Mars Science Laboratory: NASA’s Most Difficult Planetary Mission
NASA’s $2.5 billion Mars Science Laboratory mission, a two year effort to determine whether the neighboring planet hosts, or once hosted, environmental conditions suitable for some form of life, represents the most challenging U. S. planetary mission ever attempted, top space agency officials said Monday.
The one-ton MSL spacecraft, also known as the Curiosity Rover, is in the home stretch of its eight month journey to the Red Planet.
MSL/Curiosity, launched from Cape Canaveral, Fla., on Nov. 26, will reach Mars early Aug. 6. On Earth, the outcome of the risky landing strategy will not be clear until 1:31 a.m., EDT. Signals from the spacecraft it will take more than 13 minutes to reach the Earth through a small network on NASA and European craft in orbit around Mars and functioning as communications relay satellites.
“The Curiosity landing is the hardest NASA robotic mission ever attempted,” John Grunsfeld, the associate administrator for NASA’s science mission directorate, told aWashingtonnews briefing on Monday. “This is a risky business.”
Acutely aware of the wide public interest in the outcome of the landmark mission, NASA and its partners have established a “one stop” web site that offers background on the mission, educational materials and links to web casts of the landing.
If the six wheeled Curiosity successfully reaches its target, the nearly 100 mile wide Gale Crater, scientists have a good chance of sizing up the evolution of the Martian environment over millions of years and make comparisons with the Earth as it too evolved. Findings from previous spacecraft suggest Mars was once warm and wet enough for water to flow across the surface. As the Martian magnetic field faded, a once thicker atmosphere disappeared and the planet became cold, dry and exposed to ultraviolet and cosmic radiation. The water that once flowed appears to have retreated underground near the Martian poles and in dust covered glacial bunkers close to the equator.
MSL is equipped with 10 instruments, including drills and lasers as well as cameras, developed to look deeper into the Martian mystery. By probing the soil and rocks like the much smaller NASA rovers Spirit and Opportunity, MSL will look for sulphites, clays and other minerals that form readily in water on the Earth. If the big rover gets lucky, it could identify “organics,” the complex carbon based structures, perhaps locked under ground, that are considered the building blocks for life.
However, even with evidence of organics on Mars, scientits will likely puzzle over their origins — biological or the result of some other natural physical process.
“So, it’s not just one thing we are after, it’s several things, and we may find one here and one there” said John Grotziger, the MSL project scientist from the California Institute of Technology, “This is a mission that requires a lot of patience. This is not something for which there is a slam dunk discovery. It will take many bits of information to get there. It will take us a while to get there.”
MSL’s target was selected from over 100 potential Martian landing sites.
Rising more than two miles from the center of Gale Crater is Mount Sharp. Gale is centered along a geological transition between the highlands of the Martian southern hemisphere and the northern lowlands. If water once flowed through the region,, as scientists believe, then it likely collected in Gale, and Mount Sharp is a composite of the soil and rocks washed along for millions of years.
MSL, once it lands, will undergo a one to two month check out by engineers and scientists at NASA’s Jet Propulsion Laboratory, where the mission was developed. Then, the rover will begin its trek up Sharp, sampling the rocks and soil as it goes.
Unlike previous Martian rovers, MSL has a nuclear power source, which means it will not have to power down at night or hibernate during low sun angles.
Since lifting off, MSL has sailed toward Mars with no significant difficulties.
Engineers are still unraveling a problem with Mars Odyssey, an older NASA Mars orbiter that is to function as a communications relay during the landing. A reaction wheel failure on Odyssey could mean that probe cannot take on the relay task. However, NASA’s Mars Reconnaissance Orbiter andEurope’s Mars Express will record and relay MSL events within their range as best they can. NASA’s Deep Space Network, a collection of radio telescopes in California, Australia andSpain, will be listening as well.
However, that won’t ease the tension on Earth as MSL barrels toward its destination at more than 13,000 miles per hour and a sequence of pre-programmed events intended to bring the rover to a stop on the surface within seven minutes, using a new landing strategy.
“The team is very excited. They are coming to the end of a long journey. Many of them have worked on on this mission for six, seven, eight years.” said Pete Theisinger, NASA’s JPL-based, MSL project manager. They feel they have done everything they can do to make this successful. That being said, success is not assured. We could have any one of a number of different problems.”
Those could include a sudden Martian dust storm, strong high altitude winds or a sudden change in atmospheric density.
At any rate, MSL will release its inter-planetary propulsion source 10 minutes before landing. The craft’s protective aeroshell will plunge into the Martian atmosphere at an altitude of just under 80 miles. Quickly descending, MSL deploys a parachute, drops its heat shield and activates a radar to track the distance to the ground.
At 1.2 miles altitude, the action grows more intense as MSL exposes a rocket engine for a powered descent. At less than 200 yards from the terrain, MSL deploys a novel sky crane. While hovering under rocket power, the sky crane lowers the rover to the Martian surface on lanyards. If all goes well, the lanyards will be cut and the sky crane will power safely away, leaving MSL ready to for its challenging mission.