The 2,000-pound, six-wheeled mobile space laboratory and sister components designed to land it safely on the Red Planet’s surface later this year were on display in the facility’s 9,600-square-foot “clean room.” Here, engineers, scientists and reporters alike must remain covered head-to-toe in special white suits to prevent the interplanetary spread of earthly bacteria spores.
Curiosity continues the search by previous rovers Spirit and Opportunity for evidence that past or present conditions on Mars could sustain life, but rover design changes and new equipment — including a rock-zapping laser, onboard chemistry lab and self-sustaining nuclear power generator — promise an increased scientific payload.
“This time we’re carrying much more capabilities, including an analytical lab instrument suite that can look for [arrangements of carbon-based molecules that are] the building blocks of life. We’re looking for the hydrocarbons that would tell us whether the conditions for life existed, and that helps us cement the story of what kind of past Mars had,” said Peter Illsley, a lead rover engineer.
At about 10 feet long, Curiosity is twice the size of both Spirit and Opportunity. And though its sturdy aluminum chassis is relatively lightweight, Curiosity is also about five times as heavy, partially because it carries its own plutonium-based power source.
Spirit and Opportunity, which drew power from solar panels, were limited to exploring near the planet’s equator, where sunlight levels remain high enough to provide heat and power for the vehicles. Curiosity is free to explore landing sites much further away from the planet’s center, but like previous orbiters will communicate with Earth via satellites orbiting Mars.
The new rover’s size and weight also required scientists to abandon Spirit and Opportunity’s airbag landing system for a parachute mechanism that will land Curiosity on its 20-inch aluminum wheels.
Curiosity will launch sometime between Nov. 25 and Dec. 18 from Cape Canaveral, Fla., carried by rocket to Mars for an August 2012 landing, protected inside a heat-shielding Apollo-style capsule made of material similar to the tiles that insulate the space shuttles.
After entering the Mars atmosphere, a parachute will deploy to slow travel below supersonic speed before the rover and an attached “descent stage” vehicle break away from the capsule, said Jennifer Knight, lead engineer for the “cruise stage” and aerospace integration.
The descent stage vehicle is an attachment with eight rocket engines that will further slow the rover’s journey to the surface of Mars to the point that cables can gently lower it into place.
“The descent stage will act as sort of a hovercraft or jetpack for the rover. It’ll slow it down and actually lower the rover on three cables, down about seven meters. It’ll then touch down on the surface of Mars right on its wheels,” said Mark Yerdon, the project’s descent stage integration lead. “After it touches down, the rover will cut the three cords, and the descent stage will fly away and eventually crash” far from the landing site.
Once safely on the ground, Opportunity offers scientists many different options for analyzing the chemical makeup of the planet.
Scientists will use onboard cameras to identify rock formations, then test their chemical composition with a laser blast to determine whether it’s worth moving in for a closer look.
“We kind of burn a hole in the rock, and looking at the light that’s created tells us about the composition of the rock. If it looks different or interesting, then we’ll drive up with the rover, put the arm out and analyze it. If those instruments are able to confirm what the laser saw, and if it still looks good, then we drill,” explained chief project scientist John Grotzinger.
Curiosity’s robotic arm also has a drill sampling system that extracts powdered rock samples, which are then drawn into the body of the rover for chemical analysis. Capabilities include exposing rocks to vaporizing heat in order to extract and identify organic compounds.
The rover’s drilling capabilities can bore about five millimeters into rock.
But while the laser offers scientists more than a decade of use, Grotzinger said the rover is designed to remain functional for only 72 drill samples — hence the check, double-check process before drilling.
On the ground, the rover can roll over obstacles two feet high and travel at a maximum speed of about two inches per second —up to about 12 miles in its two-year life expectancy — but scientists will probably take it slower.
“You have to be careful. There’s no service station if you blow a tire,” said Illsley.
The rover comes equipped with a hazard avoidance cameras and software that will automatically stop the vehicle if an obstacle ahead poses a threat of damaging the vehicle, and its six-wheel drive capability also “can turn the rover in place, literally on a dime,” he said.
JPL engineers will continue electrical component tests on the rover and coordinating components for several weeks before the segments are shipped to the Kennedy Space Center for final assembly in that facility’s clean room.
Those wishing to view a live “Curiosity Cam: video feed of work in progress can visit www.ustream.tv/nasajpl.