The MGS Radio Science Team began to acquire raw data from the atmosphere of Mars on January 26, and we are continuing to acquire this martian meteorological data on every orbit of the Mars Global Surveyor spacecraft. The aerobraking sequence has reduced the MGS orbit period to approximately 14 hours, so we are now able to record new data nearly twice each day! Due to spacecraft operations constraints, we are now only able to acquire new data during the entry of the spacecraft into occultation behind Mars. During the MGS mapping mission, we will acquire data during both entry and exit occultations.
It was more complicated than originally anticipated, but all of the martian meteorological surface data which the Team has acquired as of today is now available on this Web site. Registered participants may use the Data Transfer and Visualization Tools to retrieve the data records and to generate graphs of the martian atmospheric data and the experimental conditions under which it was acquired. The database of martian meteorological data records will now be updated regularly with new data as it is acquired and processed by Team members.
Even after only five weeks of data collection, the data set is already very exciting! The latitudes of the measurements began at 30 degrees North, and has drifted to its current value of -63 degrees South. The local time of the measurements on Mars started between 5:30 and 6:00 am and has smoothly drifted earlier in time to just past midnight where it is today. It is now summer in the southern hemisphere of Mars and winter in the northern hemisphere; the solstice occurred about one month ago on February 6 when the solar longitude passed through 270 degrees. The current solar longitude is approximately 287 degrees, so it is still early summer in martian South and early winter in the martian North.
The first surface temperature measurements were approximately -105 degrees Fahrenheit. The latest measurements have "warmed" considerably to -30 to -25 degrees Fahrenheit! Recent surface pressures in the martian South have been approximately 5 millibars. By comparison, the typical surface pressure on Earth is over 1000 millibars!
The MGS Radio Science Team will be continuing to gather atmospheric data from Mars until May. Due to planetary and orbit geometry, there will not be any occultations of the spacecraft for a number of months beginning in May. We will not be able to acquire new data during this period. The main MGS mapping mission is scheduled to begin next March and to continue for one full martian year (687 days). We will of course be acquiring data during the occultations which occur in the mapping mission (and for which Deep Space Network tracking of the spacecraft is available). The MGS orbit period will be down to two hours at that time and we will be able to acquire data from both entry and exit occultations of the spacecraft. As a result, we will be collecting much more data during the MGS mapping mission than we are today.
An Atmospheric Analyses department will soon be added to this Web site with questions to aid students in their comparisons of the atmospheres of Earth and Mars. If registered classes have not already done so, they should begin recording their daily observations of their own local atmospheric conditions with the tools on this site. The MGS Radio Science Team has been recording their daily observations at Stanford for two months now, and the data are very interesting due in no small part to the wet and wild El Nino which we have been experiencing this winter in Northern California! Registered classes my view our data; the MGS Radio Science class ID is CA0001.
Educators are welcome to register classes for this program at any time. The program will continue through the end of the MGS mapping mission in the year 2000. Interested teachers should contact joe@nova.stanford.edu.