Thursday, October 31, 2013

NASA's Asteroid Retrieval Mission is a good next step for mankind

There is a battle brewing in Congress over the future of the US Space Program. On one side is the Obama Administration, which is following the "Flexible Path" recommendation of the Review of U.S. Human Space Flight Plans Committee (otherwise known as the Augustine Committee). On the other side are House Republicans who want to see us go back to the Bush Administrations Vision for Space Exploration by directing our attention to setting up a base on the Moon and then going to Mars.

The most visible sign of this dust-up came recently when, on a party-line vote, the House Science Committee voted to bar all spending on plans for the manned mission to an asteroid and pass a bill that establishes priorities for returning astronauts to the Moon, perhaps as soon as 2020, and ultimately sending them on to Mars. And to do this with less money than requested.

There are quite a few concerns brought up by lawmakers and scientists opposed to the Flexible Path. They claim that the Asteroid Retrieval Mission (ARM)  was "announced without any detailed technical study or clear-cut direction." Rep. Steven Palazzo (R-MI) claims the agency hasn't explained the budget, purpose of technical requirements of the mission. Rep. Lamar Smith (R-TX) asked if the mission contributes to NASA's long term goals.
Smith, the House science committee chairman, says the mission won’t advance NASA’s long-term agenda. “The proposed mission does not advance science, protect us against dangerous asteroids or develop technologies necessary to explore deep space,” he said. “Congress and the American people simply need more information about why an asteroid retrieval mission is necessary before billions of taxpayer dollars are spent.” 
And Palazzo added that his "primary goal is launching American astronauts on American rockets from America,” 
Other legislators complained that the project...would not advance America’s bragging rights in space the way a return to the Moon could.
Even a Democrat expressed skepticism about it
"I was never very excited about it,” said Representative Donna F. Edwards of Maryland, a Democrat on the committee.   
The mission is pretty simple to understand
NASA’s asteroid initiative is in preliminary stages, and the capture mission isn’t even an official program yet. 
The plan has robotic and human spaceflight components. First, an unmanned spacecraft would rendezvous with a small asteroid — roughly 20 to 30 feet in diameter — and swallow it with a tent-like contraption. Then the spacecraft would nudge the rock to an orbit around the moon. Astronauts would visit the captured asteroid in the Orion spacecraft that is being developed in tandem with a heavy-lift rocket called the Space Launch System (SLS).
What NASA should (and should not) be doing

The whole discussion brings up the existential question of "what is NASA's mission?" The answer tends to depend on who you ask, but NASA sees itself as have four not-necessarily overlapping missions. NASA does aeronautical research; they gather science on every thing from the Earth-Sun system to the depths of space; they develop test and prove new technologies and they create a path for the human exploration of space.

The first three of those missions, NASA does very well and with little criticism from the outside. There is no sense of drift within these programs. NASA takes proposals for projects, reviews them along with subject matter experts, narrows them down and then conducts those missions. In a lot of ways it mimics other scientific grant programs and is often not subject to much politics. Because these missions stand largely on their own, they don't need 20-30 year long vision with the commitment that requires. In Solar System exploration, for example, NASA can build upon the more recent missions and discoveries to design the next ones.

In a sense, each of these is already on a flexible path. These missions cost less than human exploration and their objectives are easier to explain. NASA is gathering science, making air and space travel better and funding basic research and development of various technologies. Even though the lives of most people won't change at all based on the final determination of the Hubble Constant, people in general support the idea of scientific advancement as its own good.

But the exploration of space by humans is different. It doesn't create safer airplanes or work primarily as an R&D program or create very much science. It has to be justified on the more emotional sense that exploration is, like science, inherently good and that mankind's destiny lies in the stars. It is funded in part because people feel a need to keep moving forward and because the program is inspirational. All of that is real, but it is harder to translate into a goal. And because human spaceflight is so much harder and so much more expensive, it means that doing anything truly inspirational or truly exploratory is unjustifiably costly.

Why the "Flexible Path" is the right path

The Augustine Committee report presented the nation with three options: Moon first, Mars first or the Flexible Path. The first two are pretty self-explanatory, but the Flexible Path was meant to allow humans to go to many places we'd never been before on a lower budget. As they wrote:
On this path, humans would visit sites never visited before and extend our knowledge of how to operate in space—while traveling greater and greater distances from Earth.  Successive missions would visit: lunar orbit; the Lagrange points (special points in space that are important sites for scientific observations and the future space transportation infrastructure); near-Earth objects (asteroids that cross the Earth’s path); and orbit around Mars. Most interestingly, humans could rendezvous with a moon of Mars, then coordinate with or control robots on the Martian surface.
The kicker is that no one would walk around on any moons or planets. From a science and engineering standpoint, that might actually be a worthwhile trade. Getting a geologist onto Mars for a month would likely result in a huge yield, but the cost would go up significantly since travelers would  need to launch off of a 2nd planet. But a mission to orbit an asteroid would be much cheaper and might have a better cost/benefit ratio. But from a political standpoint, these kind of missions would not advance "bragging rights" the way that planting a flag on Mars would. Even though the Augustine report noted that the flexible path "would provide the public and other stakeholders with a series of interesting “firsts” to keep them engaged and supportive" it's pretty clear that orbiting Mars and then coming back just isn't as appealing to people as watching the first person walk on the red planet is.

While building a lunar base or walking on Mars would be undeniably cool, and building a radio-astronomy telescope on the dark side of the Moon a possible scientific boon; the question of whether or not any of these are worth the cost has largely been settled by Congress. There simply isn't enough money appropriated to NASA to do any of those things, and in the days of sequester and debt limit showdowns it's unlikely that more is going to be found. In fact, the Augustine Commission said that the NASA budget would be insufficient to leave Low-Earth-Orbit without increased funding, so even this more modest space program may be beyond NASA's reach.

Nonetheless, a scaled-down version of the Flexible Path is the best option for the money we're willing to spend. It let's astronauts get out of low Earth orbit for the first time since the '70's and go places they've never been before - and there are bragging rights to that (Does Rep. Palazzo want to see a taikonaut take the first step onto an asteroid?) . It allows a new generation of NASA engineers to gradually develop the skills and knowledge necessary to eventually do the more ambitious projects that every one wants to see NASA do some day - just as the Mercury and Gemini programs did two generations ago. And "because the path is flexible, it would allow many different options as exploration progresses, including a return to the Moon’s surface, or a continuation to the surface of Mars."

Why an asteroid visit?

The Flexible Path as defined in the Augustine report gave several options for missions including lunar fly-bys, visits to Lagrange points and near-Earth objects, Mars fly-bys and rendezvous with Mars’s moons. Of these the most valuable is a visit to an asteroid. This is because such a mission will help us to develop and test the skills necessary to change the orbit of an asteroid that might someday hit the Earth.

Earth is hit by small space meteors every day. And occasionally the planet is hit by larger ones capable of causing damage, as happened in Chelyabinsk, Russia earlier this year. On a few occasions, meteors caused mass extinction events on Earth. These are low probability/high cost events, but the cost is so high that it's not a bad idea to start thinking about how to deal with them. A speaker I saw once pointed out that we were in a unique window of human history, where we might be smart enough to see an asteroid coming for us but not smart enough to do anything about it. It would be nice to close that window.

Part of that is trying to map all the asteroids that might be a threat to us, a project that NASA and astronomers have been working on for over 15 years now. But the next part is to see if we can effectively nudge a satellite. If we identify a hazard far enough in the future, a little nudge is all it will take. So the ARM will help us to better understand the composition of an asteroid while practicing anchoring techniques for moving one around and also expand our capabilities to send people to them. It will help us to understand the composition of asteroids, the dust environment around them and the proximity operations near one.

Furthermore, asteroids could serve us later as mining sites or as shielding for deep space vehicles. Space is filled with deadly Gamma radiation that astronauts must be shielded against. It may be cheaper to use asteroids already in space than to launch materials from Earth to perform this shielding.

The project thus has a practical element - rehearsing asteroid nudging, a scientific element - studying asteroids, a technological element - demonstrating capabilities of the Orion and a programmatic element - helping train engineers in deeper space mission. 

The first test launch of the new Orion spacecraft  is less than a year away and the first manned mission, a lunar orbit mission, is planned for the 2019-2020 time frame. The ARM would follow that as early as 2021. It's hard to imagine another mission that could be completed in that time frame that would give as much of a benefit for the money spent.

It would be great to go to Mars or build a radio astronomy antenna on the dark side of the Moon, but there just isn't the necessary committment from Congress to do those things.

Then, of course, we need to start working on a robot satellite that will track down and de-orbit space junk.