ars beckons us. The nearest, most Earth-like
world to our own, it shines with a reddish
glow of reflected sunlight in the night sky,
calling out to our curiosity and spirit of
adventure. It has an atmosphere (of sorts) and, at noon on a
summer’s day, ground temperatures can reach 25 ̊C. A day
lasts about 24 hours, as on Earth. But there the familiarity
ends. That atmosphere is 95 per cent unbreathable carbon
dioxide, at less than one per cent of the atmospheric pressure
on Earth, so there’s little insulation and winter nights can be
-140 ̊C. Mars is a tenth of the mass of Earth, so gravity has only
a third of the pull we experience. And a year lasts 687 days.
The next frontier
After the Apollo Moon missions in the 1970s, sending
astronauts to Mars seemed the next logical step, but it would
be a ‘giant leap’, politically and financially. Space is big: while
it took the Apollo astronauts only four days to reach the
Moon, with present technology it would take about nine
months to reach Mars. By the time the planets align
favourably for a return, a complete mission might last two or
three years. Throughout that time, the astronauts would need
food, water and oxygen, plus protection from radiation.
At this point, the success rate for robot missions does not
inspire confidence. Russia has launched 21 Mars rockets to
date, including five unmanned landers, but only two orbiters
completed their missions. The US has been more successful,
losing only five out of 23 missions. But there has yet to be a
return mission. Clearly some more work is needed before we
can contemplate sending humans to Mars. But, sooner or
later, we will go. With the political will, it could be within 20
years. And one thing that can be done in the meantime is test
human psychological resilience for such a mission. The
current record holder for the longest spaceflight is the
Russian astronaut Valeri Polyakov, who returned to Earth
from Mir in March 1995 after 437 days in space. Such a feat
Tests to discover how humans might
cope with a mission to Mars include
the Mars Society’s prototype base
in the Utah desert. The longest space
flight ever recorded was on Mir
(below), which provided information
on the effects of long-term
weightlessness and radiationM
Isolation experiments:
six men lived in this
mock-up spacecraft for
520 days, while another
simulation took place in a
geo-dome on Mauna Loa
volcano in Hawaii (right)
062 / / JANUARY 2017