NASA’s Jet Propulsion Laboratory is taking developing of the Mars Science Laboratory (MSL) rover mission down to the wire, and probably will need another shot of funding before the mission’s launch window opens Nov. 25 to avoid a costly delay until the next planetary window in 2013.

Agency managers believe they hold enough funding and schedule reserves to meet any remaining issues, and expect to get the $2.5 billion mission off the pad on time to meet this year’s planetary launch window. However, they do expect to dip into a $22 million funding reserve held at NASA headquarters to finish the work.

Evaluators from NASA’s Office of Inspector General (OIG) found that while most of the technical problems that forced a slip from the 2009 planetary window have been resolved, three remained open when they drafted their report in February.

One of them — manufacturing contamination in the system designed to collect samples of Martian soil and rock — has since been resolved with a thorough cleaning, according to Dave Lavery, program executive for robotic Solar System exploration at NASA headquarters. Plans are in place to resolve the others — open issues in flight software and fault-protection system development — although some surface-operations software won’t be loaded into the spacecraft until it is on its way to Mars, Lavery says.

“Because of technical issues related to these three and other items, project managers must complete nearly three times the number of critical tasks than originally planned in the few months remaining until launch,” states a June 8 report from NASA Inspector General Paul Martin. “ … We are concerned that management may be pressured to reduce mission capabilities in order to avoid another 2-year delay and the at least $570 million in associated costs.”

Responding to the OIG report, Lavery insists there will be no need to descope the mission or delay the launch, barring a serious, unforeseen problem. The delay from 2009 boosted development costs 86%, to $1.8 billion from $969 million, and added 56% to the estimated life-cycle costs of the mission, which grew from $1.6 billion in 2009 to $2.5 billion today, according to the OIG.

Redesigning the mission for a launch when the next planetary window opens after 26 months, in 2013, would cost “at least” $570 million, the report states. However, in addition to the $22 million development reserve held at NASA headquarters to meet the current launch window, Lavery says there also is another $22 million in headquarters reserves for operations, all within the $2.5 billion total.

The OIG attributes the project’s overall schedule and funding problems to the complexity of the MSL mission, which will send a nuclear-powered rover the size of a small car to a precise landing on the surface of Mars, where it will use a robotic arm and a suite of 10 instruments to survey an area as large as 20 km (12 mi.) across for evidence of current and past habitability.

Of particular concern is the “sky crane” landing scheme, which will lower the Curiosity rover — four times heavier than the Mars Exploration Rovers Spirit and Opportunity — to a gentle touchdown from a hovering lander after it has separated from the atmospheric-entry heat shield.

Lavery says the project will have a 20-day schedule margin before the launch window opens if the remaining mission elements, including the rover, can be shipped to Kennedy Space Center, Fla., by June 22, as is now planned. There is a three-day margin at JPL in meeting that date, he says.