World Library  
Flag as Inappropriate
Email this Article

Mars Surveyor '98 program

Article Id: WHEBN0000390986
Reproduction Date:

Title: Mars Surveyor '98 program  
Author: World Heritage Encyclopedia
Language: English
Subject: Mars Polar Lander, Sojourner (rover), Viking program, Mars Exploration Rover, Phoenix (spacecraft)
Collection: Missions to Mars, NASA Programs
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Mars Surveyor '98 program

Mars Polar Lander mission logo

The Mars Surveyor '98 program comprised two spacecraft launched separately, the Mars Climate Orbiter (formerly the Mars Surveyor '98 Orbiter) and the Mars Polar Lander (formerly the Mars Surveyor '98 Lander); on board the Mars Polar Lander spacecraft were two surface-penetrator probes (Deep Space 2). The two missions were to study the Martian weather, climate, water and carbon dioxide (CO2) budget, to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes.

Both spacecraft were launched during the 1998 Mars orbit insertion launch window. Both were lost, including the penetrator probes.

Contents

  • Loss of the orbiter 1
  • Loss of the lander 2
  • Cost 3
  • References 4

Loss of the orbiter

The orbiter was lost due to a miscalculation in trajectory caused by an unintended and undetected mismatch between metric and English units of measurement.[1] The use of metric units as well as the data formats to employ were specified in a navigation software interface specification (SIS) published by JPL in 1996. Despite this, the flight operations team at Lockheed Martin provided impulse data in English units of pound-force seconds rather than newton seconds. These values were incorrect by a factor of 4.45 (1 lbf = 4.45 N). This caused erroneous course corrections that caused the orbiter to descend too low in Mars's atmosphere. The vehicle either burned up or bounced off into space.

Loss of the lander

Investigators concluded that the most likely cause of the lander's failure was that a spurious sensor signal associated with the craft's legs falsely indicated that the craft had touched down when in fact it was some 40 meters above the surface. When the landing legs unfolded they made a bouncing motion that accidentally set off the landing sensors, causing the descent engines to shut down prematurely and the lander to fall. Another possible reason for failure was inadequate preheating of catalysis beds for the pulsing rocket thrusters. Hydrazine fuel decomposes on the beds to make hot gases that are forced out of the rocket nozzles, generating thrust; in crash review tests cold catalysis beds caused misfiring and instability.

The Polar Lander under construction in the NASA lab

Cost

The Mars Surveyor 1998 program spacecraft development cost US$193.1 million. Launch costs for the Mars surveyor 98’ program was estimated at US $91.7 million and mission operations at US $42.8 million. The Mars Climate Orbiter was part of NASA's 10-year Mars Surveyor Program, with launches every 26 months when the Earth and Mars are favorably positioned.

References

  1. ^ [BBC News Sci/Tech http://news.bbc.co.uk/1/hi/sci/tech/462264.stm "Confusion leads to Mars failure"], Thursday, September 30, 1999 - Retrieved 24 June 2014
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.