terça-feira, 5 de fevereiro de 2008

Moon Stuck

Space leaders work to replace lunar base with manned asteroid missions

Posted: January 18, 2008


Some of the most influential leaders of the space community are quietly working to offer the next U.S. president an alternative to President Bush's "vision for space exploration"--one that would delete a lunar base and move instead toward manned missions to asteroids along with a renewed emphasis on Earth environmental spacecraft.

Top U.S. planetary scientists, several astronauts and former NASA division directors will meet privately at Stanford University on Feb. 12-13 to define these sweeping changes to the NASA/Bush administration Vision for Space Exploration (VSE).

Abandoning the Bush lunar base concept in favor of manned asteroid landings could also lead to much earlier manned flights to Mars orbit, where astronauts could land on the moons Phobos or Deimos.

Their goals for a new array of missions also include sending astronauts to Lagrangian points, 1 million mi. from Earth, where the Earth's and Sun's gravity cancel each other out and spacecraft such as replacements for the Hubble Space Telescope could be parked and serviced much like Hubble.

The "alternate vision" the group plans to offer would urge far greater private-sector incentives to make ambitious human spaceflight plans a reality.

There would also be some different "winners and losers" compared with the Bush vision. If the lunar base is deleted, the Kennedy Space Center could lose additional personnel because there would be fewer Ares V launches and no lunar base infrastructure work that had been assigned to KSC. On the other hand, the Goddard Space Flight Center and National Oceanic and Atmospheric Administration near Washington, along with the Jet Propulsion Laboratory (JPL) in California, would gain with the increased space environmental-monitoring goal.

Numerous planetary managers told Aviation Week & Space Technology they now fear a manned Moon base and even shorter sorties to the Moon will bog down the space program for decades and inhibit, rather than facilitate, manned Mars operations--the ultimate goal of both the Bush and alternative visions. The first lunar sortie would be flown by about 2020 under the Bush plan.

If alternative-vision planners have their way, the mission could instead be flown to an asteroid in about 2025.

Participants in the upcoming meeting contend there's little public enthusiasm for a return to the Moon, especially among youth, and that the Bush administration has laid out grandiose plans but has done little to provide the funding to realize them on a reasonable timescale.

Planners say the Bush plan is beginning to crumble, with only companies that have won major funding still enthusiastic about the existing plan.

"It's becoming painfully obvious that the Moon is not a stepping-stone for manned Mars operations but is instead a stumbling block," says Robert Farquhar, a veteran of planning and operating planetary and deep-space missions.

The prospect of challenging new manned missions to asteroids is drawing far more excitement among young people than a "return" (as in going backward) to the Moon, says Lou Friedman, who heads The Planetary Society, the country's largest space interest group.

The society is co-hosting the invitation-only VSE replanning session with Stanford. A lot of people going to the meeting believe "the Moon is so yesterday," says Friedman.

"It just does not feel right. And there's growing belief that, at high cost, it offers minimal engineering benefit for later manned Mars operations."

Under the alternative VSE, even smaller, individual lunar sorties would be reduced, or perhaps deleted entirely, says Noel W. Hinners, who had extensive Apollo lunar science and system responsibility at Bell Laboratories before heading all of NASA's science program development. He also led Lockheed Martin Spaceflight System.

Hinners believes the group should examine dropping all the lunar sorties to accelerate the human push to Mars in the revised VSE proposal to the new administration.

The James Webb Space Telescope, with a 21.3-ft.-dia. mirror, will be launched in 2013 to one of these "L" points. With little fanfare, it was recently approved to carry a lightweight Crew Exploration Vehicle docking system just in case a manned CEV has to make a house call a million miles from Earth for emergency servicing.

A growing corps of scientists, engineers and astronauts are emerging to argue for this chance to accelerate manned spaceflight operations outward well beyond the Moon--faster toward Mars than can be done by using the Moon as a stepping-stone only 240,000 mi. away.

"The notion that the Moon could serve as a proving ground for Mars missions strains credulity," says Farquhar, who holds the Charles A. Lindbergh Chair for Aerospace at the Smithsonian National Air and Space Museum. He also was mission director for the Applied Physics Laboratory's Near Earth Asteroid Rendezvous mission that was the first to land a spacecraft on an asteroid.

A return to manned Moon operations has become "a bridge too far" in the Bush administration's VSE, says Wes Huntress, another former planetary mission manager.

Huntress is director of the Washington-based Carnegie Institution's Geophysical Laboratory and had a long career at JPL and NASA headquarters, where he led NASA space science development and operations--including the highly successful Discovery planetary mission series. He's also helping to organize the Stanford workshop that will have about several dozen participants, including several top NASA and contractor exploration managers.

"There is little left of the 2004 Vision for Space Exploration except the real need to retire the space shuttle," he says. "Even this goal is being pursued with great sacrifice from all other parts of the agency because the administration has simply not put its money where its mouth is."

"Inadequate NASA budgets are leading to collapse of the VSE Moon focus and to incredibly slow progress for the Moon," says Hinners.

"The nation's space enterprise is under great strain even to build Ares I and Orion CEV," Huntress stresses. "There are alternate destinations for human deep-space missions that do not require building a lot of new hardware to [come and go between Earth and the Moon]. These are missions to near-Earth asteroids or to scout the Sun-Earth Lagrangian points for future space telescope construction and servicing," he notes.

The Earth-Sun Lagrangian points (also called libration points) are at the very edge of the Earth's gravitational well, and a mission would represent a first excursion to the limit of Earth's influence in the Solar System--a significant step beyond Apollo, says Huntress.

Missions sent to "L" points can stop just there, orbiting only above and below the ecliptic plane without any significant use of station-keeping fuel. Also, L points offer a much cleaner option for advanced astronomy than the dusty lunar surface, where you have to land everything in addition to launching it.

"As the nation seems to be turning to environmental threats to our own planet, a mission to a near-Earth asteroid to assess their nature for good or ill would also seem to be a real winner," says Huntress.

These stepping-stones would allow for the development of a broader vision of human spaceflight than simply reinventing Apollo.

Major lunar-related contracts for the Constellation Crew Exploration Vehicle Orion command ship, a lunar lander design and Ares V launcher have yet to be awarded, giving the next administration some breathing room in post-Bush administration VSE contracting.

Some basic asteroid mission design work--part of it volunteer--using the CEV hardware is already underway at the Johnson Space Center (AW&ST Sept. 25, 2006, p. 21). Other, more in-depth and long-standing manned asteroid analysis is underway under International Astronautical Assn. and Smithsonian National Air and Space Museum sponsorship.

Scott Hubbard, consulting professor in the Stanford Aeronautics and Astronautics Dept., conceived the reassessment meeting. Hubbard was previously the director of NASA Ames Research Center and, before that, NASA Mars program director. "We have planned this invitation-only workshop to elicit frank and open discussion about the future of the 'vision' as the administration changes," he says.

"The Stanford workshop will address a broad range of issues touching on many elements of space exploration. The attendees will discuss the balance between space science and human exploration, the need for continuing and enhancing Earth science observations, the relative utility of humans and robotics, and progress or impediments to human exploration of Mars, asteroids and the Moon," says Hubbard. "In addition, the workshop will discuss the status of access to space and the emerging entrepreneurial space industry.

"This is the kind of debate that will go on--beyond whether a lunar base really makes sense. But manned asteroid missions first--ahead of a lunar base--are drawing strong attention," he says. Hubbard and Friedman are co-hosting the event, along with former astronaut Kathy Thornton, associate dean of the University of Virginia's Science, Technology and Society Dept. Thornton flew on four space shuttle missions, including the initial critical repair of the Hubble Space Telescope in 1993.

The alternative vision would also include far greater private-sector incentives for participation at all levels, an area public surveys cite as very important. Missions to asteroids and Lagrangian points, for example, are likely to carry along Bigelow-type commercial inflatable modules. A recent informal space program survey by The New York Times found substantial public frustration about NASA's doing what entrepreneurs could do better.

Under the alternative concepts, astronauts using an upgraded CEV would initially be sent on long-duration missions, not to the Moon, but to land on asteroids where they would sample terrain perhaps more ancient than the Moon's. These visits would also help develop concepts for diverting such near-Earth objects, should they threaten a potentially devastating impact on Earth.

Although it may be hundreds of years before used operationally, an emergency asteroid diversion would be "the ultimate 'green mission'--one that could save a large portion of the Earth from impact destruction," says Friedman.

To reinforce that point, he notes that on Jan. 30, a 150-ft.-long asteroid will pass close to Mars. The asteroid visit and Lagrangian mission concepts would use much of the same CEV Ares I and Ares V heavy-lift booster infrastructure, but in ways that would be much faster stepping-stones to Mars than developing a manned lunar base. Asteroid and Lagrangian point missions would each last several weeks or months. Both the libration points and asteroids would be about 1 million mi. from Earth, requiring operations more like much longer trips to Mars at least 40-100 million mi. away.

Robotic options for all mission elements also will be reviewed, and one working group will be devoted to better defining manned versus robotic tradeoffs.

Another issue is international participation.

Aviation Week discussed an unrelated European International Space Station topic with NASA Administrator Mike Griffin last week, who in comments aside also addressed the basic Moon/Mars issues between the U.S. and Europe.

"A large portion of the scientific community in the U.S. also prefers Mars over the Moon," he acknowledged. But "interest in the Moon is driven by goals in addition to and beyond the requirements of the science community. It is driven by the imperatives that ensue from a commitment to become a spacefaring society, not primarily by scientific objectives, though such objectives do indeed constitute a part of the overall rationale.

"We continue to experience intense international interest concerning our plans for lunar exploration," Griffin told Aviation Week.

With Frank Morring, Jr., in Washington.

This story appears in the Jan. 21 issue of Aviation Week & Space Technology, p. 24

Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil

Nenhum comentário:


Related Posts Plugin for WordPress, Blogger...