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Ask the Expert

Ask the Expert

Leslie Tamppari

Dr. Leslie Tamppari is Co-Investigator and Project Scientist for the Phoenix Mars Mission at NASA's Jet Propulsion Laboratory in Pasadena, California. As part of her role on the mission team, Tamppari analyzes mission data related to the martian atmosphere and water transport issues. Her recent work includes the study of dust devils and water-ice clouds near Mars's North Pole. Tamppari completed her bachelor's of science in applied mathematics at the University of Arizona and earned her master's degree and Ph.D. in geophysics and space physics at UCLA. Before joining the Phoenix mission team, she worked as the deputy project scientist for the JPL's Mars Science Laboratory.

On August 5, 2008, Leslie Tamppari answered selected viewer questions about the Phoenix mission, what she and the other team members hope to find, and how she feels about a possible manned mission to Mars. Please note we are no longer accepting questions, but see Explore the Red Planet and our Links & Books section for more information.

Q: Hello,

To what complexity of biology can the TEGA [Thermal and Evolved Gas Analyzer] ovens detect? In other words, are the TEGA ovens capable of detecting life?
Andrew Lynn, Marlborough, Massachusetts

A: We cannot detect life with any instruments on the Phoenix spacecraft. With the TEGA, we can detect organic (carbon-containing) molecules. Any organics may be life-related or not, but if we find them, that is very important because it will indicate that organics can survive in those conditions and not be destroyed. And, as life is made up of organic molecules, such a discovery would enhance the argument that this may be a "habitable" place.

Q: Thank you 4 taking the time 2 answer my question: What would be the real benefit of finding proof of life in Mars 4 us (it's millions of miles away)? Oh, and I mean life that could have existed millions of years ago, like... microscopic.
David Rivera Nieves, Bayamon, Puerto Rico

A: First, to clarify, Phoenix cannot detect if life is present on Mars. However, if sometime in the future life were discovered to have ever existed on Mars, it would be very important. It would indicate that either life started on planets other than the Earth or was transported in some way to Mars from Earth or from Mars to Earth! Either way, this would open up the possibilities for life in the universe outside of Earth.

Q: I watched with fascination the NOVA scienceNOW on 7/30, especially the thought that there might have been water-ice crystals in a trench dug by Phoenix. Could that have been dry ice, carbon dioxide(s), though? The narrative stated it "vaporized" over time, and temperatures certainly support frozen carbon dioxide.
Will, Houston, Texas

A: At this season, the temperatures are too warm for carbon dioxide. Carbon dioxide freezes at about -184°F (-120°C), but the current surface temperatures are about -135°F (-93°C). In the winter at the Phoenix location, the temperatures certainly get cold enough to condense carbon dioxide, and there will be a carbon dioxide polar cap that extends south of the lander. We expect that carbon dioxide to become permanent at the lander latitude near the beginning of March, 2009.

Q: I love space exploration and am afraid that politics and our obsession with a manned mission to Mars will not return nearly as many discoveries as robot missions can. Not to mention the potential injury and death of dedicated men and women to accomplish such a mission. What do the science communities you interact with think about this?
Greg, Costa Mesa, California

A: I can only speak for myself, and this is not an official JPL or NASA position. I believe that we must continue robotic exploration. I believe that we gain a lot from it and also, as you mention, it does not risk human life. But it is certainly inspiring to dream of humans someday walking on the surface of Mars, as we have done on the Moon. However, my understanding is that it is incredibly difficult to solve all the technical challenges with doing that. If we are going to do that, it does require bright minds to be thinking about it and working towards good solutions to the technical problems.

Q: Now that they have found water ice, what would be the next most exciting thing that Phoenix could discover? Is there any chance that Phoenix could find evidence of life, either past or present? How great of a long shot do you think that is?
John C., Grand Junction, Colorado

A: The next most exciting discovery that we'd like to make would be to detect organic molecules (carbon-containing molecules) and to prove that they are from Mars (and not ones we brought along with us). We can do this in our TEGA experiment. Phoenix does not have the capability to detect life itself.

Q: Dear Dr. Tamppari,

If NASA asked you to be the first woman to go to Mars, would you?!!! Thanks!!!
Betsy, 9th Grade, Bryn Mawr, Pennsylvania

A: I would only go if I was very sure that I would be able to come back! It certainly would be something to walk on the surface of Mars and see the scenes with my own eyes and touch the dirt, rocks, and ice with my own hands!

Q: Could you explain Delta-V with regards to how hard it is to get off Earth, travel to Mars, then land and take off again? Maybe compare it to lunar missions.

Also, how does water on Mars affect this as far as returning from the surface?
Joe, St. Petersburg, Florida

A: Delta-V is short for Delta velocity, which means a change in speed. To escape the pull of Earth's gravity starting from the surface, a traveler must exceed a speed of 11.2 km/sec (25,000 mph). An additional change in speed is needed to transfer from the orbit Earth travels around the sun to the larger orbit of Mars. About every 26 months the positions of Earth and Mars provide the smallest required speed change. Upon arriving at Mars, a speed decrease is necessary to land safely. With the thin atmosphere of Mars, heat shields, parachutes, and retro-rockets are used to decelerate from 5.4 km/s (12,000 mph) to nearly zero in a matter of minutes.

The return trip doesn't require as much speed change to escape Mars, because the planet is roughly half the size of Earth and about nine time less massive. The escape speed is also roughly that of the arrival speed at 5.2 km/s (11,600 mph). Thanks to Joe Guinn, Phoenix Strategic Mission Manager, for explaining this one so nicely.

Q: Hi Dr. Tamppari,

The results from Phoenix and from the rovers have been thrilling. But we all know that, in part because of the extraordinary complexity of pulling off a successful landing etc., a goodly number of Mars missions unfortunately fail before they even send back the first piece of data.

My question is: How did you prepare yourself for the possible failure of Phoenix? How were you expecting to respond if those first signals saying "I'm here! I made it!" never came from the lander (as they fortunately did)?

A: Of course, I was nervous about the spacecraft landing safely, since it is very hard to do. It was very hard to think about it not landing safely, however, after all the hard work over the last five years. Also, having worked closely with the team, especially the Entry, Descent, and Landing team, over the last five years, I did have a lot of confidence that we would land safely. So, I'm not sure I really did prepare myself for not landing safely!

Q: Assuming Mars had an 80/20 nitrogen/oxygen atmosphere, with Mars's weak magnetic field, how much atmosphere (cubic km) would have to be added each day to balance loss due to solar wind? (Idea, of course, would be to create a new human-compatible atmosphere on Mars...)
Herb, Augusta, Georgia

A: Gee, this is way outside my area of expertise, so I don't know the answers. I suspect that people have looked at these issues, perhaps scientists and engineers at Johnson Space Center. Perhaps there is some information on their Web site.

Q: Greetings:

Ever since I watched the Apollo 11 moon landing live as a sleepy 9-year-old (my parents dragged me out of bed to see it), I've been fascinated by the incredible number of people and the amount of teamwork that goes into a space mission. Clearly missions such as Phoenix wouldn't work without many, many experts working together selflessly. But we're all human, after all, and many of us seek personal recognition. How does individuality evince itself in such missions? Thank you.

A: Good for your parents to get you out of bed for such an historic event! During the lead up to and just after major events, there is usually a lot of press interest. At that time, members of the team are usually on press briefing boards and will do interviews. The scientists will publish science papers after analyzing the data. Recognition for a scientist comes from papers for which he or she will be the lead author.

Q: How old is Mars?
Autumn Greene, Harrogate, Tennessee

A: Mars was formed along with the other planets in our solar system about 4.5 billion years ago.

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