Space Transportation - mmmt_transportation.pdf - Moon Society

By Peter Kokh
Early Orbit-Based Shuttles
The first expeditions to Mars will have to use orbit-based self-unloading, self servicing and self-launching
shuttles. There are no ready to use port facilities on Mars. An aero-braking shuttle cannot land like Columbia and
siblings. It can glide-in only to lose most horizontal momentum, but then must either finish the job by using
retrorockets to land on its tail or vectorable thrust to land like a harrier.
Preparation of a runway for wheeled horizontal landing and take off would make sustained operations easier,
but is a down-the-list priority.
NIMF shuttles and hoppers {nuclear rockets using indigenous made-on-Mars fuels like methane and oxygen)
will be enormously cheaper to fly than those that must carry launch and return fuel down with them from orbit,
indeed, all the way from Earth.
The NIMF scenario is versatile. Shuttles that will be on a location long enough to process their launch and
return fuel can land anywhere. For quick trips, a fuel processing plant must be pre-landed on a selected site. A depot
network of NIMF plants around the Martian globe at well chosen sites will accelerate the opening of the planet.
Early traffic to Mars would also benefit from a fuel processing plant on Deimos or Phobos, at least marginally.
This would be an early high priority item, especially for traffic (processed hydrogen, nitrogen, and carbon volatiles
such as liquid methane and ammonia for trade to the Moon in exchange for made-on-Luna equipment / provisions) to
the Martian moonlets themselves might be a major development on which Mars surface operations are economically
piggybacked and subsidized.
Later Ground-based Shuttles
If sustained traffic warrants (a decision to establish a permanent exploration base etc.) a true port facility can
be established. In effect, this would change “Home Port” from Earth to Mars. Such a full-function port facility would be
site preemptive, in that by making it far cheaper to land and take off from that location, traffic to other “undeveloped”
sites on Mars would struggle at a major competitive disadvantage. Infrastructure is a strong magnet and activity
polarizer. First site to establish it, wins.
Any Martian spaceport could also double as an airport. Cargo and passenger aviation on Mars, perhaps with
hydrogen-buoyancy lift assistance is a strong feasibility. Its early development will be crucial to opening up the planet.
Up/Down Western/Eastern Pavonis
One of the most specially advantaged pieces of real estate in all the solar system is the very high (15-23 km?)
extinct shield volcano Mons Pavonis (“Peacock Mountain)” which sits astride the Martian equator on the Tharsis uplift.
Its gentle western slope is a textbook site for launch track operations of any kind, far better than any of the mountain
candidates on Earth (see earlier article this issue).
A launch track is a captive ground-based virtual first stage which shaves major engine, tank, and fuel weight
off the remaining mass that has to be accelerated into orbit and subsequently maneuvered.
A Pavonis — Deimos Elevator
On Earth, the idea of a space elevator to a Geosynchronous facility 23,000 miles up using yet-to-be invented
filaments of unbelievable tensile strength is an attractive, if very far off, theoretical possibility (Arthur C. Clarke’s
“Fountains of Paradise). It would reduce the cost of access to space to that of a small electric bill. Such a construct will
b e much easier (therefore much earlier) to install for an asteroid (like Ceres) where the distance to be covered and
gravitational stresses involved will be orders of magnitude less.
On Mars, two assets will hasten the opening of a space elevator: Pavonis Mons and Deimos, a potential
elevator-anchoring mini asteroid like body only slightly further out than Mars-synchronous orbit, and conceivably
movable into place. But the timetable for such a development will be contemporary with major efforts to terraform (we
prefer “rejuvenate)” Mars itself into a friendlier place for human habitation.
Relevant Readings From MMM Back Issues
MMM # 18 SEP ‘88 “Pavonis Mons”
MMM # 73 MAR ‘94, pp. 3-5, “Urbs Pavonis / Peacock Metroplex: the Site for Mars’ Main Settlement.”
MMM # 56 JUN ‘92 “Harbor & Town”
37