Self portraits and when losing 40 minutes a day can mean the world

In other words, while no methane has been detected in the first sampling, the team remain confident that if it is in the Martian atmosphere, they may yet sniff it out. Despite the “no methane – yet” result, SAM has yielded important information on the composition and formation of the Martian atmosphere, as hinted at in Webster’s comment. Findings from the instruments suggest that loss of a fraction of the atmosphere, resulting from a physical process favouring retention of heavier isotopes of certain elements, has been a significant factor in the evolution of the planet. Isotopes are variants of the same element with different atomic weights.

This is important. as scientists theorise that in Mars’ distant past its environment may have been quite different, with persistent water and a thicker atmosphere, which was gradually “worn away” over time. As such, SAM’s findings are a precursor to NASA’s next Mars mission, MAVEN, the Mars Atmosphere and Volatile Evolution. The orbital vehicle is designed to investigate possible losses from the upper atmosphere when it arrives at Mars in 2014.

The SAM results themselves show an increase of five percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed. These enriched ratios of heavier isotopes to lighter ones suggest the top of the atmosphere may have been lost to interplanetary space. Losses at the top of the atmosphere would deplete lighter isotopes. Isotopes of argon also show enrichment of the heavy isotope, matching previous estimates of atmosphere composition derived from studies of Martian meteorites on Earth.

So, in Curiosity’s first three months on Mars, SAM has analysed atmosphere samples with two laboratory methods, its mass spectrometer and the TLS. The former has investigated the full range of atmospheric gases gathered in a sample “inhaled” by SAM, and TLS has focused on carbon dioxide and methane content in the air. Both have yielded interesting results which further scientists’ understanding of the complex and very thin Martian atmosphere. However, there is a third card in SAM’s hand, whcih has yet to be played, and which is potentially the most exciting of all.

The gas chromatograph is an instrument designed to separate and identifies gases contained in both air and soil samples obtained on Mars. It is an exciting instrument because it can be used to identify any organic compounds evident in samples gathered from the Martian soil, and so may well yield further clues on the possibility of microbial life having once existed on the surface of Mars.

Bak to Earth – in Time, at Least

Until now, the science and mission teams overseeing Curiosity’s explorations on Mars have been operating on Mars Time. As the Martian day is approximately 40 minutes longer. This means that in order to work on the Martian day cycle and maximise the use of daylight on Mars, the teams have to work on Mar Time, which leads to their days becoming increasingly out-of-synch with the normal day/night cycle in their Earth timezone, with the result that they end up working exceptionally strange hours.

As from November 5th, the teams have started reverting to a more normal Earth-based day, working from 8am through 8pm Pacific Time, rather than matching the Martian day / night cycle. They are able to do this because of the increased confidence they have in Curiosity’s capabilities to manage itself, and because the overall speed and efficiency of planning the rover’s activities, etc., has improved as the various teams have settled into working together.

Alongside this shift in working, the “Curiosity Team” will also be dispersing. In all, there are some 600 people directly involved in Curiosity’s operations. These include some 200 NASA / JPL personnel based at JPL’s campus in Pasadena, California, and some 400 scientists from institutions across America and around the world, 200 of whom have also been based at JPL since the rover’s arrival on Mars on August 5th/6th. These latter 200 will now be returning to their “home” institutions, where they will continue to work on the mission via remote means.

“The phase that we’re completing, working together at one location, has been incredibly valuable for team-building and getting to know each other under the pressure of daily timelines,” said Mars Science Laboratory Deputy Project Scientist Joy Crisp, of JPL. “We have reached the point where we can continue working together well without needing to have people living away from their homes.”

These moves not only mean a return to “normal” working hours for those involved in mission planning and operations, it also means that they get to re-integrate themsevles back into the lives of their families and loved ones on something approaching a normal schedule.

Looking Ahead

Curiosity still has a couple more things to do prior to bidding farewell to Rocknest and resuming its journey to Glenelg. In particular, this week should see the delivery of the first soil sample in to SAM for detailed analysis. A further sample – the third – will also be delivered to CheMin, allowing scientists to carry out simultaneous analysis of the same sample material.

To prepare for this, CheMin dumped the second sample it had been analysing (from the fourth scoop of Martian soil) on Sol 89 (November 5th, 2012). I covered analysis of this sample in my last MSL update.  Also on Sol 89 came confirmation that SAM had completed an overnight analysis run on a blank sample cup in preparation for it to receive a soil sample, so the way is now clear for a fifth sample to be gathered, processed via CHIMRA and delivered to both.

MSL posts in this blog

All images reproduced courtesy of NASA/JPL

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