[meteorite-list] Mars Science Laboratory: Big Wheels on A Red Planet

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon Jan 23 18:04:12 2006
Message-ID: <200601232131.k0NLVMe17154_at_zagami.jpl.nasa.gov>

http://www.space.com/businesstechnology/060118_msl_wheels.html

Mars Science Laboratory: Big Wheels on A Red Planet
By Leonard David
space.com
18 January 2006

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.
Received on Mon 23 Jan 2006 04:31:21 PM PST