NASA has suspended the March 2016 launch of its InSight mission to Mars because of problems with a key scientific component, the US space agency said Tuesday.

The next launch window will not occur until around May 2018 and NASA said it does not yet know if it will be able to continue with the mission given budget constraints.

The InSight lander was set to delve deep beneath the Red Planet's surface in order to discover how the solar system's rocky planets formed.

"Learning about the interior structure of Mars has been a high priority objective for planetary scientists since the Viking era," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington.

"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," he said in a statement.

The problematic instrument is a seismometer provided by France's Centre National d'Etudes Spatiales (CNES), designed to measure ground movements as small as the diameter of an atom.

"It's a hard blow," CNES president Jean-Yves Le Gall told AFP.

"This is one of the risks of the job. The good news is that our system was able to discover the problem when it was still here on Earth."

NASA said the decision to delay follows unsuccessful attempts to repair a leak affecting the device, which requires a vacuum seal around its three main sensors to withstand the harsh conditions of the Martian environment.

A leak discovered earlier this year, that prevented it from retaining vacuum conditions, was successfully repaired, and the mission team "was hopeful the most recent fix also would be successful."

However, the instrument once again failed to hold a vacuum during testing on Monday in extreme cold temperature.

"It's the first time ever that such a sensitive instrument has been built," said Marc Pircher, Director of CNES's Toulouse Space Centre.

"We were very close to succeeding, but an anomaly has occurred, which requires further investigation. Our teams will find a solution to fix it, but it won't be solved in time for a launch in 2016."

The relative positions of the planets are most favorable for launching missions from Earth to Mars for only a few weeks every 26 months, according to NASA's statement.

"For InSight, that 2016 launch window existed from March 4 to March 30," the space agency said.

"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," added Grunsfeld.

While the InSight launch is important, Grunsfeld said the suspension "doesn't affect the sequence of any other missions."

Plans to send a manned mission to Mars in the 2030s remain "on track," NASA said.

NASA is currently working on three Mars missions with the European Space Agency and plans to send another rover to Mars in 2020.