Mars Pathfinder Mission Breakthrough on the Surface of Mars

A Few Facts On The Mission… Launch: 4 December 1996 UT 06:58 Arrival: 4 July 1997 UT 16:57 Final Transmission: 27 September 1997 PDT 03:23 Launch Vehicle: Delta 2 Mass: 264 kg (Lander), 10.5 kg (Rover) Dimensions (Rover): 0.28 m high X 0.63 m length X 0.48 m wide, 0.13 m ground clearance Power System: Solar panels Total Cost: $265 million (including launch and operations)

A Few More Facts On The Mission… Lander was operational for 30 days (3 times its expected life); Rover was operational for 83 days (12 times its expected life). Over course of mission, relayed 2.3 GB of data, including images from the Lander’s camera, 550 images from the Rover camera, 16 chemical analyses of rocks and soils, and 8.5 million measurements of atmospheric pressure, temperature, and wind.

Mission Objectives Mars Pathfinder was the second launch in the Discovery Program, a NASA initiative for planetary missions with a maximum 3 year development cycle and a cost cap of $150 million for development (1/15 th the cost of the Viking missions). To demonstrate NASA’s commitment to low-cost planetary exploration on the surface. To demonstrate the mobility and usefulness of a microrover on the surface.

Landing the Pathfinder Landing zone chosen according to images taken during the Viking mission in the mid-1970s. Pathfinder landed downstream from the mouth of Ares Vallis, a giant catastrophic outflow channel. This landing zone was chosen, as it was believed the examination of the different surface materials would allow a first-hand scientific investigation of early differentiation and evolution of the crust, the development of weathering products, and a sense for early environment and conditions that once existed on Mars.

Landing the Pathfinder

ScientificObjectives Scientific Objectives To land a single vehicle with a microrover (Sojourner) and several instruments on Mars in The mobility of the Sojourner was to allow “ground truthing” on an area of over 100 m 2 on Mars. To investigate the surface with 3 additional instruments: IMP – Imager for Mars Pathfinder APXS – Alpha-Proton X-ray Spectrometer ASI/MET – Atmospheric Structure Instrument/Meteorology Package

Instruments Aboard Sojourner

IMP – Imager for Mars Pathfinder Reveals Martian geological processes and surface-atmosphere interactions similar to what was observed at the Viking landing sites in the mid-1970s. Makes observations of general landscape, surface slopes and distribution of rocks obtained by panoramic stereo images at various times during the day. Makes regular sky and solar spectral observations, and monitors windborne particle size, particle shape, distribution with altitude, and abundance of water in vapour.

Instruments Aboard Sojourner APXS – Alpha-Proton X-ray Spectrometer Determines the dominant elements that make up rocks and other surface materials at the landing site. Gives an understanding of the materials that may lead to the determination of the composition of Martian crust, as well as secondary weathering processes (such as different types of soils). Investigations provide calibration points for orbital remote sensing observations such as the Mars Global Surveyor. Along with the magnetic targets distributed at various points around the craft, it is possible that the mineral composition of the rocks can be inferred.

APXS

Instruments Aboard Sojourner ASI/MET – Atmospheric Structure Instrument/Meteorology Determines the temperature and density of the atmosphere during Entry, Descent and Landing (EDL). 3-axis accelerometers are used to measure atmospheric pressure during EDL. Once on the surface, meteorological measurements (pressure, temperature, wind speeds, atmospheric opacity) are measured on a daily basis. Wind directions and speeds are measured by a wind sensor mounted atop a stable mast.

Discoveries of the Pathfinder Mission Major Discoveries The immediate vicinity of the landing appears to have been dry and unchanged for the past 2 billion years. Chemical analysis of rocks by the APXS suggest that all rocks studied by the Rover resemble andesite, a volcanic rock with high silica content, covered in a fine layer of dust. Martian dust includes magnetic, composite particles, with a mean size of one micron. Dust is confirmed as the dominant absorber of solar radiation in Mars' atmosphere, which has important consequences for the transport of energy in the atmosphere and its circulation.

Discoveries of the Pathfinder Mission Evidence of wind abrasion of rocks and dune-shaped deposits was found, indicating the presence of sand. Rock size distribution was consistent with a flood-related deposit. It was determined that clouds, not fog, obscured the view of Martian mornings from space. The possible identification of rounded pebbles and cobbles on the ground, and sockets and pebbles in some rocks, suggests conglomerates that formed in running water, during a warmer past in which liquid water was stable.

Discoveries of the Pathfinder Mission

Conclusion “Done quickly and within a very limited budget, Pathfinder set a standard of 21 st century space exploration.” Dr. David Baltimore, president of the California Institute of Technology, which manages JPL for NASA

References  Mars Pathfinder Mission Home Page  Mars Pathfinder Project Information  Mars Pathfinder – Science Results – Mineralogy and Geochemistry  Mars Pathfinder – APXS Preliminary Results