LONG BEACH, Calif. — In the wake of a launch accident and a critical report, the two companies with NASA commercial crew contracts say they’re committed to maintaining their development schedules, but not at the expense of safety.

During a panel session at the AIAA Space 2016 conference here Sept. 14, officials with Boeing, SpaceX and NASA went to great lengths to emphasize they would not rush the development and test flights of crewed vehicles despite a desire to have at least one company’s system ready to start ferrying astronauts to and from the ISS before the end of 2018.

Prior to the Sept. 1 pad accident that destroyed a Falcon 9 rocket and its satellite payload, SpaceX had planned to perform a demonstration mission of its Crew Dragon spacecraft to the International Space Station without a crew as soon as May 2017, with a crewed demo mission to follow later in the year. But at the conference, Benji Reed, director of crew mission management at SpaceX, declined to give estimated dates for those missions.

“Our focus is getting able to fly again soon from our overall fleet perspective,” he said of returning the Falcon 9 to flight. That investigation is not affecting various commercial crew activities, he added. “We’re full steam ahead on crew, while we listen to the data and understand what’s going on.”

However, he did not commit to even approximate schedules for those key demo flights, or when he expected NASA to certify the Crew Dragon for operational missions. “We need to get that capability going, and we need to do it right,” he said. “We’ll fly when we’re ready.”

Kathy Lueders, NASA commercial crew program manager, said her program is participating in the accident investigation team established by SpaceX after the pad explosion. NASA’s ISS and launch services programs are also represented on the team, which is led by SpaceX and also includes the U.S. Air Force and Federal Aviation Administration.

Chris Ferguson, deputy program manager for commercial crew at Boeing, restated a schedule for development of the CST-100 Starliner that the company has been reporting for several months. That plan includes an uncrewed flight test in late 2017 and a crewed flight test in February 2018. That schedule, he said, would allow the CST-100 to be certified in time for an operational mission in June 2018.

That schedule is more optimistic than an assessment in a Sept. 1 report by NASA’s Office of Inspector General. That report found issues delaying development of commercial crew vehicles at both companies, and concluded that it was unlikely either would be certified to carry NASA astronauts before late 2018.

“It’s a very aggressive schedule,” Ferguson acknowledged of Boeing’s plans. “We’re optimistic that we’re going to meet the deadline, but we’ll fly when we’re ready, and that’s really what it comes down to. And if it takes a couple of extra months to ensure we have a safe vehicle, we’ll do just that.”

Both Ferguson and Reed discussed the technical progress they are making with their commercial crew efforts, including a series of tests of various spacecraft components. Those efforts also include finalizing upgrades to launch sites in Florida for crewed Atlas 5 and Falcon 9 launches, which both said are nearing completion to support those missions, whenever they take place.

“Obviously, from a commercial crew program standpoint it’s really important that we make sure that we are all ready to fly when we feel like it’s safe to fly our crews,” Lueders said. “We’ve been working schedules, and the goal is to fly as quickly as we safely can, with a goal to fly in 2018.”