Mars Science Laboratory: Big Wheels on A Red Planet

PASADENA, California - Make way Spirit and Opportunity - big daddy is coming!

The next wheels on the red planet will belong to the Mars Science Laboratory (MSL)--a huge step in how that planet is further poked, probed, and more fully plumbed for new information.

MSL is a huge chunk of machinery. At liftoff in September 2009, it will carry the largest, most advanced set of instruments for on-the-spot science duties ever dispatched to the martian surface. The nuclear-powered rover is being designed to assess whether Mars ever was, or is still today, an environment able to support microbial life.

On one hand, MSL closes out an intensive period of surveying Mars...while setting the stage for an aggressive agenda of future robotic Mars exploration that ultimately leads to the planting of the first footprints on the red planet.

Chemist on Mars

"This is a good mission to end the decade on, but also the stepping stone for the next 10 years after that," said MSL Project Manager, Richard Cook, here at the Jet Propulsion Laboratory (JPL). "It's kind of a good transition mission."

Cook said the MSL team now consists of nearly 200 people, with everyone benefiting from years of plotting out the vehicle's design and how best to build and land the mega-rover. "We've looked at a lot of the technical issues and, hopefully, have our arms around a lot of them," he told SPACE.com.

The still going strong, golf cart-sized Mars Exploration Rovers (MER)--Spirit and Opportunity--have often been characterized as field geologists.

"MSL is like a chemist on Mars," Cook said. "From a technological point of view, people will be fairly amazed by both the size and the capability of MSL. It will certainly be able to drive circles around MER to a certain extent. Not speed wise. But from how long MSL can go every day...it will be able to do much more," he added.

Single, go-it-alone rover

The MSL mission, including cost of a launcher, is in the range of $1.5 billion, Cook said. Under consideration to boost the Mars Science Laboratory is either the Delta IV or the ATLAS V rocket.

The primary MSL launch/arrival period is scheduled to extend from September 15 through October 4, 2009. That equates to a rover arrival period at Mars starting on July 10, 2010 and lasting until September 22, 2010.

Once down on Mars in 2010, MSL is to demonstrate long-range mobility on the surface of the red planet of about 3 to 12 miles (5-20 kilometers) for accomplishing a range of exploration tasks.

There will be no doubling-up on Mars like Spirit and Opportunity. MSL is a single, go-it-alone rover tipping the scales at about 1,708 pounds (775 kilograms). And that's where the Mars Reconnaissance Orbiter (MRO)--now outbound toward the red planet--will provide a big step up, Cook advised.

"We're going to be able to learn much more from orbit. And I'm confident that in the end we'll pick out the best MSL landing site. If you only have one to send, you send it to the best place you can on Mars," Cook said.

Plutonium-powered

While the cruise to Mars, as well as descent onto the planet mirrors past missions, the landing part of MSL is new.

Mars Science Laboratory is to use precision landing techniques, steering itself toward the martian surface similar to the way the space shuttle controls its entry through the Earth's upper atmosphere. In this way, the spacecraft would fly to a desired location above the surface of Mars before deploying its parachute for the final landing.

Given that capability, the plutonium-powered MSL will land within a 12-mile (20-kilometer) ellipse. NASA is also considering a solar power alternative for the rover that could meet the mission's science and mobility objectives.

"It's not the same mission with the solar arrays. It would have to be a conscious decision on NASA's part to say we want to change the basic parameters of the mission," Cook said.

MSL's arrival on Mars will not rely on airbags.

"While airbags are certainly great they have certain limitations," Cook said, explaining that the future rover package is to be lowered onto Mars via an engine-firing "Sky Crane". This never-flown-before concept will lower the upright and ready-to-roll MSL on a tether to the surface.

Wringing out the risks

"Obviously, the entry, decent and landing is a very big challenge. I think we're going down the path...retiring a lot of the risk in the technology. But there's still the whole validation process...and still a lot of effort ahead to make that work," Cook said.

While putting all your Mars eggs in the one and only MSL basket would appear to the squeamish a risky approach, consider the Cassini at Saturn mission now underway, as well as the one and only Mars Pathfinder project that unloaded the tiny Sojourner rover onto Mars in 1997.

There's a lot more attention to details, best practices in management style, and a tightening of review processes in spacecraft missions of today, advised Brian Muirhead, JPL's Chief Engineer. For example, MSL's Sky Crane system, he pointed out, has been put through layers of review..."and it stands up."

"The thing that impacts all this is the cost. As you provide more rigor to wringing out the risks the cost goes up," Muirhead said. "And nobody should be surprised at that."

Muirhead told SPACE.com that now underway is a strengthening of the role of engineering across NASA. Outreach beyond JPL to NASA field center expertise is taking place, as well as vice versa, with NASA centers able to request JPL engineering know-how.

"That's a big win for the whole agency if we can do more of that," Muirhead said. As has been noted over the years, "we're in a one strike and you're out business. That's why everybody has to be paying attention."

Piecing it together

At present, MSL project officials don't see any full-up and costly hover tests of the Sky Crane here on Earth. Pieces of the system, like the parachute and Viking-class retro-rocket engines on the Sky Crane framework can be individually tested. "We think we can do a pretty good job of piecing it together," Cook emphasized.

Along with the "reinvented" Viking-class engines from the 1970s, another big enabler for MSL is a better radar system than what's been flown before.

On the challenging work agenda, Cook also said, is MSL's state-of-the-art instrument package.

Two biggies on the tough-to-do list of devices to be toted to Mars on MSL are the Sample Analysis at Mars (SAM) instrument suite that will take up more than half the science payload onboard the wheeled rover. SAM features chemical equipment found in many scientific laboratories on Earth.

An additional tough assignment is readying MSL's Chemistry & Mineralogy X-Ray Diffraction/X-Ray Fluorescence Instrument (CheMin) that can identify and measure the abundances of various minerals on Mars.

"Both are super-complicated...taking very sophisticated lab experiments and compressing them down smaller to fit into a very tight space...as all rovers tend to be," Cook said.

Lengthy drives

Where exactly MSL will be targeted to land on Mars is still-to-be-determined. NASA's en route MRO and its zoom lens scouting camera system will help discern top landing site candidates.

"The number of interesting places goes up exponentially as you decrease the size of the landing footprint" which MSL will do, Cook said. "They'll be many more places of interest than I suspect scientists can ever hope to really look at in any detail. So they'll have to do some culling out before they come back to us," he said.

MSL can chalk up several hundred meters of driving a day. While the rover is to be targeted to an initial, sure-to-be-safe touch down locale, its range can permit lengthy drives to exotic spots on Mars in terms of getting to varying types of geologic terrain.

With Spirit and Opportunity still wheeling and dealing with Mars--each far exceeding their original 90 martian day warranty--what are the expectations for a live long and prosper MSL?

This hefty rover is being crafted to have a primary mission time of one martian year - or at least 687 Earth days.

Cook said that testing of rover components is being geared to a two-year mission. "If it lasts for five times that...I wouldn't be all that shocked. But we certainly don't want to go into it thinking that way," he said.