NASA has decided its precision landing gear is accurate enough to let it land the Curiosity Mars rover a lot closer to its target than expected.
But it needs to be careful, as the new site is also much nearer to the slopes of Mount Sharp, which could pose a landing hazard.
"We're trimming the distance we'll have to drive after landing by almost half," says Pete Theisinger, Mars Science Laboratory project manager at NASA's Jet Propulsion Laboratory. "That could get us to the mountain months earlier."
Since the spacecraft was launched in November 2011, engineers have continued testing and improving its landing software. Over the last two weeks, it's had an upgrade to its flight software, and upgrades for Mars surface operations will be sent to the rover about a week after landing.
The original landing target was an ellipse around 12 miles wide and 16 miles long, and this is now to be shrunk to an area to just four miles by 12 - assuming winds and other atmospheric conditions turn out as predicted.
"We have been preparing for years for a successful landing by Curiosity, and all signs are good," says Dave Lavery, MSL program executive.
"However, landing on Mars always carries risks, so success is not guaranteed. Once on the ground we'll proceed carefully. We have plenty of time since Curiosity is not as life-limited as the approximate 90-day missions like NASA’s Mars Exploration Rovers and the Phoenix lander."
Curiosity is scheduled to land at around 10:31 pm PDT on August 5, when it will begin a two-year study of whether the area might ever have been favorable for microbial life.
NASA scientists have identified a possible problem with sample collection, but say it should be manageable. They're concerned that, as the rover drills for samples, Teflon from the drill could contaminate what it finds.
"The material from the drill could complicate, but will not prevent analysis of carbon content in rocks by one of the rover's 10 instruments. There are workarounds," says John Grotzinger, MSL project scientist at the California Institute of Technology in Pasadena.
"Organic carbon compounds in an environment are one prerequisite for life. We know meteorites deliver non-biological organic carbon to Mars, but not whether it persists near the surface. We will be checking for that and for other chemical and mineral clues about habitability."