Those are the kinds of numbers that Elon is shooting for, because he
views them as necessary to achieve his Mars goals. If the vehicle is
fully and rapidly reusable, which is the design requirement, the
marginal cost per flight would be a few million in propellant. So the
issue is flight rate, to allow the average cost to asymptotically
approach that marginal cost, which is why he is building not just a
ship, but a shipyard. Even if it's forty, or a hundred bucks a pound
(he's about a thousand currently with FH), it's still revolutionary.
On 2022-12-19 20:46, roxanna Mason wrote:
$20/Lb was what Aerojet was forecasting in 1960's dollars was what Sea
Dragon would orbit, that's 1000 tons.
Putting that in perspective, $20 would buy nearly an ounce of gold in
1960.
It will be a long time, if ever, that we see those kinds of #'s.
Ken
On Mon, Dec 19, 2022 at 7:24 PM Rand Simberg <simberg@xxxxxxxxxxxxxxx>
wrote:
When costs come down to twenty bucks a pound, which SS/SH can do at
the
planned flight rates, demand will be the opposite of inelastic.
People
will be buying rides and staying in space hotels for the current
cost of
a cruise. Not to mention space manufacturing, space assembly, SBSP,
and
the other things we've wanted to do for decades, and were
technically
feasible, but economic non-starters at current launch prices.
On 2022-12-19 19:08, Matthew JL wrote:
The reality is, harsh as it is to admit, that reusable systemsjust
don't present the kind of cost advantage needed to drive up humanthis
space activity to some meaningful level. We've been operating in
"cost/kg is the only thing that matters" paradigm for, what, 30years,
and the most that's ever come of it is Jared Isaacman's joyride to20%
LEO? The only existing reusable vehicle has presented a perhaps
savings in launch costs and hasn't increased space activity byturnaround.
anywhere close to the same. The only provable point, beyond any
reasonable doubt or skepticism, is that reuse enables fast
per
Yes, accepting a higher failure rate would allow launch costs to
lower, and the only situation where that would be acceptable is in
lofting tens or hundreds of tons of propellant a handful of times
year. Amortizing that against operational costs for a fleet ofprofit
reusable vehicles and doing internal subsidization with small
margins (i.e., profits from inelastic demand redirected intopaying
for one or two manned flights per year) is pretty much the onlything
I can see enabling a space-based economy within this century.It's
very much against the consensus but at some point someone's goingto
have to be the Copernicus in this argument.Musk
Within the next few years it's going to be starkly apparent that
is no savior, Starship is no silver bullet, and the expert opinionthis
that's dominating the industry was wrong - I'm just telling you
ahead of time.<alain245@xxxxxxxxxxxx>
On Mon, Dec 19, 2022 at 7:31 PM Alain Fournier
wrote:it
On Dec/19/2022 at 18:25, Henry Spencer wrote :
On Mon, 19 Dec 2022, Matthew JL wrote:fungible
That’s exactly the idea - propellant is a low-risk, highly
commodity and the kind of vehicles that might exclusively ship
oncan
failureaccept a low reliability and thus a low cost.
I've never been able to buy this. In practice, the costs of a
go well beyond just the loss of the cargo, and the tolerablefailure
rate is therefore lower than you might at first think.(Exception:
some types of military hardware *in wartime*.)basically
Moreover, I don't know how to design a vehicle with (say) 80%
reliability. If you don't get the design and manufacturing
right, the number will be variable and unpredictable and couldeasily
go much lower than that. If you *do* get the basics right, thenumber
will generally be rather higher than that. Only when you startwhere
chasing the second or third digit, do you get into the regime
expensive things like multiple redundancy make significantcontributions.
We have, um, I think it's 45 satellites in orbit now. (Depends
inhow
you count a few cases where we didn't build the whole thing.) 43got
off the launcher intact, all of those worked, and almost all arestill
working. Our first, MOST, with a three-year design life, finallydied
in its 16th year. Almost all of them have been almost alldidn't
single-string, with redundancy in only a few places where it
cost much or seemed especially desirable. Those bits ofredundancy
did lengthen MOST's life, but they haven't been relevant toAISSat-1
(still in operational service in its 13th year). They've come
operatehandy in, um, I think one or two cases other than MOST.implicitly
Despite what some antiquated reliability-estimation methods
claim, most failures are *not* random component failures -- theyare
design defects of one kind or another. Those can give you a 50%probably
failure rate just as easily as a 0.5% failure rate, and they can
easily affect all copies of a redundant system. Clean them out,
getting up into the range where random component failures and
semi-random weird happenstances actually matter, and you're
well above 90% reliability already. The idea that you can savelots of
money by setting your sights lower than that seems like sheerfantasy.
Henry
I agree. Also, the cheap way to orbit seems to be with reusable
rockets.
A more expensive rocket that is reusable can be cheaper to
than
a less expensive rocket that is loss to failure now and then.
Alain Fournier
