Lidar experiment cover story

On the 3-rd of January 1999 NASA has launched another object within the frames of Mars Surveyor scientific programme. Delta-2 launching vehicle delivered on a flight trajectory to the Mars the Polar Lander spacecraft. Polar Lander would land on Mars surface on December, 1999 near the border of Southern polar cap. The main scientific goals are: Martian surface research, especially its light fractures and atmosphere research. Polar Lander carries panoramic color video camera, video camera that would film landing in atmosphere, manipulator hand to collect surface samples and to put them to the light fractures analyser. Also there are various instruments to atmospheric research available. The atmospheric sounding instrument aboard Mars Polar Lander is the LIDAR - Light Detection and Ranging, developed by team of Space Research Institute, RAS.

Lidar side view

The LIDAR system is a laser sounder located on the Mars Polar Lander deck. It is composed of a sensor and electronics assembly. The LIDAR transmitter uses a galium-aluminum-arsenic laser that emits energy in pulses at a constant rate and wavelength. The sensor is registering laser impulses dispersed on different altitudes in Martial atmosphere

It is the first time when NASA space craft carries Russian instrument within the frames of Solar system planetary research mission. Nasa has given russian scientists the opportunity to participate Mars Surveyor 1998 space research programme, according to Russian-American joint project "Together on Mars" which emerged in the mid 90's.

Russian researchers on the other hand included American scientists and their instruments into their projects. For instance, on a Mars'96 lander there was an American instument that would detect the main oxidant on the ground and in atmosphere.

The main scientific goals of Lidar are research of aerosol spread in Martian atmosphere, in the inner layer up to 1 km high, research of correlation between aerosol spread and altitude with other meteorological parameters.

The instrument consists of Lidar itself. Another istrument is a highly sensitive atmosphere pressure meter that is needed to register different atmospheric layers passed by measuring pressure changes in infralow frequency band. The third part is a microphone to measure energy spectrum and sound around Lander in Martian atmosphere. The microphone is being developed in USA.
Development of Mars Microphone and recording of amospheric and Lander sounds is being held by the Planetary Society.

The diagram below depicts how LIDAR is attached to Mars Polar Lander platform.