Space travel by humans is not possible now

Of robust and rad-hard types of micro-robotics in space isn't where
the big payoff is, as that's doable as is and getting per kg cheaper
by the day.
.. -Brad Guth


jacob navia wrote:
Human space travel is a big source of profits for aerospace companies.

The advantages are that the scientific returns are very low or zero, so
there is no need to spend money paying scientists to gather and
understand data, all the profits go in building hardware that is
used for a few days/weeks and the thrown away.

In the ISS, for instance, billions have been paid to aerospace
industries for hardware that has produced not a single intersting
scientific result, and that has dwarfed the budget of science within
NASA.

Take for instance a mission like the Mars Rovers. After four years in
Mars, those machines are still working perfectly, returning scientific
data and allowing the exploration of Mars in an unprecedented scale.

The total budget of the Mars rovers was around 900 million, and it has
returned gigabytes of data, measurements, photographs, etc.

This is more or less what a single trip of the space shuttle costs.

In this group, one of the most vocal advocates of this "humans
into space and to hell with science" is Mr McCall, that will not
hesitate to insult anyone disagreeing with his views.

Mostly his arguments are just at the level of

"bull ****"

or

"stupid".

Personally I do not care, but facts are stubborn. Human presence
in space is unnecessary, even more so in the moon. The basic
groundwork is not there, in terms of working life support
systems that can stay in space for 4 years without any failure.

It can be argued that astronauts can "fix" a life support system,
and this is partially true, but it depends heavily on the type
of failu to repair a life support system you need a life support
system that keeps you alive.

There is an emergency escape frm the ISS. That choice is not available
halfway from the distance to Mars.

This is a basic UNSOLVED problem.

Space radiation is another, completely unsolved one. The experience
of the ISS is of no use since the earth magnetic field protects the
ISS, a protection that people in the way to Mars will not have.

This is another UNSOLVED problem.

Gravity effects (or rather its absence) is another problem. We just
do not know since we have no data about the long term effects on
the body of 2 years without gravity. It is a fact that exercise
and countermeasures do NOT work, and there is a continuous bone
mass loss in space.

This is another UNSOLVED problem.

You can say that "artificial gravity" etc, but the problems to solve to
put that to work are quite big.

Another unsolved problem is how to land in Mars, what is a very
difficult problem that is very complex to solve for small
mass vehicles and completely unknown for huge mass vehicles
like a spaceship with 4 people and its life support, supposing the
2-3 years supplies are previously sent to Mars by robots.

This host of problems (all of them unsolved) makes any proposition for
manned Mars missions just a waste of money.

All of this problems CAN be solved, and (I am sure) they WILL be solved,
but not before this century has finished.

A new society is needed to give the drive to go into space. A society
that cares about exploration and that is ready to pay make the effort
it will take to develop a life-support system that can take us to the
stars.

Before that life support system is there, all the things being
done here are just pipe dreams.

--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32