August 3, 2012
Mars Curiosity Rover Mission Connects Past and Future
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April Flowers for redOrbit.com - Your Universe Online
John Donne, the poet, wrote, "No man is an island, Entire of itself." That is as true of technology as it is of people.
"Curiosity is a bold step forward in learning about our neighboring planet, but this mission does not stand alone. It is part of a sustained, coordinated program of Mars exploration," said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington. "This mission transitions the program's science emphasis from the planet's water history to its potential for past or present life."
After the Curiosity rover lands, NASA will be using the Mars Odyssey Orbiter, in service since 2001, to relay landing confirmation to the flight team and the rest of the world. Earth will be below the Mars horizon, preventing line of sight communication and direct radio contact. Two new orbiters will also be recording and relaying Curiosity's transmissions, but that data will see a delay of several hours.
Curiosity will land about 1:31 EDT, August 6 in a rather precise location beside a mountain inside a crater. The 1-ton rover's two-year prime mission will officially begin at that point, but Curiosity has already been collecting data on the 221 day journey since launching from Cape Canaveral on November 26, 2011.
The Radiation Assessment Detector (RAD) has recorded radiation spikes from five solar flare events. Radiation from galactic cosmic rays, originating from supernova explosions and other extremely distant events, have accounted for more of the total radiation than the solar events. Despite shielding roughly equal to what surrounds the astronauts on the ISS, RAD recorded radiation inside the spacecraft that would amount to a significant contribution to a NASA astronaut's career-limit radiation dose.
"Our observations already are being used in planning for human missions," said Don Hassler of Southwest Research Institute in Boulder, Colo., principal investigator for Curiosity's RAD.
Curiosity's main goal, however, is to study the past and present viability of microbial life on Mars. Scientists want to know if Mars ever offered the right environmental conditions. To assess that, Curiosity is carrying a science payload weighing 15 times as much as the science instruments on preview Mars rovers. The landing target, an area 12 miles by 4 miles inside the rim of Gale Crater, sits in a safely flat area between the less-safe slopes and the crater's central peak, informally dubbed Mount Sharp. One of the attractions of this landing zone is the easy distance to layers of interest on Mount Sharp, where minerals that formed in water have been seen from orbit.
"Some deposits right inside the landing area look as though they were deposited by water, too," said John Grotzinger of the California Institute of Technology (Caltech) in Pasadena, project scientist for Curiosity. "We have a great landing site that was a strong science contender for earlier missions, but was not permitted for engineering constraints because no earlier landing could be targeted precisely enough to hit a safe area inside Gale Crater. The science team feels very optimistic about exploration of Mount Sharp and the surrounding region that includes the landing ellipse."
Mission engineers designed a sky crane maneuver, a total departure from previous landings, for Curiosity using nylon cords attached to a rocket backpack. This had to be done because Curiosity is too heavy to use the airbag systems of the past.
"We know it looks crazy," said Adam Steltzner of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, leader of the team that developed the system. "It really is the result of careful choices." By designing the aeroshell enclosing Curiosity to create lift and be steerable, engineers were able to build a system that lands much more precisely instead of dropping like a rock.