Mars polar lander

The main goals of Mars Polar Lander (MPL) were to study the polar regions of Mars, primarily the local climate, to search for ice in Martian soil and estimate its amount, and to take a detailed survey of the surface at the landing site. The landing site was the boundary of the southern Martian polar cap , between 74 and 77 ° S. w. and 170 and 230 ° C. e. The landing time was chosen in such a way that a polar day reigned there throughout the life of the apparatus. According to Mars Global Surveyor’s images, the landing area at this time of the year was intermittent light and dark areas - remnants of snow and ice mixed with bare soil. MPL carried on itself 2 penetrators of “ Deep Space 2 ” - uncontrolled ballistic capsules, which were supposed to separate before entering the atmosphere and, upon reaching the surface, go deeper into the ground and transmit information about its composition.

MPL launched from the Earth as part of the flight stage and landing craft. The overflow stage is equipped with solar panels , orientation motors and communication systems. The total mass of the lander ("Land") is 576 kg.

The landing gear is equipped with four blocks of orientation and stabilization propulsion systems; at the bottom there are three groups of landing engines of four liquid-propellant engines with a thrust of 60 pounds (266 N , 27.1 kgf ) each. Fuel for all engines comes from two fuel tanks located under the main solar arrays of the Lander. When working on the surface, the lander has a height of 1.06 m and a transverse dimension (with solar panels deployed) of 3.6 m. The supporting body of the spacecraft (landing gear) and landing supports are made on the basis of a honeycomb aluminum structure fastened with graphite-epoxy panels. Inside the chassis are the main and backup set of the on-board computer , power distribution unit, battery, radio systems, electronics units. The power supply of the landing apparatus with a total power of 200 W is carried out from six sections of solar panels. In low light conditions, the power will be supplied by a 16 Ah battery, designed primarily to heat the central electronics unit to −30 ° C at night (at −80 ° C outside). “Lander” is equipped with 2 radio systems.

• UHF - for communication with the Earth through the Mars Climate Orbiter repeater (which has never entered orbit around Mars) or for one-way data reset via the Mars Global Surveyor AWS . Data transfer rate - 128 kbps .
• X-band system for direct communication with the Earth through a medium-gain antenna, the maximum data transfer rate is 1400-5000 bit / s. Due to the fact that when observing from the south pole of Mars, the Earth rises above the horizon very low, a direct connection would be possible only with a very even surface topography, even small hills could interfere with communication.

The MPL scientific equipment includes a set of instruments for studying the volatile substances and climate of Mars MVACS (Mars Volatiles and Climate Surveyor), an amphibious assault chamber and a lidar. The MVACS kit includes:

1. The manipulator, the length of which in the deployed position is 2 meters. At its end, a RAC camera (Robotic Arm Camera), a bucket for soil collection and a temperature sensor are installed. The RAC camera allows you to take high-resolution photographs showing the structure of the surface material and the surface layer.
2. Stereo camera SSI (Surface Stereo Imager). The camera is located on a 1.5-meter mast and is used for panoramic shooting of the surroundings of the landing site.
3. Meteocomplex . Meteorological sensors are located on two masts. On the first mast 1.2 m high on the top cover of the spacecraft there is a wind direction and speed sensor, a temperature sensor and semiconductor lasers that measure air humidity, the content of isotopes of water and carbon dioxide . The second mast, 0.9 m long, is directed downward and is designed to study atmospheric effects at a height of 10 to 15 cm above the Martian surface. On it are a wind sensor and two temperature sensors.
4. TEGA gas analyzer (Thermal and Evolved Gas Analyzer). Using a manipulator, a soil sample weighing 0.1 g is placed in the analyzer receiver. Next, the receiver is closed with a lid, forming a miniature stove. The sample is gradually heated with a spiral heater to a temperature of 1027 ° C, and the gas released is transmitted through a semiconductor laser, the light of which is incident on the photodetector. By the intensity of light absorption, one can quantitatively determine the gas composition, and above all, the presence of water vapor and carbon dioxide.

• Lidar is designed to determine the moisture and dust content in the atmosphere to a height of 2-3 km. The device was developed at the Space Research Institute of the Russian Academy of Sciences under the direction of Dr. V. M. Linkin with the financial participation of the Russian Space Agency . This is the first Russian experiment aboard the American AMS.
• For the first time, a microphone was to be delivered to Mars to record the noise of the wind and the noise of the working mechanisms of the lander .

Mars Polar Lander was launched into space on January 3, 1999 using the Delta 2 launch vehicle . The 11-month flight to Mars passed without any comments. On September 23, 1999, the crash ended in orbit around Mars of the automatic interplanetary station Mars Climate Orbiter, the "brother" of the MPL, which was supposed to relay up to 90% of the data to Earth. On December 3, the MPL for the last time corrected its trajectory and entered the atmosphere of Mars. Neither the lander, nor the penetrators got into contact. Searches for the signal were conducted both from Earth and from the Mars Global Surveyor automatic interplanetary station for a month and a half, but to no avail.

The reasons for the failure remain a mystery. Telemetry transmission during the most intense sections of the descent and landing was not provided, so it is not possible to restore the course of events. Among the probable causes of the accident are called premature shutdown of brake engines (MPL used the old landing method - braking with rocket engines, like the Viking’s, rather than inflatable bags, like the Mars Pathfinder’s or rovers). The general conclusion of the commission stated that the Mars Surveyor 98 program initially included technical solutions with a high level of risk, which led to the accident of two stations at once (MCO and MPL).

The main reason for the failure of the mission to conclude an independent commission is insufficient funding and pressure on deadlines. According to an independent commission, the project was underfunded by at least 30% of the real need.

• Mars Surveyor 98 .
• Deep Space 2 - penetrator probe.
• Penetrator
• Mars-96 - Russian AMS with penetrators on board.
• Phoenix (spacecraft)

1. ↑ (English) Mars Polar Lander Timeline (neopr.) . NASA Archived December 4, 2012.
2. ↑ LOCKHEED MARTIN ASTRONAUTICS TO BUILD MARS '98 SPACECRAFT ( unspecified ) . NASA Archived December 4, 2012.

• Mars Polar Lander on NASA
• Mars Polar Lander on NASA
• Mars Polar Lander at Jet Propulsion Laboratory
• National Aeronautics and Space Administration (December 8, 1998). Press Kit: 1998 Mars Missions (.PDF). Press release . Retrieved 2009-04-22 .