WASHINGTON -- US space agency NASA said Wednesday that its Mars lander is now targeting a new launch window that begins May 5, 2018, with a Mars landing scheduled for Nov 26, 2018.

"We're excited to be back on the path," John Grunsfeld, NASA's associate administrator, said in a statement.

NASA originally planned to launch the Seismic Investigations, Geodesy and Heat Transport (InSight) mission this month, but it was forced to call it off in December due to a vacuum leak in the prime science instrument of the lander.

The instrument involved was the Seismic Experiment for Interior Structure (SEIS), a seismometer provided by the French Space Agency (CNES) that will help answer questions about the interior structure and processes within the deep Martian interior.

Designed to measure ground movements as small as the diameter of an atom, the instrument requires a vacuum seal around its three main sensors to withstand the harsh conditions of the Martian environment.

In announcing the new schedule, NASA said that its Jet Propulsion Laboratory will redesign, build and conduct qualifications of the new vacuum enclosure for the SEIS that failed in December's leak testing and that the CNES will lead instrument level integration and test activities.

The US agency also said the cost of the two-year delay is being assessed with an estimate expected in August.