When SpaceX got the green light from NASA to proceed with a planned April 30 launch to the ISS last week, that go-ahead was a provisional one: NASA officials said more software testing was planned, and that there would check again a week later, April 23, on whether the mission was still on track for launch.
Late Monday, SpaceX announced that, in fact, they would need more time to test the vehicle’s software. A tweet from SpaceX founder Elon Musk broke the news:
Am pushing launch back approx a week to do more testing on Dragon docking code. New date pending coordination with @NASA.
— Elon Musk (@elonmusk) April 23, 2012
The company provided a little more information about the delay in an email shortly after Musk’s announcement. “After reviewing our recent progress, it was clear that we needed more time to finish hardware-in-the-loop testing and properly review and follow up on all data,” the company announced. “While it is still possible that we could launch on May 3rd, it would be wise to add a few more days of margin in case things take longer than expected. As a result, our launch is likely to be pushed back by one week, pending coordination with NASA.”
SpaceX hasn’t announced a new launch date yet. A one-week delay would push the
April 30 launch to May 7. However, SpaceX previously indicated that they had preferred launch windows every three days in order to minimize the propellant needed to achieve orbit, preserving as much as possible for maneuvers around the ISS. That would suggest launch dates on May 6 or 9, if that three-day span between launch attempts holds.