By Leonard David
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(SPACE.com) -- Progress is being made on defining a human mission to an asteroid. Experts at several NASA centers are sketching out a prospective piloted stopover at an asteroid -- a trek that could return samples from a targeted space rock as well as honing astronaut proficiency and test needed equipment for other space destinations.
At the heart of such a mission is drawing upon the technology of NASA's Constellation initiative -- the overarching program that is gearing up to extend human presence at the moon, on Mars and beyond.
One key ingredient is the Orion spacecraft -- a post-space shuttle vehicle now under design to thrust crews further than low Earth orbit.
Meanwhile, NASA is wrapping up a report required by the U.S. Congress on how best to search for, catalog and even deal with the hazard of Earth-bruising rocks from space. That space agency report is to be turned over to Congress by year's end.
If lawmakers give the green light to a next generation Near Earth Object (NEO) search program, there could be 40 times the current discovery rate of these celestial bodies. By the time a human mission to an asteroid is ready, there's likely to be a healthy list of suitable targets.
A feasibility study to stage a human mission to an asteroid is underway, said Carlton Allen, Astromaterials Curator and Manager of the Astromaterials Acquisition and Curation Office at NASA's Johnson Space Center (JSC). "It would involve flying people to one of the NEOs and, among other things, collect samples and bring them back," Allen told SPACE.com.
Edward Lu, veteran shuttle and international space station astronaut, is a member of the JSC study team. They are looking into use of Orion technology earlier than 2020, as well as utilizing Delta or Atlas Evolved Expendable Launch Vehicles to enable non-low Earth orbit missions.
"There are many asteroids that have very low relative velocities with respect to Earth," Lu observed. Identifying an "ideal" NEO is one that's both slow moving and comes close to Earth -- sort of a match made in heaven.
"Those are easy targets," Lu said. They wouldn't require a lot of rocket oomph to rendezvous with, he said.
Lu told SPACE.com that NEO exploration study members are posing the following question: How can already existing or currently planned Constellation hardware be used or minimally changed to permit other exploration agendas?
Constellation boosters and spacecraft hardware are now geared to support NASA's return to the Moon and onward to Mars plans. "The whole point of Constellation is that it is an exploration system," Lu noted. "So what else can you do?"
Lu said that their report will be completed by the end of this coming January. "We're in the midst of it right now...and it's looking interesting."
A human voyage to an asteroid would not only trial run Orion equipment -- particularly putting high-speed heat shield technology through its paces -- but also could become part of the test program for lunar landings, Lu said.
Moreover, NASA needs to wean itself off from Earth orbiting missions -- round and round our planet with the space shuttle and space station. Ground controllers are set up for essentially zero light-time, instantaneous communications with space crews.
There will be some lag time keeping in touch with future moon explorers, and more so when expeditionary adventurers travel to faraway Mars, Lu advised. A NEO mission could help in the readiness of ground teams to work issues beyond low Earth orbit, he said -- stepping stone conditioning for robust lunar and Mars operations.
Once you pull up to some asteroid...what's an astronaut to do?
"There are no handholds on the surface," Lu said. "It may not be a solid surface anyway."
Lu said that an Orion spaceship would hover in close proximity to the NEO. "We're talking about an object that's more than likely just 330 feet (100 meters) across, or less. We're talking a big rock or probably a big rubble pile, and likely rotating."
From their spot in space, a crew could deploy a remotely-piloted vehicle. Looking out spacecraft windows, an astronaut might fly a robotic probe via a joy stick, Lu envisioned, dropping off packages on the NEO or scooping up select samples for return to Earth.
"A human flying something remote-controlled is way smarter than anything you can program. You could look for interesting spots on the asteroid and make real-time decisions," Lu added.
A NEO mission would deepen NASA's quest for deep space experience, Lu said. There's interest in asteroids for a range of reasons, he continued, for exploration, for pure science, resource utilization, as well as learning how to mitigate the threat from a sniping space rock that has its crosshairs on Earth.
"It brings it all together," Lu concluded, "which is nice."
"We're looking seriously at this," said Chris McKay, deputy scientist in the Constellation science office at JSC. He is stationed at NASA's Ames Research Center located in California's Silicon Valley, part of a study team there delving into the scientific output from a piloted asteroid flight.
NASA Ames officials are looking at how the Orion exploration vehicle could be used for a human mission to an NEO, McKay explained. The study is only about halfway complete but initial results look to be positive, he said.
McKay said that the main question seems to be finding a NEO that allows for missions that are not too long.
Once on station at an asteroid, crewmembers might release a probe to crash onto the asteroid as they watch from a distance, McKay added.
"A human mission to a NEO, and the associated robotic probes, will return a lot of science and this will be valuable. But as a lifelong resident of Earth...I think that being prepared to save the planet ranks higher on the priority list than insights into the formation of the solar system. But we can do both."
Asteroids: Ready for them or not?
NASA Administrator Michael Griffin, told an audience recently at NASA's Langley Research Center that "our species hasn't been around long enough to have experienced a cataclysmic extinction event. But they will occur again, whether we are ready for them or not."
So, in the end, Griffin said, "human expansion into our solar system is fundamentally about the survival of the species, about ensuring better odds for our survival through the promulgation of our species."
"But one assumption that I know will be justified is that the Moon, the near-Earth asteroids, and the rest of the solar system contain the resources that will take mankind to the next level of civilization and prosperity. I don't know when it will occur or who will do it, but it will happen. I hope that it will be soon, and that we will be the agents of this great endeavor," Griffin explained.
NASA's upswing in asteroid interest is good news, reported William Burrows, author of The Survival Imperative -- Using Space to Protect Earth (Forge, 2006). He's also a professor of journalism at New York University.
"The cliche that we should land on one or more asteroids 'because they are there' certainly applies, since the need to explore is an ancient and deeply-held human trait," Burrows explained. "But more pragmatically, knowledge is never wasted, so there will be things to learn from being on asteroids that we cannot anticipate but that can only be beneficial," he said.
Burrows said that resource mining in the distant future is part of that learning process.
"But far more important, it will teach us valuable things about them and the need to spread the human seed, not only for adventure, but as a hedge against a civilization-threatening catastrophe on the home planet," Burrows said.
In a few months time, NASA is set to co-sponsor the 2007 Planetary Defense Conference to be convened in Washington, D.C.
The March meeting is organized to capture the state-of-the-art in terms of protecting Earth from NEOs, said William Ailor of The Aerospace Corporation in El Segundo, California and general chair of meeting.
"There are a lot of unknowns relative to asteroids," Ailor said, like how they are put together -- a key piece of information required in order to deflect any Earth-threatening space rock. "One of the issues that you have is that there's probably some variability asteroid to asteroid."
Ailor said that piloted flight to an asteroid would yield additional detail on dealing with a future hostile object. However, the real challenge, he said, is that no one country is going to have the wherewithal to cover every aspect of the problem.
So the question is, Ailor added, just how does the world community get together to incrementally add information about these objects and offer mitigation ideas?
"I think it's becoming more of a credible issue now. People recognize that these kinds of events can happen...and we actually have the capability now to do something about it," Ailor suggested.
"The [space] community -- and I would include the political community -- is beginning to take this more seriously. We've progressed a long way over the last few years...but we still have a long way to go," he said.
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Constellation hardware is currently geared to support NASA's return to the moon and Mars.