InSight lander
This artist’s conception shows the InSight lander on Mars. The SEIS instrument is deployed to the right of the lander, while a subsurface heat probe is buried at left. (Credit: NASA / JPL-Caltech)

NASA says it’s worked out a plan to redesign a faulty instrument on its InSight lander in time to send it to Mars in 2018.

The lander had been scheduled for liftoff this month from Vandenberg Air Force Base in California, but in December, mission managers said they had to scratch the launch off their schedule because they couldn’t fix the instrument in time.

InSight is designed to monitor seismic activity deep beneath Mars’ surface. The mission’s name comes from a quasi-acronym for “Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport.” Studying the Martian subsurface could provide insights into the planet’s evolution and current geological activity.

One of the lander’s key instruments – known as the Seismic Experiment for Interior Structure, or SEIS – was built for NASA under the direction of France’s space agency, the Centre Nationale d’Etudes Spatiales, or CNES.

SEIS’ sensors are meant to measure seismic movements as small as the diameter of an atom. They were supposed to be enclosed in a vacuum-sealed sphere to insulate them from Mars’ harsh surface conditions. However, repeated tests showed the sphere couldn’t hold a vacuum.

Now NASA’s Jet Propulsion Laboratory has worked out a plan to redesign, build and test a new vacuum enclosure for the SEIS instrument. CNES will oversee instrument-level integration and testing.

“The science goals of InSight are compelling, and the NASA and CNES plans to overcome the technical challenges are sound,” John Grunsfeld, NASA’s associate administrator for science, said today in a news release. “The quest to understand the interior of Mars has been a longstanding goal of planetary scientists for decades. We’re excited to be back on the path for a launch, now in 2018.”

The timing is determined by the orbital mechanics for Earth-to-Mars transits. NASA said the revised schedule calls for InSight to be launched during a window that begins on May 5, 2018, with landing planned for Nov. 26, 2018.

In December, NASA officials said $525 million of the $675 million that was budgeted for the InSight mission had already been spent. Today, NASA said the cost of the two-year delay was still being assessed. It said a cost estimate should be available by August, once the launch details were worked out with United Launch Alliance.

A different mission to Mars is due for launch from Russia’s Baikonur Cosmodrome in Kazakhstan on Monday. The European Space Agency’s ExoMars 2016 mission aims to send an orbiter and mini-lander toward the Red Planet atop a Russian Proton rocket. The Trace Gas Orbiter will look for signs of methane and other trace gases linked to biological activity. Meanwhile, the Schiaparelli lander will test technologies for a rover that ESA plans to send to Mars in 2018.

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