NASA plans to launch its next mission to Mars in 2018, two years later than expected, the space agency said today. Called InSight, the mission was originally supposed to launch this month, sending a lander to the Red Planet. But the project was put on hold indefinitely after a leak was found in one of the spacecraft's instruments. It was unclear if the project would move forward at all, but NASA said it is now targeting May 5th, 2018 for the launch of InSight, with the spacecraft scheduled to land on Mars on November 26th, 2018.

The InSight mission aims to send a lander to Mars to study the planet's interior and learn more about how the rocky world formed. The project had been on track for its intended March 2016 launch date, but everything came to a halt in December after scientists at NASA's Jet Propulsion Laboratory discovered a problem with one of the lander's two main instruments.

The mission gets a new life — for now

The instrument — called SEIS — was constructed by the French space agency Centre National d'Études Spatiales (CNES), and is designed to measure quakes on Mars, as well as extremely tiny ground movements. But the instrument must be sealed inside a vacuum chamber in order to be sensitive enough to work, and on December 3rd the agency discovered leaks in the chamber. John Grunsfeld, NASA's science lead, said at the time that the leaks were "big enough that [they] would prevent us from accomplishing the mission."

The InSight mission originally had a launch window that stretched from March 4th to March 30th of this year, but efforts to repair the leak in time failed. The orbits of Earth and Mars won't be close enough to favor a launch until 2018, so NASA is using that time to fix the problem. NASA's Jet Propulsion Laboratory is taking over the redesign and construction of the failed vacuum enclosure, and after that CNES will integrate the seismic instrument. The cost of this work, and of the delay, is still being assessed. The agency expects an estimate in August.

InSight would have been NASA's first mission to the Martian surface since the Curiosity rover landed in 2012, and the third overall. (Two orbiters — NASA's MAVEN and India's Mars Orbiter Mission — reached the planet in 2014.) NASA says that InSight's delay will not affect any of the agency's other plans to go to Mars, which include landing another rover in 2020 and human missions in the 2030s. The European Space Agency and Roscosomos, Russia's space agency, are sending two spacecraft — one orbiter and one lander — to Mars next week as part of the joint ExoMars mission.