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If the US is to send astronauts to Mars, nuclear propulsion will be
essential, according to a group of eminent academics and industrialists.

Thomas Stafford, who was the US commander during the Apollo-Soyuz linkup
in 1975, headed the group, whose brief was to come up with two or more plans
for exploration of the Solar System and to detail technologies essential
for the exploration.

The exercise grew out of President Bush’s speech in 1989 celebrating
the 20th anniversary of the first Moon landing. In his speech Bush directed
NASA to plan for a return to the Moon and for exploration of Mars.

At the request of Vice President Dan Quayle, NASA sent out 34 500 letters
soliciting ideas to fulfil Bush’s aims. The agency received 1697 responses
from academics and industrialists, and from schoolchildren in every state
but Arkansas, Wyoming and Alaska.

Stafford’s group drew the ideas together and outlined four different
approaches to exploring Mars. All the missions would rely on nuclear propulsion
to shorten the time it takes to reach Mars. This would reduce the astronauts’
exposure to cosmic radiation and solar flares. Nuclear power plants would
also weigh less than chemical propellants, cutting the cost of launching
the craft.

Stafford’s group released its report only five days after the House
of Representatives voted to reinstate funds for the international space
station Freedom. According to Steven Aftergood from the Federation of American
Å®ÉúСÊÓƵs: ‘Many representatives guilt-tripped into voting for the station
may well feel that NASA should not come back for more funds for manned exploration
for 30 years.’ That, he says, would be the final absurdity. ‘NASA may find
it has played its ‘manned exploration’ card too early and for the wrong
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The recommendation that nuclear propulsion is essential for exploration
of Mars is likely to be controversial. Aftergood says: ‘Some people, who
are not particularly exercised one way or the other about nuclear power,
but who believe that manned exploration of Mars is a grotesque abuse of
this country’s limited resources, may use the nuclear issue as a focus for
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Not all those who support an expedition to Mars believe that nuclear
propulsion is the best option. An alternative would be to use chemical propellants
to accelerate the craft to Mars combined with ‘aerobraking’ to slow down
the spacecraft as it approaches the surface of the planet. Relying on the
Martian atmosphere to act as a brake would reduce the mass of propellant
the spacecraft would need. Stafford’s group says that aerobraking would
not work.

Over the coming months, NASA will evaluate the group’s findings and
report to Quayle.