astronomy

MOM Captures Mars Storm

A global view of Mars showing a regional dust storm over part of Chryse Planitia. Taken by the Mars Orbiter Mission. Courtesy Indian Space Research Organization.

A global view of Mars showing a regional dust storm over part of Chryse Planitia. Taken by the Mars Orbiter Mission. Courtesy Indian Space Research Organization.

The Mars Orbiter Mission from the Indian Space Research Organization has started off its work at the Red Planet by storm. No, seriously — it captured a view of a regional dust storm over the northern part of Chryse Planitia (the regions of Mars where Viking 1 and the Pathfinder missions landed).  This remarkably clear image was taken on September 28th as part of the mission’s early science work.

Global dust storms are an important part of the Martian climate system. The first spacecraft to directly image one was Mariner 9, which arrived in 1971 and had to wait for nearly a month before it could return surface images of the planet.  Today we know that dust storms, particularly regional and global storms occur most often when the planet is at or near perihelion (closest to the Sun in its orbit). This makes sense, since the increased heat the planet gets at that time helps kick these storms up.

During a Martian dust storm, the winds send sand grains skipping across the surface, as well as blowing dust up into the air. You may have seen images and animations of dust devils on Mars — these are small, localized “tornadoes” that whirl across the surface and kick up dust. Dust storms are much larger, and cover huge regions and alternately scour the surface of dust and then redeposit it elsewhere.  Most of the dust storms we see on Mars (except for the very large-scale or global ones) cover an area of the surface for a short time (typically a few days). The winds range in speed from about 50 to 100 kilometers per hour (30 to 65 miles miles per hour).

Martian dust storms are a fact of life on the Red Planet, something our landers can be affected by as clouds of dust and swarms of sand blast past them. The Mars Exploration Rover teams noticed a big effect when the battery power on Spirit and Opportunity dropped during and after  dust storm. This happened because dust particles settled onto the solar arrays, partially blocking sunlight. As luck would have it, dust devils later whirled over the rovers and cleared off their panels.

In the future, when humans are exploring Mars, knowledge of dust devils will help them plan expeditions and get themselves to safety. Images like these and others provided by orbiting spacecraft will provide an early warning system for them.

Two New Orbiters Get Right to Work

MAVEN’s first UV “views” of Mars. Courtesy Laboratory for Atmospheric and Space Physics /University of Colorado and NASA.

When the going gets tough, the tough do science!  No doubt about it, getting to Mars is a challenge, and once you get there, the rewards are great. So it is this week with two spacecraft who took up residence in Mars orbit.

Within days of their arrival at Mars the NASA MAVEN spacecraft and the Indian Space Research Organization’s MOM/Mangalyaan orbiter returned their first data and images of the Red Planet. MAVEN was sent to Mars s0lely to study the atmosphere, and its first data show the planet from the spacecraft’s viewpoint of 36,500 km (58,765 miles) above the surface. Its ultraviolet-sensitive imaging spectrograph (an instrument) studied the fine changes in UV light as it passed through the upper atmosphere.  It showed ultraviolet light from the Sun scattered by atomic hydrogen gas, which lies in an extended cloud that goes to thousands of kilometers above the planet’s surface. The blue (leftmost) part of this image shows how extensive that cloud is. The green image (middle left) is a different wavelength of UV light that is primarily sunlight reflected off of atomic oxygen. Mars’ gravity is holding the oxygen closer to the surface. Red (middle right) shows ultraviolet sunlight reflected from the planet’s surface. The final panel is a composite map of the other views. The bright spot in the lower right is light reflected either from polar ice or clouds.

These gases are a result of water and carbon dioxide breaking down in the atmosphere. The trick for MAVEN now is to chart the escape of hydrogen and oxygen from the planet over time. Its nominal mission is one year, and should give scientists a much better understanding of how much water has escaped from the Martian atmosphere over longer periods of time.

MOM Gets Her First Images of Mars

The atmosphere of Mars as seen form the MOM Color Camera. Courtesy ISRO.

The atmosphere of Mars as seen from the MOM Color Camera. Courtesy ISRO.

The MOM Mangalyaan mission is busily snapping and sending back images of the Red Planet from its orbit roughly 7,000 km (4,300 miles) above the surface. As you can see, it’s traveling in a closer orbit so as to allow the mission to study the surface more closely. MAVEN is is in a longer higher orbit that will (at first) allow it to study most (if not all) of the planet’s atmosphere.

As MAVEN is doing, the MOM is performing early science observations (sometimes called “commissioning” science) to calibrate and test the instruments after their long voyage from Earth. MOM is a multi-purpose mission, combining imaging with other science to get a complete view of Mars and its atmosphere.

The first image of Mars from MOM. Courtesy ISRO.

The first image of the Martian surface, as seen by MOM. Courtesy ISRO.

The results are exciting, and are proving that the MOM approach (which is a science “proof of concept” mission) is working. The camera’s images give an immediate positive feedback. Not only will it be used to track changes in surface features, but it can show (as it does here) the thin atmosphere of Mars. Further along in the mission, the spacecraft’s controllers hope to capture images of Mars’s two moons: Phobos and Deimos. Fairly soon we should hear about data from the other instruments aboard MOM: the thermal infrared system (which helps take the temperature of the planet), the methane sensor (looking for methane emissions from the surface), the Lyman-alpha photometer (which specifically looks for deuterium and hydrogen in the atmosphere), and the Mars Exospheric Neutral Composition analyzer, which is another instrument used to study the components of the atmosphere. There’s more to come from these two missions, so stay tuned!