— One of the last two astronauts to walk on the lunar surface has parted ways with the Planetary Society for urging the
United States
postpone its planned return to the Moon.

The Pasadena, Calif.-based Planetary Society unveiled its “Roadmap to Space Exploration” at the National Press Club here Nov. 13 urging U.S. President-elect BarackObama and the incoming Congress to reconsider a 2020 goal for returning humans to the Moon and focus instead on incremental missions aimed at achieving an earlier human Mars landing. Apollo 17 astronaut Harrison “Jack” Schmitt is criticizing the Planetary Society’s proposal for failing to take into account multiple studies identifying lunar exploration as a necessary springboard for Mars missions.

“The fastest way to get to Mars is by way of the Moon,” Schmitt said. “If we were to back off from that space policy, I fear all the momentum will be lost. … I don’t want to waste a generation of enthusiasm and intelligence just to get to Mars.”

Schmitt is a geologist and former astronaut who logged more than 22 hours on the lunar surface during NASA’s final human mission to the Moon in December 1972. He served one term as a Republican senator from his home state of
New Mexico
from 1977 to 1983, and since has worked in academia and as a consultant. In October, he resigned as chair of the NASA Advisory Council, a post he had held since 2005. He told Space News that the U.S. Office of Personnel Management would no longer grant waivers necessary to pay him for more than 130 days per year of advisory council service.

Schmitt criticized the Planetary Society’s roadmap in a Nov. 14 letter, one day after Executive Director Lou Friedman and two other members of the roadmap team held a press conference here to announce the recommendations. The roadmap was the result of a February workshop at
Palo Alto
, in which 50 space experts explored President George W. Bush’s 2004 Vision for Space Exploration and its subsequent implementation under two NASA administrators. Workshop participants told members of Congress in April they feared building a lunar outpost would serve to anchor the
space program to the Moon.

Under the Constellation program, established in 2005 to implement Bush’s call for returning to the Moon, NASA has embarked on the development of the partially space shuttle-derived Ares 1 launcher and the Orion Crew Exploration Vehicle, which is slated to enter service in 2015 to carry astronauts to the international space station. The development of the Ares 5 heavy-lift cargo launcher, a cryogenic Earth Departure Stage and the Altair lunar lander are due to get under way in the year ahead, and eventually operate in conjunction with Orion and Ares 1 to enable human lunar expeditions.

NASA Administrator Mike Griffin told Space News in a Nov. 13 written statement that he “categorically disagree[d]” with the Planetary Society’s assertion that NASA is focused on the Moon to the exclusion of Mars and other targets of human exploration. He also defended NASA’s plans to establish a lunar outpost as a crucial step toward Mars missions, and underscored the importance of milestones such as Orion and Ares 1.

Schmitt told Space News in a Nov. 18 interview he is in lockstep with
, adding that NASA’s stated milestones are critical to maintaining funding for Constellation in the face of what he characterized as opposition within the U.S. Office of Management and Budget (OMB) to adequately fund human spaceflight . Despite the election of a new president pledging support for NASA’s human space exploration goals, career OMB employees likely are to remain in their current positions, he said.

“They will continue to look for excuses to cut back on space flight, and I think that would be a tragic mistake for our country,” Schmitt said. “I want to get to Mars as bad or maybe even more than anyone, but I want to do it in a rational way.”

In response to Schmitt’s letter, which served as his resignation from the Planetary Society, Friedman sent an open letter to Schmitt asking him to reconsider dropping his membership.

“Jack – Despite this current ‘dust-up,’ you are one of us. Because I worked with you when you were a Senator on a very bi-partisan NASA Authorizing Committee, I know you are a supporter of inclusiveness – and we in the space community are too small to be productively fragmented,” Friedman’s letter said. “The disagreements we have (even the strong ones) are of less importance than these things which we share. These include disagreements on exactly what activity to do on the Moon, other steps that might be inserted in the sequence for human space flight, and whether American leadership can be exercised in a way that the world will be excited to follow.”

Another Apollo-era astronaut, Buzz Aldrin, who walked on the Moon in 1969 during the Apollo 11 mission, supports the Planetary Society’s roadmap emphasizing a human presence on Mars, and said Nov. 13 that future Moon landings should be deferred to allow international participation.