The National Aeronautics and Space Administration yesterday rescheduled the aborted launch of the space shuttle Challenger for July 29 and delayed by as much as two weeks the maiden voyage of the shuttle Atlantis, which had been scheduled to carry a secret Pentagon payload into orbit Sept. 19.

The launch abort last Friday, three seconds before liftoff, forced NASA to drum up a new schedule that maintains a Discovery blastoff for Aug. 24, delays another Challenger mission from Oct. 30 to early November and keeps a Nov. 27 Atlantis flight and a Dec. 20 mission by Columbia. Atlantis is the fourth and last spaceliner in the shuttle fleet and Columbia has just undergone an 18-month overhaul at the Rockwell International plant in California, where it was built.

Meanwhile, work crews at Florida's Kennedy Space Center removed three parts from Challenger's No. 2 engine that engineers suspect could have triggered computers into ordering all three engines to shut down on the launch pad. One was a valve that failed to close when it should have, a second was a hydraulic actuator that orders the valve to close and the third was a controller that sends commands to the actuator.

"We still suspect the actuator, and nothing we've found suggests anything else," Kennedy center spokesman Hugh Harris said yesterday. "We are replacing all three parts and continue to analyze and test the parts we remove."

The fresh parts will be tested on the pad, leading to a July 23 "flight readiness review." This does not involve a test-firing of the engines, only electronics and leak checks of parts like pumps, turbines and valves.

The delay set off by Challenger's launch abort means that a "flight readiness firing" test set for July 30 for Atlantis will have to be postponed to Sept. 12, which will delay Atlantis' maiden flight from Sept. 19 to late September at the earliest.