Author Topic: Falcon 9 Heavy w. Raptor US; Speculative Roadmap  (Read 2645 times)

Offline malu5531

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Falcon 9 Heavy w. Raptor US; Speculative Roadmap
« on: 08/17/2013 01:00 AM »
I find it interesting to think about how SpaceX might move forward and slowly build the capability to colonize Mars.

After playing around with the numbers on Falcon 9 and Falcon Heavy, when new information came from the re-designed website (total mass for F9 and FH), I have revisited my previous calculations. With some reasonable assumptions (?) it's possible to show;

- Falcon 9 R: 13150 mT to LEO; reusable first stage, expendable second stage. (http://tinyurl.com/Falcon9R-5)
- Falcon Heavy: 53000 mT to LEO; reusable boosters, expendable core and second stage. (http://tinyurl.com/Falcon9H)

Note; LEO; 200x200 orbit, 26 deg incl from Boca Chica
Note2; IANARS, please check my calculations and give feedback

For Falcon Heavy, the relatively tiny upper stage (same as F9R) makes it hard to reuse the core while delivering large cargo. I suspect, based on past behaviour, that SpaceX will build a backlog of customers willing to ship up to 53 mT cargo to LEO, or less to GTO, using the current advertised expendable FH. But actually launch some of the manifest later with a reusable version having the same performance, when the technology is mature.

Looking at what we know of Raptor (and the fact it started it's life as a rumoured dedicated upper stage engine), it's interesting to ask how a Falcon Heavy "Raptor US" would perform; with a more reasonably sized Raptor based upper stage. My findings indicate very nice performance gains:

Falcon Heavy (raptor) ReusableExpendable
Payload to LEO, kg59'00075'000
Stage 0 burn, s135141
Stage 1 burn, s152180
Stage 2 burn, s205205
Time to orbit, s497531

Calculations: http://tinyurl.com/Falcon9HR2
Note; Boosters easy to reuse, core reused through costly boost-forward
Note2; Reusable upper stage reduce payload further, however probably still capable of 53 mT

It's interesting to note that this "Raptor-enhanced" FH, in expendable edition, would be able to compete with SLS Block I - and only in a few years, since Raptor development have been going on for quite some time now. It would not be out of character for Elon to announce suddenly something like; "btw, we have this new FH capable of SLS levels of performance, prices start at 150 MUSD".

SpaceX would have dual benefits of a larger Raptor upper stage on Falcon Heavy;
1) Launch FH backlog fully reusable, saving lots of cash.
2) Compete for SLS Block I sized cargo or show policy makers how newspace can do it on the cheap.

Similarly, looking further ahead, developing a full size MCT Rocket would have tripple benefits;
1) Launch two FH backlog items at the same time (110 mT to LEO, reusable)
2) Compete for SLS Block I and Ia sized cargo (fully reusable) & open a new market
3) Enable Elon's mars ambitions and later the even bigger "MCT Heavy" with a massive 300+ mT to LEO (reusable)
http://tinyurl.com/MCT-9Raptor, http://tinyurl.com/MCTHeavy

What's your thoughts on this - the way forward for SpaceX; how might they evolve the Falcon Heavy using Raptor, the "all-raptor" MCT rocket, and how will they find business / move contracts over to these bigger / badder / reusable systems when they are available (like Jason-3)?

Offline SpacexULA

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Re: Falcon 9 Heavy w. Raptor US; Speculative Roadmap
« Reply #1 on: 08/17/2013 01:02 AM »
Pretty much everything you said has been covered a LOT, just search Falcon x
No Bucks no Buck Rogers, but at least Flexible path gets you Twiki.

Offline malu5531

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Re: Falcon 9 Heavy w. Raptor US; Speculative Roadmap
« Reply #2 on: 08/17/2013 01:36 AM »
Pretty much everything you said has been covered a LOT, just search Falcon x

Yes, I've been in those discussions quite a lot.

Now we have new facts/numbers, not least from the new website, and new calculations make for more certainty in predicting and understanding the performance. I've just remade my calculations from scratch with some different results (and they easier to read). There are still unknowns, such as the exact residual fuel needed for RTLS, dry/wet ratios and relative masses between stages. Iterating the discussion helps us figure out the missing pieces, so I'm looking for any feedback / thoughts on the calculations and assumptions above.