|Texture of landing sites. Upper left, the moon; upper right, Venus; middle left, Pathfinder 1997 Mars; middle right, Viking 1977 Mars; lower left, airbag imprint in Eagle Crater, Meridiani Planum 2004; lower right, airbag drag mark, Meridiani Planum, 2004 Opportunity site.
Image Credit:NASA/ JPL
The successful arrival of the European Space Agency's Huygens atmospheric probe on the distant Saturnian moon of Titan in mid-January was a moving event. Many in the multinational contingent of scientists, engineers and administrators that had gathered at ESA's control facility in Darmstadt, Germany had worked on the mission for a decade or more. Once it was clear that the probe was working as planned, a palpable euphoria -- a compound of relief and pride -- pervaded the proceedings. One of ESA's high-ranking NASA visitors was Al Diaz, director of the agency's new science organization, the Science Mission Directorate.
Although the Huygens part of Cassini-Huygens was designed and built in Europe and led by ESA, the mission was conducted in close collaboration with NASA. Huygens itself had been brought to Saturn by Cassini. The interview took place at ESA Headquarters in Darmstadt on January 15th, the day after Huygens's pictures of smoggy Titan revealed an icy orange-tinged topography sculpted by liquid ethane rivers and lakes - a place of shorelines, creeks and fog that's utterly alien, and yet also fascinatingly Earth-like in many respects.
Michael Benson (MB): You were head of NASA's Goddard Space Flight Center.
Al Diaz (AD): I was.
MB: So you know about earth science.
AD: I do.
MB: To what extent is the exploration of the solar system about discovering processes on Earth? For instance, taking information about the atmospheres of Titan, Mars, or Venus, and then using this larger context of the solar system to learn about atmospheric processes here on Earth.
AD: That's an excellent question, because what we're learning about earth science can be informed by our exploration of the solar system, as well as benefit our exploration of the solar system, in a far more substantial way than we've taken advantage of.
When you think about the kinds of issues that we're going to be dealing with if humans are going to go to Mars, many of them are the same kinds of issues that we've tried to deal with on the Earth. So we think that there's a lot of competency, capability, and a lot of tools that have been developed for earth science that we can apply to missions to Mars. We've already seen evidence of that.
In the case of the Spirit and Opportunity Mars landings, earth science-developed models were used to better design the second landing, based on the uncertainty in the density of the atmosphere.
I don't believe that would have happened 10 years ago, because the modeling hadn't reached that level, and people weren't as aware of the kinds of capabilities that the models could introduce. So we think there's a tremendous opportunity to integrate earth science and space science for the benefit of both. And that's what we're trying to do.
MB: What about vice versa. I mean, Venus has a runaway greenhouse. Mars has lost most of its atmosphere and is exposed to merciless ultraviolet radiation. We are in the middle...
|South Pole view from Space.Six years ago, then NASA Associate Administrator Wesley Huntress, Jr., stated , "Wherever liquid water and chemical energy are found, there is life. There is no exception."
AD: This is Goldilocks and the three bears.
MB: You mean, which bowl of porridge is just right...
AD: And Earth is just right. But why is it just right? Why is the water cycle on Mars apparently inactive? Why do we have a runaway greenhouse on Venus? And to what extent does that inform our understanding of what is happening on Earth, and where we might end up? So, yeah, there's a lot of comparative planetology that we think will benefit both earth science and solar system exploration.
MB: Recently there was a call for papers from the scientific community, connected to this Moon, Mars and Beyond vision. It seems like all the examples given had to do with finding water.
AD: We've had some discussions about that recently in developing our Mars strategy. The whole Mars strategy has been following water. The whole search for life strategy has been following water. That's really because of this habitability issue. Astrobiologists tell us that, without water, there isn't any evidence that life as we know it can be supported.
MB: The Galileo probe was ordered to dive into Jupiter at the end of its mission for planetary protection reasons. There may have been Earth microbes that had survived on Galileo, so they wanted to make sure that there was no chance the probe would impact on Europa.. We don't know if there's any life on Mars, but we have landed a number of missions on the surface that were sterilized as much as possible. Now we're planning on landing astronauts, eventually. How are we going to protect the potential biosphere there from our own microbes, our own life?
AD: That's a good question, and it's the focus of a whole discipline called interplanetary protection. For every mission that we send, we have to do a consequence analysis that looks at what the impact is to the planet in terms of introducing any overburden of biology. For Mars, every analysis that we've done has indicated that the introduction is so small as to be considered innocuous in terms of any consequence.
Now, you're right, at some point in time, we are going to have to do something more substantial. I think, between now and the human landings on Mars, we want to do analyses that would indicate whether or not there is life extant there. We need to determine that before the human landings. We also don't want to disturb the pristine environment for future attempts to search for life. That discussion is taking place right now, in our strategic road mapping about the Mars Sample Return mission. So that debate is ongoing.
|Cover of Science Magazine devoted to Opportunity rover initial results.
MB: What's your sense of what really motivates people when it comes to their interest in space exploration?
AD: People are interested in space exploration for the same reason that I got emotional about the Huygens probe landing on Titan. This is something that's bigger than life! And it's an opportunity for people to participate in something that has historic proportions. I believe that it is not motivated by economic returns, although there are people that have that vision. It is not motivated by national defense, although it has that benefit as well. I really believe that the public's interest in it is that it's an activity of historic proportions that they have an opportunity to be involved in.
And I think in the future, they won't be satisfied with being able to visit web sites to see what we are doing. I think in the future, they are going to demand that they be involved, and that they have the opportunity to participate in some significant way.
- Mars Reconnaissance Orbiter (MRO) launch, Mars Orbiter to collect high-resolution, 1-meter, images in stereo-view of Mars
- European Venus Express, Venus Orbiter for two-year nominal mapping life [486 days, two Venus year]
- New Horizons, Pluto and moon Charon flyby, mapping to outer solar system cometary fields and Kuiper Belt
- Dawn, Asteroid Ceres and Vesta rendezvous and orbiter, including investigations of asteroid water and influence on meteors
- Kepler, Extrasolar Terrestrial Planet Detection Mission, designed to look for transiting or earth-size planets that eclipse their parent stars [survey 100,000 stars]
- Europa Orbiter, planned Orbiter of Jupiters ice-covered moon, Europa, uses a radar sounder to bounce radio waves through the ice
- Japanese SELENE Lunar Orbiter and Lander, to probe the origin and evolution of the moon
- Japanese Planet-C Venus Orbiter, to study the Venusian atmosphere, lightning, and volcanoes.
- Mars Scout mission, final selections August 2003 from four Scouts: SCIM, ARES, MARVEL and Phoenix
- French Mars Remote Sensing Orbiter and four small Netlanders, linked by Italian communications orbiter
- BepiColumbo, European Mercury Orbiters and Lander, including Japanese collaborators, lander to operate for one week on surface
- Mars 2009, proposed long-range rover to demonstrate hazard avoidance and accurate landing dynamics
Michael Benson, author of the book "Beyond: Visions of the Interplanetary Probes," is a writer and film-maker. He has contributed to such publications as The New Yorker, The Atlantic, The New York Times and Smithsonian.
Listen to sounds from the microphone onboard the Huygens during its descent (wav file format, approx. 600 kB each):
Related Web Pages
Rendezvous with Titan
Huygens, Phone Home
Saturn-- JPL Cassini Main Page
Space Science Institute
Moon To Mars Commission
The Bigger Picture
Ray Bradbury: The Illustrated Spaceman
What Would a Martian Drive?
Three Tough Questions
Search for Life in the Universe I