{"id":2606,"date":"2015-01-22T15:12:58","date_gmt":"2015-01-22T20:12:58","guid":{"rendered":"https:\/\/www.bu.edu\/federal\/?p=2606"},"modified":"2015-01-27T16:23:15","modified_gmt":"2015-01-27T21:23:15","slug":"mission-to-mars","status":"publish","type":"post","link":"https:\/\/www.bu.edu\/federal\/2015\/01\/22\/mission-to-mars\/","title":{"rendered":"Mission to Mars"},"content":{"rendered":"

BU physicist John Clarke looks to the red planet for clues about Earth\u2019s future<\/h2>\n
\n

\"John
\nJohn T. Clarke, director of BU\u2019s Center for Space Physics, was part of the team that proposed MAVEN and is now a scientific co-investigator on the mission. Photo by Rob Timko.<\/em><\/p>\n

At this moment, a\u00a0NASA<\/a>\u00a0satellite called\u00a0MAVEN<\/a>\u00a0is circling Mars, and it\u2019s covered with Boston University fingerprints. (Not literally, of course. That would be tacky.) MAVEN stands for Mars Atmosphere and Volatile EvolutioN mission, and it\u2019s the first satellite dedicated to studying Mars\u2019 upper atmosphere. Understanding the thinning Martian atmosphere might explain how the planet went from warm and wet\u2014as many scientists believe it once was\u2014to cold and dry, and what that might mean for climate change on Earth.<\/p>\n<\/div>\n

Back to those fingerprints. The director of BU\u2019s\u00a0Center for Space Physics<\/a>\u00a0John T. Clarke<\/a>\u00a0was part of the team that proposed MAVEN in 2006; he is now a scientific co-investigator on the mission. Professors\u00a0Paul Withers<\/a>\u00a0and\u00a0Michael Mendillo<\/a>\u00a0are participating scientists, and postdoctoral fellow\u00a0Majd Matta<\/a>\u00a0is analyzing data and helping plan MAVEN\u2019s observation program. The satellite began orbiting Mars on September 21, 2014, and the first preliminary scientific data was announced three months later, on December 16, 2014, at the fall meeting of the\u00a0American Geophysical Union<\/a>. There, MAVEN scientists told the world about the satellite\u2019s close encounter with a comet called Siding Spring, and what it\u2019s already learned about charged particles and solar wind in the Martian atmosphere.<\/p>\n

BU Today<\/em>\u00a0spoke with Clarke about MAVEN and its historic mission to Mars.<\/p>\n

BU Today<\/em>: Why are you studying Mars\u2019 atmosphere? It hardly has any atmosphere to study!<\/h5>\n

Clarke:<\/strong>\u00a0Mars probably started out with an atmosphere like the Earth\u2019s, and then early on, because of its weaker gravitational pull, lost much of it. But we don\u2019t really know how much of the atmosphere escaped into space and how much may have frozen into the ground. There\u2019s a lot of evidence on the ground for flowing water, maybe 3.5 billion years ago. There\u2019s a lot of erosion, a lot of places that look like dry riverbeds.<\/p>\n

Will understanding Mars\u2019 atmosphere tell us about Earth\u2019s history, or what might happen to Earth in the future?<\/h5>\n

Absolutely. MAVEN is a global climate change mission for Mars. We\u2019d like to understand what happened to Mars and how it got to its present state. We\u2019d like to know how much water is still there\u2014both as surface ice and underground\u2014and how much is gone. And this relates directly to climate change on the Earth. It\u2019s a different case, a smaller planet, a little farther from the sun, but still relevant. So the purpose of MAVEN is to orbit around Mars and measure the physics of the escape of the atmosphere into space. Once we understand those basic principles, then we can extrapolate back in time and understand what Mars may have been like in the past.<\/p>\n

Why do you think the atmosphere is escaping?<\/h5>\n

The gravity of Mars is about 40 percent of the gravity on the Earth. So a gas at a certain temperature will travel much higher than it would on Earth, and it\u2019s just easier for the molecules to escape. We understand the basic principles. What we don\u2019t know is exactly what\u2019s going on at Mars. MAVEN has to go there and measure it.<\/p>\n

\"MAVEN
\n MAVEN is studying Mars\u2019 atmosphere for clues about the planet\u2019s past. Image courtesy of NASA\u2019s Goddard Space Flight Center.<\/em><\/p>\n

MAVEN arrived at Mars in September?<\/span><\/h5>\n

In September, correct.<\/p>\n

What has been the most nerve-wracking part so far?<\/h5>\n

The two most dangerous moments are the launch, and then the engines firing at Mars, when MAVEN settles into orbit. People argue which is riskier for the satellite. They both have a pretty good chance of success, but there\u2019ve been enough failures in the past that you worry.<\/p>\n

Really?<\/h5>\n

Well, if you go back 20 or 30 years, it\u2019s been about a 50\/50 chance of success when a spacecraft gets to Mars. The odds are better than that in recent years, and the company that built this spacecraft\u2014Lockheed Martin<\/a>\u2014has a pretty good track record, but it still makes you nervous.<\/p>\n

What happened to the 50 percent that didn\u2019t get there\u2014did they get lost in space or did they blow up?<\/h5>\n

Nothing \u201cblew up\u201d but a couple of spacecraft never left Earth\u2019s orbit, and many failed to stop at Mars and enter orbit. They are now lost in space, in the sense that they cannot study Mars.<\/p>\n

What is MAVEN doing now?<\/h5>\n

Right now, we\u2019re testing the instruments, sending different commands to the spacecraft, making sure they\u2019re working correctly. When you first turn something on, there are always surprises. So far, we haven\u2019t found any real problems, but we have to understand how things are working. And once we\u2019ve done that, we\u2019ll be in a mode where we repeat the same measurements, every orbit around Mars, which is about four and a half hours, and we\u2019ll do that for a year. And once we start seeing trends over time, that\u2019s when the science results will come out.<\/p>\n

Do you have a favorite instrument on the spacecraft?<\/h5>\n

My favorite instrument is the one that I work on! It\u2019s called the\u00a0Imaging Ultraviolet Spectrograph<\/a>\u2014IUVS\u2014which includes an echelle channel based on a BU design.<\/p>\n

A what?<\/h5>\n

Every element emits certain wavelengths of light\u2014that\u2019s called the emission spectrum. Scientists use an optical element called a diffraction grating to separate the wavelengths, and an echelle spectrograph is an instrument with a specially shaped diffraction grating (that\u2019s the echelle) that gives you a very high resolution of the spectra. So we are able to separate out emission spectra of hydrogen and oxygen, and study them in greater detail than has been possible in the past, because this is the first time that this type of spectrograph has ever flown to another planet. It\u2019s directly based on a similar instrument that I designed, which was developed by grad students and is now in the basement of the CAS building. So an instrument developed by BU grad students was the prototype for the one now at Mars! And it\u2019s working well, and it\u2019s very exciting to see these data come down.<\/p>\n

Hydrogen and oxygen are particularly interesting because they make water?<\/h5>\n

Right, and that\u2019s really what we want to learn about, the history of water on Mars.<\/p>\n

There\u2019s been big news from Mars recently\u2014it sounds like the\u00a0Curiosity<\/a>\u00a0Rover found some methane, a gas that some scientists regard as a sign of life. What do you think? Will MAVEN be able to help explain these findings?<\/h5>\n

This is exciting, but it\u2019s way too soon to say that anyone has discovered life on Mars. MAVEN is not expected to measure methane, partly because it\u2019s unlikely to make it to the upper atmosphere.<\/p>\n

\n
\n
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Are the Mars satellites and rovers all working together?<\/h5>\n

Yes. There are several spacecraft still orbiting around Mars, and the Curiosity and Opportunity Rovers are still sending back data. We scientists compare notes after we get our results. For example, MAVEN is measuring the escape of hydrogen and oxygen from water at the top of the atmosphere. We\u2019d like to know what\u2019s going on with the water down near the surface, because all the water comes from the ground at some point. And there are other spacecraft that are able to measure that.<\/p>\n

Do all the spacecraft send data back to Earth, and you scientists share it? Or do the satellites talk to each other?<\/h5>\n

They don\u2019t really talk to each other so much, except in the case of the rovers, which have enough power to communicate with an orbiter but not with the Earth. That\u2019s likely to be the future of MAVEN: after the prime science mission is done, it will become a telecommunications relay for the rovers to the Earth.<\/p>\n

Aw, that\u2019s nice! It gives the rovers a lifeline.<\/h5>\n

It gives them a longer lifetime. That\u2019s right.<\/p>\n

I also heard that MAVEN recently encountered a comet?<\/h5>\n

Yes.\u00a0Comet Siding Spring<\/a>\u00a0flew by, very close by Mars, on the 19th and 20th of October, and MAVEN was taking measurements at that time.<\/p>\n

Did you discover anything interesting?<\/h5>\n

Yes, very interesting. The comet was not as active as we had thought it might be\u2014active in terms of sending out gas and dust. It was quieter, so it wasn\u2019t as big a disturbance of the Martian atmosphere as it might have been. Nonetheless, we clearly saw the signature of the comet flying by.<\/p>\n

Were you worried that it would get too close to your satellite?<\/h5>\n

Well, we knew where it would be. The orbit of MAVEN was timed so that at the closest approach, and when the cloud of dust from the comet went by, the satellite was hiding behind the planet. We didn\u2019t really think that there would be a problem, but why take a chance? Other spacecraft did the same thing. And there was no damage, as far as we can tell, to any of the spacecraft.<\/p>\n

I think one of the most exciting things in science is to finally have fresh data come in and maybe discover something completely new.<\/h5>\n

It\u2019s very exciting, yes. I was looking at some Hubble data yesterday and I had an experience like that. After all these years that I\u2019ve been working in this field, I thought I knew what I was looking for, and then I analyzed the data and realized, oh, no, I can\u2019t see that, but here\u2019s this other thing that\u2019s just as important, and I didn\u2019t think of it. It\u2019s a new result and not published yet, but it has to do with the hydrogen and oxygen and how they are changing in the atmosphere of Mars with a seasonal effect much stronger than had been expected.<\/p>\n

And you thought, \u201cThis is why I do science!\u201d<\/h5>\n

Exactly.<\/p>\n

A version of this article originally appeared on<\/em> BU Research<\/a>.<\/p>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

BU physicist John Clarke looks to the red planet for clues about Earth\u2019s future John T. Clarke, director of BU\u2019s Center for Space Physics, was part of the team that proposed MAVEN and is now a scientific co-investigator on the mission. Photo by Rob Timko. At this moment, a\u00a0NASA\u00a0satellite called\u00a0MAVEN\u00a0is circling Mars, and it\u2019s covered […]<\/p>\n","protected":false},"author":7048,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[8],"tags":[67,13,69,5,68],"_links":{"self":[{"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/posts\/2606"}],"collection":[{"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/users\/7048"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/comments?post=2606"}],"version-history":[{"count":5,"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/posts\/2606\/revisions"}],"predecessor-version":[{"id":2611,"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/posts\/2606\/revisions\/2611"}],"wp:attachment":[{"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/media?parent=2606"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/categories?post=2606"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bu.edu\/federal\/wp-json\/wp\/v2\/tags?post=2606"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}