Thursday, October 18, 2007

Breaking News: NASA Extends Operations for Its Long-Lived Mars Rovers

Credit: NASA/JPL-Caltech

Sorry for such an irregular posting schedule, but between work and family I've found that I've been extremely lucky to get anything posted to this blog in the past two months. I will resume my history of Mars exploration as and when I can. In the meantime, here is some breaking news with regard to the two rovers on Mars, Spirit and Opportunity, from the NASA website:

NASA is extending, for a fifth time, the activities of the Mars Exploration Rovers, Spirit and Opportunity. The decision keeps the trailblazing mobile robotic pioneers active on opposite sides of Mars, possibly through 2009. This extended mission and the associated science are dependent upon the continued productivity and operability of the rovers.

"We are extremely happy to be able to further the exploration of Mars. The rovers are amazing machines, and they continue to produce amazing scientific results operating far beyond their design life," said Alan Stern, associate administrator for NASA's Science Mission Directorate, Washington.

The twin rovers landed on Mars in January 2004, 45 months ago, on missions originally planned to last 90 days. In September, Opportunity began descending into Victoria Crater in Mars' Meridiani Planum region. At approximately 800 meters wide (half a mile) and 70 meters deep (230 feet), it is the largest crater the rover has visited. Spirit climbed onto a volcanic plateau in a range of hills that were on the distant horizon from its landing site.

"After more than three-and-a-half years, Spirit and Opportunity are showing some signs of aging, but they are in good health and capable of conducting great science," said John Callas, rover project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The rovers each carry a suite of sophisticated instruments to examine the geology of Mars for information about past environmental conditions. Opportunity has returned dramatic evidence that its area of Mars stayed wet for an extended period of time long ago, with conditions that could have been suitable for sustaining microbial life. Spirit has found evidence in the region it is exploring that water in some form has altered the mineral composition of some soils and rocks.

To date, Spirit has driven 7.26 kilometers (4.51 miles) and has returned more than 102,000 images. Opportunity has driven 11.57 kilometers (7.19 miles) and has returned more than 94,000 images.

Among the rovers' many other accomplishments:

  • Opportunity has analyzed a series of exposed rock layers recording how environmental conditions changed during the times when the layers were deposited and later modified. Wind-blown dunes came and went. The water table fluctuated.

  • Spirit has recorded dust devils forming and moving. The images were made into movie clips, providing new insight into the interaction of Mars' atmosphere and surface.

  • Both rovers have found metallic meteorites on Mars. Opportunity discovered one rock with a composition similar to a meteorite that reached Earth from Mars.

  • The above image was taken by the panoramic camera on the Mars Exploration Rover Opportunity, showing the view of Victoria Crater from Duck Bay. Opportunity reached Victoria Crater on Sol 951 (September 27, 2006) after traversing 9.28 kilometers (5.77 miles) since her landing site at Eagle Crater. Victoria Crater is roughly 800 meters (one-half mile) wide -- about five times wider than Endurance Crater, and 40 times as wide as Eagle crater. The south face of the 6 meter (20 foot) tall layered Cape Verde promontory can be seen in the left side of the inner crater wall, about 50 meters (about 165 feet) away from the rover at the time of the imaging. The north face of the 15 meter (50 foot) tall stack of layered rocks called Cabo Frio can be seen on the right side of the inner crater wall.

    This approximate true color mosaic was taken on Sols 952 and 953 (September 28 and 29, 2006), and was released to the public on September 28, 2007. There are 30 separate pointings through 6 different filters at each pointing. This mosaic was generated from Pancam's 753 nm, 535 nm, and 482 nm filters.

    Tuesday, October 9, 2007


    Credit: ESA-OMEGA

    We continue our discussion of Mars Express, focusing now on the instrumentation and various discoveries that have been made.

    OMEGA is a mineralogical mapping spectrometer that observes in both visible and infrared light. It gives spectra of the surface and the atmosphere between 0.35 and 5.2 microns (µm) with a ground resolution varying from 350 m to 10 km. Such observations allow mapping of the main minerals, which has allowed a map to be created of the surface composition in 100 meter squares. The spectral resolution (from 13 to 20 nm) is also sufficient to study atmospheric phenomena, such as the abundance and variability of minor components, aerosols, etc.

    OMEGA was developed by the Institut d'Astrophysique Spatiale (IAS; Orsay, France) and the Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique (LESIA) (affiliated with l'Observatoire de Paris), with the support of the Centre National d’Etudes Spatiales (CNES; the French space agency) and the participation of Istituto di Fisica dello Spazio Interplanetario (IFSI; Rome, Italy) and the Space Research Institute (IKI; Moscow, Russia). The instrument was originally developed for the Russian mission Mars-96, which was lost during the launch in November 1996.

    The above image is a map of Mars' south pole, as derived from OMEGA infrared spectral images. Astronomers have known for years that Mars possessed polar ice caps, but early attempts at chemical analysis suggested that the northern cap was composed of water ice while the southern cap was composed of carbon dioxide ice ("dry ice"). Recent space missions suggested that the southern ice cap, which exists year round, could be a mixture of water and carbon dioxide. OMEGA has confirmed that this is indeed the case.

    OMEGA measured the amounts of sunlight and heat reflected from the Martian polar region. The results showed that hundreds of square kilometres of "permafrost" surround the south pole. Permafrost is water ice, mixed into the soil of Mars, and frozen to the hardness of solid rock by the low Martian temperatures. This is the reason why water ice has been hidden from detection until now - because the soil with which it is mixed cannot reflect light easily and so it appears dark.

    The south polar region of Mars can now be split into three separate parts. Part one is the bright polar cap itself, a mixture of 85% highly reflective carbon dioxide ice and 15% water ice. The second part comprises steep slopes known as "scarps," made almost entirely of water ice, that fall away from the polar cap to the surrounding plains. The third part was unexpected and encompasses the vast permafrost fields that stretch for tens of kilometres away from the scarps.

    The OMEGA observations were made between 18 January and 11 February of 2004, when it was late summer for the Martian southern hemisphere and temperatures would be at their highest (approximately -130° Celsius).

    In the above image, the polar cap, which is rich in carbon dioxide, is colored light pink. The water-rich ice, free of carbon dioxide, is colored green to blue.