Who's Who at NASA

NTB: In April 2010, noted British astrophysicist Dr. Stephen Hawking attracted a lot of media attention by commenting that in our search for extraterrestrial life, humans should think very carefully about whether or not we should broadcast our existence to a potentially hostile universe. I don’t know if it was in direct response to Dr. Hawking’s comments or not, but around that same time you were quoted in the media as saying that NASA is ready to “protect Earth and our species.” Exactly what did you mean by that statement?

Dr. Green: Well, indeed, Stephen is a really well-respected, deep-thinking scientist, and when he comments on topics it’s something that we should really think about and consider. But we’re really a long way away from encountering the kind of intelligent life that I believe Stephen was referring to. As I mentioned earlier, planetary science at NASA is really all about stepping out into our own solar system, and we know that in our own solar system, Earth is the only unique body in this environment that houses life as we know it in terms of human and complex life. However, that doesn’t mean that life in other forms – perhaps in microbes and other less complex life – hasn’t evolved elsewhere in the solar system, and that’s what we’re seeking in these new steps.

To be able to do that and do it right, we do, indeed, follow the international rules of planetary protection. Planetary protection is really quite clear and it’s really all about if we’re going to go somewhere and study life, we have to be careful about contaminating that life with our own life. In other words, we send sterile spacecraft. When Phoenix dug into the dirt on Mars, that arm and the equipment – the tray that was acquiring the material – were all sterilized and very carefully managed such that we didn’t contaminate that environment.

In a similar way, we’ve actually brought back samples from comets. Stardust flew by Wild 2 and brought back some fabulous samples that we’ve started to study and, in fact, in those samples most recently we found the amino acid glycine. Now glycine is just a fabulous find for us and it’s discovery really allows us to start thinking about how comets could’ve seeded not only the Earth but other planets with some basic materials that are important for life and sustaining life. In that respect we have to be very careful about whatever we bring back so that we don’t contaminate the Earth. So there are a variety of policies and procedures – rules if you will – that we follow very closely, that will enable us to manage and carefully analyze any sample that we bring back and protect the Earth.

NTB: One of the backbones of the Planetary Science Division appears to be the Research and Analysis Program. What is the Research and Analysis Program, how does it work, and what are some of the benefits it produces for NASA?

Dr. Green: The Research and Analysis Program is really all about providing a variety of opportunities for the community to move our science forward. For example, we have opportunities in our Research and Analysis Program that allow scientists to propose to do research in the outer planets area, propose to do research in planetary atmospheres, small bodies such as comets and asteroids, study the geology of Mars and other terrestrial planets, just to name a few. Fabulous discoveries have been made from our planetary data, and that data is there to continue to be mined and analyzed.

We also use this program to do some development on planetary instruments, whether for astrobiology purposes or in situ measurements, or imaging and remote sensing purposes. We do want to fund some really critical new technologies and developments to see how those might be applied to planetary instruments for our future. So the program is really quite broad. We spend well over $200 million a year on that and it’s really reaping enormous benefits. I think it’s the heart of the science discoveries that you’ve seen coming out of NASA on a regular basis in planetary science.

NTB: Throughout your career you’ve been involved with data collection, management, and dissemination technology. The amount of scientific data being generated has increased exponentially over the last three decades. Has the technology required to manage and archive it kept pace, and how does NASA deal with that problem?

Dr. Green: That’s a good question. I would say with respect to the planetary science data, the answer would be yes. The reason I say that is, we don’t bring in as much data as, say, Earth Science, because Earth is right here and those satellites orbit this planet and can beam directly down to the Earth huge amounts of data. It’s much harder to do that with our spacecraft that are so far away. Consequently, what is called the bit rate, or the rate of the data that comes from planetary spacecraft, is much less. Therefore, the volume of data that we have in our archive is much less. That means we have several hundred terabytes of data that we’ve acquired over the last four years. That’s an enormous amount of data. However, Earth Science sometimes has terabytes in a few days, so consequently the technologies for storage and dissemination of Earth science data can easily be applied to planetary science since we don’t have quite that data volume.

Now, with that said, the best thing to do with data that comes into our archive is to provide it online and provide it in a way where the information about the data is available for scientists to make decisions about using it or not using it, and even more importantly, how to use the data correctly. That we call metadata, and we generate metadata along with the archive data. We’ve developed a system called the Planetary Data System – it’s one of NASA’s oldest distributed data systems. We have quite a few nodes stretched all across the country and data is constantly pouring into these nodes at NASA centers and other universities. The Planetary Data System is doing an outstanding job. We’re going to continue on with that structure, and continue to improve it with time.

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