NASASpaceFight.com reports that Boeing has proposed a multi-step humans-to-Mars program that would feature a reusable solar electric-propelled Mars Transfer Vehicle to be deployed by the heavy lift Space Launch System.
Step One: Deploy Mars Transfer Vehicle
The first step of the Boeing Mars campaign would be to launch a Mars Transfer Vehicle on a Space Launch System heavy lift rocket that would consist of a solar electric propulsion unit and an inflatable Crew Transfer Habitation module into low Earth orbit, according to NASASpaceFlight.com. The CTH would inflate and then the SEP would lift the MTV to the deep space station that NASA envisions for the Earth/Moon Lagrange Point 2.
Step Two: mission to Phobos
Next, according to the NASASpaceFlight.com story would be to use a second SLS to launch an Orion Multi-Purpose Crew Vehicle with astronauts, along with a chemical propulsion In-Space Stage and a supply of xenon or krypton gas for the MTV's SEP unit. The crew would board the MTV for final checkouts, dock the In-Space Stage to the vehicle and top off the fuel tanks for the SEP. Then the In-Space Stage would blast the MTV into a trajectory to Mars. Once the chemical rocket's fuel is expended, the SEP would take over to accelerate the MTV to Mars-Phobos orbit. The concept is similar to one presented by JPL engineer Nathan Strange recently with a MP3 file and a slide presentation. The MTV would rendezvous with Phobos, explore the Martian moon while tele-operating Mars surface assets, and then return to the deep space station at the Earth/Moon L2 for a return to Earth.
Step Three: cargo mission to Mars
Since the MTV is envisioned to be reusable, it would be used for subsequent missions to Mars. The next step, according to the NASASpaceFlight.com story is to launch a Mars Cargo Lander on an SLS to dock with the MTV along with more propellant for the SEP. The Mars Cargo Lander would contain supplies for future Mars astronauts, a surface habitation, and perhaps an In Situ Resource Utilization (ISRU) device to create rocket fuel and other consumables from the Martian atmosphere similar in the manner described by Dr. Robert Zubrin's Mars Direct Concept. The MTV would deploy the MCal on the Martian surface and then return.
Step Four: humans to Mars
The final step would be to use the MTV to send a human crew to the Martian surface, the holy grail of NASA space exploration planning. A Mars Crew Lander (MCL) would be transferred to the deep space station and docked with the MTV. Then a crew of astronauts would be launched to the MTV, as with the Phobos mission, with an In-Space Stage and fuel for the SEP. The MTV would take the crew to Mars orbit. Then the crew would use the MCL to land near the pre-deployed MCal where they would conduct Mars surface operations until the window opens for a return to Earth
Mark R. Whittington is the author of Children of Apollo and The Last Moonwalker. He has written on space subjects for a variety of periodicals, including The Houston Chronicle, The Washington Post, USA Today, the L.A. Times, and The Weekly Standard.