It also launched a new Mars exploration plan, which was launched on November 7, 1996, and ended the mission on November 2, 2006 due to loss of communication.
Mars global mapping
Announce
edit
The Mars Global Surveyor orbits Mars for 117.65 minutes at an altitude of 378 kilometers.Its orbit is nearly circular and passes near the pole (with an inclination of 93 °).The orbit at this altitude is chosen to orbit Mars in a sun synchronous orbit, so the image of the Martian surface taken by MGS is that the same surface area will also be taken under the same lighting conditions on different days.Under each orbit, the surface of Mars photographed by MGS will shift westward by 28.62 ° due to the rotation of Mars.In fact, MGS always moves from one time zone to another at the same speed as the sun at 14:00.After 7 Martian solar days and 88 times of circling Mars, MGS will reroute the previous route in a similar way, but will shift 59 kilometers to the east;This ensures that MGS can explore the entire surface of Mars.
In the extended mission of MGS, research outside the surface of Mars was carried out.MGS often performs rolling and pitching movements to take images beyond the lowest point of the orbit.
Mars Global Surveyor
Phobos monolith (right of the image center), shot by MOC of MGS in 1998, image number 55103 (MOC Image 55103).
In addition, MGS also filmed otherMars probeAnd the moons of Mars.In 1998, the MOC of MGS photographed an independent boulder on Phobos, called Phobos monolith, with image number 55103.
Scientific instruments
Announce
edit
Mars Global Surveyor carries five scientific instruments in total:
Mars Orbiter Camera (MOC)
Mars Orbiter Laser Altimeter (MOLA)
Thermal Emission Spectrometer (TES)
Magnetometer and electron reflectometer (MAG/ER)
USO/RS Ultrastable Oscillator for Doppler measurements
Mars Relay, signal receiver
The Mars orbit camera has three instruments in total. One narrow field camera is responsible for taking black and white images with high resolution (1.5-12 pixel/m), one camera can take red and blue images to take background images (240 m/pixel), and the third camera takes global images every day (7.5 km/pixel).MOC sent back more than 240000 images in 4.8 Mars years from 1997 to 2006.The width of high-resolution images is about 1.5 or 3.1 km, but most of them are smaller in order to show the surface characteristics of certain areas.The length of the high-resolution image is about 3 to 10 kilometers.When shooting a high-resolution image, a lower resolution background image is also taken to indicate the shooting position of the high-resolution image.The general length and width of the background image is 115.2 km, and the resolution is 240 m/pixel.
Main Task Results
Announce
edit
The exploration results of Mars Global Surveyor during its main mission (1996-2001) were published in the Journal of Geophysical Research by M. Malin and K. Edgett.The findings of MGS are as follows:
1. At least 10 km thick strata have been found on Mars.To form such a thick stratum, a large amount of materials must be weathered, transported and deposited.
2. There may be a large number of impact events in the northern hemisphere of Mars as in the southern hemisphere, but most of the impact craters in the northern hemisphere have been buried under the sedimentary layer.
3. Many surface features such as impact crater have been covered and reappeared in recent years.
4. Hundreds of valleys formed by liquid water have been found, which may be formed in recent years.
5. A wide range of strata on the surface of Mars cover all steep slopes.Some of these strata have flat surfaces and some have many holes.Some scientists think it may be because the underground ice sublimates into water vapor and then escapes.
6. Some areas are covered by hematite.Hematite represents that there may have been liquid water in the area.
7. The dark stripes on the surface of Mars are caused by dust wind.Dust Devil Tracks are found to change frequently, even within a month
8. The surface features similar to "Swiss cheese" are found in the South Pole Crown of Mars.The depth of the hole on the surface is about several meters.The volume of the hole continues to grow every year, and Mars may be warming now
9. The Thermal Emission Spectrometer (TES) on MGS found that almost the entire surface of Mars was covered by volcanic ash
10. Hundreds of house sized boulders were found in some areas;This means that there is enough material on the surface of Mars to condense with each other, even when moving downhill.Most boulders are found in volcanic rock area, so these advantages may be generated from the weathering of lava flow plain
11. Thousands of dark stripes on steep slopes were found;Most scientists believe that this is due to dust avalanches.But some scientists think it may have something to do with liquid water.
Discovering the presence of water
Announce
edit
Internal smaller channel at the bottom of Narendi Canyon
The photos released from NASA on December 6, 2006 found that there were geographical features of liquid water between 1999 and 2001 in the Terra Sirenum and Centauri Montes.
Hundreds of valleys that may be formed due to water flow are considered to be formed in recent years, and these valleys appear on steep slopes and at specific latitudes.
Several rivers even have smaller rivers that can retain liquid water. The most famous of these rivers are Nanedi Valles and Nirgal Vallis.
Chronicle of Events
Announce
edit
November 7, 1996: launch
September 11, 1997: Arrive at Mars and enter orbit
April 1, 1999: The main surveying and mapping task began
February 1, 2001: the first extended mission started
February 1, 2002: start of the second extension mission
January 1, 2003: Relay mission started
March 30, 2004: Shoot the track of the tire where Spirit passed in the first 85 Martian average solar days.
December 1, 2004: Science and Support Mission Begins
April 2005: Mars Global Surveyor is the first to photograph other planets outside the EarthSpace probeDetectors for.MGS took two pictures2001 Mars OdysseyAnd a picture of Mars Express.
October 1, 2006: the scheduled two-year extension mission begins.
November 2, 2006: Communication was lost due to an error in the repositioning of the solar panel.
November 5, 2006: A weak signal was detected, indicating that MGS was waiting for instructions, and soon the signal was interrupted.
November 21, 2006: NASA announces the end of MGS mission
December 6, 2006: NASA announced that MGS had taken a new image of the ravine, proving that liquid water still exists on Mars.
April 13, 2007: NASA released the report of MGS loss.
