In late 2010, NASA announced its plans to develop a mission to further explore the planet Mars. The mission is called MAVEN, short for the Mars Atmosphere and Volatile Evolution, and it’s scheduled to launch in 2013. We spoke with MAVEN’s principal investigator, Bruce Jakosky.
Bruce Jakosky: Our mission is designed to explore the upper atmosphere of Mars. What we’re trying to do is look at how gases escape from the atmosphere to space. What we want to do is understand how the climate has changed, how the atmosphere has changed over time.
The atmosphere on Mars today is thin, similar to what you’d find in Earth stratosphere, a few kilometers up in our atmosphere, where jetliners fly. Evidence from previous Mars missions – landers and orbiters – suggest there was plentiful water on Mars over 3.5 billion years ago, said Jakosky.
Bruce Jakosky: Yet today’s atmosphere is cold and dry. So we know that things have changed. What we want to do is understand why they’ve changed. The biggest difference is that we think that early Mars had a thick CO2 rich atmosphere that provided warming. The big question has been, Where did the CO2 go? Where did the water go?
He said that MAVEN will try to determine how much of that CO2 has been lost to space, as well as what’s keeping the Martian atmosphere intact and how quickly it’s thinning out. Jakosky said that MAVEN will orbit the planet Mars and measure how the solar wind, charged particles spewing from the Sun, mixes with the martian atmosphere.
Bruce Kakosky: We’re going to look at Mars at a time when the solar cycle is changing significantly, a time in the solar cycle when the energetic drivers of the atmosphere are changing. The ultraviolet energy that drives the chemistry that drives escape, and the solar wind are changing significantly at the time we’re going to be measuring. So we’re going to be able to see the response of the atmosphere directly to those changes in the solar wind and in the sun. We know what the sun was like in the past, from studying other stars, so that immediately allows us to extrapolate backwards in time.
Dr. Jakosky explained more about what NASA’s MAVEN mission will discover about the planet Mars.
Bruce Jakosky: What we want to do is determine what the current state of the upper atmosphere and the ionosphere is, how escape processes operate today, and then understand the processes that are responsible for controlling these. We can’t measure what happened over four billion years, which is what we’d like to do. No spacecraft mission can last that long, and it’s hard to measure things in the past. But we can understand what happened in the past by looking at what’s happening today. When we have the measurements of what’s happening today, we can extrapolate to earlier times and determine what the integrated loss to space has been through time.
Jakosky explained why it’s important to study Mars.
Bruce Jakosky: Mars is a very Earth-like planet. We see a lot of evidence for many of the same processes operating on Mars that operate on Earth. It has seasons much like the Earth, polar caps, we see geological features that are very much like those we see on Earth, volcanoes, sand dunes, channels carved by water, things like that. And by studying Mars, we can study a planet that is different than the Earth, but on which different processes operate. In essence, that gives us different boundary conditions, if you will, to study a system. It lets us understand how planets in general work. You study two very different planets, but with the same processes, and try to understand, why are they so different.
Dr. Jakosky said that one question people have is whether there is life on Mars. Or has there ever been life on Mars?
Bruce Jakosky: We’re not going to determine whether there was life, but our mission was designed to understand the planetary context: What was the climate like and why has it changed over time? And that lets us understand questions about the nature of planetary habitability in general, and on Mars in particular. So we want to understand the degree to which Mars was habitable and how it changed over time.