Mars Pathfinder

Term Paper Title	Mars Pathfinder
# of Words	2569
# of Pages (250 words per page double spaced)	10.28

Mars Pathfinder

What is the Mars Pathfinder mission? The Mars Pathfinder Mission is the second launch in the Discovery Program, a NASA initiative for planetary missions with a maximum three-year development cycle and a cost cap around $150M (FY92) for development. The Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, manages the Mars Pathfinder for NASA.
The mission is primarily an engineering demonstration of key technologies and concepts for eventual use in future missions to Mars employing scientific landers. Pathfinder also delivers science instruments to the surface of Mars to investigate the structure of the Martian atmosphere, surface meteorology, surface geology, form, and structure, and the elemental composition of Martian rocks and soil. In addition, a free-ranging surface rover is deployed to conduct technology experiments and to serve as an instrument deployment mechanism

Pathfinder landed a single vehicle, which is either called Rover, Microrover, or Sojourner, on the surface of Mars on July 4, 1997. Once there it will carry out a number of engineering, technology and science experiments. A primary technology objective for Pathfinder was to demonstrate a low cost cruise stage and the Entry, Decent and Landing (EDL) systems required for putting a payload safely on the Martian surface. The Mars Pathfinder lander was built at a cost of $171 million, this includes the $25 million cost to build the microrover.

The Mars Pathfinder spacecraft was launched from Kennedy Space Center at 1:58 a.m. EST on December 4, 1996. It is on a Type 1 Earth to Mars transfer trajectory which took it about seven months to get there. During its trip to Mars there were four corrections made to its trajectory. These are called Trajectory Correction Maneuvers or TCM's and are used to adjust for things like launch injection errors, small previous TCM errors and any other trajectory vector errors. Also, the final TCM (the last of which occurred on June 25th) will ensure that the spacecraft will enter the proper 14.2� Mars atmospheric descent angle, not too steep or too shallow. EDL is a very complex chain of events that must take place exactly in order for the landing to be successful. During this time, spacecraft data is sent back to Earth in the form of semaphores (more specifically, shifts in the RF carrier & sub-carrier when certain events occur). These semaphores are a kind of Morse code that we will decipher to tell if the chain of events took place as planned. A FSR (Full Spectrum Recorder) is used to detect the weak radio signals. The Madrid Spain Deep Space Network (DSN) facility (and for a brief time the Goldstone DSN site) will be the first station to acquire these signals and Pathfinder mission operations engineers from JPL will be on station there to analyze these signals. In addition, a whole array of measurements is made inside the lander during descent, which will be stored in memory for later transmission to earth. Careful analysis of this engineering data later provided a clear insight into what the lander experienced during its 4.5-minute trip to the surface.
After landing, Sojourner will stand up and drive down one of the two ramps mounted to the lander petal. The ramps are a pair of deployable metal reels which will provide a track for the rover as it slowly rolls off the lander, over the spacecraft's deflated airbags, and onto the surface of Mars. One or both of the ramps will be unfurled, and then scientists will decide whether the rover will use either the forward or backward ramp for its descent. A lander IMP (IMager for Pathfinder) camera mission panoramic image as well as images taken on either side of the rover petal will assist the mission operations engineers in deciding which ramp is safest to drive down. After a successful ramp egress we will begin a nominal 7 sol (1 sol = 1 Martian day) mission to conduct science and technology experiments. This mission is conducted under the constraint of a once-per-sol opportunity for command and telemetry transmissions betw...

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