Humanity's path to Mars may go through Phobos, one of the Red Planet's two tiny moons.

Humanity's path to Mars may go through the Red Planet's tiny moon Phobos.

An incremental, multiple-mission approach that envisions getting astronauts to Phobos by 2033, then down to the Martian surface by 2039 could make manned Mars exploration technologically and economically feasible, said Firouz Naderi, head of the Solar System Exploration Directorate at NASA's Jet Propulsion Laboratory in Pasadena, California.

NASA can't count on another "John F. Kennedy moment" — the 1961 call by the then-president to land people on the moon by the end of the decade — to boost its budget, Naderi added. (NASA's share of the federal budget reached about 4.5 percent during the height of the Apollo years; it is now less than 0.5 percent.) [5 Manned Mission to Mars Ideas]

"Is anybody really going to be excited if we're going to Mars in 2070 [or] worse yet, sometime in the future but we don't know when?" Naderi asked delegates Wednesday (May 6) during the Humans to Mars Summit in Washington, which was hosted by the nonprofit organization Explore Mars, Inc.

The Phobos-first approach would rely on NASA technology already under development, such as the Orion crew capsule and the Space Launch System (SLS) megarocket, leaving out exotic future technologies such as nuclear thermal propulsion. (SLS and Orion are scheduled to fly together initially in 2018, and to launch crews for the first time in 2021.)

Several space tugs, powered by solar-electric propulsion, would be placed in Mars orbit with supplies that future crews could use for landings. The mission to Phobos — one of the Red Planet's two miniscule moons; Deimos is the other — would require four SLS launches, while a six-day stay on Mars on top of that would bring the total to six liftoffs.

Keeping the cost of manned Mars exploration down will also require in-situ resource utilization — living off the Martian land as much as possible, said Oliver de Weck, an aeronautics and astronautics professor at the Massachusetts Institute of Technology, in a separate panel.

A study performed by de Weck and his graduate students suggests that using Mars' water, methane and hydrogen could cut the initial mass sent to low-Earth orbit for a Mars mission by 48 percent. Further, de Weck suggested money could be saved by treating Mars exploration as a network of missions with linked objectives, rather than a series of one-offs.

Common elements among various missions will also save on cost, since the same technology can be recycled, added Brand Griffin, a senior aerospace engineer at NASA's Marshall Space Flight Center.

"Commonality: it has to lead and it can't follow. It has to be at the front end of the program," Griffin said.

The Humans to Mars Summit ran from Tuesday (May 5) through Thursday (May 7).

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