Thanks, Jon. I'll take being off by a factor of two - it's when I'm off by
an order of magnitude that I've had real problems ;)
Bill Bruner
New Frontier Aerospace
bill@xxxxxxxxxx
925-456-4553
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On Tue, Feb 13, 2018 at 11:51 AM, Jonathan Goff <jongoff@xxxxxxxxx> wrote:
Bill (Bruner),
Careful, the $90M number is for the Falcon Heavy with all three first
stage cores recovered, and the 63.8mT number is for the fully expended
Block 5 version. The max LEO payload for the all-three-stages recovered
Falcon Heavy is probably less than half of 63.8mT, and the price for a
fully-expended Falcon Heavy is apparently ~$150M according to Elon
yesterday. In both cases, you're talking nearly twice the price in $/kg
($2400-2800/kg to LEO).
I think $100/kg may be achievable, eventually, with fully-reusable rockets
flying every day for 1000s of flights. I'd be surprised if that happened
anytime soon though. SpaceX is closer to this than anyone else in the
market, and even they've only barely scratched the surface of rapid
turnaround, low-maintenance, high total cycle reuse.
~Jon
On Tue, Feb 13, 2018 at 12:42 PM, Bill Bruner <bill@xxxxxxxxxx> wrote:
....about $100/kg to LEO. I don't think rockets can reach thatnumber...
Falcon Heavy is currently at about $1411/kg to LEO (advertised numbers:
$90,000,000/63,800kg).
Elon says a BFR launch will cost less than Falcon 1. Some people
<https://www.nextbigfuture.com/2017/10/spacex-bfr-to-be-lower-cost-than-falcon-1-at-7-million-per-launch.html>
think that works out to less than $50/pound or about $100/kg.
If this number is even close to right, BFR will be the "Caravel" of the
space frontier.
Bill Bruner
New Frontier Aerospace
bill@xxxxxxxxxx
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On Tue, Feb 13, 2018 at 11:08 AM, William Claybaugh <
wclaybaugh2@xxxxxxxxx> wrote:
Is anyone aware of a careful comparison of LH2 vs. Propane fueled SSTO?
Hydrogen tanks generally weigh around 10% of the fuel mass whereas
Propane tanks are closer to 1%....
Bill
On Tue, Feb 13, 2018 at 11:56 AM Rand Simberg <simberg@xxxxxxxxxxxxxxx>
wrote:
I'd hope that we learned from Shuttle that the key to reducing the cost
of access to space is not a massive government program.
On 2018-02-13 10:53, Keith Henson wrote:
Henry Spencer wroteputs
On Sat, 10 Feb 2018, John Dom wrote:
... Who knows where the Skylons would be by now if they got the same
help SpaceX got..
Probably not much farther than they are now, given that the help to
SpaceX
was hundreds of millions to produce flying rockets with flying
capsules on
top, while Skylon development is still forecast to cost tens of
billions and
there is no plan for a less-expensive demonstrator first. (Which
Skylon in the "need not be taken seriously" category, in my opinion,
since
nobody is going to spend that kind of money on an unproven concept.)
Let's turn this around. What would it take for someone (governments
most likely) to fully develop Skylon?
The last time this happened was nuclear weapons during WW II. So it
would take the moral equal of a war of survival. Is the threat to
climate due to CO2 high enough for that to happen? I don't know, but
there are not a lot of other carbon-free energy sources on tap.
I am agnostic about how we transport parts into space for power
satellites. Skylon, BFR, witches brooms, all the same to me. The
critical thing is cost. If you can't get the cost per kW of installed
power to $2400 or less, then power satellites are a hard sell. At the
current design point, that needs about $100/kg to LEO. I don't think
rockets can reach that number, but if they can, we have the tools to
solve the carbon and energy problems.
Keith
PS. The other option is to go to the moon or asteroids for materials.