WASHINGTON — NASA and SpaceX plan to postpone an in-flight abort test of the crewed version of SpaceX’s Dragon spacecraft until after an orbital test flight, a decision they say is not linked to the June 28 Falcon 9 launch failure still in the early phases of its investigation.

In a July 1 statement, NASA announced SpaceX was delaying the test, where a Dragon spacecraft separates from its Falcon 9 launch vehicle during ascent, from later this year until after an orbital test flight of the crewed version of the Dragon vehicle. That test flight, which would not carry people onboard, is currently planned for late 2016 under SpaceX’s Commercial Crew Transportation Capability contract with NASA.

SpaceX’s original plans for the in-flight abort test called for using the same Dragon spacecraft that flew in a pad abort test in May from Cape Canaveral Air Force Station. However, the Dragon design has changed since construction of that spacecraft started more than two years ago, so SpaceX will instead use the Dragon that flies the uncrewed test flight.

“Testing the actual flight design always results in higher fidelity data and ultimately reduces risk for later crew flights,” William Gerstenmaier, NASA associate administrator for human exploration and operations, said in the statement. “This change supports a philosophy of testing as you fly, which our experience has shown to be a good strategy for development and complements well the earlier system information gained from the pad abort test.”

The change in schedule for the test also includes a change in venue. SpaceX’s previous plans for the in-flight abort test called for launching the Falcon 9 from Vandenberg Air Force Base in California. The test will now be carried out from Launch Complex 39A at NASA’s Kennedy Space Center in Florida, the same pad that SpaceX will use for crewed Dragon missions.

Because the in-flight abort test was a milestone in SpaceX’s earlier Commercial Crew Integrated Capability award, a funded Space Act Agreement with NASA issued in August 2012, the term of that agreement will be extended. That extension, however, would not involve any additional funding. The in-flight abort test milestone is valued at $30 million under that 2012 agreement, which originally scheduled the test for April 2014.

SpaceX executives had hinted in recent weeks that the in-flight test might be delayed. SpaceX Chief Executive Elon Musk, speaking with reporters after the May 6 pad abort test, said at the time that SpaceX was considering postponing the in-flight until after the uncrewed orbital flight. “It’s not clear which will precede the other,” he said then of the two tests.

At a June 27 press conference at KSC, Hans Koenigsmann, vice president of mission assurance at SpaceX, also said the company was reconsidering the schedule of the test. “We are going back and considering where the in-flight abort fits,” he said, based on an ongoing review of data from the pad abort test. “It’s right now in flux.”

In its July 1 statement, NASA said that discussions about delaying the in-flight abort test started prior to the June 28 Falcon 9 launch failure. The Falcon 9 rocket broke apart nearly two and a half minutes after liftoff from Cape Canaveral, destroying a Dragon spacecraft carrying more than two tons of cargo to the International Space Station.

Initial comments by company officials indicated the failure was linked to an “overpressure event” in a liquid oxygen tank in the rocket’s second stage. The company has not offered more details publicly since a tweet by Musk early June 29. “Cause still unknown after several thousand engineering-hours of review,” he said, adding the company was taking additional steps to obtain data from the vehicle’s final milliseconds.

“The process for determining the root cause of Sunday’s mishap is complex, and there is no one theory yet that is consistent with the data,” SpaceX spokesman Phil Larson said in a July 1 statement. “Our engineering teams are heads down reviewing every available piece of flight data as we work through a thorough fault tree analysis in order to identify root cause.”

A SpaceX executive not authorized to speak on the record said July 1 that the company was meeting daily with NASA and the U.S. Air Force about the investigation, with oversight provided by the Federal Aviation Administration, which licensed the launch. The investigation is examining more than 3,000 channels of telemetry from the rocket, including video, as well as any rocket debris the company can recover in the Atlantic Ocean.

“We believe we are in an extraordinary position to identify the issue and fix it as quickly as possible,” the executive added, because most of the vehicle’s components are built by SpaceX itself rather than provided by subcontractors.