In a setback to future Mars exploration, NASA has decided to suspend the planned March 2016 launch of the Interior Exploration using Seismic Investigations Geodesy and Heat Transport (InSight) mission to Mars.
The decision follows unsuccessful attempts to repair a leak in a section of the prime instrument in the science payload, the US space agency said in a statement on Tuesday.
"We push the boundaries of space technology with our missions to enable science but space exploration is unforgiving and the bottom line is that we're not ready to launch in the 2016 window," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington, DC.
"A decision on a path forward will be made in the coming months, but one thing is clear: NASA remains fully committed to the scientific discovery and exploration of Mars," he added.
The instrument involved is the Seismic Experiment for Interior Structure (SEIS), a seismometer provided by France's Centre National d'Études Spatiales (CNES).
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.
"InSight's investigation of the Red Planet's interior is designed to increase understanding of how all rocky planets, including Earth, formed and evolved," said Bruce Banerdt, InSight principal investigator.
Mars retains evidence about the rocky planets' early development that has been erased on Earth by internal churning Mars lacks.
"Gaining information about the core, mantle and crust of Mars is a high priority for planetary science, and InSight was built to accomplish this," he added.
A leak earlier this year that previously had prevented the seismometer from retaining vacuum conditions was repaired, and the mission team was hopeful the most recent fix also would be successful.
However, during testing in extreme cold temperature (-45 degrees Celsius), the instrument again failed to hold a vacuum.
NASA officials determined there is insufficient time to resolve another leak, and complete the work and thorough testing required to ensure a successful mission.
"It's the first time ever that such a sensitive instrument has been built. We were very close to succeeding, but an anomaly has occurred, which requires further investigation," said Marc Pircher, director of CNES's Toulouse Space Centre.
"Our teams will find a solution to fix it, but it won't be solved in time for a launch in 2016," Pircher noted.
The spacecraft, built by Lockheed Martin, was delivered to Vandenberg Air Force Base in California.
With the 2016 launch canceled, the spacecraft will be returned from Vandenberg to Lockheed's facility in Denver.
For InSight, that 2016 launch window existed from March 4 to March 30.
NASA is on an ambitious journey to Mars that includes sending humans to the Red Planet.
