From: Kennedy Space Center
Posted: Monday, April 17, 2000
Shuttle Processing Note: Over the weekend, Shuttle engineers completed the frequency response test that was required after the rudder/speed brake power drive unit replacement effort. Preliminary evaluation indicates that Shuttle Atlantis' hydraulic system is operating normally and that the PDU replacement was a success. Shuttle engineers continue to analyze the cause of the initial PDU failure to ensure that it was an isolated incident.
At about 1 a.m. today, engineers completed a hot fire test of auxiliary power unit (APU) No. 1 confirming a successful hydraulic flex hose replacement. Tomorrow, technicians will also replace a quick disconnect located on an APU No. 2 gaseous nitrogen line. All three APUs will be brought up to flight pressure on Wednesday as part of standard prelaunch testing.
The minor dings located on the vacuum jacket of two liquid hydrogen lines in Atlantis' aft engine compartment have been cleared for flight. Thorough engineering and X-ray analysis confirmed that the documented dings were minor in nature and did not compromise the integrity of the internal propellant lines.
Aft compartment close-outs are in work and ordnance installation begins tomorrow morning. Orbiter midbody umbilical unit mating and leak checks begin today. Preparations are in work to pick up the 43-hour launch countdown on Friday at 7 p.m.
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