Freitag, 20. Mai 2016 - 16:00 Uhr
Andy Weir, author of the best selling book and movie The Martian, was the feature attraction himself today at a House hearing on deep space habitats. While representatives of NASA and three aerospace companies explained their habitat plans, Weir honed in on a more fundamental issue, insisting that humans are not meant to spend long durations in zero gravity and the focus should be on developing artificial gravity.
Weir is the first to stress that he is not a space expert, but "just an enthuasiast" offering his own views. Noting that astronauts on the International Space Station (ISS) must spend two hours per day exercising to counteract the effects of life in microgravity, Weir argued that instead of trying to ameliorate those effects "we should concentrate on inventing artificial gravity." He acknowledged that it would be "a huge engineering challenge," but that "is what NASA is all about. I have no doubt they would rise to the occasion."
He is not envisioning the type of "huge wheel in-space construction" that may leap to mind when thinking about artificial gravity -- like the one in the iconic Chesley Bonestell painting or the movie 2001: A Space Odyssey. Instead, Weir described a space station with a crew compartment connected by a long tether to a counterweight with the entire structure rotating.
The idea is not new. In its 1986 report Pioneering the Space Frontier, the congressionally-chartered National Commission on Space, for example, recommended a Variable Gravity Research Facility in earth orbit. It was to be comprised of two modules connected by a tether whose length could be varied to produce different gravity levels for scientific research. The Commission's Earth-Mars transit vehicles would use the same principle and spin down to one-third g on the way to Mars so the crew was acclimated when it arrived, and back up to 1g during the trip home.
That's what Weir has in mind (though he made no mention of the Commission's report). He also made it clear at the hearing and at the Humans to Mars summit earlier in the day that he does not plan to make the trip himself.
Weir also answered a question from subcommittee chairman Rep. Brian Babin (R-TX) about how to deal with the negative effects of radiation for crews traveling in deep space. He remarked that NASA recently increased the permitted lifetime radiation dosage for its crews, so part of the problem was solved "by a simple policy decision." He also offered that someone had calculated the radiation risk for his fictional characters and concluded that the person most affected would have had just a 4 percent greater mortality risk. (That character was the mission commander, not Mark Watney, the character stranded on Mars, because he was partially protected by the Martian atmosphere. The commander was young and female and therefore at greater risk.)
The hearing was before the Space Subcommittee of the House Science, Space and Technology (SS&T) Committee. Subcommittee member Rep. Dana Rohrabacher (R-CA), who is not a humans-to-Mars enthusiast, pointedly asked Weir why money would not be better spent on protecting Earth from asteroids or cleaning up space debris than sending people to Mars. Weir said that money is already being spent on protecting humans from asteroids by tracking them and that there are no Earth-threatening asteroids for at least the next 50 years. As for space debris, Earth orbit is a very large area and it would like trying to clean up all the "gum wrappers in the Pacific Ocean" and is not viable. Instead, the focus should be on preventing the creation of future space debris. Rohrabacher was not convinced.
Weir's presence overshadowed the main purpose the hearing, which was to receive testimony from NASA, Boeing, Lockheed Martin and Orbital ATK about their plans for building space habitats for deep space exploration. NASA, Boeing and Orbital ATK are focused on habitats in cis-lunar space, while Lockheed Martin yesterday announced a "vision" for a Mars Base Camp in orbit around Mars in 2028.
In the FY2016 appropriations bill, Congress directed NASA to spend $55 million this year on habitats and to build a prototype by 2018. Jason Crusan, NASA's Director for Advanced Exploration Systems, explained that the agency is funding habitat studies by Boeing, Lockheed Martin, Orbital ATK and Bigelow Aerospace through its NASA Space Technology for Space Exploration (NextSTEP) Broad Area Announcement.
Rep. Jim Bridenstine (R-OK) challenged Crusan about whether the agency is following congressional direction. He said NASA's FY2016 operating plan shows that only $25 million is being spent on NextSTEP. Crusan responded that NASA is spending more than $70 million this year on habitats. The rest of the money is being spent on developing systems that would go inside the modules. As for having a prototype ready by 2018, Crusan explained that the agency is on track to accomplish that, but it will be a ground demonstrator designed for "form, fit and function" tests, not a space module.
House SS&T full committee chairman Lamar Smith (R-TX) and Bridenstine both used the hearing to criticize the Obama Administration's Asteroid Redirect Mission (ARM). As he has many times previously, Smith called ARM "unjustified" and a "distraction" with no relevance to human exploration of the solar system. The Government Accountability Office (GAO) recently estimated the cost of the robotic portion of the ARM mission (not including launch) at $1.72 billion, money that Smith said would be better spent on habitats and propulsion technologies.
Rep. Don Beyer (D-VA) asked Crusan if Smith was correct that ARM is unjustified. Crusan answered that ARM is needed for developing, testing and operating high power Solar Electric Propulsion (SEP), which will be needed for Mars missions. Bridenstine pressed Crusan on that answer later in the hearing, however. Crusan responded that ARM is an "opportunity" to test SEP, leading Bridenstine to stress that it is an "just an opportunity," not "necessary."
Boeing's John Elbon and Orbital ATK's Frank Culberston both advocated for habitats in lunar orbit as the next step for humans into deep space. Lockheed Martin's Wanda Sigur, however, outlined the company's new Mars Base Camp concept. The timeline shown on the company's website has little time for activities in cislunar space. It does envision assembling the base camp -- comprised of two Orion spacecraft, a habitat, a laboratory module, and solar panels and other systems -- in lunar orbit beginning in 2021, but the goal is to send it to Mars orbit for arrival in 2028. Sigur's message was "Mars is closer than you think. We're ready to accelerate the journey."
Editor's Note: In the interest of full disclosure, I was Executive Director of the 1985-1986 National Commission on Space, which was chaired by former NASA Administrator Tom Paine.
Quelle: Space and Technology Policy Group