Shop Windows to the Universe

Learn about planets outside our solar system through Exoplanets and Alien Solar Systems by Tahir Yaqoob, Ph.D., a book in our online store book collection.
An artist's rendition of the Mars Express spacecraft in orbit around Mars. The long, thin white line extending from the spacecraft is the antenna of the MARSIS radar.
Click on image for full size
Image courtesy the European Space Agency (ESA)

Mars Express Orbiter

The European Space Agency (ESA) launched a mission to Mars called "Mars Express" in June of 2003. The Mars Express spacecraft has two parts: an orbiter that will circle Mars for at least one Martian year (687 Earth days), and a lander named "Beagle 2" which is scheduled to touch down on the surface of the Red Planet on December 25, 2003. The Mars Express orbiter has seven major science instruments and experiments onboard the spacecraft. Those experiments will search for water, map the surface and subsurface of the planet, and measure the composition of the Martian atmosphere.

One of the orbiter's main purposes is to search for water beneath the surface of Mars using a radar system called MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding). Scientists are very curious as to whether there might be life on Mars, and water deposits are a good place to look for living creatures. The surface of Mars is too cold and dry for water, but there may be water underground in aquifers. The 40-meter (130-foot) long MARSIS antenna will bounce low-frequency radio waves off of Mars. This will help us determine the depth of dust deposits, the thickness of the sand in the large dune fields, and the subsurface structure of the planet to depths as great as a few kilometers (miles). If aquifers exist beneath the Martian surface, MARSIS should be able to detect them.

The High Resolution Stereo Camera (HRSC) will capture full color 3D images of the planet at a resolution of 10 meters (3.3 feet). Some areas will be imaged at a resolution of 2 meters (6 feet). The OMEGA Visible and Infrared Mineralogical Mapping Spectrometer will create a map of the mineral composition of the surface with a resolution of 100 meters (328 feet). Scientists hope to determine the iron content of the surface, the water content of the rocks and clay minerals, and the abundance of non-silicate materials such as carbonates and nitrates. OMEGA will also help scientists determine some aspects of the composition of the atmosphere.

The SPICAM Ultraviolet and Infrared Atmospheric Spectrometer will measure the abundance of atmospheric ozone and water vapor. The Planetary Fourier Spectrometer (PFS) will measure the amount and distribution of carbon dioxide (the main constituent of Mars' atmosphere), water, carbon monoxide, methane and formaldehyde. Over the course of the mission these instruments will determine the variation of the Martian atmosphere over time.

The ASPERA Energetic Neutral Atoms Analyzer will help scientists understand the upper atmosphere of Mars and its interaction with the solar wind. Mars has a weak magnetic field, so the solar wind is eroding its upper atmosphere. This may explain why Mars has such a thin atmosphere today, possibly having lost much of its atmosphere to space over time. ASPERA will measure ions, electrons and energetic neutral atoms in the outer atmosphere to reveal the numbers of oxygen and hydrogen atoms (the constituents of water) interacting with the solar wind and the regions of such interaction.

Radio signals from the spacecraft will be used to study the Red Planet via the Mars Radio Science Experiment (MaRS). Radio signals passing through the atmosphere as Mars Express circles behind Mars will help scientists understand the structure of the atmosphere and the ionosphere. Slight variations in the vehicle's orbit, which appear as tiny changes in the arrival times of radio signals, will help us map Mars' gravity field and thus provide a better picture of the planet's interior. Radio signals reflected from the surface of Mars will provide a glimpse into the roughness of the surface at various locations.

Last modified December 24, 2003 by Randy Russell.

Shop Windows to the Universe Science Store!

Our online store includes issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, ranging from seismology, rocks and minerals, oceanography, and Earth system science to astronomy!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Mars Express - Beagle 2 Lander

The European Space Agency (ESA) launched a mission to Mars called "Mars Express" in June of 2003. The Mars Express spacecraft has two parts: an orbiter that will circle Mars for at least one Martian year...more

What Is a Mineral?

Minerals occur naturally on rocky planets and form the building blocks of rocks. They are non-living, solid, and, like all matter, are made of atoms of elements. There are many different types of minerals...more

The Martian Magnetosphere

An important new result from the Mars Global Surveyor (MGS) mission is the definite confirmation of the presence of a magnetic field near Mars. The magnetic field leads to the formation of a magnetosphere,...more

The Martian Ionosphere

The Martian ionosphere is a layer of gas composed of ions and electrons that extends from about 75 miles up to several hundred miles up above the surface. The layer is shown schematically by the shaded...more

Overview of the Mars Express Mission

The European Space Agency (ESA) launched a mission to Mars called "Mars Express" in June of 2003. The Mars Express spacecraft has two parts: an orbiter that will circle Mars for at least one Martian year...more

Mars Express Landing Site - Isidis Planitia

The European Space Agency (ESA) launched a mission to Mars called "Mars Express" in June of 2003. The Mars Express spacecraft has two parts: an orbiter that will circle Mars for at least one Martian year...more

Hubble Space Telescope

The Hubble Space Telescope (HST) was one of the most important exploration tools of the past two decades, and will continue to serve as a great resource well into the new millennium. The HST is credited...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA