Mason Peck Official Portrait Mason Peck, NASA’s Chief Technologist, was on Reddit a few days ago gamely fielding questions from all sides. The story trended near the top spot and was dominated by questions about Mars, including a fascinating discussion about radiation shielding. Here are the top 10 question and answers from that chat (with thanks to Reddit).

I am Mason Peck, NASA’s Chief Technologist. Ask me anything about our future in space

I see massless exploration, long-duration crewed missions to and Mars, and protecting our planet from the ever-present threat of asteroids. As NASA’s chief technologist, my job is to champion technology and innovation – in space and on our home planet. That means encouraging partnerships with small companies to transfer NASA-developed technology into the market. It also means opening up technology challenges to citizen scientists to get everybody involved in solving the issues we face. I think our future is bright, and I believe it’s going to take all of us to get there. What do you see as our future in space?

1) Could you please clarify what you mean by “massless exploration”?
I mentioned something about this a moment ago. Let me describe it this way: right now, the mass we use in space all comes from the Earth. We need to break that paradigm so that the mass we use in space comes from space. The more we can leverage the resources of the solar system, the less we have to spend to make science and human space exploration successful. There are materials science challenges here, as well as new technologies needed for manufacturing with in situ resources.

2) In your opinion, what aspect of our current space technology (besides funding) is truly keeping us back from a trip to Mars?
It comes down to survival of the crew. We need to create ways to help astronauts survive exposure to galactic cosmic rays and other hazards on the trip there and back. Getting there quicker would help. So that inspires the creation of advanced propulsion capabilities, but right now there’s nothing on the horizon to shorten the trip time enough so that we don’t have to worry about radiation.

3) Has much thought been given to a spacecraft essentially surrounded in water to help shield radiation? Are there any technologies currently being worked on that may prove promising for shielding?
That’s been proposed, but water is heavy. It might be a little less heavy to surround astronauts themselves with water, but even that is not very efficient and is difficult to achieve. The solution ultimately will be a combination of technologies, some having to do with human health and some having to do with the design of the vehicle and some having to do with the timing and operation of the mission.

4) For those of us who know nothing about blocking radiation, comic rays, etc, will you explain how surrounding yourself, or the ship, in water would help block that radiation?
I’ll put it like this, you could go swimming in a pool of spent radioactive rods.

There followed a long discussion about radiation and the cost of putting waterinto NEO until “HadronLee” offered this excellent summation: “Radiation physicist here- Water is only a good type of shielding for Beta radiation, which is composed of electrons. Cosmic radiation however is composed of many types of radiation including Gamma rays (high energy photons), Alpha rays (Helium nuclei), and many other types of subatomic particles. Water is a good shield against electrons because it is a light-weight material.Otherwise, if it were heavy, the electrons could produce bremsstrahlung (German for braking-radiation)- a process where high energy electrons slow down abruptly and emit gamma rays. In contrast, if any of the other types of radiation came in the light-weight water would be unable to stop them as they are better attenuated by heavy materials like Lead.”

5) Regarding the growing space debris … what measures will be taken to reduce it? I imagine that as more countries are putting things up in orbit that it will be hard to avoid the debris.
Right now, there are regulations in place to prevent the growth of space debris population. In addition, NASA and other government agencies are working on early stage technologies to remove debris. A lot of that work is sponsored by NASA’s new Space Technology Mission Directorate.

6) With companies like SpaceX wanting to put man on Mars in the foreseeable future, is there any competition at all between NASA and other space frontier companies to reach certain goals?
NASA is working with a number of commercial companies, including SpaceX, to bring about a future in which American industry will provide access to space for the sake of science or human exploration. In the past, NASA has entered into agreements known as data buys, where NASA agrees to procure the results of investigations – science data – instead of prescribing every step along the way. I believe this model can be very successful, and I hope we see more of it.

7) Do you agree with Stephen Hawking when he said this?
“It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million,””Our only chance of long-term survival is not to remain inward-looking on planet Earth, but to spread out into space.”
Do you think we are doing enough to secure our place in the universe?
Are we failing?

I make it a practice to never disagree with Stephen Hawking. I think our destiny lies among the planets of our solar system. It’ll take a combination of NASA, other governments of the world, and the participation of all of you to make this happen.

8) Would it be possible or practical to bring samples back from Mars to Earth?
Both, definitely. We have been working toward bringing samples back from Mars for some time, and the “Mars 2020” robotic mission will take us further along that path.

9) Can we bring back Spirit?
Arthur C. Clarke said something similar about Syncom, the first geosynchronous communications satellite, on its 40th birthday, he promised it a nice spot in the Smithsonian. It’ll be an interesting day when you can visit the Smithsonian and see Spirit, Curiosity, the first asteroid NASA brought back and relics from the first explorers on Mars.
To which “rafival” replied: “Would it not be more in the spirit of the enterprise that people travel to Mars to see them rather them bringing them back to Earth?”

10) What are the main difficulties on finding (and going to) Lagrangian orbit points? Also, there are plans to use them as places for space telescopes? (Am I wrong in thinking they would make nice places to put a telescope?)
A great point. In fact, the James Webb Space Telescope will be located at the Earth-Sun L2 point because it will be far from the Earth’s albedo. But it’s not easy to navigate to there and keep something in place. It requires some subtle approaches to mission operations because the Lagrange points are barely stable or completely unstable. But what we learn from JWST will serve as a pathfinder for future science missions and possibly future human missions.

With thanks to Reddit. Click here for the original interview

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