Jules Richardson wrote:
On Sun, 26 Aug 2012 12:17:52 +0100, Grimly Curmudgeon wrote:
"Which is what we were absorbed with 40 years ago - after the Moon, what
about Mars?
With 70s technology, it would have been an utter, unparalled,
unmitigated disaster in slowmotion.

Why? What's so different about it to landing on the moon, other than the
distance involved? An understanding of Martian climate (or rather lack
thereof) may have knocked it on the head, and also the additional cost of
developing equipment to get there (and back), but I'm surprised that the
technology itself was a limiting factor.

Call it an order of magnitude harder and more expensive. The Superpowers
could just about afford the race to be first to the moon. To be the
first to Mars would have bankrupted them.

The technology was a limiting factor, as are the laws of physics, and
the biological aspects of the mission.

The journey to the moon took a few days. The quickest possible journey
to Mars and back takes several months, so you need to carry about fifty
times the amount of food and other consumables. You also need to find a
crew who can get along with each other in total isolation for a couple
of years without killing each other or themselves, rather than the week
or two that they had to put up with each other for the moon missions.

The escape velocity from Mars is over double that of the moon, so the
lander has to carry much more fuel to lift the same mass into orbit,
which makes it bigger, so it has to carry even more fuel, and all that
fuel has to be launched from Earth. As a rough guess, the Mars Excursion
Module (including fuel) would be about ten times the mass of the Lunar
Excursion Module.

We could do it now, but only by launching many rockets and assembling
the Mars mission vehicles in Earth orbit. They couldn't have done that
in the 1960s.

--
Tciao for Now!

John.