The Mars Pathfinder Mission
Status Reports - First Week

4 July, 1997, 4:00 pm PDT

Mars Pathfinder successfully landed on the surface of Mars at 10:07:25 a.m. Pacific time, marking NASA's historic return to the red planet after more than 20 years.

The Pathfinder flight team received nearly instantaneous confirmation that the spacecraft had landed from an independent antenna mounted on one of its petals. Detection of the very weak signal, which came as a surprise, also indicated that the craft had come to rest on its base, thus eliminating the spacecraft's next task: to stand itself upright before deploying all of its petals.

Approximately 90 minutes after landing, engineering data indicated that Pathfinder had fully deployed its petals and was awaiting sunrise on Mars to power up. The flight team reported that the lander came to rest about 12 miles southwest of its targeted landing spot and was resting on the surface at a very slight tilt of about 2.5 degrees.

Pathfinder's first low-gain antenna transmission was received right on time at 2:07 p.m. PDT. The transmission contained preliminary information about the health of the spacecraft and rover, the spacecraft's orientation on the surface, data about its entry, descent and landing, and a first look at the density and temperatures of the Martian atmosphere.

Preliminary data from the atmospheric science instrument indicated that temperatures are somewhat warmer than they were in the Viking days of the mid-1970s. Dr. Timothy Schofield, principal investigator of the atmospheric science team, said early data suggested it was about minus 220 degrees Kelvin (minus 64 degrees Fahrenheit) at the landing site.

4 July, 1997, 9:15 pm PDT

The Mars Pathfinder imaging team tonight unveiled the first photograph of Ares Vallis, an ancient water channel that at one time in Mars' early history carried more than 1,000 times the amount of flowing water carried by the Amazon River today. The color panorama, which drew enthusiastic applause at a 6:30 p.m. press briefing, was taken by the lander's Imager for Mars Pathfinder camera -- called the "IMP" -- before the camera was deployed on its mast. The photograph revealed a rocky desert scape with numerous large boulders and mountains on the horizon.

The images were transmitted during Pathfinder's first high-gain antenna transmission, which began at 4:28 p.m. PDT today. Totaling about 120, the postage stamp-sized black-and-white frames also included close-up photographs of the lander petals with the rover sitting in its stowed position in the foreground. Closer examination showed that one of the airbags did not fully retract and had become draped slightly over the edge of the rover's petal.

The Pathfinder flight and rover teams decided to test a new command sequence that would pull the obstructed petal up about 45 degrees, further retract the airbag, then lay the petal down again. The team tested this command sequence before uplinking it to the spacecraft starting at about 7:08 p.m. PDT. Return images from that transmission will be used by the rover team to determine if the "petal move" sequence cleared the petal enough to allow for safe deployment of the rover ramps.
Part of the image data were not received during the next downlink session due to a problem with the Deep Space Network tracking station. The remaining images were scheduled to be retransmitted during the last transmission of the day, which was to begin at 10 p.m. PDT.

If ramp deployment is postponed, the flight team will perform this activity Saturday morning. The rover would then be ready to roll off its ramp and onto the surface of Mars by about 5 p.m. PDT July 5.

NASA-JPL, Saturday, 5 July 1997:

Both ramps on the Mars Pathfinder spacecraft have been successfully deployed, and the rover has been commanded to stand up, and is ready to roll down the ramp. Commands will be sent to command the rover down the rear ramp, and the rover should be on the surface of Mars within the hour.

The Mars Pathfinder rover has just rolled down the ramp off the lander and is now on the surface of Mars. This marks the first time ever that a rover is operated from the surface of another planet.

Stand up was confirmed during the final downlink session of this historic day, and the IMP again provided dramatic pictures of the rover moving down the selected ramp onto the surface of the Red Planet. Clear tracks were visible in the dusty soil, and the rover came to rest about 10 cm from a nearby rock. During the martian night it will deploy its Alpha Proton X-Ray Spectrometer (APXS) onto the surrounding soil for 10 hours, and finally go into "sleep" mode to await the dawn of the next exciting new sol. (Martian day)

5 July 1997, 11:30 pm PDT

After a very tense early morning, when communications with the still stowed Sojurner rover were intermittent and unreliable, the second sol on Mars has turned to triumph.

At approximately 5:00 pm Pacific Daylight Time, confirmation that communications were reliably re-established with the rover was received in Mission Control. Two hours later, during the next downlink session, confirmation was received that the rover deployment ramps were deployed on both sides of the petal on which it rested. After careful analysis of the images provided by the IMP camera, rover controllers decided to deploy the rover off the right-hand ramp. Stand up was confirmed during the final downlink session of this historic day, and the IMP again provided dramatic pictures of the rover moving down the selected ramp onto the surface of the Red Planet. Clear tracks were visible in the dusty soil and the rover came to rest about 10 cm from a nearby rock. During the martian night it will deploy its Alpha Proton X-Ray Spectrometer (APXS) onto the surrounding soil for 10 hours, and finally go into "sleep" mode to await the dawn of the next exciting new sol.

6 July 1997, 11:30 am PDT

Today is a working day on Mars. Both the Imager for Mars Pathfinder and the Sojourner Rover have their work cutout for them today.

First, the Imager will be taking what the Mars Pathfinder team affectionately calls the "monster panorama". It will image the entire 360 degree view using both "eyes" and its red filter. The use of spectral filters enables geologists to get a good idea of the composition of rocks and soil.

The resulting stereo image will also be an important planning tool for Sojourner controllers since they will be able to see in 3 dimensions and plan for the upcoming activities accordingly. The rover driver will be able to put on his stereo goggles and plan the route the rover will be taking to get to the first designated target rock.

This rock, now named "Barnacle Bill" has interesting features that Mars Pathfinder scientists and geologists are eager to see close-up. Today the rover will make a 20 degree turn and back up to this rock in order to place its Alpha Proton X-Ray Spectrometer (APXS) there.

Good news coming out of Mars Pathfinder Mission Control: the data rate at which the lander communicates back to Earth has been increased to 8 kb/sec, an unprecedented communication rate this early in a mission. This will allow more data to be received back here on Earth, and more commands to be sent up to Mars.

7 July 1997, 7:00 pm PDT

What another excellent day. I know you all must be getting tired of hearing that, but we are still exhilirated. The entire Jet Propulsion Laboratory is floating about 3 feet off the ground...

Meanwhile, on Mars: moderate weather yesterday, temperatures hovering around minus 76 degrees Fahrenheit, pressure about 6.8 millibars, steady light winds blowing from the southeast. Afternoon temperatures reached about 10 degrees Fahrenheit. The forecast for today: 10 degrees Fahrenheit, cooling overnight to about minus 105 degrees Fahrenheit.

A little extreme for an Earthly weather report? Perhaps, but with that, scientists on the Mars Pathfinder mission today presented the first weather report from Ares Vallis, an outflow channel on the surface of Mars.

Four days into surface operations, the Mars Pathfinder lander, rover and instruments are performing perfectly and returning a wealth of new data on the rocks, soils and atmosphere of Mars.

"The site is everything we hoped it would be", said Dr. Matthew Golombek, Pathfinder project scientist, at a 10 a.m. PDT press briefing. "We are finding more and more surprises as we look in detail at the rocks and terrain".

Images presented this morning included the first photograph of the lander taken by the rover. The image showed final retraction of the airbags in a very high, puffy clump that blocked most of the lander from view.

Meanwhile, the lander's Imager for Mars Pathfinder (IMP) camera has provided a new perspective on rocks and hills on the Martian horizon now that it is deployed on its mast and photographing the site at an elevation of 1.0 meters (3.2 feet) above the lander, said Dr. Peter Smith, IMP principal investigator from the University of Arizona.

Another new image presented this morning showed Sojourner Truth, the 23-pound rover that has begun to explore rocks around the landing site, as it was gathering data overnight on "Barnacle Bill". This rock, which was about 36 centimeters (1.2 feet) from the rover after it exited the lander, is thought to be about 8 to 10 inches tall, Smith said, and has a very distinctive surface that looks almost as if it is covered with barnacle-shaped objects.

"Here we have proof that Sojourner sort of nestled up and kissed Barnacle Bill", Golombek said as the photograph was presented.

"We have also received data from the rover's first soil experiment. The APXS (alpha proton X-ray spectrometer) is working perfectly", Golombek continued. "However, because we started taking data earlier in the day than we originally planned, the temperatures on Mars were warmer than the detectors liked and we have a bit of noise in the spectra. The team needs an extra day to try to figure out how to subtract that noise out".

The science team said a full chemical analysis of both the Martian soil and Barnacle Bill would be reported at tomorrow's 11 a.m. PDT press briefing. Meanwhile, Sojourner will travel to a larger rock later today, called "Yogi", and study the composition of the soil around it using the alpha proton X-ray spectrometer. Several scientists have commented that a smooth depression of soil around the rock resembles a moat.

Looking south at a pair of sloping hills, called "Twin Peaks", that are about a mile away, Smith pointed out new observations made possible by the fully deployed IMP camera. A depression in the landscape in front of the peaks suggests the presence of a channel. "This is actually a channel back behind those rocks, we're on the edge of a channel", he said.

A high resolution close-up of the Martian soil near the base of the lander also revealed a texture perfectly preserved in the Martian environment. Dr. Jim Bell of Cornell University explained the calibration targets that are used to achieve the true color of the Martian landscape. Color variations allow scientists to identify different types of minerals that are present in the environment. The bright reddish color of the soil, for example, points to the presence of oxidized iron in surface materials.

"The surface of Mars is rusting", Bell said. "We don't know when or how fast it's rusting, but we hope to find these things out. Not all of the surfaces are the same, though. There's lots of diversity and variation in the landscape. We can see some surfaces that are much less red, for example, and more consistent with volcanic rocks".

Building on comments made yesterday by Dr. Ronald Greeley (Arizona State University) about the evidence for floods in this region, Dr. Michael Malin, an interdisciplinary scientist, said the floods were so catastrophic that they would have filled up the Mediterranean basin here on Earth. Evidence, he said, can be seen in the variety of rocks, sediments and "puddles" left in the Martian soil, that materials from the highlands were swept into this flood basin.

A full color, 360-degree panorama of the Pathfinder landing site will be presented at tomorrow's 11 a.m. press briefing, as will data about the composition of the Martian soil and Barnacle Bill.

8 July 1997, 5:15 pm PDT

The first in-situ chemical measurements ever obtained of a rock on Mars - nicknamed Barnacle Bill for its rough, barnacle- like surface - surprised scientists and raised questions about the duration of volcanic activity occurring on Mars in its early formation.

Dr. Rudolph Rieder, of the Max Planck Institute for Chemistry, Germany, and principal investigator on the Alpha Proton X-Ray Spectrometer (APXS) team, reported that Barnacle Bill, an 8-to-10-inch tall rock near the Mars Pathfinder lander, was unusually rich in silicon, which is more characteristic of Earth rocks than Martian rocks. On Earth, volcanic rocks contain significant amounts of free silica in the form of quartz. The rich silicon content puts Barnacle Bill in one of the most common categories of volcanic rocks on Earth, known as "andesites".

"It turns out this rock has some rather peculiar chemical characteristics, which make it very unlike the other SNC meteorites", said Dr. Hap McSween, University of Tennessee, who is a participating scientist on the APXS team. (The SNC meteorites are those found on Earth that are believed to be of Martian origin).

"In particular, it has a very high content of silicon or silicon dioxide (quartz)", McSween said. "It appears that Barnacle Bill falls into a category called 'andesites', which are among the most common volcanic rocks on Earth".

Andesites are mixtures of very fine crystalline and other minerals that are formed through a process known as differentiation. Differentiation is the process by which crustal materials deep within a planet's interior are repeatedly melted and remelted, thereby shaping and reshaping the surface of the planet. Mars today has very few volcanoes and no continental plates like those found on Earth to suggest it was internally active for very long. Barnacle Bill's chemical signature may throw that theory into question.

Today's weather report was similar to yesterday's: at 3 p.m. local Mars time, it was about 5 degrees Fahrenheit, pressure was about 6.74 millibars, with very light winds out of the northwest.

"The weather on Mars is pretty boring", said Dr. Jeffrey Barnes, Oregon State University, who is a member of the atmospheric/meteorological experiment. "Northern summer in the subtropics on Mars is pretty much the same from day to day. Fifty or 60 days from now, we'll start to see dramatic changes with fall".

Atmospheric opacity - or how clear the sky is according to Pathfinder's atmospheric experiment - showed that Mars is moderately dusty up to about 40 kilometers (25 miles) above the surface. The dust appears to be uniformly distributed, and is expected to rise as Mars approaches its dusty season in the fall, Barnes said. The visibility on Mars was estimated to be about 32 kilometers (20 miles) or more, roughly equivalent to a moderately smoggy day in Los Angeles.

The rover's next task later today will be to perform a chemical analysis of the soil around a large rock named "Yogi". Once the soil measurements are taken, Sojourner will then back up to the left side of the rock and begin a chemical analysis using the APXS instrument.

On the fifth day of surface operations since Pathfinder's historic July 4 landing, all spacecraft and rover systems continue to operate extremely well. Pathfinder is returning data at an unprecedented rate of more than 8,500 bits per second and has returned 1,575 images of the Martian surface to date. A 360-degree, color panorama of the Ares Vallis landing site has just been placed on the Mars Pathfinder website.

July 9, 1997, 3 p.m. Pacific Daylight Time

Six days after landing in an ancient outflow channel called Ares Vallis, the Mars Pathfinder lander and rover continue to operate extremely well, returning unprecedented amounts of data during daily downlink sessions.

Yesterday, Pathfinder returned 85 megabits of data on the Martian atmosphere, weather, soil, and a rock called "Barnacle Bill", the first rock on Mars ever to be studied up close and personal. Additional rover and lander imaging was also returned.

Tonight the operations team will perform a low-gain antenna session from 6:30 p.m. - 7 p.m. PDT to acquire data on the health of the lander and rover. A three-hour high-gain transmission will begin later this evening, at 10 p.m. - 1:30 a.m. PDT, at the higher data rate.

The rover has completed its soil analysis of the smooth, moat-like terrain around a large boulder named "Yogi". After completing the analysis, the rover retracted the alpha proton X-ray spectrometer, then conducted a wheel abrasion experiment in which it dug into the soil and disturbed the crusty material as it was turning its wheels. This soil abrasion test is one of many technology and mobility experiments planned for the rover to help engineers understand the dynamics of its mobility on Martian soil for future generations of rovers.

"We used the rover as sort of a bulldozer to push this rock and crusty material up", said Dr. Matthew Golombek, Pathfinder project scientist, at a 1 p.m. PDT press briefing. "Next the rover moved slightly to the left and imaged Yogi with its front cameras, then turned around and imaged the lander with its front cameras. After that, the rover will photograph Yogi at close range. That data will be returned tonight".

Further preliminary analysis of "Barnacle Bill" showed that its texture seems to be consistent with volcanic "andesites", the second most common volcanic rock on Earth, said Dr. Jeff Johnson, of the U.S. Geological Survey in Flagstaff, AZ, who is on the Imager for Mars Pathfinder (IMP) camera team.

Scientists will use reflectance spectra collected by the lander and rover cameras to determine whether the rock, which measures about 40 centimeters (1.3 feet) across and 1.1 to 1.5 centimeters (8-to-10-inches) tall, is a sedimentary rock composed of many different rock fragments, or whether it is "homogenous", which would be consistent with scientists' first impression that it is a volcanic rock.

On a lighter note, Dr. Peter Smith, principal investigator of the IMP team, shared some of his personal insights on what it's like to be living on local Mars time, which means working on a 24-hour, 37-minute clock each day.

"When you say good morning, and the Sun is setting, now that's living on Martian Solar time. When your sunglasses start looking like this (holding up the red-and-blue stereo glasses used to view images in 3-D), that's living on Martian time. When you start admiring strange-looking rocks and giving them names, then telling your friends, that's living on Martian time. When your days are called Sols, and your nights are called days, that's living on Martian time. But when you start laughing at the engineers' jokes, you know you're living on Martian time".

Next on the rover's schedule of investigations are two rocks that appear white or very light in color: "Casper" and "Scubee-Dubee-Doo", located off to the left of the Pathfinder lander.
Among the many images planned in the next week are shots of the Martian sunset and sunrise; pictures of the Martian moons Phobos and Deimos; and pictures of "Twin Peaks", two sloping hills that are about 800 meters (about half a mile) away from the landing site.

The next scheduled press briefing will be held at 12:30 p.m. Pacific Daylight Time on July 10 in JPL's von Karman Auditorium.

10 July 1997, 4:15 p.m. PDT

Seven days into surface activities on the Mars Pathfinder mission, all spacecraft systems and instruments are continuing to perform well. The rover remains in excellent health and appears to be driving a little bit faster when left to its own devices than when it receives instructions from Earth.

"Basically the rover overshot its target rock, Yogi, by a little bit last night", explained Dr. Justin Maki, of the University of Arizona, who is a member of the Imager for Mars Pathfinder (IMP) team. Maki showed a movie of Sojourner as it approached the large boulder and began to climb up its side with one wheel. In this type of dead reckoning, the rover performed just as it should have, which was to back off the rock once it knew the rock was in the way, then turn and move away from the object. Although the rover travels about 1 centimeter per second (about 2 feet per minute), it appeared to be moving a little bit faster on its own.

The science team targeted the left side of Yogi for alpha proton X-ray spectrometer study because it appears to be dark and free of Martian dust. However, that side turned out to be tricky for the rover because of the rock's uneven contours and the slight depression in the soil beneath the rock. The rover team will instruct Sojourner to attempt instrument placement again tonight. Multiple attempts to position the science instrument were anticipated, making this repeat attempt nothing out of the usual.

The navigation team also announced the Ares Vallis landing site coordinates today as 19.33 degrees north latitude, 33.55 degrees west longitude.

Dr. Carol Stoker of NASA Ames Research Center showed some of the virtual reality products that her team is beginning to produce from the Pathfinder data during today's press briefing. Data from the lander camera's stereo images are overlain with terrain models to create the three-dimensional perspective, which can then be rotated in any direction on any plane on a computer screen. The 3-D perspective will be very useful to the science team in planning rover traverses and in analyzing data.

Dr. Julio Magalhaes, also of NASA Ames Research Center, a team member of the atmospheric structure instrument/meteorology package (ASI/MET) on board the Pathfinder lander, reported that atmospheric temperatures in the upper atmosphere of Mars are extremely cold. The science team has recorded temperatures at an altitude of 80 kilometers (50 miles) above the surface as minus 171 Celsius (minus 275 degrees Fahrenheit). In the lower atmosphere, between 60 km to 13 km (37 to 8 miles), the temperatures are warmer and very close to those recorded by the Viking landers of the mid-1970s.


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Status reports prepared by:
Office of the Flight Operations Manager
Mars Pathfinder Project
NASA Jet Propulsion Laboratory
California Institute of Technology
Pasadena, CA 91109


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EDT = PDT + 3 hrs. = UTC - 4 hrs. Venezuelan Time = UTC - 4:30 hrs.

Updated: July 23 '97

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