[meteorite-list] Landing Sites for 2003 Mars Exploration Rovers Mission Identified

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:48:13 2004
Message-ID: <200110191853.LAA09232_at_zagami.jpl.nasa.gov>

http://www.space.com/missionlaunches/missions/mars_2003_landings_011019.html

Landing Sites for 2003 Mars Exploration Rovers Mission Identified
By Leonard David
space.com
19 October 2001

PASADENA, CALIFORNIA -- Scientists have produced a short list of "sweet
spots" on Mars.

A clear consensus of experts have now identified four sites from which to
select the final two landing spots for the Mars Exploration Rovers now being
built for launch toward the red planet in mid-2003.

And the winners are, in no ranking order: Melas, Hematite, Gusev, and
Elysium (Athabasca Vallis).

But picking places that are scientifically rewarding, but also sane and
safe-to-land locales is no easy task. It is a delicate dance between Mars
explorers keen on maximizing science return and stick-to-the-book engineers
that sweat the technical details of entry, chancy landings on rough terrain,
and the long-term survival of wheeled robots geared to inspect a world of
extremes.

Show and tell time

In a packed room of scientists, program managers, software specialists, and
spacecraft builders, it was show and tell time.

The scene is the Mars Landing Site Selection Workshop, held here October
17-18. Those gathered are assigned the duty to reduce the number of possible
landing places for the dual rovers. Among the sites: Melas Chasma, Central
Valles Marineris, Isidis Basin, the craters Gusev and Gale, and Eos Chasma.
Each area is steadfastly backed by a "science spokesperson" making the case
that their piece of Martian real estate is where to go.

"The real problem is that we've got a bunch of really exciting sites. It's
not that they are all boring and not going to offer scientific potential,"
said John Grant, co-chair of the Landing Site Steering Committee from the
Center for Earth and Planetary Studies at the Smithsonian's National Air and
Space Museum. "We've got some really good ones. There's going to be some
hard decisions to make," he told SPACE.com.

Science and safety

This week's meeting is part of a step-by-step process to whittle down a
large number of Mars landing targets. Around April of next year, a final
selection of the two sites will be determined. "I think we're on a
reasonable track to do that," said Matt Golombek, a Mars scientist at the
Jet Propulsion Laboratory here, and also a co-chair of the Landing Site
Steering Committee.

Finding the sweet spots on Mars - large ellipses within which the rovers
land and are exciting for scientists - is also a game of pinning down
landscape that is flat, smooth, and non-threatening to the rovers. "Everyone
has to work together to make sure we get the best site for the science that
is absolutely safe, as best as you can determine," Golombek said.

The just chosen four sites -- Hematite, Melas, Gusev, and Elysium (Athabasca
Vallis) - will now get extra-special scrutiny by Mars rover engineers as
well as scientists. More images of these sites are to be taken by the now
orbiting Mars Global Surveyor.

Additional data is likely to be accumulated by the Mars Odyssey, set to
arrive at the planet next week, Grant said

Getting down and dirty

The Mars 2003 missions mimic that of the Mars Pathfinder project in 1997.

After aeroshell entry into the thin Martian atmosphere, a parachute deploys
to slow the spacecraft. Then small rocket engines fire to slow the vehicles
down prior to impact. Airbags inflate and then cushion the delicate rovers
as they bounce over Martian landscape. The Mars Exploration Rovers (MER) are
individually launched and go through the same nail-biting sequence called
entry, descent, and landing.

After touchdown on Mars, the rovers will each have far greater mobility than
Sojourner, the cute and cuddly craft that rolled about a small area. These
bigger Mars Exploration Rovers (MER) can trek up to 330 feet (100 meters),
per Martian day. That is almost as far in one Martian day as the Sojourner
rover did over its entire lifetime.

Each MER will drop atop different regions of Mars. They are built to scout
about and be on the lookout for evidence that liquid water may have been
present in the planet's past. Rocks and soils will be analyzed with a set of
five instruments on each rover. They are collectively known as the Athena
payload.

Starting in January 2004, MER surface operations will last for at least 90
Martian days. Depending on the health of the twin rovers, science collection
work could continue longer.

Balancing act

Engineers are busy at work on readying the Mars rovers for launch in 2003.

"From our point of view, we're ahead on some things and behind on others.
But we think we have the time, the energy, and the resources to pull it
off," said Robert Manning, JPL manager for systems engineering of the Mars
2003 rovers. "This has a similar feel as we had on Mars Pathfinder. We learn
some new things, change or modify this. We're testing and building equipment
as fast as we can. It's an amazing production and a lot of parallel work,"
he said.

"We're at a point where the pencil sharpening is done and now physics and
testing is giving us information of what to do next," Manning told
SPACE.com.

While a number of constraints about the rovers dictate where they will
ultimately land, the balancing act between science and engineering
requirements is a friendly tension.

"Everyone knows the importance of getting down safely and working," said
Mark Adler, Mars Exploration Rover Deputy Mission System Manager at JPL.
"We're going to pick two sites that are safe enough and that have the best
science that we can get," he said.
Received on Fri 19 Oct 2001 02:53:58 PM PDT