Thanks for the video.
Many people don't realize that the current Constellation mission to the Moon is meant primarily as a stepping stone for a manned Mars mission. In
fact the logo for the Constellation Program has three "worlds" on it, signifying The Earth, Moon, and Mars:
Constellation
Logo
Mars is far away and is only in range for a manned mission every 2 years or so. Therefore, a manned mission to mars will take 2+ years, with about
500 days spent on the surface of Mars. NASA needs to make sure the equipment they send to Mars works the first time -- if the astronauts get there
and something goes wrong, they just can't come home early (the Earth will be out of range).
We (humans) need to practice how to live in habitats on the Moon before we can do the same on Mars, and make sure those habitats are built properly.
We need to learn about the hardware and tools needed to explore a world before we go to Mars. That's what the current Moon missions are all
about.
If NASA just wanted to go to the Moon to say "we made it" like they did in 1969, then they could have gotten back there pretty quickly if they
wanted. But the Constellation Program is about much more than simply "going" to the Moon -- it's about gaining the experience to live on and
explore another world, experience that is vital to a future Mars mission.
Also as part of the Constellation Program, the Ares V cargo launch vehicle is being developed to do the heavy lifting of the equipment that will take
humans to the Moon, and eventually to Mars. (The Ares I is only for launching the Orion Capsule that will dock in orbit with the rest of the "heavy"
equipment).
Those who say
"why is it taking longer this time to go back to the Moon than it did in the 1960s" don't seem to realize that the overall
goal this time around is far more ambitious than it was in the 1960s.
...and one clarification regarding what was said in the OP:
The Orion Spacecraft will not
really be used as the cruise vehicle for getting people to Mars. There will probably be a whole new larger craft
built in orbit for that purpose. The Orion will probably only be used to launch the astronauts into low Earth orbit to dock with the "Mars Cruise
Vehicle". Another Orion would probably be launched 2 1/2 years later to meet-up with the returning Mars astronauts in low Earth orbit for re-entry.
The Ares V cargo vehicle will probably be used to get pieces of a Mars Cruise Vehicle into orbit (for final assembly in orbit).
The Orion is primarily the means to get to and from Earth's orbit, but it will be used as the crew capsule as part of the larger Moon cruise vehicle
(along with the command module and Lunar lander). It's fine for the 3-day trip to the Moon, but it's much too small for the 6-month trip to
Mars.
All of the details I mentioned of a future Mars mission are only at the "very preliminary concept" phase, and things may change...but at least it's
good to know that NASA is at least giving it some thought.
[edit on 7/20/2009 by Soylent Green Is People]