Mars Observer Replacement Fleet - Abstract

The Mars Observer Replacement Fleet (MORF)


A Proposal



Submitted by

Michael Kline
Dragos Crisan
Thomas Connolly
Shahed Aziz
Ralf Huber
Michelle Zimmerman
Scott Striepe



In fulfillment of the requirements for the graduate course:
ASE 396 - Space Systems Design


Department of Aerospace Engineering and Engineering Mechanics
The University of Texas at Austin


December 1993


Introduction

On Saturday, August 21st, 1993, engineers at JPL lost contact with Mars Observer. The spacecraft would have entered Mars' orbit only three days later and begun a series of geoscience and climateology experiments designed to last at least two years. This would have been the first U.S. probe to study Mars since the Viking landers sent in the 1970's. The mission was designed to send an array of instruments on a single spacecraft to gather a wealth of useful information about Mars. There would have been more data collected by Mars Observer than by all previous U.S. interplanetary spacecraft combined except Magellan. This tremendous amount of data would have included maps of the Martian surface, analysis of subsurface mineral content, improved gravity field information, data on atmospheric circulation, composition, and characteristics, and the possibility of data from an encounter with Phobos. This information in turn would have been a great help to scientists and engineers planning future Mars missions. Through Earth-Mars comparisons, it was also hoped that the data would play an important role in leading to a better understanding of the evolution of Earth's surface. However, now that Mars Observer is lost, that data will remain uncollected until comparable spacecraft and sensors are sent to Mars to do the job. With this fact in mind, a graduate student design team at The University of Texas took on the challenge of coming up with a new way to get the same or better data from Mars in a future interplanetary mission.

The official initiative to go to Mars was a directive of the Solar System Exploration Committee (SSEC) formed in 1980 as an advisory council to NASA. The committee was responsible for developing a core program for planetary exploration through the year 2000, and a Mars observing mission was selected as one of its top goals. In 1985, the Mars Observer program was started, and after a 2 year delay due to the Challenger accident, the spacecraft was finally launched in 1992. During the course of its development, five major science objectives were chosen for the mission, and seven sensors were then designed specifically to meet those objectives. The original objectives were as follows:


  1. To determine the global, elemental, and mineralogical character of the surface material of Mars
  2. To define globally the topography and gravitational field
  3. To establish the nature of the magnetic field
  4. To determine the time and space distribution, abundance, sources, and sinks of volatile material and dust over a seasonal cycle
  5. To explore the structure and aspects of the circulation of the atmosphere


These objectives were taken as the basis for the scientific goals of a Mars Observer replacement mission. Of course, the most important aspect of such a mission would be to create a design that would succeed. To better define what would qualify as a successful Mars mission, a study was done of Mars Observer to determine what changes or improvements should be made in any future missions. Several aspects of the Mars Observer design were identified as potentially detrimental to the reliability of the overall mission. Single point failures, like redundancies within systems, and an indiscriminate application of advanced technology are three areas of 'risky design' that stood out. It is not certain what caused the loss of Mars Observer, but improvements in any of these three areas would have increased the chance of mission success.


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