International Planetary Rover Efforts
Mobile robots are opening up new horizons in planetary exploration.
Eventually, humans will explore the planets directly: but mobile robots can
help us learn a great deal about planetary surfaces right now. The
Lunokhod missions of the 1970's and the 1997 Sojourner mission have hinted
at the possibilities, and today's researchers are demonstrating advanced
capabilities that will allow future missions to have an even grander scale.
I have collected together below some of the resources available on the
Internet that talk about planetary rover efforts. Please note that many of
the links here go directly to web pages of the institutions doing the work;
this page is mainly a summary of useful links, not an attempt to document
all the efforts myself. It is certainly incomplete, so please let me know
if you have other links or information that would be useful to add to these
pages! This collection was inspired by a presentation
that summarized the IROS'97 Planetary Rover Workshop.
- One of the defining characteristics of a planetary rover is its ability
to handle rough, unknown terrain. The locomotion system must be able to
negotiate large rocks, loose soil, and steep slopes. Many types of
locomotion systems have been proposed, e.g.: 4-wheel, 6-wheel, 8-wheel,
1-wheel, legged, balloons, and egg-shaped hoppers.
- Communication of data and images back to Earth is critical. Possible
solutions to the problem of communications include having a tether from the
rover to a fixed lander/communications platform, using a short-range
wireless link instead of the tether, communicating from the rover directly
to an orbiting satellite relay station, and the holy grail of direct
- Science Payload
- For purely scientific missions, it is necessary to tailor the rover's
capabilities to the needs of the science package, so the science
requirements need to be specified far in advance of the rover's design and
- Obstacle and Hazard Detection
- Rovers need to learn about their environment as they drive. Internal
sensors like gyros, Inertial Measurement Units, inclinometers,
accelerometers, and limit switches can be used to determine when the robot
has entered a dangerous position (e.g., when it might be starting to roll
over). But potentially even more useful are sensors that can test the
environment before the rover gets there. Sensors like stereo
vision cameras, laser rangefinders, sonar, and radar sensors can provide
advance warning about obstacles around the robot.
- Position and Pose Estimation
- One of the hardest problems in developing control software for rovers
is in knowing where the rover is at all times. In unknown planetary
environments, maps may not be available and landmarks may be hard to find.
Internal sensors like wheel encoders, gyros, and Inertial Measurement Units
can be used to determine position. Unfortunately they are subject to much
error as the robot moves, since it is likely to slide on loose dirt or steep
slopes, fall off of small rocks and so on. GPS systems could provide much
better data, if only we had networks of GPS satellites around other
planetary bodies. Pose information (i.e., "which way am I pointing") can be
gleaned from star trackers, sun sensors, accelerometers, Inertial
Measurement Units, wheel encoders, and vision-based landmark tracking.
- Autonomous Operation
- Autonomous operation is critical for planetary exploration because the
communications delay between Earth and planets can be many minutes. With
autonomous driving, a robot can explore a much greater distance because it
doesn't have to wait for a person to decide a safe route. The rover would
be able to see obstacles and recognize them on its own. The more autonomous
control the robot has, the farther it can progress on its mission. It is
not enough to merely detect obstacles, the rover must have a higher-level
system that can determine the best way to get around the obstacle, while
still attempting to satisfy a higher-level goal.
- Power System
- One of the most challenging aspects of building a planetary rover is
finding an appropriate and adequate power source. Solar power is probably
the best renewable resource, but has a low yield and results in more than
50% downtime guaranteed. Other options include batteries, fuel cells,
RTGs, and wind power.
- User Interface
- Human controls for the robot are just as important to mission success
as is the robot itself. Designing the user interface to match the
specifications of the mission can dramatically improve the mission results.
The ability to quickly assess and modify the vehicle state makes it possible
to accomplish more tasks in a short time.
- Data Logging
- The rover and the ground station must both be capable of storing the
data acquired during a mission. For some planetary operations, a rover may
have a small number of communications opportunities (e.g., Mars Pathfinder
had two 5-minute windows per day), so the ability to store data over time is
critical. Ground stations on Earth must also have enough storage facilities
to accomodate the complete mission results.
- Space Qualification
- After the launch cost, the greatest expense in the construction of a
planetary rover is the space qualification process. Rover components must
withstand the stresses of launch, landing, the conditions
encountered while travelling to the destination planet (radiation, vacuum,
heat, cold), and any planetary surface hazards (dust storms, crevasses).
Teleoperated Planetary Rovers: Then and Now
The following table combines robots that have been to other worlds with
current ongoing research efforts. Follow the links to learn more about each
Deployment and Field Test Summary
These days it is not enough to just develop technology on the bench, it must
be demonstrated in the context of an active, mobile platform. Here are some
of the most fully developed Field Tests of planetary rovers that have been
These days everyone wants to get into space, not just governments. Several
industrial and government consortia have grown over the last view years.
They have the novel and laudable goal of launching a planetary rover using
(some, most, or all) funding from non-governmental sources.
- Euromoon 2000 (nee LEDA)
The first phase would survey lunar surface
regions (e.g. poles) using orbital and in-situ
measurements, including a modest lunar rover.
Components are being tested now, e.g. the
wheels and tether for the IDD/MIDD at DLR in Germany.
- Lunar Rover Initiative
LunaCorp and CMU are pursuing commercial
sponsorship of a two rover exploration venture to
the Moon. They would visit Apollo and Lunokhod
landing sites, and travel 2000 km in two years.
- Earthrise 2001
A consortium of Japanese companies (e.g.,
Nippon TV, Mitsubishi, Shimizu) plan to
land a lunar rover in the year 2001.
Recent Workshops and Public Events
Planetary rovers are beginning to enter the public consciousness, thanks in
large part to the success of NASA's 1997 Mars Pathfinder mission. Some of
the events that have helped spur this interest in the last year are listed
- NASA Mars Pathfinder Mission
- From 4 July to October 1997, the Mars Pathfinder mission's Sojourner rover
captured the public's imagination. This mission was the first to deploy an
intelligent mobile robot to the surface of another world. Daily reports
appeared in international news media, and web site hit count records were
- Disney Epcot Space Celebration
- From 3-7 October 1997, several planetary rovers were on display at Epcot
Center in Disneyworld, Florida, USA.
- IROS'97 Planetary Rover Workshop
- On 7 September 1997, the IROS Planetary Rover Workshop was held in
Grenoble, France. Results from several rover research groups were
presented, and a summary of the presentations is
available here. For more information, please contact the workshop
organizer, Dr. Richard
Volpe of JPL.
- 1997 Atacama Desert
- From 15 June to 31 July 1997, visitors to the Carnegie Science Center in
Pittsburgh had the opportunity to test-drive the Nomad robot through the
Atacama Desert in northern Chile. Part of the CSC's Robotics exhibit, tens
of thousands of visitors not only got to see live images from the Atacama,
but also got to pick the viewing direction. A lucky few even got to drive
the robot. Many more got to participate by viewing the project's web pages,
viewing live imagery on the web and reading the daily field reports.
- Lavic Lake Field Test
- From 22-30 May 1997, several high schools got the opportunity to drive the
Rocky 7 robot over desert terrain in California.
- 1997 Rover Roundup
- On 1 February 1997, the Planetary
Society sponsored a planetary
in Santa Monica, California, USA.
email@example.com Last modified 11 November 1997