NASA postponed Friday's launch because of a faulty heating part. They said Sunday that the further delay is because technicians need to replace a switch box in the engine compartment. Two days of testing are required once the new box goes in, said a NASA spokesman.
Another launch was not scheduled.
As late as Saturday, the astronauts and their families were still hoping for a possible launch attempt on Monday. But NASA gave up on that once it became clear extensive repair work would be needed aboard the shuttle.
Obama also met briefly with Kelly's wife, Rep. Gabrielle Giffords, who was shot through the head in January.
The Associated Press contributed to this report.