Mars Rover to Use Alternate Ramp

The Spirit rover's path to the surface of Mars remains blocked by airbags and it will have to turn and use a secondary ramp, but while still parked it has revealed the presence of minerals that may have formed in a lake believed to have once filled the landing site, NASA (news - web sites) said Friday.

The first indications of the geologic makeup of Spirit's surroundings could support theories that liquid water persisted on the surface of the planet during its ancient past, providing an environment conducive to life.

Scientists stressed that finding the minerals, called carbonates, does not immediately prove the lake theory. Instead, the carbonate dust could have formed through interactions with the tiny amounts of water vapor found in the martian atmosphere.

"We've got a bunch of ideas and we don't know which one is right yet," said Steven Squyres, of Cornell University, and the mission's main scientist. Another NASA spacecraft previously has spotted carbonates from orbit as well.

Spirit remained parked on its lander, nearly a week after safely arriving on Mars.

Engineers said the six-wheeled robot won't roll off the lander and onto Mars until late Jan. 15 or early Jan. 16 at the earliest.

A last-ditch effort failed to draw in two sections of the air bags that cushioned Spirit's landing. The sections of tough fabric still block the safest path the rover could follow to the surface.

Engineers will now command Spirit to turn in place 120 degrees to its right and roll off a secondary, unobstructed ramp, said Matt Wallace, mission manager.

While immobile, Spirit has continued to carry out science work, including snapping a sweeping panorama of its surroundings with its color camera. NASA has received 73 percent of that 360-degree view as the rest trickles in, said Albert Haldemann, deputy project scientist.

Spirit also has begun measuring the temperature and makeup of the rocks and soil around it with its mini-thermal emission spectrometer.

The instrument sees infrared radiation — heat — emitted by objects, including rocks and soil. It can measure that radiation in 167 different "colors," information that scientists use to deduce the mineralogical composition of what Spirit sees.

Determining what the rocks and soil are made of opens up the martian geological history book they contain, and allows scientists to begin in earnest the job of picking targets they want Spirit to examine up close, once it rolls off its lander.

On Friday, scientists displayed the first of that data, showing off psychedelically colored views of the surface of Mars.

The rover also completed the first step in standing up to its full height, unfolding its two front wheels and locking them into place.

The $820 million Mars Exploration Rover project includes a second, identical rover named Opportunity, which is expected to land on the Red Planet on Jan. 24.

NASA sent the two robotic geologists to prospect for evidence that Mars may have been a wet world conducive to life in its ancient past.

That connection is something like an ISDN speed or so, I thought. Less than 200K a minute, at best.

The following Wednesday Reuters article talks about "stickiness" causing a problem in pointing the main antenna at Earth, but says it was corrected Tuesday evening.

NASA Scientists Want Mars Rover 'Down in Dirt'

Wed Jan 7, 6:06 PM ET

By Gina Keating

PASADENA, Calif. (Reuters) - The U.S. robotic rover on Mars has suffered some minor technical problems that will delay by three days its planned landing pad roll-off to search for signs of water in an arid rock-strewn crater, officials at NASA (news - web sites)'s Jet Propulsion Laboratory said on Wednesday.

The rover Spirit now is set to drive onto the rocky, wind-scoured surface of Mars next Wednesday, or "sol 12" in Mars time, a development that has scientists "champing at the bit" to "get down in the dirt and take some measurements," geologist Ray Arvidson said.

Spirit is equipped with an array of cutting-edge scientific tools on its movable arm that will allow the NASA team to take the closest look yet at the mineral composition of the Martian soil and landscape.

Arvidson said the science team was studying high resolution color photos taken by the rover's twin panoramic cameras, as well as data from a mass spectrometer to determine where the rover would go first in its search for signs of water in the rocks and soil. The team chose to land inside the massive Gusev Crater because they believe it once held a lake.

"Once we egress we want to stop and drop and make measurements that have never been made before," he said. "There's a lot to do in the immediate vicinity of the lander just to see what is there."

Meanwhile, NASA administrators took time during "sol four," the rover's fourth day on the red planet, to dedicate the rover's landing site to the memory of the crew of the space shuttle Columbia, who perished last February when the spacecraft broke apart while re-entering Earth's atmosphere.

"In our personal lives in moments of great joy ... we often remember and long for lost members of our family," Firouz Naderi, Mars program manager, told reporters on Wednesday. "And so it is in this moment of triumph in our professional lives that we remember members of our NASA family that we lost with the space shuttle Columbia."

NASA engineers designed a plaque for the rover's main antenna memorializing the seven-member Columbia crew, and the landing site was named the Columbia Memorial Station.

Two glitches in Spirit's otherwise flawless performance have delayed the rover's first drive off the lander by three days. On Tuesday night, NASA engineers fixed a "stickiness" that hampered their efforts to point the rover's main antenna directly at Earth.

The team planned to retract two airbags that blocked the six-wheeled rover's exit path with a "lift and retract" maneuver on Wednesday night, or sol five, Art Thompson, rover technical lead, said.

Another NASA team was keeping an eye on a retreating dust storm that could cause problems for the Jan. 25 landing of Spirit's twin, Opportunity, which is headed for the opposite side of the planet.

Spirit is the fourth probe to successfully land on Mars, following in the footsteps of two Viking landers in the 1970s and the Pathfinder mission in 1997.

Here's onfo on communications from Mars and the rovers to earth.

It's a "dog" circuit-wise,, but...

FRom the JPL NASA site

http://marsrovers.jpl.nasa.gov/mission/comm_data.html

How Fast and How Much Data the Rovers Can Send Back

The data rate direct-to-Earth varies from about 12,000 bits per second to 3,500
bits per second (roughly a third as fast as a standard home modem). The data
rate to the orbiters is a constant 128,000 bits per second (4 times faster than a
home modem). An orbiter passes over the rover and is in the vicinity of the sky
to communicate with the rovers for about eight minutes at a time, per sol. In
that time, about 60 megabits of data (about 1/100 of a CD) can be transmitted
to an orbiter. That same 60 megabits would take between 1.5 and 5 hours to
transmit direct to Earth. The rovers can only transmit direct-to-Earth for at most
three hours a day due to power and thermal limitations, even though Earth may
be in view much longer.

Mars is rotating on its own axis so Mars often "turns its back" to Earth, taking
the rover with it. The rover is turned out of the field of view of Earth and goes
"dark", just like nighttime on Earth, when the sun goes out of the field of view of
Earth at a certain location when the Earth turns its "back" to the sun. The
orbiters can see Earth for about 2/3 of each orbit, or about 16 hours a day. They
can send much more data direct-to-Earth than the rovers, not only because
they can see Earth longer, but because they can operate their radio for much
longer since their solar panels get light most of the time, and they have bigger
antennas than the rovers.

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