PATHFINDER AND SOJOURNER ON MARS

ASTRONET was abroad from July 12 - July 28. Therefore no updates on Pathfinder and Sojourner were possible during that period.

Scientific results

Geology of Mars more like the Earth than the Moon

During the third day or 'sol' on Mars (July 6/7) Sojourner explored the Martian surface. It travelled 36 centimeters and bumped into a rock nicknamed "Barnacle Bill" to 'sniff' it with its APXS (Alpha Proton X-ray Spectrometer).

The first chemical analysis of Barnacle Bill was a "real surprise" according to scientists on the Pathfinder project. The geology of Mars may be much more like the Earth than the Moon. Barnacle Bill has more free silica in the form of quartz in it than expected. Data from Sojourner's APXS suggests that this rock may be a kind of andesite, the second most comon type of lava on Earth. This does not mean however that Barnacle Bill formed by volcanic activity. It can be a sedimentary rock or an impact product caused by a meteorite.

Life on Mars:

Barnacle Bill's 'chemical fingerprints' were alsmost identical to the 12 meteorites found on Earth that probably originated on Mars billions of years ago. In August 1996, evidence of possible fossile lifeforms was found in such a meteorite.

Ancient floods on Mars:

Scientists now have photographic proof that there were once floods on the red planet. Pathfinder landed in a plain where one to three billion years ago a million cubic meters of water was flowing, according to JPL scientist Michael Malin. A flood like that on Earth would have filled the Mediterranean Basin.

The evidence is based on photographs that show boulders attached against each other as if piled up by flood waters. Crusts on rocks indicate a sedimentation process from floodwaters as they receeded, leaving puddles on the rocks.

Pathfinder lands on Mars

Functioning nominally

On July 4, 10:08 a.m. PDST (17:08 GMT) JPL detected a radio signal indicating that Pathfinder had landed on the surface of Mars.

At 11:36 a.m. PDST (18:36 GMT) a signal was received that the lander had fully retracted the air bags and had opened the petals. It appears to be functioning nominally.

To conserve battery power the lander turned off its transmitter very soon after rolling to a stop. The transmitter was automatically turned on again briefly at the end of air bag retraction, lander righting, etc.

Not until 2:06 p.m. PDST (21:07 GMT) was the Earth high enough above the Martian horizon for us to be able to receive the spacecraft's full radio signal.

At 2.20 p.m. PDST (21:20 GMT) the first telemetry data were received from the spacecraft indicating that it's OK and working fine.

The first grainy black-and-white pictures of the surrounding were transmitted to Earth.

First color picture of Mars

At 6:35 p.m. PDST (July 5, 01:35 GMT) this dramatic color picture was sent by Pathfinder's from its landing site in Ares Vallis.

Interactive panorama photograph

Virtual Reality Modela an Animation of the Pathfinder Mission: 360 degrees interactive panorama.

Sojourner rides on Mars!

Pathfinder's small rover, named Sojourner, should have been riding on the Martian surface at 9:00 p.m. PDST (July 5, 04:00 GMT) already. Unfortunately this was delayed by problems. Not fully deflated airbags were in Sojourner's way. JPL tried to lift the petal on which Sojourner is standing and retract the airbag. But that operation took time so could not be solved before the first day on Mars ended. After the airbags were retracted, Sojourner was ready to ride down the ramp.

Before Sojourner could go, problem #2 had to be solved as well. NASA engineers worked all Saturday to fix a communications problem with Sojourner. Only small patches of data could be exchanged between Pathfinder and Sojourner and hence between Sojourner and Earth.

That's one small ride for Sojourner, one giant roll for Robotkind!

On July 5 at 5 p.m. PDST (23:00 GMT) a special press conference at the Jet Propulsion Laboratory was held. NASA engineers told that they began to to receive data sent from the rover to the lander to Pasadena, indicating that their efforts were succesful. On 10:38 p.m. PDST (July 6, 05:38 GMT) Sojourner finally rode down the Mars lander, which has been named the Carl Sagan Memorial Station in honor after the late Dr. Carl Sagan. After an hour of riding, Sojourner stopped because of nightfall on Mars.

On sol 3 (July 6/7) Sojourner bumped into a rock nicknamed "Barnacle Bill" to 'sniff' it with its APXS (Alpha Proton X-ray Spectrometer). On sol 4 (July 7/8) Sojourner made a high resolution photograph from a rock near Barnacle Bill, nicknamed "Yogi" by the JPL team. Visit of Yogi was delayed because photographs showed that front side of this rock sits in a hollow. It was feared that Sojourner might slip into the depression and damage its solar arrays.

On sol 5 (July 8/9) Sojourner approached Yogi from a side where there was no depression. On sol 6 (July 9/10) Sojourner took photos of Yogi from its front and rear camera's. Sojourner went a few centimeters too far and ended up with one wheel perched precariously on the rocks's side. Fortunately Sojourner stopped itself before any damage was done.

On sol 7 (July 10/11) Sojourner should have been backed of the rock. Yet Sojourner remained stuck at Yogi. A problem with timing communications between Earth and Mars forced the whole day to be scrabbed. A command to turn on the receiver on the Pathfinder lander was given 11 minutes too late. The mistake wasn't discovered for several hours and during that time the lander wasn't receiving any instructions. Because of the delay, it was decided to postpone all activities until the next day.

On sol 9 (July 11/12) Sojourner backed of Yogi. Then a new communication glitch occured. It was not until July 12, 00:15 GMT that a signal was received that everything was working alright. On sol 10 (july 12/13) Pathfinder transmitted to Earth one-third of a color panorama image. Because transmission of the picture was given priority, the rover was left idle.

Sojourner was to perform a 7 days primary mission of surface exploration. The mini-rover is performing so well that is expected to move on for at least a month. The primary lander mission will last for 30 days and may also be extended.

Where to look for images and information?

The following Internet sites feature updates on mission activities and also provide Pathfinder/Sojourner photographs of the Martian surface.

At the bottom of this page other useful links are mentioned.

Mars Pathfinder mirror sites

Choose the location nearest you:

International Mirror Sites:

Location	Site Address	Load Capacity (Hits/Day)
ESO - GERMANY	http://mars.eso.org	3,000,000
NASDA - JAPAN	http://mars.tksc.nasda.go.jp/JPL	2,000,000
Web2Mil - URUGUAY	http://web2mil.intercanal.com/mars	2,000,000
Aalborg University - DENMARK	http://sunsite.auc.dk/mars	1,500,000
Visuanet - FRANCE	http://www.visuanet.com/jpl	1,500,000
CNES - FRANCE	http://www-mars.cnes.fr	1,000,000
CSIRO - AUSTRALIA	http://sparkli.tip.csiro.au/mars	1,000,000
CDSCC/JPL - AUSTRALIA	http://tid.cdscc.nasa.gov/mars	500,000
IKI - Moscow, RUSSIA	http://www.iki.rssi.ru/jplmirror/mars	250,000

U.S.A. Mirror Sites:

Public Sector Mirror Sites

Location	Site Address	Load Capacity (Hits/Day)
NASA, AMES - USA	http://mpfwww.arc.nasa.gov	5,000,000
NASA, JPL - USA	http://mpfwww.jpl.nasa.gov	5,000,000
NCSA - National Center for Supercomputer Applications - USA	http://www.ncsa.uiuc.edu/mars	4,000,000
Cornell Theory Center - USA	http://mars.tc.cornell.edu	4,000,000
National Center for Atmospheric Research #1 - USA	http://www.mars.ucar.edu	4,000,000
San Diego Supercomputer Center - USA	http://mars.sdsc.edu	4,000,000
NASA, KSC - USA	http://www.ksc.nasa.gov/mars	2,000,000
NASA, JPL - USA	http://www.jpl.nasa.gov/mpfmir	1,000,000
National Center for Atmospheric Research #2 - USA	http://mars.nlanr.net	1,000,000
Pittsburgh Supercomputing Center - USA	http://www.psc.edu/Mars	750,000
NASA, Lewis Research Center - USA	http://marsmirror.lerc.nasa.gov	500,000
Hawaii Institute for Geophysics and Planetology - USA	http://mars.pgd.hawaii.edu	500,000
The Catlin Gabel School - USA	http://mars.catlin.edu	500,000

Corporate Mirror Sites

Site	Site Address	Load Capacity (Hits/Day)
Silicon Graphics, Inc. - USA	http://mars.sgi.com	15,000,000
CompuServe - USA	http://mars.compuserve.com	10,000,000
SUN Microsystems, Inc. - USA	http://www.sun.com/mars	6,000,000