NASA officials said Wednesday that the space agency continues to make progress preparing the massive Space Launch System rocket and Orion spacecraft for a launch later this summer. Moreover, they now have enough confidence to set a launch date: August 29.

Under the agency’s current plans, the stacked SLS rocket and Orion spacecraft will roll out to its launch site at Kennedy Space Center on August 18. Then, there would be three opportunities—August 29, September 2, and September 5—to launch the vehicle before the window closes.

“These are the dates we are working toward today,” said Jim Free, the chief of NASA’s human exploration systems development program.