IEEE Spectrum June, 2009 - 40

phase 2

Unmanned payload

Manned spacecraft

In 2016, two more rockets
head to Mars. The first
payload consists of
another unmanned fuel
factory and another ERV.
The second is a habitation
module with a human
crew of four, food and
other provisions, and
a pressurized rover.

Food and supplies
Tether

Pressurized
crew rover

Spinning creates
artificial gravity.
Booster's
upper stage

phase 3
The crew uses the
pressurized rover to
explore; with 12 metric
tons of fuel, they can
travel up to 24 000
kilometers. At landing
site 2, the fuel factory
produces propellant
for the second ERV.

Mars

Crew's habitat

Four-person crew

ERV

Landing site 2

200 to 300
kilometers
Habitat

phase 4 (inset)
After 18 months, the
crew heads home in
the ERV. Meanwhile,
two more rockets are
launched-one carrying
a crew, the other to
prepare landing site 3.

bryan christie design

other physiological problems brought on by weightlessness.
Arriving at Mars, the manned craft drops the tether, aerobrakes,
and lands at the 2014 landing site, where a fully fueled ERV awaits.
The second ERV lands several hundred kilometers away, at landing site 2, and starts making propellant for the third mission, to take
place in 2018. The third mission, in turn, will fly a crew to site 2 and
an additional ERV to open up landing site number 3, and so on.
The first crew spends 18 months exploring Mars; they'll
have enough fuel to drive the pressurized rover a total of 24 000
kilometers. That should suffice: The circumference of Mars is
about 21 000 km. Among other things, the crew will be able to
conduct a serious search for evidence of past or present life.
By remaining on the surface, the crew will benefit from the
planet's natural gravity (about one-third that of Earth) and will
be protected by the Martian environment against most of the
cosmic rays and all of the solar flares. Thus there will be no need
for a quick return to Earth, a problem that plagues conventional
Mars mission plans that envision living aboard an orbiting
mother ship that sends down landing parties for brief jaunts.
Finally, the crew returns to Earth in the ERV. Meanwhile,
a second crew is on its way to Mars. Thus every other year,
two heavy-lift boosters are launched: one to carry a crew, the
other to prepare a site for the next mission. As the missions
progress, they leave behind a string of bases that open up ever
broader stretches of territory. At an average launch rate of just
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one booster per year to pursue a continuing program of Mars
exploration, this plan is clearly affordable. In effect, it removes
the manned Mars mission from the realm of megafantasy and
reduces it to a task whose difficulty is comparable to that faced
in launching the Apollo missions to the moon.
But why do it? First, for the knowledge. We are now fairly certain that Mars once possessed oceans in which life could have
developed. If we discover fossils on Mars or extant life surviving
in subsurface water, it would be the most important discovery
since Copernicus theorized that Earth revolves around the sun.
Second, for the challenge. People thrive on challenge and
wither without it. The space program also needs a challenge.
Between 1961 and 1973, with the impetus of the moon race, NASA
produced a rate of technological innovation immeasurably greater
than anything it has shown since, for an average budget that was
only about 25 percent bigger than today's. It did so because it was
reaching for a seemingly impossible goal. The Apollo program
also strongly stimulated the U.S. economy and inspired a generation of schoolkids to pursue science and engineering. A humansto-Mars program would do the same.
Third, for our future. Mars is not just a scientific curiosity.
It is our New World. Someday, millions of people could live
there. Today we have the opportunity to be the founders, the
parents, and the shapers of a new and dynamic branch of the
human family. It is a privilege we should embrace.
o
juNE 2009 * iEEE SpEctrum * NA

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Table of Contents for the Digital Edition of IEEE Spectrum June, 2009