Although the Mars Exploration Rover mission is managed by NASA's Jet Propulsion
Laboratory (JPL) in Pasadena, California, NASA Ames Research Center has played
an important role in the areas of science operations, thermal protection,
wind tunnel testing, landing site selection, mission support software, human-centered
computing and fatigue countermeasures support. Each area is described in
detail below.
In addition, NASA Ames Research Center Director G. Scott Hubbard served
as NASA's first Mars program director at NASA Headquarters from April
2000 until June 2001, and was instrumental in restructuring NASA's Mars
program after several failures. Hubbard recommended selecting the Mars
Exploration Rover 'twins' as the agency's Mars mission in 2003/2004.
Science Operations
Three NASA Ames researchers, Dr. David Des Marais, Dr. Nathalie Cabrol
and Dr. Michael Sims, are co-investigators in the Mars Exploration Rover
(MER) mission. As members of the Science Operations Working Group, they
will take part in directing the rover's day-to-day operations during the
mission.
Des Marais will serve as a lead of the MER working group's long-term
planning group. He will help coordinate day-to-day rover operations with
the mission's overall objectives and long-term strategies. Day-to-day
team operations will entail coding science team requirements into command
sequences that the rovers will execute. Des Marais also will help coordinate
activities between the two rovers and the Mars orbiters. As an astrobiologist,
he will investigate how liquid water might have influenced rocks and soils
at the sites.
Cabrol will serve in the Mars Exploration Rover geology group and as
a documentarian for the long-term planning group. She will interpret data
from the rover's panoramic camera and Microscopic Imager, an instrument
that will take high-resolution close-ups of martian rocks and soils in
order to understand the origin of the sediments deposited at the landing
sites.
Sims will provide robotics and intelligent software expertise for the
mission. He will study the elements of the current visualization software
that could be used in future Mars missions. Sims also will work on enhancement
and modeling for the Microscopic Imager instrument aboard each rover.
In addition, he will serve as one of the spacecraft downlink coordinators,
managing data transfer between the MER mission operations team and the
science team.
Landing Site Selection
NASA Ames developed a set of collaborative software tools known as 'Marsoweb'
that is used by planetary scientists to review available Mars data and
determine the best and safest sites for the Mars Exploration Rover landings.
Marsoweb serves as a clearinghouse
for all data relevant to the Mars landing site selection process for the
mission, and has archived studies of more than 100 landing sites. Marsoweb
features an archive of more than 500 high-resolution Mars Orbiter Camera
(MOC) images of the candidate landing sites, as high as 1.5 meters per
pixel.
Marsoweb became a de facto official
website of the landing site selection process as Mars Exploration Rover
landing site scientists analyzed, visualized and compared data from past
Mars missions, including Mars Global Surveyor and Mars Odyssey data. Over
120,000 users from government, academia and the public have accessed the
site to date. Marsoweb is the result
of a four-year effort by the Center for
Mars Exploration (CMEX) at NASA Ames, the NASA Advanced Supercomputing
(NAS) Division's Data Analysis Group at Ames and the Mars Exploration
program. Web site development has been overseen by principal investigator
Dr. Virginia Gulick and implemented by web developer Glenn Deardorff.
Parachute Wind Tunnel Tests
A series of tests conducted in NASA Ames' 80- by-120 Foot Wind Tunnel,
which took place from September 2002 through January 2003, aided the selection
of the optimum parachute design for the Mars Exploration Rover mission.
Parachutes play an important role in the MER mission. When each 400-pound
rover, encased in a lander, enters Mars' atmosphere, a parachute 28 feet
in diameter will slow its descent.
During the tests, which simulated entry into the thin martian atmosphere,
engineers tested a dozen different parachutes, firing them from mortars
in the test section, with the wind tunnel running at speeds of up to 100
miles per hour. The Mars mission structural requirement for the parachute
was that it be able to sustain an opening drag load of at least 24,200
pounds, 25 percent greater than the expected load on Mars. The testing
involved NASA JPL, NASA Ames and NASA Langley Research Center teams.
The parachute tests at Ames were conducted in three phases. Phase one
demonstrated that NASA could get the data it needed using a wind tunnel.
Phase two tested different parachute candidates provided by Pioneer Aerospace
Corp., enabling engineers to choose the best design. Phase three tested
the chosen parachute to ensure that it met structural standards for the
Mars mission.
Thermal Protection Systems
NASA Ames Research Center supported the design, manufacture and test of
the thermal protection system (TPS) used on the Mars Exploration Rover
aeroshell structure. The TPS protects the aeroshell, which contains components
like the parachute, payload and rover, from the extreme heating caused
by deceleration into Mars' atmosphere during the entry phase of the mission.
NASA Ames' Arc Jet complex was used in qualifying all of the MER aeroshell
TPS materials in a simulated high-temperature entry environment.
Ames-manufactured TPS material, known as SIRCA (Silicone Impregnated
Reusable Ceramic Ablator), was attached to the back part of the aeroshell,
called the backshell interface plate. SIRCA also was used to protect the
three Transverse Impulse Rocket System (TIRS) located on the sides of
the aeroshell. The SIRCA TPS material originally was developed at Ames
and flight-tested during the successful July 4, 1997 Mars Pathfinder landing.
Mission Support Software
NASA Ames' Information Sciences and Technology Directorate has developed
software technologies and tools that are helping JPL's engineering and
science teams meet the Mars Exploration Rover's technical and logistical
challenges for operations.
Ames' Computational Sciences Division developed a suite of mission support
software for the ground control and operations of the two surface rovers,
Spirit and Opportunity. During the Mars Exploration Rover mission, 240
engineers and scientists will collaborate to oversee the actions of the
two rovers, which will be working in two different Mars time zones.
To assist Mars Exploration Rover scientists and engineers in complex
collaborative operations tasks, Ames developed the MERBoard, a computing
platform that provides an immersive and interactive computing environment.
The MERBoard provides a large touchscreen workspace for team members to
view, analyze and share data from Mars. This computing tool provides a
data storage and retrieval space that makes data accessible to scientists
and engineers throughout the mission operations area. Team members can
view and control one MER-Board from another, allowing for quick collaboration
between teams.
The MERBoard is the primary computer tool used by the rovers' long-term
strategic planners to create flow charts for each rover's traverses across
Mars.
A multidisciplinary team of computer scientists, human computer interaction
designers and ethnographers created the MERBoard's unique design.
To keep the ground operations crew up to speed and coordinated during
each rover's tightly scheduled actions in two different Mars time zones,
Ames developed the MER Collaborative Information Portal (CIP). This collaborative
data distribution and situational awareness tool is used for information
display and data access of vital information to scientists and engineers
working the mission in real time.
Using CIP, at any time, on any computer, using a custom-built interface
designed specifically for the Mars mission, team members can immediately
access reports, images, daily schedules or mission plans stored in a variety
of databases.
NASA Ames also developed the Mixed
Initiative Activity Planning Generator (MAPGEN), a ground-based science
planning support system for Mars Exploration Rover operations. This is
a critical tool that helps the round-the-clock science teams at JPL plan
science goals and program computer command sequences for the rovers' day-to-day
operations. This system was co-developed with JPL to enable the mission's
complex science requirements to be achieved while best utilizing the rovers'
power and time. This tool helps to increase the amount of science data
returned from the rovers.
To inspect the science data, Mars scientists will use the Ames-developed
'Viz' software tool. This software uses images from stereo cameras on-board
the rovers to construct a realistic, three-dimensional model of the martian
environment. Since a 20-minute communications delay between Earth and
Mars rules out real-time viewing of the rovers' immediate surroundings,
Viz provides a virtual reality simulation, letting rover operators explore
its immediate environment and plan upcoming traverses. With Viz, they
can 'travel' over the Mars surface, measure distances and select the best
sampling sites and routes, using virtual reality.
Human-Centered Computing and Fatigue Countermeasures
NASA Ames' computational science and human factors teams have collaborated
to provide the JPL Mars Exploration Rover teams additional support in
'human-centered' computing. They provided input about 'best practices'
in shift handover procedures and assisted the MER team in developing processes
for naming 'target' rocks the rovers will examine.
Ames also collaborated on the design of human interfaces for MER software
tools.
In addition, Ames' fatigue countermeasures group of the Human Factors
Research Division played an important role in developing fatigue countermeasures
to alleviate the MER surface operations team's need to work around the
clock on a Mars day schedule. A Mars day (or 'sol') is 24 hours and 29
minutes long.
Researchers have never studied the long-term effects on human performance
of a Mars work schedule, which shifts 39 minutes later each day. The fatigue
countermeasures group is designing fatigue countermeasures, such as well-timed
naps or drinking coffee, and documenting the team's sleep/wake cycles.
A non-intrusive Actiwatch device will collect activity data and sleep
cycle data. Results will be used to develop mission work schedules that
help to minimize fatigue and maximize performance and alertness in future
Mars operations.
Other software technologies developed by NASA Ames information sciences
include C Global Surveyor, which verifies and validates outcomes for large
software systems related to the mission and Brahms, which models and simulates
mission operations.
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