![]() ![]() Since then, engineers and scientists on both sides of the Atlantic have run multiple simulations, using computers and spare flight hardware, to ensure minimal risk to the spacecraft. A week before its originally scheduled deployment in April of 2004, an engineer at Astro Aerospace, the California company that designed the antenna, ran a computer simulation suggesting the antenna might spring backward and graze the spacecraft. Image credit: NASA/JPLĬoncerned about its unconventional design, mission controllers in Europe have delayed the deployment of MARSIS more than once. JPL engineer Ali Safaeinili helped design MARSIS to see what would otherwise be hidden from view. "So far, for the most part, we have only observed the surface of Mars, but with MARSIS we can see rock and ice beneath the surface." "MARSIS will let us 'see' the invisible Mars," says Ali Safaeinili, an electrical engineer and radar scientist at the Jet Propulsion Laboratory in Pasadena, California. If spaces are filled with water, the signals will bounce back. If spaces between rock grains are empty, most of the radar waves will penetrate. One of the things scientists will look for are aquifers, zones in buried rocks that are rich in liquid water. MARSIS will use radar signals with wavelengths hundreds of meters long to detect features up to 5 kilometers (3.1 miles) deep. When radar waves encounter a boundary between different materials, some energy is reflected and some is transmitted. The radar will search for underground features much the way an ultrasound device looks at an unborn child inside a mother's womb. Scientists will use MARSIS to probe beneath the surface of Mars. Italian radar specialist Daniela Biccari will monitor the antenna's function without being able to see it. "We will monitor the spacecraft’s orientation with gyroscopes and accelerometers." "There is no camera to tell us if the antenna has deployed correctly," notes electrical engineer and radar scientist Daniela Biccari, of the University of Rome. In this case, losing the signal for a short time will be the first sign of success. ![]() The motion will cause the spacecraft, the European Space Agency probe called the Mars Express, to rotate slowly 45 degrees, temporarily losing contact with Earth. On each of its two main "arms," thirteen segments will quickly uncoil, taking a few seconds to reach their full length of 20 meters (65 feet) after tiny explosive charges open a pair of compartment doors. Weighing in at a mere 4 pounds (1.8 kilograms) and packing a pyrotechnic punch, the MARSIS antenna, which stands for Mars Advanced Radar for Subsurface and Ionospheric Sounding, will spring into operation in May. This artist's concept shows the three segments of MARSIS as they will appear after deployment, two of the segments extending horizontally on either side of the Mars Express spacecraft and one extending vertically. During the next couple of weeks, if all goes as planned, the martial arts champion of radar antennas will kickbox its way into space. ![]()
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