Studio Chamisa, Taos, N.M.
A journey to Mars is not a small undertaking, but as most of us realize [Mars Society members] not an impossibility. The book Case for Mars by Zubrin exemplifies how this is done with existing technology at a cost that is not out of line. With existing technology, some new technology that could be deployed in the next six years, and incorporating the lessons and good ideas of the past we can move rapidly forward with a manned mission.
This paper is on a vehicle that is light, will get to Mars in 120 days or less and use the Moon to assist the trajectory. All numbers are approximations, estimates and arrived at using basic principles [rocket equation etc]. The spacecraft, I like to call it a ship since there are many similarities, is a ROMULAS type vehicle [rapid orbital module ultra-light astronomical ship]. The total mass in LEO [low earth orbit] is approximately 160ton. The ship consists of 3 RL10 engines, 6 LAMP engines [lightweight augmented methane propulsion], a nuclear electric module, crew of 2 with provisions as well as tanks and materials required for burn times as required for the trajectory. There are 3 ships, so a total of 6 astronauts.
The mission is as follows: The 3 rocket motors will fire for 26+ minutes and bring the ship to the moon in a little over 1 day. Here 2 RL10s and their tanks are discarded and maybe crash on the moon. Here the fun begins-- as the ship leaves the moon, lightened up by 70+ tons, with an optimized vector going into the "S" trajectory the LAMP engines will fire for approx. 10 days and impart a hyperbolic velocity of about 6miles/sec. Since the LAMP's are a hybrid engine between a rocket [low eff.] and MHD [hi eff]--xxxisp the additional mass requirement for propulsion is quite small, 9+ tons. After traversing an elliptical path of about 120+- million miles the ship, going faster than Mars, will catch up and needs to slow down for about 10 days. Before this happens, a crew exchange plus some provisions are done between ships. Now we have 4 astronauts in ROMULAS III and one each in the other two ships [quick return around Mars]. After orbiting the red planet 2 will stay with the ship and 2 will depart to Mars in a small lander [parachutes] a la the Apollo program. Those on Mars will go to a LEM type vehicle, previously dropped off by a supply ship.