[Editor : With the launch of Curiosity spacecraft to Mars last Saturday, we are bringing back an article from earlier this year when Dr. Jim Bell answered questions from our Youngzine comunity.
Dr. Jim Bell is a NASA scientist who designed the cameras on the twin rovers - Spirit and Opportunity. Besides appearing on several television shows, Dr. Bell has published a book with fascinating pictures of the Red Planet, some of which we had shared with you in a slide show.]
[Matthew14] Is there any chance of Martian life?
[Jim Bell] Absolutely! Life, especially simple (like bacterial) life forms, exists in an enormous range of environments and conditions on the Earth, and scientists believe that many similar environments exist or have existed on Mars. For example, while the very upper surface is likely to be harsh and unsurvivable for life as we know it (because of extreme cold, low pressure, and high ultraviolet sunlight levels), there could be water and/or higher temperatures in the deeper subsurface that could be habitable. That's pretty exciting, and is one of the main motivations for scientists to study Mars.
[Arjun] How long ago would Mars have been able to support life? In the dinosaur-early human age or far back?
[Jim Bell] As the above answer indicated, life could be supported on Mars today, in the deep subsurface. But scientists think that the environment may have been best for life as we know it on the surface only very early in Martian history, perhaps only for the first 10-20% of the history of the planet. Also, I can't resist double-checking to make sure that you're aware that there's a HUGE gap in time between the dinosaur age (tens to hundreds of *millions* of years ago) and the early human age (tens to hundreds of *thousands* of years ago), and that there's another HUGE gap between the dinosaur era and "early Martian history", which was 3 to 4 *billion* years ago!
[Visitor] Is there any chance of finding liquid water on mars?
[Jim Bell] Absolutely. Pure water can't exist as a liquid on the surface--the temperature and pressure are too low. But if it's very salty, water could stay liquid even under current Mars conditions. More likely, though, even pure water in the subsurface could be a liquid if the subsurface gets warmer as you go deeper down. But we don't know how the temperature changes as you go into the subsurface on Mars--is it warm and geologically active like the Earth's subsurface? Or cold and "dead" like the Moon's? We need to find out!
[Kiwi_BJ] Is Spirit all right? Will it wreck or will you get information from Spirit?
[Jim Bell] Spirit went into what engineers call a "low power fault" in the spring of 2010, when there wasn't enough power to run its onboard computer or radio transmitter. We haven't heard from the rover since then, but the engineers are hoping that it is in a controlled sort of hibernation, conserving battery power until it has recharged enough to call home and continue the mission. We had hoped to hear from the rover by now, and while NASA is still listening and there is still hope, that hope gets a little less every day. If we don't hear from Spirit in the next few months, I am afraid that the controllers may decide that the rover's mission is officially over and they will stop listening for signals. If that happens, it will of course be a shame, but it will have been a rover's life well lived!
[TDenise] Will any human ever be sent to Mars?
[Jim Bell] I believe so! There is no official plan or timeline, though. First, NASA and other space agencies need to build the infrastructure--rockets, life support systems, Mars landers--that will let astronauts travel into deep space again. We had some of that infrastructure in the 1960s and 1970s when astronauts went to the Moon, but it was all abandoned when NASA decided to focus on the space shuttle. The space shuttle cannot go into deep space, only into very low Earth orbit--the edge of space only a few hundred miles up. NASA is retiring the space shuttle soon, however, so many people, as well as space interest organizations like The Planetary Society, are hoping that they and other space agencies will build new rockets that can once again take people into deep space. Once that happens, I believe that people will go to Mars, and back to the Moon, and to visit asteroids--lots of destinations become possible once the infrastructure exists! I am hoping that people will go to Mars relatively soon, perhaps within 20, 30, or 50 years. (that's "soon" on the timescale of human history!). Who knows, maybe the first Martians will be some of you?
[Sammy02] What will happen if these robots like Spirit get damaged and are unable to function anymore? Would it be left to rot out there or would it be retrieved?
[Jim Bell] Well, they will be left there, but they will not "rot" because there is no rain or snow to break down their metallic components. Rather, like the Apollo landers and rovers and most of the other missions sent to explore the solar system, the rovers were never designed to return to Earth. They were built for Mars and will be on Mars forever. My prediction is that some day they will become museum exhibits--maybe in a Smithsonian on Mars--and be the most lasting reminders of some of the great things that our species has done during this time in our history.
[Arjun] Does the rover and cameras have to be made any differently to suit Mars than Earth? What special features does it have to work on Mars.
[Jim Bell] Yes, absolutely. The rovers and their cameras and other equipment were designed to withstand the very low temperatures of Mars (down to -110C at night, for example), the very thin atmospheric pressure (near vacuum--only 1% the pressure of Earth's surface at sea level), and the dusty environment (smoke-sized dust grains get into everything on Mars. Plus they had to be built to survive the intense shocks of launch and landing. Normal commercial digital cameras or other off-the-shelf parts usually won't work in the harsh environment of space.
[Genna] What is the most amazing thing you have seen with the cameras?
[Jim Bell] Where do I begin??? I wrote a whole book about this, called "Postcards from Mars," showing off more than 150 photos of some of the most amazing things that we've seen. Highlights include seeing beautiful blue-ish Martian sunsets, finding millions of little iron-bearing spherical rocks covering the ground, watching dust devils spin on another world, and getting to see Mars sand dunes in garish false color using our camera's infrared filters. Mars is stunningly beautiful in its own, different-from-Earth kind of way. I'm always amazed at how many shades of red and brown there are in the landscape, for example. Like the Eskimos who have 50 different words for "snow", I think that when people eventually live on Mars they will develop a distinctly Martian vocabulary with 50 different words for "red".
[Genna] What is one thing you would have done differently with Spirit and Opportunity?
[Jim Bell] Not much, but the ONE thing I would like to have had was a faster internet connection to Mars! We are communicating with the rovers using radio signals at a rate that is roughly the same as a decent dial-up computer modem (if anyone remembers what those are). That really limits the number of pictures that we can send back to Earth. I want high-speed internet from Mars!
[Sammy02] What new technologies have been used in Curiosity that was not used in Spirit and Technology?
[Jim Bell] The Mars Science Laboratory (MSL) or Curiosity rover has a number of new or different technologies from Spirit and Opportunity. For example, there is an organic chemistry laboratory onboard that can detect tiny amounts of carbon and hydrogen molecules that might be biomarkers for past (or present?) life on the planet. The rover uses a radioactive power source (like the Voyager and Viking space probes from the 1970s) instead of solar power. And there are a number of improvements to the mobility system, computer, and other instruments that update them from 1990s to 2000s technology. MSL really will be a state of the art space vehicle!
Thanks for all of your interest in Mars and space science!