[meteorite-list] ESA Tests Self-Steering Rover in 'Mars' Desert

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 18 Jun 2012 13:40:22 -0700 (PDT)
Message-ID: <201206182040.q5IKeM9t008097_at_zagami.jpl.nasa.gov>

http://www.esa.int/SPECIALS/Space_Engineering/SEM64M8X73H_0.html

ESA tests self-steering rover in 'Mars' desert
European Space Agency
18 June 2012

ESA assembled a top engineering team, then challenged them to devise a
way for rovers to navigate on alien planets. Six months later, a fully
autonomous vehicle was charting its course through Chile's Mars-like
Atacama Desert.
 
May's full-scale rover field test marked the final stage of a StarTiger
project code-named "Seeker".

Standing for "Space Technology Advancements by Resourceful, Targeted and
Innovative Groups of Experts and Researchers", StarTiger involves a
multidisciplinary team gathered at a single site, working against the
clock to achieve a technology breakthrough.
 
"Our expert team met at the Rutherford Appleton Laboratory in the UK,"
explained Gianfranco Visentin, head of ESA's Automation and Robotics
section.

"Their challenge was to demonstrate how a planetary rover - equipped
with state-of-the-art autonomous navigation and decision-making software
- could traverse 6 km of Mars-like environment and come back where it
started."
 
Long-range rovers risk getting lost
 
Mars rovers cannot be remotely "driven". It takes radio signals up to 40
minutes to make a round trip between Mars and Earth. Instead, rovers are
given instructions to carry out autonomously.

"ESA's ExoMars rover, due to land on Mars in 2018, will have
state-of-the-art autonomy," added Gianfranco.

"However, it will not travel more than 150 m per individual "Sol" - a
martian day - or much more than 3 km throughout its mission.
 
"The difficulty comes with follow-on missions, which will require daily
traverses of five to ten times longer.

"With longer traverses the rover progressively loses its absolute
localisation - sensing where it is.

"Lacking martian GPS, the rover can only determine how far it has moved
relative to its starting point, but this 'dead reckoning' is still
subject to errors, which build up into risky uncertainties."

The Seeker team aimed at a less than 1% distance error, and being able
to fix their position on a terrain map to 1 m accuracy.

The rover acquired visual odometry systems to assess its distance moved,
stereo-vision reconstruction to map its surroundings and advanced
path-planning and obstacle avoidance systems.
 
Desert testing
 
Prototypes underwent indoor and outdoor testing. Then, in May, the
Seeker team - including experts from SciSys UK, BAE Systems UK, Roke
Manor UK, MDA-UK, the University of Oxford and Laboratoire d'Analyse et
d'Architecture des Systemes in France - took their rover to the Atacama
Desert, one of the driest places in the world, which was selected for
its similarities to martian conditions.

"The European Southern Observatory's nearby Very Large Telescope was an
additional advantage," Gianfranco added. "The observatory kindly
provided refuge for the cold and windy desert nights."
 
For two weeks the team put the rover into action within a particularly
Mars-like zone. Like anxious parents, the team watched the rover go out
of sight, maintaining only radio surveillance.

Their daily efforts culminated in the official trial, when the Seeker
rover was programmed to perform a single 6 km loop.

"The whole day was needed as the rover moves at a maximum 0.9 km/h,"
Gianfranco recalled.

"But this was an unusual day. The usual desert winds counteracting the
fierce heat of the Sun died away.

"The rover grew dangerously warm, and had to be stopped around midday.
Then, when the wind finally picked up there wasn't enough time to
complete the loop before sundown.
 
"We managed 5.1 km, somewhat short of our 6 km goal, but an excellent
result considering the variety of terrain crossed, changes in lighting
conditions experienced and most of all this was ESA's first large scale
rover test - though definitely not our last."
Received on Mon 18 Jun 2012 04:40:22 PM PDT