Elon Musk is delaying Space Exploration Technologies Corp.’s (SpaceX) first manned launch of its Dragon capsule from 2016 to 2018.

The company informed the National Aeronautics and Space Administration (NASA) of the decision earlier this year.

The nearly one-year delay that would push the launch from the spring of 2017 to the second quarter of 2018 was confirmed Monday.

Problems with loading supercooled fuels might have caused an explosion that destroyed an unmanned Falcon 9 rocket during a ground test in September, which could present significant risks for manned missions.

Over a year ago, a NASA advisory committee discussed possible concerns regarding SpaceX’s plan to fuel rockets with astronauts already inside capsules loaded on the crafts.

The committee has received an updating briefing from SpaceX, but procedural details have not been shared with reporters or the general public.

Members of the panel were said to have signed confidentiality agreements.

On Monday, a SpaceX spokesman said in an email:

“We are carefully assessing our designs, systems and processes” to incorporate lessons learned and take corrective actions in the wake of the September explosion. The schedule change “reflects the additional time needed for this assessment and implementation,” he added. But in his comments, the SpaceX spokesman also suggested some prospective fueling changes are likely in response to the panel’s specific safety concerns. “As needed, additional controls will be put in place to ensure crew safety.”

SpaceX had previously discussed altering the strategy for ground preparations, including fueling.

NASA’s website, updated Monday afternoon, said that SpaceX has aimed for May 2018 for the first manned mission.

SpaceX is on a similar timeline for launching a manned operation as Boeing Co., which announced a similar delay in October.

In October, SpaceX had initially stated that they were confident its first manned flight would take off in 2017.

NASA is relying on both companies to take the place of Russian rockets and capsules, which are currently the sole means of transportation for U.S. crews to reach the international space station.

The agency has not committed to purchase seats on Russian crafts beyond 2018, and may need to find an alternate strategy if U.S. manned endeavors cannot meet deadlines.

SpaceX’s Falcon 9 blastoffs have been delayed since the explosion in September. It hopes to resume unmanned launches by January.

NASA originally planned to launch manned capsules by 2015.

SpaceX has experienced challenges including problems with space suits, onboard life-support systems, and leaks in unmanned Dragon capsules upon return when entering water.

NASA’s inspector general believes that future delays may be possible as both companies begin testing emergency crew-abort systems and other crucial elements of space travel.

NASA is SpaceX’s largest customer, awarding the company contracts of over 6.5 billion dollars for both manned and unmanned missions.