NASA has certified SpaceX’s Falcon 9 to launch the agency’s most important science missions, giving the agency new options that could result in lower costs.

SpaceX said that the NASA Launch Services Program (LSP) awarded its Category 3 certification for the company’s Falcon 9 rocket. That certification allows NASA to use the Falcon 9 for its highest-value science missions.

“LSP Category 3 certification is a major achievement for the Falcon 9 team and represents another key milestone in our close partnership with NASA,” Gwynne Shotwell, president of SpaceX, said in a statement. “We are honored to have the opportunity to provide cost-effective and reliable launch services to the country’s most critical scientific payloads.”

The Category 3 classification requires a vehicle to have performed at least 3, and as many as 14, successful launches. The difference in number of launches depends on the amount of additional NASA audits and reviews of the vehicle are performed to verify its reliability; more reviews allow NASA to certify the vehicle with a fewer number of launches. SpaceX did not specify what approach it used with NASA to obtain the Category 3 certification.

The current version of the Falcon 9, the Block 5, has performed six launches to date, all successfully. The overall Falcon 9 family has carried out more than 60 launches dating back to 2010, with one in-flight failure on a Dragon cargo mission in 2015 and a pad explosion in 2016 during preparations for a pre-launch static-fire test. There have been 34 consecutive successful Falcon 9 launches since that 2016 explosion.