Discovery's robotic arm and the four space suits the astronauts will use on Wednesday, Thursday and Friday space walks, checked out with no major problems.
As the crew prepared for its sleep period, Discovery was 1,100 statute miles behind Hubble, closing at a rate of 150 statute miles per orbit. Discovery's orbit had been adjusted by firing the two Orbital Maneuvering System engines, mounted in pods on either side of the spacecraft's vertical tail fin. That burn added 79 feet per second to the orbiter's speed. A subsequent firing of Discovery's smaller Reaction Control System jets further refined the orbit by changing Discovery's speed by about eight feet per second.
The pressure in Discovery's cabin was lowered to 10.2 psi at about 1 p.m. Monday. This is part of the procedure to reduce the amount of nitrogen in the blood of space-walking astronauts. Later they will breathe pure oxygen. Those steps are designed to eliminate the possibility of nitrogen bubbles forming in their blood during spacewalks and causing an attack of the "bends," a condition that can affect deep-sea divers brought to the surface too quickly.
A little after 8:30 p.m. CST, four members of the crew, Commander Curt Brown, Pilot Scott Kelly, and Mission Specialists Jean-Francois Clervoy and Mike Foale, participated in an on-orbit interview with three organizations - CBS News, the Hal Uplinger Millennium TV Network and ABS-PBS Millennium Broadcast.
On Tuesday Discovery will approach the space telescope with a series of burns to match its orbit. The rendezvous' terminal initiation burn is to occur at about 4:30 p.m. when Discovery is about eight miles behind Hubble. Brown and Kelly will maneuver the orbiter to a point directly beneath Hubble, then move upward toward it. Clervoy, using the orbiter's robotic arm, will grapple Hubble about 6:40 p.m. and place it on the Flight Service System in the rear of Discovery's cargo bay. There, it can be rotated and tilted to enable space-walking astronauts to better access its equipment bays.
Discovery is in an orbit with a high point of 367 statute miles and a low point of 352 miles. All systems are in excellent condition.