DIY space transport

It is a bit of a dream of mine to build a small semi self sufficient
space station in LEO, (with a large engineering workshop of course), and
set up as a developer and tester of space based infrastructure as
required for what would eventually pass as the space handy person
market. Refining the development of small solar power systems, farming,
mining, refining, manufacturing, habitat making, transport systems,
etcetera.

This is a DIY job which requires a small cheap and convenient space
transport pickup truck and the means with which to build a small space
station - that would grow in an organic fashion. Could this potentially
be accomplished by a lone, well off and capable person, (assuming use of
earth based contractors), as opposed to a standing army?

Spaceshipone has a drymass around 2000kg. A space transport capable of
carrying a single person, and a reasonable excess baggage allowance,
might have a drymass as low as half of this - and perhaps even a similar
cost? The space transport might look something like the t/Space CXV
with much larger propellant tanks, much smaller cabin volume - and no
aeroshell.

Air launch is necessary for a number of reasons, starting with the need
to avoid aerodynamic drag at such a small scale. Obviously high launch
pad fees will not be sustainable, this will want launch site flexibility
and perhaps the capacity to launch from international waters. This
needs to be capable of less than $100/kg to LEO.

It should be possible to build a specialist carrier aircraft for only a
few million, this is more about climb and ferrying than efficiency -
large fabric covered wings, basically an oversized ultralight. It would
be nice to be able to carry bulky but light weight components in front
of the space transport vehicle, (like thin wall habitat pressure
vessels). This should be possible with air launching, the aircraft
would likely have a large protective aeroshell for the space transport,
and release at low dynamic pressure. If need be a very light weight
fabric tent like structure could be placed over such external loads to
ease asymmetric aerodynamic loads. With such a space transport a small
transport it should be feasible to eventually assemble a very large
space station.

Along the minimalist design philosophy I was considering a skydiving
parachute approach to landing. Using various tricks it should be
possible, for a 2-3% drymass mass cost, to have pin point flared landing
of the space transport on its side on a soft surface, (e.g. sand). The
seat would probably be a very light weight hammock type design and I am
even wondering about closed circuit TV, (some entirely independent),
instead of portholes. If need be one might pop the hatch and stick ones
head out to control the landing - or have an outside seat. Another
thought is mid air LOX fuelling of the space transport from the carrier
aircraft so as to minimise insulation.

The question of two stage verse one stage is a tricky one. I am
starting to favour single stage, which will be technically more
challenging, as second stage recovery from flexible launch locations
will be highly problematic. Single stage is more in keeping with the
single person operation - excepting the carrier aircraft pilot of
course. The point of the carrier aircraft design is that GLOW is not a
design constraint. Space transport GLOW might be around twenty ton.

I am considering the absence of an external aeroshell over the entire
space transport. The nose might consist of a large diameter miniature
capsule in which the pilot is situated. This would take the brunt of
the re-entry load and might even offer various separation and abort
capacities. The perhaps axis-symmetric multiple tanks would be aft of
this and while possessing some direct insulation and shielding there
would be no covering aeroshell over the intertank and capsule regions.
Hopefully the small scale, low re-entry heat loading, and high altitude
launch would make such an un-aerodynamically compromised design
possible. The open tank format would hopefully make maintenance easier,
increase frontal area during re-entry, and enable the capsule door to be
located at the back of the capsule away from the re-entry shield.

Such a miniature space transport design can I think reach assisted SSTO
performance requirements. If one can air launch, scale effects actually
favour smaller vehicle size with regard to drymass, and re-entry -
except for fixed guidance system weights, which continue to reduce with
each passing year. The engine design will be critical, something like a
miniature Merlin designed solely for vacuum. Throttling will be highly
desirable, and/or a multiple engine design.

The price tag to develop such a space transport and to start building
such a space station is probably 50 million at a minimum, (~twice
Spaceshipone, ~maybe half the larger Falcons). I had better start
putting away a little extra each week. :-)

Pete.