PASADENA - Getting stuck is never fun, especially when you’re over 30 million miles from Earth. NASA’s Spirit rover is mired in dirt on Mars and now scientists at the Jet Propulsion Laboratory are working hard to free the over-worked robot.
Spirit first ran afoul of the Martian surface on May 6 when it hit some patches of dirt that made its wheels spin in place. Now the wheels (two of which are not working properly) are sunk in up to their hubcaps.
Like a remote Auto Club for robots, JPL engineers have built a sandbox filled with a mixture of materials that closely mimic the consistency of Martian soil as well as a rock to high-center the rover. They've driven a replica of the Spirit into the box and are working diligently to figure out the best way to escape the talcum-like trap – a technique used with Spirit's twin rover, Opportunity, back in 2005 when it also became stuck.
The first Mars Exploration Rover landed on the red planet in January 2004. Initially, the mission was supposed to last 90 Martian days, but Spirit exceeded that by over 20 times. Thanks to a recent dust storm, the fine dust that coated Spirit’s solar panels was blown off and it has been operating at full power for months now. If this latest obstacle can be overcome, Spirit can keep exploring even longer.
Read on to see how the JPL scientists created a little piece of Mars on Earth and get up close and personal with Spirit's predicament.
Above: A JPL technician attaches a grounding strap to the rover before measuring the distance it traveled during the previous move. Below:
A Discovery Channel Canada film crew films the engineers as they work to get the rover unstuck.
Photos: Dave Bullock/Wired.com
The test-bed where the rover will attempt its escape is separated by a plastic sheet and positive pressure to keep the dust out of the other side of the lab.
You can’t see it, but behind the white plastic sheet the Mars Science Lab rover is being constructed. In the photo above, it's early on in the construction process and only a few loads of soil have been added.
The lab floor is covered with a fine gravel to provide a malleable base for the sandbox.
Photos: Dave Bullock/Wired.com
Originally NASA had planned to use some simulated Martian soil they had created for previous testing. Unfortunately the huge pile of soil was left outside. The rain and elements washed away the fine particulate matter leaving behind a blend too coarse to accurately simulate the type of soil Spirit is stuck in.
A box of volcanic rocks of terrestrial origin await being put into use as “the one" – the Earth counterpart of the pesky rock that has Spirit in a jam.
Photos: Dave Bullock/Wired.com
To mimic the fine soil in which the Spirit is caught, a mixture of Lincoln Fire Clay – normally used to create sewer pipes – and other ceramics are mixed with food-grade amorphous silica.
Amorphous silica, also known as Fossil Shell Flour, is used as an anti-caking agent for livestock feed. A cement mixer is used to combine the fire clay and silica to get the right consistency.
Photos: Dave Bullock/Wired.com
The Spirit rover has some specialized tools for exploring the surface of Mars including drills that can bore into rocks and take samples. The terrestrial rock above displays marks from the drill.
Apparently there are rovers crossing the street at JPL, although the only rovers seen were inside the lab.
While our imaginations immediately think JPL + Restricted Area = Alien Cover-up, the red tape is likely just to keep bystanders from breathing in too much dust.
Photos: Dave Bullock/Wired.com
Once the soil has been mixed for a few minutes it is transferred into a wheelbarrow and taken into the lab where it is dumped into the sandbox; an engineer then smoothes out the simulated soil in preparation for the next load.
Photos: Dave Bullock/Wired.com
Inside the sandbox the rover struggles to get free. Moving only fractions of an inch for every few meters the wheels turn, the rover will not have an easy time getting out of its predicament.
An engineer waits with a safety stop button in case anything goes horribly wrong, but the process is fairly uneventful.
The intricate rover, covered with gold foil, appears to strain its neck while attempting to look under its belly at the large rock on which it's stuck.
Photos: Dave Bullock/Wired.com
The rover’s wheels provide little traction in the fine, loose soil it is trapped in. Like being stuck in sand in your car, spinning the wheels tends to just dig you in deeper.
The Spirit's wheels are having trouble gaining traction in a patch of loose dirt.
The rover can communicate directly with earth using its aim-able, disk-shaped, high-gain antenna.
Photos: Dave Bullock/Wired.com
Since these photos were taken, engineers and scientists at JPL/NASA have tried out several other techniques for freeing Spirit, including a backwards motion and a crab-like walk with the wheels turned at an angle.
Once the team has a plan they're confident with, they'll transmit the directions to Spirit and watch what happens. The engineers predict that they'll have such a plan in a few weeks.
Even if Spirit remains trapped, it has already greatly exceeded its mission on Mars and sent back vast amounts of important data.
