Astronomy and Space articles
by Martin George of the Launceston Planetarium
27 September 2014
Two Mars Craft Arrive
On Monday our time this week, mission controllers held their breaths as NASA's latest
Mars craft, called MAVEN, entered orbit around the Red Planet. MAVEN joined three
other orbiters - NASA's Mars Odyssey and Mars Reconnaissance Orbiter, and the
European Space Agency's Mars Express - and NASA's Curiosity and Opportunity rovers
on the surface.
In addition, on Wednesday, the first Indian Mars Orbiter, called the Mars Orbiter Mission,
or MOM for short, also arrived in orbit, making a current total of seven active Mars
missions.
MAVEN stands for Mars Atmosphere and Volatile Evolution Mission. It's an exciting
mission that has arrived at Mars at a time when, coincidentally, the United Nations
Climate Change Summit has been taking place in New York. The connection? We are
not the only planet whose climate change we are studying. Climate change on Mars, too,
is a topic of great interest, and has been ever since we realised that Mars once had
running water.
Things are very different on Mars today. The temperatures and pressures do not allow
liquid water to be stable: it would quickly evaporate or freeze. The main goal of MAVEN
is to find out why Mars has changed.
Although is now clear to us that Mars once had flowing water, we know that this must
have been billions of years ago. We also know that for liquid water to have been stable,
Mars must have had a more substantial atmosphere.
Much of the original atmosphere is now gone, and it seems that a significant amount of it
escaped into space. We think that the most likely cause of this loss is the atmosphere's
interaction with the solar wind, which is a stream of particles from the Sun that can erode
the atmosphere. The absence of a general Martian magnetic field, which existed only for
a relatively brief period in Mars' history, means that the atmosphere is not protected from
this effect.
So MAVEN's job is to study the processes currently taking place in the upper
atmosphere, allowing us to project back into the past and give us vital information about
Mars' atmospheric history. It will be an important piece of the jigsaw puzzle of
information.
India's mission is also called Mangalyaan, meaning 'Mars craft'. It's a wonderful
achievement for India, especially given its price: only about A$82 million, which is only
about 11% that of MAVEN.
Astronomy and Space articles
by Martin George of the Launceston Planetarium
27 September 2014
The main role of that mission is to study the current content of the atmosphere. In
particular, we have evidence of the presence of methane in Mars' atmosphere, although
its actual existence, and its source, are the subject of much discussion. Earlier evidence
of methane came from data returned by Europe's Mars Express mission. However, is the
methane really there, and what processes have produced it? One idea is that it could be
produced by volcanic activity. MOM may answer the question once and for all.
You can currently see Mars in the western sky each evening, moving slowly from night to
night against the starry backdrop. As I gaze at the Red Planet, I find it wonderful to think
of all of the craft that are working for us up there.
Article by Martin George, Launceston Planetarium, QVMAG.
Reproduced with permission of the Mercury newspaper.