The end of the last post rhetorically asked: What is Orion?
In short, Orion is the Space Shuttle replacement and the best way to understand Orion is to understand Apollo. So let me back up a little.
Everyone remembers (or at least knows about) the Apollo missions. Giant rockets shooting tiny (in comparison) astronauts into space. NASA’s pretty much going back to that system, except smaller and bigger (yes, I understand the dichotomy there).
Apollo used the Saturn V as a launch vehicle; and as launch vehicles go, it was pretty hefty, shooting 118000 kg of cargo into Low Earth Orbit (LEO). By comparison, Orion will use the Ares I rocket. The Ares I is about 15 meters shorter and 5 meters less in diameter. With its smaller size, it’s only able to launch 25000 kg into LEO. Don’t forget that the area of a circle is proportional to the square of the radius. Thus, if you reduce the radius to half, you end up reducing your area to 1/4.
However, the Crew Module and Lunar Module will both be bigger, carrying six people all the way to the Moon instead of three into space and two to the Moon.
Now you may be asking yourself, “But wait, I thought NASA abandoned the one-time-use Apollo in favor of a reusable Space Shuttle? Why are we going back?” Right you are, for the most part. Apollo was single-use-only and NASA did cut two missions from the end the Apollo program so they could divert funding to the Space Shuttle program. However, Orion is a newer, better, and cheaper Apollo-style space vehicle. Additionally, the Orion capsule will be reusable up to six times. And while I don’t know for sure, it seems that having a partially reusable spacecraft is a good combination between production costs and refurbishing costs.
The other item worth mentioning is that every Orion mission will comprise not one, but two launches. First, the Lunar Module is launched. Then the Command Module and Service Module are launched some time later. The units rendezvous in space and then continue on to the Moon.
That’s Orion in a nutshell.
Next up: How to Save Men From Exploding Rockets
Sources: Data and Pictures from Wikipedia and Lockheed Martin.0