ScienceDirect - Technol Rep Tohoku Univ ... - Garryck Osborne

94 The Hunt for Zero Point
woman from public affairs. As we moved through the lobby, she sketched
in some of the background to the program I'd come to talk about with its
manager, Garry Lyles.
Under the Advanced Space Transportation Program, ASTP, officials
at NASA Marshall have been working since the mid-1990s on methods
to reduce the cost of space access. Using today's generation of launch
vehicles—the Space Shuttle Orbiter, the Delta and Atlas rockets—it
costs around $10,000 per pound to put a satellite into low Earth orbit.
One short-term payoff of ASTP will be the development of a family of
reusable rocket planes that should cut these costs by a factor of ten by
the end of the present decade. A mid-term goal, due to yield results
in around 2015, is to develop a hybrid "combined cycle" engine—
half-rocket, half-jet engine—that will reduce launch costs by a factor of
a hundred. Even though the hybrid engine, if it can be mastered
technologically, will give NASA space access for as little as $100 per
pound, it will never lead to anything other than a delivery system to low
Earth orbit.
For missions beyond Earth, scientists will either have to rely
on improvements to the chemical rocket or on something radically
different.
For a mission to the planets of the inner solar system a nuclear rocket
could be developed in a relatively compressed timescale to cut round-trip
journey times from Earth to Mars from many months to possibly just
weeks. The feasibility of nuclear rockets had been proven in two NASAdeveloped
solid core fission reactor test programs, NERVA and ROVER,
between 1959 and 1972. These never came to fruition, my PR guide told
me, due to concerns over safety and also because emerging and more
advanced nuclear fusion technology was seen as yielding three times the
efficiencies. Like the fission rockets, however, fusion systems never
happened either—not in the white world, anyhow. In the early 1990s, the
Pentagon was reported to be working on a classified nuclear thermal
rocket under the code name "Timberwind," but soon afterward it was
canceled. Since the black world is publicly unaccountable, it is impossible
to know whether this really was the case.
Lightweight nuclear fusion propulsion is one methodology being
studied for a manned NASA mission to Mars, my guide continued as
we drifted toward the elevators, alongside "light-sails," "magnetic
sails," "antimatter fusion drives," lasers and other exotic-sounding
technologies.
While the physics behind these ideas is generally well understood, she
added, the challenge in turning them into hardware is enormous.