[ExI] Fwd: Power satellite infrastructure deployment

Keith Henson hkeithhenson at gmail.com
Fri Feb 19 04:53:05 UTC 2016

This is rough, and not yet integrated into the business case.

We assume that the Skylons fly every other day and each delivers at
least 15 tons of payload or fuel to a 300 km cargo accumulation orbit.
Because 300 km is relatively low (and high drag), we don’t keep
anything in LEO any longer than it takes to accumulate the cargo.  The
first cargo delivered to LEO is a kit to build the first propulsion
power satellite (PPS).  It’s about 4000 tons plus 1550 tons of
reaction mass spit between LOX/LH2 for the rocket engines and LH2 for
the arcjets.

This takes 370 Skylon flights.

Cargo to build the first PPS we boost to 2000 km using a Hohmann
transfer orbit.  We propose using rockets with performance similar to
SSME.  The reason for chemical rockets and sending it up as a kit is
to avoid a long exposure of a large object to space junk.  We unpack
and assemble the PPS at 2000 km and turn it on.  Using arcjets, the
PPS goes up in a spiral orbit under its own power to 18,000 km.

The second cargo assembly in LEO is the second PPS plus a tug, plus
worker habitat and tools/jigs for the construction base (CB) at 12,000
km.  The first PPS beams powers the tug which moves the combined stack
from LEO to the CB.  The workers (who go up with the cargo) put
together the 2nd PPS and it spirals out using its own power and a set
of arcjets to 18,000 km.  The tug returns at the same time from the CB
to LEO.  Both the first and second PPS probably have a few people as
crew to fix what robots can’t.  (We can afford habitat for a few
people in an object ten times as large as the ISS.)

Starting mass is ½ of nominal, 10,500 tons, 700 flights.

On power from one PPS the tug takes about the same 30 days with a half
load as a full load would take with twice the power.

While this is going on, Skylon flights take up the parts for the 2nd
tug plus a full load of power satellite parts plus fuel, 15,000 tons
of parts, plus 4000 tons of reaction mass plus a 2000 ton tug.  This
takes 1400 flights.

Now there are two tugs and two PPSs in space, so the 4th and following
cargo stacks plus fuel mass 19,000 tons or 1267 flights.  Since we can
power two tugs at a time, we need 2533 flights per month, or 84/day.
This would take a vehicle fleet of 168 Skyons if we can fly them every
other day.

There are a number of minor uncertainties.  One of them is salvaging
fuel from the Skylons.  This would somewhat reduce the number of


This went to the power satellite economics group.  If you want to
reply, please cc it there.

It's the basis of the talk I will be giving in the UK on March 4.


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