shuttlefan - 29/5/2006 11:22 PMDo they close the pad this week to all non-essential personnel for storable propellant loading--about a 2-day operation?
shuttlefan - 30/5/2006 9:39 AMPerhaps it is to make the vehicle more sturdy because it will be slightly heavier once they load some of the hypergolic propellants onboard?
OKAY with all the talk of hypergolic laoding I will post this:
The Hypergolic Propellant Loading Procedure Know as S0024 (pronounced “Sue 24") is designed to load Monomethyl Hydrazine (fuel) and Nitrogen Tetroxide (oxidizer) propellants into the RCS (reaction control system) and OMS (orbital maneuvering system) tanks. The 44 RCS thrusters are used for attitude control of the orbiter and small velocity changes (usually less than 6 feet per second). The two 6000 pound thrust OMS engines are used for orbital altitude and velocity changes.
During the procedure Hydrazine is loaded into the 3 Orbiter APU (auxiliary power units) fuel tanks and the 4 SRB HPU fuel tanks (2 units per booster). The APUs provide the mechanical shaft power to operate the orbiter hydraulic pumps which in turn operate the main engine valves, thrust vector control system, aerodynamic surfaces, landing gear deploy, wheel brakes, and nose wheel steering. The SRB HPUs are used to provide thrust vector control of the SRB nozzles (also called “rock” and “tilt”).
This is a brief rundown of the S0024 procedure. Many tasks listed here actually occur in parallel. For example the fueling of an SRB HPU, and OMS tank, and an APU may be occurring at the same time.
T + 0
T + 6 Hours
Resume limited Pad accessConduct Engineering walk downAPU console preparations – the APU consoles are configures in the launch control center
T + 28 Hours
The S0024 procedure is completed about 48-50 hours from operation start (not including pre-operation setups). The attached picture shows one of the hypergolic storage facilities and it's relative location to the Pad. The other facility is on the opposite side of the Pad.
Mark Kirkman
DaveS - 30/5/2006 6:24 AMNow they have lowered the "beanie cap" over the ET.