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Old May 26th 19, 04:45 PM posted to sci.space.policy
Fred J. McCall[_3_]
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Default Two Starships in "bolas" rotation

David Spain wrote on Sat, 25 May 2019 08:58:45
-0400:

On 5/21/2019 2:15 PM, Niklas Holsti wrote:

So that's the suggestion. Comments are welcome...


This very type of configuration of Starships has been discussed here
before. It is not an unrealistic approach. However I was unaware that
the SpaceX plan called for two Starships to make the journey all the way
to Mars.


The SpaceX plan (which I consider wildly optimistic) is to send two
cargo Starships to Mars in 2022, followed by two more cargo Starships
plus two crewed Starships in 2024. Moon flights before 2022. I think
you need to shift everything 2-4 years to the right to get to
something that removes the "wildly" from "wildly optimistic".


Two Superheavys (or whatever SpaceX is calling the BFR these
days) where planned but one of them was not a Starship destined for Mars
but a fueling pod for the Starship that was. That's the plan I remember.


It takes at least 3-4 tanker launches to refuel a single Starship for
a Mars (or a Moon, if you intend to land and return to Earth) trip.


But frankly I think Mars is a long way off. In fact the Moon is becoming
a major distraction. And that actually makes sense since all this
hardware can be tested out far more easily on lunar missions. There is a
push within NASA to refocus on the Moon and a lunar base, by any means
possible. If that means contracting with private enterprise to do it, so
be it. We will have to wait and see how Starship does in this regard.


I'm not convinced NASA has its own direction, other than to build some
hardware (like Gateway). They vacillate with whatever the then
current President wants. So we've seen things go from Mars to
Asteroid Retrieval to Moon over the last three Presidents. Musk plans
on Mars, regardless of what NASA does. Blue Origin appears to be Moon
focused.


We are along a familiar trajectory here. Same one as was taken for
recoverable Falcon 9 stages. I think Starship will focus on P2P
suborbital trajectories first to establish launch and return procedures
that must work anyway.


I think pursuit of P2P as a first goal is unlikely. Expect to see
some non-orbital hopper tests, followed by some hopper 'dives' to
validate thermal protection and such. These will all launch and
return in Texas with no Falcon Super Heavy booster involved. From
there the next stop is probably the free return trip around the Moon.


Then a push to orbit, then a push beyond. Opening
out the envelope becomes easier the further along the curve you get.
However the first part of that curve is the hardest. Or would appear so
from where we stand today. What is interesting, to me, is how much
SpaceX is going to rely on automation before committing crew to the
Starship. At what point will they crew the vehicle? After it completely
passes all P2P and orbital tests or before? Will crew be considered an
essential part of Starship operation or not? (i.e. will Starship require
pilots or provide crew with a flat screen they can follow the action
on?) If the past is any indication I'd say no. At least not in the
initial stages.


I don't think 'crew' will ever be considered 'essential' just to fly
the vehicle. After all, the Mars plan has the first two ships to Mars
as cargo only. And that's really what you want, since you want your
first trips to do things like set up something to manufacture fuel so
that your later manned flights can refuel to get home.


Your bolas configuration could be tried out in LEO. If such a plan were
part of a SpaceX requirement this would make a lot of sense. It could
provide an orbital gravity lab "on the cheap" in the sense that it
doesn't require "bending steel" that a specialized orbital lab would.


Except such a plan is NOT part of the SpaceX requirements. THEIR plan
is to do transits that are sufficiently fast in a ship that is large
enough to carry along whatever exercise equipment is required.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw