Who's Who at NASA

David Mitchell is the project manager of the MAVEN mission, which will examine environmental changes on Mars. MAVEN instruments will look beyond the planet's surface and provide a better understanding of solar interactions, magnetic fields, and the atmosphere in general.

NASA Tech Briefs: What is the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft?

David Mitchell: MAVEN is a Mars orbiting spacecraft, which will study the Mars upper atmosphere, the interactions with the Sun, and will obtain a better understanding of climate change at Mars over time. It will go into an elliptical orbit with an orbital period of 4.5 hours. The closest that MAVEN will get to the Mars surface in this orbit is approximately 125 kilometers.

altThe MAVEN Project is being managed by the Goddard Space Flight Center on behalf of the Principal Investigator, Bruce Jakosky, from the University of Colorado in Boulder (CU-LASP). In addition to the University of Colorado and Goddard, the MAVEN partner organizations include the University of California/Berkeley, Lockheed Martin/Denver, and the Jet Propulsion Laboratory. There are a total of eight science instruments on MAVEN delivered by UC/Berkeley, CU-LASP, and Goddard. These eight instruments are grouped into three instrument packages: the Particles & Fields Package; Remote Sensing Package (also known as the Imaging Ultraviolet Spectrometer); and the Neutral Gas and Ion Mass Spectrometer (NGIMS). We have to look at the three instrument package data sets as an integrated collection of data. We’re looking at a complex system with the Mars atmosphere. We will be looking at the atmosphere in situ as we pass through the thickest part of the atmosphere, and study the important solar interactions. There is also an Electra telecomm relay package (provided by JPL) that is installed on the spacecraft. The Electra package enables high-quality communications between surface assets at Mars (such as MSL) and Earth.

NTB: How is the MAVEN mission different from previous Mars missions?

Mitchell: MAVEN is the first mission to study the upper atmosphere in-depth. It continues the successful “follow the water on Mars” theme. Previous Mars missions were focused largely on the history of the planet’s surface. MAVEN goes after the other half of the story: the atmosphere.

Rovers are sampling the soil or visually observing the terrain or the temperatures. Orbiters have high-resolution cameras on-board like the Mars Reconnaissance Orbiter, which focus on what’s going on with the surface. There have been orbiters with some sensors onboard that give the MAVEN science team some tantalizing hints on what might be happening with the atmosphere.

MAVEN is the first mission that was put together specifically to answer the questions about what’s happening in the upper atmosphere. A lot of the scientists on this team have been a part of Mars missions for a long time, and there are a lot of unanswered questions about what’s been happening up there in the upper atmosphere. In the early 2000s, there was a decadal survey that came out, [which showed] that these were areas of strong interest that the MAVEN mission is in fact answering.

NTB: You said there’s a lot of interest. Why is the study of the Mars atmosphere an important one?

Mitchell: From a pure science standpoint, it is very compelling to understand what happened to the ancient Mars atmosphere and why did it change. Where did the water go? Scientists believe there was liquid water flowing (river channels) on the surface of Mars and a much thicker atmosphere, perhaps a “greenhouse atmosphere.” Some have even suggested that there could have been a global ocean on early Mars.

There is also a hypothesis that at one time there was a much stronger magnetic field surrounding Mars. The belief is that the protective shield diminished over time and exposed the Mars atmosphere to solar winds, ripping away the atmosphere and creating a more barren Mars environment today. We hope that MAVEN’s instruments will provide a much better insight into what is occurring today in the atmosphere, understand changes that occur over a one-year period of time, and project back in time as to what drove the current state.

What they’re going to do is analyze the composition of the atmosphere right now. Scientists say that this is a strong area of interest at this particular time in the 11-year cycle. Typically, in the past, it has been a time of high volatility with the solar storms. Interactions between the sun and the Mars atmosphere [will be analyzed] in that one-year period of time, as well as what has been happening with the escape of compounds from the surface. We’re looking at the current state, the rate of escape that’s happening with the various compounds and particles, and then over a period of a year, we’ll be able to extrapolate backwards in time on what could have happened, and perhaps why things changed so dramatically over several billion years.

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