSpaceDutch]

SpaceX just posted a new animation of what the Falcon Heavy's flight profile could look like, it's pretty cool!

What's the forum's thoughts on Falcon Heavy? Will it fly? Do you think it will it be one of the most popular heavy lift rockets in the future?

Of course, hopefully even this summer.

Edited January 27, 2015 by Vanamonde
Keep it clean, please.

[astropapi1]

I wonder how they're going to take the core back to the launch site. To quote Elon Musk:

Yes, the Falcon Heavy center core is seriously hauling a** at stage separation.

I thought he had said they would land it on a barge.

[Motokid600]

Someone told me here awhile back that the the first few FH flights will use expendable cores with only the boosters flying back to land. Either way that'd be a hell of a sight seeing two boosters land next to eachother.

[How2FoldSoup]

Of course, hopefully even this summer.

Ditto. That was so damn cool!! I love these guys.

Edited January 27, 2015 by Vanamonde
Keep it clean more, please.

[Frozen_Heart]

Absolutely beautiful!

[Guest]

And to think this could be done within the next 8/9 months. Simply incredible.

[Streetwind]

If only it could actually happen the way it's shown in the video, but it doesn't look like it'll be anywhere near that cool...

For starters, the landing area shown has multiple pads only because those are emergency divert pads. The proposal that SpaceX put forth for the area calls for one single central landing pad (with surrounding emergency divert options) that will be for landing one single core only. As such, only one of the FH side boosters will be able to return. No future expansion proposals are in the works, and even this current one hasn't been approved yet (much less started any construction).

In addition, the center core of the Falcon Heavy will, to quote Elon Musk himself, be "hauling ass" at the time of burnout. It will be many times faster and many times further downrange than the other cores. It's extremely unlikely that it will ever fly a return to pad scenario. Even Elon thinks it's more realistic to have a barge way downrange in the middle of the ocean (instead of "slightly off the coast" where they're currently trying to capture F9 first stages). And even that's going to be fiendishly difficult due to the vastly higher velocities and reentry heating effects. Nobody can tell yet if the stage won't simply break apart in that regime.

So yeah, that video is pure marketing. Best SpaceX can do here is one side core returning to land, one side core aiming for a barge, and the center core getting discarded (due to lacking another barge). Much like the Falcon 9, advertised as "the world's first fully reusable rocket", will actually never be fully reusable, because the Merlin engines don't have the Isp to maintain a useful payload fraction when trying for a returnable second stage. Perhaps a Raptor-powered successor can do it, but it's never going to happen with F9 (already confirmed by Elon in an interview).

I'm as much of a SpaceX fan as the next rocketry enthusiast, but do beware of their marketing department. It's producing just as much blatant nonsense as every other marketing department out there.

[Frozen_Heart]

I suspect that somewhere down the line there will be a single core successor to the FH.

The stats most recently quoted for the Raptor show that it has a similar thrust to 3 Merlins. 9 engines in a core matches the Falcon Heavy's 27 Merlins.

A rocket this large would give them the margins needed for full reusability. Especially with the quoted ISP of the Raptor.

[How2FoldSoup]

I suspect that somewhere down the line there will be a single core successor to the FH.

The stats most recently quoted for the Raptor show that it has a similar thrust to 3 Merlins. 9 engines in a core matches the Falcon Heavy's 27 Merlins.

A rocket this large would give them the margins needed for full reusability. Especially with the quoted ISP of the Raptor.

Where can I find more information on the Raptor? Wikipedia?

[Dkmdlb]

Elon Musk did an AMA the other day and talked about it. The wikipedia entry is inaccurate.

About the raptor, he said,

Thrust to weight is optimizing for a surprisingly low thrust level, even when accounting for the added mass of plumbing and structure for many engines. Looks like a little over 230 metric tons (~500 klbf) of thrust per engine, but we will have a lot of them

Link.

[Streetwind]

I suspect that somewhere down the line there will be a single core successor to the FH.

The stats most recently quoted for the Raptor show that it has a similar thrust to 3 Merlins. 9 engines in a core matches the Falcon Heavy's 27 Merlins.

A rocket this large would give them the margins needed for full reusability. Especially with the quoted ISP of the Raptor.

The BFR (Big "Falcon" Rocket) that's going to launch the Mars Colonial Transporter vessel will indeed be a single monolithic stage. Elon said they considered going with a FH-style triple core but ultimately decided it's better to just have a single stage. Likely very much because landing all three cores back home will be extremely difficult, as mentioned above... and also, because of the following:

Three Raptors for a F9 replacement stage sounds pretty good from a basic numbers perspective. Problem is, such a "Falcon 3" first stage is probably not returnable either. Right now the F9 fires a single of its 9 Merlin engines at absolute minimum throttle to land... and even then the TWR is well above 1.0, so it cannot hover. It must suicide burn for touchdown. The pintle style injector allows the Merlin engine to throttle fairly well for a main stage launch engine; SpaceX's statements on this are ambiguous, but it's either "can throttle to 60%", or "throttle 60% down" (i.e. to 40%). This is, as mentioned, a lot. With a hypothetical Falcon 3 running on Raptor engines three times as powerful, these Raptors would need a ridiculously deep throttle to make a landing viable. Can't just "hit x" for a pulsed thrust approach either: these aren't hypergolic engines that can just turn on and off at will. The Merlin needs about four seconds to ignite and spool up its gas generator, and it has only a very limited number of restarts in it. The Raptor as a staged combustion methalox engine with a bigger turbopump is probably a little slower, and not hypergolic either.

That's not to say they can never do it, of course. Maybe the Raptor will be amazingly throttleable. Maybe they get so good at this suicide burn landing by 2020 that they can use the Raptor even if it cannot throttle as low. Maybe they'll have a smaller Raptor derivative and will fly a Falcon 5, 6 or 7 stage with it. After all, it appears the Raptor design can arbitrarily scale between 2 and 8 meganewtons already, why not scale it down? Who knows...

...but then, that is the far future. I honestly do want to see the Falcon Heavy launch this year. For all the difficulties it poses towards reusability, it's still a goshdarn great and exciting rocket

[Hal]

That is really cool. It does have a bit of an unrealistic PR spin, but that's the price for looking awesome I guess. This is a pretty ignorant question, since I really have no idea how fast the central stage is going besides "really fast," but would it be feasible for them to just try to land it on the other side of the Atlantic? I would guess not, because there doesn't seem to be an easy way to ship it back, but someone who actually knows what they're talking about shedding some light on the matter would be nice.

Also, what's with the payload? You'd think it would be a Dragon with some kind of transfer stage, but it's not. Is that just a generic commercial satellite?

[FishInferno]

I don't see why SpaceX can't land two boosters at once. But I think tat the only way to land the core is to have a barge downrange. Is the FH demo still pushing for this year?

Also: DAT MUSIC

- - - Updated - - -

That is really cool. It does have a bit of an unrealistic PR spin, but that's the price for looking awesome I guess. This is a pretty ignorant question, since I really have no idea how fast the central stage is going besides "really fast," but would it be feasible for them to just try to land it on the other side of the Atlantic? I would guess not, because there doesn't seem to be an easy way to ship it back, but someone who actually knows what they're talking about shedding some light on the matter would be nice.

Also, what's with the payload? You'd think it would be a Dragon with some kind of transfer stage, but it's not. Is that just a generic commercial satellite?

Why would Dragon need to be lifted by a FH while It cam be lifted by a Falcon 9? Remember, SpaceX is a business, and most of there customers launch "generic commercial satellites".

[cptdavep]

I guess what happens to the centre stage will depend on the mass of the payload. If it's say only 2/3 of the max mass, which given how large the capability is may well happen often, it may have enough DV to return to land, if it's heavier they might use the barge, or if max weight they might need to ditch it. We'll find out soon! :-)

And to those questioning the customers for the FH I reckon they'll come in time as if they succeed in reuseability and lowering the cost it suddenly opens lots of new possibilities for larger payloads that aren't currently there due to lack of a cheap heavy launcher. Trip round the moon in a Dragon v2 anyone?

[How2FoldSoup]

That is really cool. It does have a bit of an unrealistic PR spin, but that's the price for looking awesome I guess. This is a pretty ignorant question, since I really have no idea how fast the central stage is going besides "really fast," but would it be feasible for them to just try to land it on the other side of the Atlantic? I would guess not, because there doesn't seem to be an easy way to ship it back, but someone who actually knows what they're talking about shedding some light on the matter would be nice.

Also, what's with the payload? You'd think it would be a Dragon with some kind of transfer stage, but it's not. Is that just a generic commercial satellite?

The payload is probably some science mission bound for the outer planets...probably Saturn...and Titan(or Enceladus)...or maybe Jo- I mean Jupiter and Europa..hopefully with some sort of lander. Nasa was able to afford this mission due to the reduced costs of launch so they could spend more on the probes itself..right? right??? I can dream...

[Techpriest93]

This needs to be a challenge for people to do in the KSP challenge section... I'll get on that! XD

[Techpriest93]

Wouldn't it be cheaper to send up like a rack of satellites at a time? Like, 3-5 of them? That's what I do

[Technical Ben]

Someone told me here awhile back that the the first few FH flights will use expendable cores with only the boosters flying back to land. Either way that'd be a hell of a sight seeing two boosters land next to eachother.

Did this in KSP with Multiple Mechjebs. Never get tired of it (not sure if current build allows it, as Mechjeb may default to active craft only to save cpu use).

PS, someone plays WAY too much KSP for these rocket designs.

http://www.nasaspaceflight.com/2014/03/spacex-advances-drive-mars-rocket-raptor-power/

Will they ever add landing only engines/fuel/systems for these if the main engines cannot be throttled that much?

Edited January 27, 2015 by Technical Ben

[Frozen_Heart]

Three Raptors for a F9 replacement stage sounds pretty good from a basic numbers perspective. Problem is, such a "Falcon 3" first stage is probably not returnable either. Right now the F9 fires a single of its 9 Merlin engines at absolute minimum throttle to land... and even then the TWR is well above 1.0, so it cannot hover. It must suicide burn for touchdown. The pintle style injector allows the Merlin engine to throttle fairly well for a main stage launch engine; SpaceX's statements on this are ambiguous, but it's either "can throttle to 60%", or "throttle 60% down" (i.e. to 40%). This is, as mentioned, a lot. With a hypothetical Falcon 3 running on Raptor engines three times as powerful, these Raptors would need a ridiculously deep throttle to make a landing viable. Can't just "hit x" for a pulsed thrust approach either: these aren't hypergolic engines that can just turn on and off at will. The Merlin needs about four seconds to ignite and spool up its gas generator, and it has only a very limited number of restarts in it. The Raptor as a staged combustion methalox engine with a bigger turbopump is probably a little slower, and not hypergolic either.

That why I suggested a 9 Raptor vehicle. It would match the Falcon Heavy in almost every way but only be a single core.

- 9 Raptors means that a single centre one can be used to land.

- As its only one core it would not be too far downrange to return to the launch site. The Falcon Heavy's main core is very hard to recover due to its separation speed.

- The size of the vehicle, combined with the Raptors much higher ISP, would make 100% reusability much more feasible compared to the Falcon Heavy which cannot reuse the upper stage.

I can't think of a downside of this rocket in comparison to the Falcon Heavy.

[Streetwind]

Well, the Falcon Heavy benefits from the booster staging, i.e. it looses dry mass early and thus gains extra dV. Especially if fuel crossfeeding is enabled (yes, FH is actually expected to be able to do that).

It also needs less development because you're just reusing existing, fully developed cores instead of making a new one from scratch.

But you are right, it definitely has many advantages as well. I can easily see such a rocket existing sometime in the 2020's.

[Dkmdlb]

Also if you have one failure one the single-core landing sequence you get 0% re-usability, whereas even if you have an explosive barge failure with the three-core F9H you still can recover the other booster.

[Dkmdlb]

Florida?

[lextacy]

nice use of the Burn Together Plugin !

[Scotius]

In Elon we trust That is all