NASA’s InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission to study the deep interior of Mars is targeting a new launch window that begins May 5, 2018, with a Mars landing scheduled for November 26, 2018. The space agency announced about the mission launch on Wednesday. The mission will help study how rocky planets, including Earth, formed and evolved.

The spacecraft was supposed to lift off this month, but ended up sidelined in December by a vacuum leak in its prime science instrument, which prompted NASA to suspend preparations for launch. Project managers said the device should be redesigned in time.

“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,” said John Grunsfeld, head of NASA’s Science Mission Directorate in Washington.

NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, will redesign, build and conduct qualifications of the new vacuum enclosure for the Seismic Experiment for Interior Structure (SEIS), the component that failed in December. France’s space agency, Centre National d’Etudes Spatiales (CNES) will lead instrument level integration and test activities, allowing the InSight Project to take advantage of each organization’s proven strengths.

The two agencies have worked closely together to establish a project schedule that accommodates these plans, and scheduled interim reviews over the next six months to assess technical progress and continued feasibility, NASA said.

The cost of the two-year delay is being assessed. An estimate is expected in August, once arrangements with the launch vehicle provider have been made.

The seismometer instrument’s main sensors need to operate within a vacuum chamber to provide the exquisite sensitivity needed for measuring ground movements as small as half the radius of a hydrogen atom. The rework of the seismometer’s vacuum container will result in a finished, thoroughly tested instrument in 2017 that will maintain a high degree of vacuum around the sensors through rigours of launch, landing, deployment and a two-year prime mission on the surface of Mars.

NASA is on an ambitious journey to Mars that includes sending humans to the Red Planet, and that work remains on track. Just last week, astronaut Scott Kelly completed a 340-day mission at the International Space Station that’s considered a scientific steppingstone for sending humans to the red planet in the 2030s. Another NASA Mars lander — this one a car-sized, wheeled rover — is scheduled for a 2020 launch.

Europe is launching another Mars mission on Monday from Kazakhstan — an orbiter for measuring atmospheric gases and a lander collectively known as ExoMars 2016.