NASA's Mars Curiosityrover has been forced to alter its route after being faced withdangerous terrain. The current objective of the robotic explorer isto investigate a geological boundary between two distinct forms ofbedrock as a part of its mission to explore the heights of MountSharp, and ultimately unlock the secrets of the Red Planet's ancientpast.
As you can imagine,driving a rover the size of a small car on a planet some 140 millionmiles (225.3 million km) away is no easy task, and the job is madeall the more difficult when navigating hazardous and loose terrain. At first glance, the path to Curiosity's latest objective hadappeared to be made from consolidated rocky materials that wouldallow the explorer's six aluminum wheels a good degree of purchase,representing a safe, easy option for the mobile laboratory.
In reality, the pathselected by mission operators proved to be a challenging prospect,and after three drives, which took place between the 7thand 13th of May, the rover's software detected an excessof wheel slippage that forced it to stop in its tracks.
Wheel slippage runs therisk of appearing a relatively trivial peril for a piece of machinerythat has already survived a treacherous entry into the Martianatmosphere, not to mention the subsequent airdrop that so expertlyset the pioneer down in Gale Crater. However, rover operators havelearnt from the experiences and mistakes of the past, and are certainnot to neglect any aspect of the rover's safety.
Gizmag reached out tothe Mars rover team for comment on the potential dangers to makind'smost advanced robotic explorer. "Slippage can be detected, butonly after the fact (after we perform Visual Odometery) so there areconcerns with drive precision," stated Chris Roumeliotis of theagency's Jet Propulsion Laboratory (JPL), and team lead for theCuriosity rover drivers. "There isgreater uncertainty in Curiosity's drive path when we encounter highamounts of slipping or skidding. Cumulative slip/skid events if notaccounted for correctly can lead to driving over unsafe vehiclehazards such as large rocks, large negative features, sand pits,etc."
Roumeliotis went on toexplain that if such an error were to go unnoticed or uncorrected,Curiosity could well encounter a scenario similar to that faced inApril 2005 by the Opportunity rover, when it was stranded for over amonth on "Purgatory Dune." The rover was finally freedafter five weeks of painstaking planning, testing, and superbexecution by the highly skilled operators.
"Fortunately wehave made Curiosity much smarter, and the rover drivers now havebetter tools to avoid these types of situations on Mars," said Roumeliotis. Therefore, no such crisis was likely to occurfor Curiosity, as the rover's handlers took heed of the warningsigns, and devised a route to the secondary target location overfirmer ground.
"One factor thescience team considers is how much time to spend reaching aparticular target, when there are many others ahead," statedCuriosity Project Scientist Ashwin Vasavada of the JPL. "We usedobservations from NASA's Mars Reconnaissance Orbiter to identify analternative site for investigating the geological contact in theLogan Pass area. It's a little mind-blowing to drive up a hill to asite we saw only in satellite images and then find it in front ofus."
Curiosity has made goodprogress towards the new target, with Thursday seeing the explorerundertaking a 72-ft (22-m) drive up a Martian hill, which at pointssloped at a 21-degree angle. The rover, which its operators believeto be capable of traversing an inclination of up to 30 degrees underoptimal conditions, made light work of the hill, and will soon beunlocking more secrets of the alien environment.
Last week also saw theCuriosity team implement a fix for the rover's Chemistry and Camera(ChemCam) instrument, which is used to take detailed images, andanalyze spectrometer readings from sparks zapped by the rover'sonboard laser. Unfortunately, a separate laser needed to focus theinstrument was lost several months ago, forcing the ChemCam team tostruggle on without it.
"Without thislaser rangefinder, the ChemCam instrument was somewhat blind,"explained principal investigator of the ChemCam instrument at LosAlamos, Roger Wiens. "The main laser that createsflashes of plasma when it analyzes rocks and soils up to 25 feet (7.6meters) from the rover was not affected, but the laser analyses onlywork when the telescope projecting the laser light to the target isin focus."
Thankfully, the teamwas able to send newly-developed software to the robotic pioneerthat guides the instrument to take numerous range-finding images inorder to inform the focus of the final images, which are then sentback to Earth for analysis.
Wiens offered an optimistic conclusion, stating, "We think we will actually havebetter quality images and analyses with this new software than theoriginal."
Source: NASA
