How hard would it be to retrieve some samples from Mars?

A small rover, emerging from a landed module. Goes along the surface
and picks up say 50 kilos of samples. Then it returns to the module,
it takes off and comes back to Earth. Or, it could dispense the
samples, leave the return craft and stay on Mars doing more
experiments.
How large would such a platform need to be to escape Martian gravity
which is 1/3 that of Earth's?

"RichA" wrote in message
...

A small rover, emerging from a landed module. Goes along the surface
and picks up say 50 kilos of samples. Then it returns to the module,
it takes off and comes back to Earth. Or, it could dispense the
samples, leave the return craft and stay on Mars doing more
experiments.
How large would such a platform need to be to escape Martian gravity
which is 1/3 that of Earth's?

__________________________________________________ __
And return to earth. If robots worked as well as astronauts, its not much
harder than what Apollo 11 managed. The escape velocity of Mars is a bit
higher than the Moon, but it has an atmosphere which helps on the way down
to the surface (at least). The reason we cannot do it with humans is because
the flight would be so long we would need to take tons of life support
equipment for every stage of the trip - air, water, food, pressure,
radiation etc as well as some capability to abort the mission. This makes it
impractical. However a robot can happily sit on standby for months or years
at a time, so the mission length is irrelevant, and we are not wasting
payload on human life support. The problem is that we don't have robots
sufficiently reliable or flexible or intelligent to make this happen. Soon
we may.

On 13/10/2012 08:49, Peter Webb wrote:


"RichA" wrote in message
...

A small rover, emerging from a landed module. Goes along the surface
and picks up say 50 kilos of samples. Then it returns to the module,
it takes off and comes back to Earth. Or, it could dispense the
samples, leave the return craft and stay on Mars doing more
experiments.
How large would such a platform need to be to escape Martian gravity
which is 1/3 that of Earth's?

__________________________________________________ __
And return to earth. If robots worked as well as astronauts, its not
much harder than what Apollo 11 managed. The escape velocity of Mars is
a bit higher than the Moon, but it has an atmosphere which helps on the
way down to the surface (at least). The reason we cannot do it with

Actually ISTR that Martian atmosphere is a damn nuisance. Enough air
resistance to burn up space probes on initial entry but not enough to
give much useful deceleration with a parachute at lower levels.

Mars probes have a pretty bad record for going wrong or AWOL.

humans is because the flight would be so long we would need to take tons
of life support equipment for every stage of the trip - air, water,
food, pressure, radiation etc as well as some capability to abort the
mission. This makes it impractical. However a robot can happily sit on
standby for months or years at a time, so the mission length is
irrelevant, and we are not wasting payload on human life support. The
problem is that we don't have robots sufficiently reliable or flexible
or intelligent to make this happen. Soon we may.

I think we could make the robotic kit now, but the maximum weight we can
land on Mars reliably is about what the rover is now or maybe twice that
at a push. So your returning probe would have to be pretty small and
perhaps carry at most 1kg or less rock samples.

--
Regards,
Martin Brown