NASA's InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) lander deploying its instruments. (NASA)

NASA's InSight lander, which was originally supposed to launch this month, is now penciled in for a 2018 takeoff.

The agency announced its new plans for the spacecraft on Wednesday, weeks after scrapping a 2016 launch. The robot, which is the result of an international collaboration, has a leaky component — the Seismic Experiment for Interior Structure (SEIS), provided by CNES, France's space agency. A faulty weld left the instrument, one of the lander's two primary scientific tools, with a persistent air leak.

For this particular instrument, such a leak would have been devastating: The SEIS instrument is incredibly sensitive, because the seismic activity on Mars is itty bitty compared with Earth's. The instrument is designed to detect the most minute of planetary motions — ground movements as small as the width of a single atom. To trust those measurements, NASA scientists need to know that the instrument is suspended in a perfect vacuum, protecting it from misreading any errant rumblings from the lander itself. Seismic readings are one of InSight's main scientific missions, so a faulty SEIS would waste the mission.

Because the distance between Earth and Mars can nearly double based on their orbital positions, any launch has to take advantage of a specific time window when the two planets are as close as possible. It may take much less than two years to fix the SEIS to NASA's satisfaction, but that won't make our planets move any faster. Ready or not, the next launch window won't come until May 2018.

NASA hasn't announced how much it will cost to keep the project running during the two-year delay. During the next few months, NASA's own labs will work on fixing the vacuum chamber, while CNES turns its attention to the instrument itself.

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