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Text Archive 1997-1999




1999-12-11 Mars Surveyor Polar Lander is definitively considered lost:

Regardless of previous checks and double checks experts review all steps of the mission procedure.

Meanwhile on Mars.









04. January 1999
Into the Cold.



Mars Polar Lander, the second of the Surveyor 98 probes, was launched 1999-01-03, 20:21 UTC from Cape Canaveral/Florida/USA. The lander shall touch down near the egde of Mars' southern polar cap on 1999-12-03.

On its descend the lander will eject two microprobes. These are driven into the ground after a high speed fall of around 200 meters (656 feet) per second. In a depth of around 2 meters (7 feet) they should check for traces of water ice and will measure the subsurface temperature. Polar Lander will take images while descending and on the ground. The probe is going to observe the weather conditions of the near polar region. A robotic arm will collect soil samples. The 2 meter (7 feet) arm should be able to dig furrows to obtain subsurface samples. These samples will be analyzed for traces of water and volatiles like oxygen and carbon dioxide. Environmental sounds of ten seconds length will be recorded with a microphone.
A prelanding sound sample (WAV 111K, 10 sec :)








12. December 1998
Expanding the team.



Mars Climate Orbiter, the first of two probes of the Surveyor 98 project, was successfully launched 1998-12-11, 18:45 UTC from Cape Canaveral/Florida/USA. The orbiter shall reach Mars 1999-09-23 where it subsequently goes through a 2 month aerobraking phase. In the beginning of December 1999 it is assigned to support Mars Polar Lander, the second part of the Surveyor 98 project. In March 2000, Climate Orbiter will start its nearly two years mapping mission. Aboard are two color cameras for surface mapping and a Pressure Modulator Infrared Radiometer to measure atmospheric properties like temperature, water vapor and dust.

Mars' northern polar cap seems to consist of less water ice than expected. Global Surveyor's laser altimeter measured the height of the surface features in the northern polar region during Spring and Summer 1998. The northern ice cap has a diameter of around 1.200 kilometers (750 miles), an average thickness of around 1 kilometer (0.65 miles) with a maximum thickness around 2.9 kilometers (1.8 miles). Deep fissures in the cap can reach a depth up to 1 kilometer (0.6 miles). The total water ice volume bound in the northern cap is estimated at around 1.250 cubic kilometers (300 cubic miles). This is less than half of the ice cap over Greenland. Some observations suggest that the present ice cap is only a small rest of an up to ten times larger body of water in the past. Parts of the missing water may be found in the smaller southern polar cap and below the ground, possibly in a form similar to the Siberian permafrost. The northern ice cap is lying in an area much deeper than the surrounding terrain. This huge depression might be an indication for an old very large impact crater.

Surveyor 98 Polar Lander is scheduled for launch on January 03, 1999.

Japan's Planet B/Nozomi atmosphere probe will leave its speed building Earth/Moon orbit around December 20. for its travel to Mars where it shall arrive October 1999.

Global Surveyor Mars mapping spacecraft continues aerobraking phase.








14. November 1998
14 Nations - 1 Probe.



European Space Agency with its 14 member states has decided to join the exploration of Mars with an own spacecraft. Mars Express is scheduled for launch with a Soyuz launcher in June 2003 and shall reach Mars orbit end December 2003.
Among the science objectives are sub-surface radar search for water, measurement of atmospheric and surface temperatures, atmospheric gases and dust and the observation of their distribution and changes. Other objectives are surface high-resolution mapping, examination of surface composition and measurement of interaction between the solar wind and the interplanetary plasma with the upper atmosphere and exosphere.

A lander unit called Beagle 2 is planned to be on Mars Express. Its tasks will be searching for chemical signs of previous life on Mars and taking images of the surface.
Mission costs are comparably low with estimated 150 million ECU.

Surveyor 98 orbiter will be launched December 10, 1998.

Global Surveyor Mars mapping spacecraft continues aerobraking phase.








05. July 1998
Konnichi wa Mars.



One year after the landing of Pathfinder Japan has successfully launched the Mars probe Planet-B on 1998-07-04. The probe shall reach Mars mid-October 1999 and will turn into a two year orbit. There it will examine the outer layer of the martian atmosphere, especially the influence of the solar wind on the ionosphere. The results will help to determine the properties of the magnetic field and allow conclusions on the inner building of Mars core. A strong magnetic field would indicate that Mars may still have a a fluid core like Earth. The probe will also search with sonic impulses for traces of water under the martian surface. Planet-B will have opportunities to take close-up images of the moons Phobos and Deimos.

Planet-B is of light-weight design to be launched with Japan's 2-ton M-5 launcher. The probe only carries around 280 kg (620 lb.) of fuel and has to take a gravity induced speed acceleration by Earth's Moon. This acceleration phase around Earth and Moon will take around five month before the probe goes on its ten month journey to Mars. The costs of the mission are said to be around 85 million US Dollars.








20. April 1998
Changing face



Viking image of Mars face           Global surveyor image of Mars face
First image from Viking orbiter, second image from Global Surveyor orbiter

As we learn more about Mars, our perception of the planet changes. 22 years ago the Viking orbiter sent images to Earth from a Mars region named Cydonia Mensae (40.8N 9.6W). On few of the images was a big formation that reminds one strongly on a human face. Many people interpreted this as a possible artificial sign of intelligent life. This month the orbiter Global Surveyor took some images of that region. While the best resolution from the Viking orbiter was a pixel covering 45 meters, the resolution of Global Surveyor's image is ten times higher with a pixel covering 4.3 meters. This would show a big car as a point. NASA explained the reduced ground detail in the new image with haze or fog over the area typical for this time of the year in the northern hemisphere. What looks on the Viking image as a face appears now as a natural formation of scattered rocks.
Where information is missing, imagination completes.



Simulation sequence how Mars travels 
behind Sun


From May 11 to early May 14, 1998, Mars will be hidden from us behind the Sun. At that time observation and radio contact to Mars orbiter is not possible. Its conceivable that in the future a relay satellite on a different orbit will maintain communications at such constellations.








16. January 1998
The next generation.



Two new probes will be launched to gather more data on Mars.
Mars Surveyor 98 Orbiter will start December 1998 and should reach Mars in September 1999. The orbiter will examine Mars' climate for two years. After that time it should work for additional three years as a communication relay station for other missions.
Mars Surveyor 98 Lander will start January 1999 and should land on Mars in December 1999. Its destination is the southern polar region. Before it descends it will separate two little probes. These will descend at much higher speed. The little probes will penetrate the surface to a depth of about 2 meters (7 feet) to detect traces of water ice beneath the surface. The lander will take images while descending through the atmosphere. On the ground it will investigate atmospheric conditions and volatiles.

The Global Surveyor orbiter is still in its speed braking orbit. In mid-may radio contact to Mars will be interrupted for a while because the Sun will be positioned between Earth and Mars.








06. November 1997
Two steps forward, one back.



Pathfinder: Last signal was received on October 07, 1997. The extended mission phase is over, attempts to start communication again failed. One explanation is that Pathfinder's electrical appliances have been cooled down below working temperature because they have not been in use for some time. However there are a lot of image and scientific data from Pathfinder left to be processed and evaluated.
Without further instructions the little rover 'Sojourner' will drive back to the Pathfinder lander. There it will drive continually around it according to its program to get closer in communication range but not to bump into the lander.

Global Surveyor: It has been discovered that one of Surveyor's two solar panels does not stay fixed in the critical aero braking phase through the atmosphere and that it has moved beyond its normal path of movement. Therefore the orbiter has been sent in October on a save orbit without aero braking, in order to reduce the danger of any unpredictable results and to work out a plan to meet the new requirements. That time was also an opportunity to make a few images with Surveyour's camera.
Global Surveyor is now on a new orbit around Mars which greatly reduces the forces applied on the orbiter during the aero braking phase. As a result the speed braking mission phase is extended to a time between 8 and 12 months and the final mapping orbit will be another one than the originally planned.

The findings of these occurrences should be a great step toward development of error trapping systems for an area without repair workshops.









04. October 1997
Broken links



Pathfinder: No signals from the lander were received from September 27, 1997 till October 01, 1997 . Attempts to start communication again over the low and high gain antenna were not successful. Switching to Pathfinders auxiliary transmitter on 01. October finally results after some time in a 20 minute long response signal. On 02. October again a signal was received. Another attempt to get a signal over the auxiliary transmitter on 03. October failed. It is supposed that the problems are connected to the degradation of the battery and Pathfinder has therefore to rely solely on its solar panels. A signal was sent to put the lander in an operation mode which is appropriate for a non-operational battery and the communication problem is under scrutiny.

Global Surveyor: First results from magnetometer measurements made during speed braking phase indicate a stronger than expected global magnetic field on Mars. This means that Mars once had or probably still have a core of moving molden metal which gives hints on the geological history of Mars.









12. September 1997
Global Surveyor
enters Mars orbit.



After a flight of 750 million kilometers (465 million miles) Global Surveyour reached Mars today on September 12, 1997 around 01:15 UTC (=GMT).
On arrival the orbiter slowed down by firing its main rocket engine for 22 minutes and get caught by Mars gravity field. This operation bent Global Surveyor's flight path to a big ellipse around Mars circulating the planet every 45 hours. For the next four months the orbiter will gradually slow down by atmosphere resistance on the near Mars point of its elliptical path. During this period its average distance decreases to its final nearly circular 2 hour orbit in a height of around 400 km (=250 miles).

On Mars' surface the Pathfinder project is in good condition and working in its extended mission plan.









05. September 1997
Global Surveyor -
7 days remain to Mars



Surveyour's declining orbits around Mars

On September 12, 1997 around 01:00 UTC the orbiter Global Surveyor should reach Mars. There it will slow down to get caught by Mars' gravity field. Global Surveyor will turn in an elliptical orbit with a near point in the atmosphere and its farthest point up to 56.000 kilometers (34.800 miles) away from Mars. In the following months the orbiter will become slower through air resistance in the upper atmosphere till it reaches an orbit with an average altitude around 400 km (250 miles) above ground in January 1998.

It is planned that Global Surveyor starts preliminary mapping in January 1998 and main mapping of Mars surface in March 1998.
The orbiter will circle Mars every two hours for nearly two years (687 Earth days = 1 Mars year). After this time the orbiter will remain in orbit as a communication link for further Mars surface missions.

Global Surveyor gets its energy from two solar panels which load two nickel-hydrogen batteries. Depending on its position to the sun the solar panels provide energy between 660 and 980 Watts.

Global Surveyor's camera can distinguish objects to a size of 1.5 meter (5 foot). With its wide-angle lens the camera will provide a daily image of Mars like those weather satellite images of Earth.
A laser altimeter will measure the heights and depths of Mars' surface providing data for a topographic map.
In addition a thermal emission spectrometer will measure the heat reflected by atmosphere and surface and a magnetometer in conjunction with an electron reflectometer will detect the magnetic properties of Mars.

Global Surveyor will send back scientific data with a transmission rate of about 85.000 bits per second. That is comparable to internet highspeed modems with transmission rates of 56.000 b/s.
The data will improve our knowledge of Mars' composition and ground details, weather and climate and the properties of magnetic and gravity field.









Sunset on Mars



14. August 1997
Preliminary results



Images from the sky like this sunset on Mars help scientists to estimate how much dust is in the sky and how high it reaches into the atmoshpere. After the sunset the sky stays bright for around 2 hours which indicates that dust reaches higher atmospheric layers reflecting the sunlight.
The dust of ferric iron minerals gives Mars its reddish color. Large parts of the dust in the atmosphere seem to be slightly magnetic.

One of the important and surprising findings is the now assumed volcanic past of Mars concluded from composition and appearence of some of the examined rocks. Before this, Mars was supposed to consist mainly of Basalt.

Multispectral images done trough different filters show various kinds of rocks and soils around the landing site. Dust and rocks of a reddish color are more weathered than the dark and grey ones. In comparison to the viking landing site the soil at the pathfinder landing site has higher amounts of aluminum and magnesium and lower amounts of iron, chlorine and sulfur.

Rocks like 'Barnacle Bill' and 'Yogi' consist mainly of Quartz, Feldspar, Orthopyroxene and lesser amounts of other oxides and sulfides.

Mars rover On July 30, 1997 the little rover get one wheel blocked presumably by a stone the wheel picked off on its way from the rock 'Mini Matterhorn' to the rock 'Mermaid'. According to its program the rover moved the wheel in the other direction and the stone fell off.

Lander's batteries were recharged on August 3. and 4. 1997 with energy from its solar panels. On the contrary the batteries of the little rover can't be recharged when they are empty. Nevertheless when the rover remains in good condition it is planned to send it on a nearby hill (20 meters =60 feet high) to get a view of the adjacent area.

Wind at the landing site is strongest at early morning and noon and comparatively mild at late afternoon and early evening.
Wind comes from west in the morning, from north during the afternoon, from east in the evenning and from south at night.
Sudden short drops in atmoshperic pressure above the landing site in the last days show the presence of little dust devils which are columns of fast whirling dust.

Pathfinder landing site

No water has been detected in the area of the landing site and it has never rained in Ares Vallis since Pathfinder's arrival. At dawn thin clouds can be seen high in the sky which probably consist of water steam. However the geological features at the landing site suggest that millions of years ago large quantities of flowing water had been there.

Weather at the landing point on Tuesday 1997/08/13 around 14:30 local Mars time was very nice, with a temperature of -13 degree Celsius (= +8 degree Fahrenheit), light wind from west and a pressure of approximately 6.7 millibars.
It didn't rain, as usual.









28. July 1997
After 3 weeks
still Rocks & Roll



Rock 'Scooby Doo'. The Pathfinder lander and rover are in their fourth week on Mars and still in very good condition.
Examination of a bright colored rock named 'Scooby Doo' has shown higher amounts of calcium and silicon than in the previous two rocks. Soil experiments where the wheels of the rover dig up the soil by moving them in opposite directions showed a bright soil in a few centimeter depth. The composition of this soil has similarities to the rock 'Scooby Doo'.

On Saturday the pathfinder rover drove for the first time to the next rock without human steering. It arrived at the rock named 'Souffle' with the help of its onboard laser guidance system and made a visual scan. The use of the spectrometer was not possible because of its unfavourable position to the rock.
On Sunday the rover made a 6 meter drive around the lander.

Monday's excursion leads the rover to a rock called 'Mini Matterhorn'. After analyzing this rock the rover will continue to examine other rocks around the lander unit.









21. July 1997
It shines for all



Sunset on Mars Sunset on Mars, a moment of contemplation. On Earth a familiar sight, now seen by robotic eyes over the rocky plains of Mars. It gives one the impression that human beeings will be able to experience this sight at first hand in a not so distant future.

Color view of mars soil with lander's rover ramp After a day in silence Pathfinder goes online again today on Monday July 21, 1997. Last Saturday`s transmitted scientific data and pictures from the lander were lost because of a misconfigured antenna on Earth.

Examination of a rock named 'Yogi' with the rover's spectrometer shows differences to the rock 'Barnacle Bill'. 'Yogi' was not heated as often by volcanic processes as 'Barnacle Bill'. The Mars rover is still parking at the rock named 'Scooby Doo' waiting for new commands.


Weather update July 22, 1997:

Weather at the landing point Thuesday 22. around midday local Mars time was fine, with a temperature of -24 degree Celsius (= -11 degree Fahrenheit), wind from southwest and a pressure of approximately 6.8 millibars.









14. July 1997
Little errors introduce human touch on Mars


'Sojourner' tries to climb on the rock 'Barnacle Bill' After a near collision of mars rover 'Sojourner' with the rock 'Yogi' on Wednesday 9. due a false timed signal, Pathfinder`s computer resets itself on Friday 11. and Monday 14., breaking the connection for a while.



    The two hills at the horizon are called 'Twin Peaks'


Last weeks spectrometer examination of a rock called 'Barnacle Bill' discovered to everybodies surprise quarz instead of the expected basalt. This data will help to make conclusions about the geological past of Mars.

Weather at the landing point last Saturday around midday local Mars time was fine, with -22 degree Celsius (= -8 degree Fahrenheit), west wind and a pressure of approximately 7 millibars.









4. July 1997 Mars Pathfinder has landed

Mars Pathfinder image, July 1997 Ares Vallis The successful landing of NASA's Mars Pathfinder in the Ares Vallis region of Mars (19N 326E) was confirmed at 17:07 UTC (=GMT) on 4. July 1997. The Pathfinder lander carries a variety of instruments to measure temperature, pressure and wind velocity of Mars atmosphere. An Alpha Proton X-Ray Spectrometer will identify and determine the amounts of many chemical elements in Mars rocks. The spectrometer is mounted on a little remote controlled Mars rover called 'Sojourner' making it possible to examine rocks in a wider circumference. A color stereo camera will provide new images from Mars.

















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