“Goin’ to normal on the Caution and Warning, Jack.”
As the ET drifted away, a valve in its frosted nose popped open automatically. Unburned fuel vapors shot from the open valve like a small rocket engine. The programmed release of gas will cause the tank to tumble end over end to assure that it will incinerate when it plows into the atmosphere over the Indian Ocean. Since Shuttle had yet to perform the OMS-1 rocket burn, the jettisoned tank’s lonesome orbit is fatally low.
“Mother has our OMS-1 targets, Jack. Inertial attitude, deadbands are 3.5 degrees attitude, 0.3 degrees per second in rate, and 0.2 degrees per second in discrete rate.” The command pilot scanned the left of three television screens at the center of the forward instrument panel. “TIG at 10 plus 32; BT 01 plus 27; Delta-V 165; Alpha plus 05 degrees by DAP in Vernier mode.”
“Watching, Skipper.”
Mother’s green face told her pilots that the first burn of the orbital maneuvering system’s two rockets would occur automatically if given the go-ahead at 10 minutes 32 seconds into the flight and would ignite for 1½ minutes until Endeavor had picked up another 165 feet per second forward velocity to add to her speed over the sea of 25,668 feet per second. The digital autopilot, the DAP, and Mother set Endeavor’s upside-down nose five degrees above the sea’s blue horizon. Shuttle coasted toward Spain with the ship flying belly-up, wings level, nose pointed toward Europe.
The Colonel pressed his PROCEED computer key on the small keyboard by his gloved right hand.
“TIG minus 5, 4, 3, 2, 1. Ignition!” the AC called out.
Eighty-five feet behind the pilots, each OMS rocket in Endeavor’s tail thundered to life with each engine pounding away with three tons of thrust. As the two engines fired, the flight computers automatically began to dump overboard the unburned propellants trapped in Shuttle’s internal fuel lines from the quiet main engines. First, 3,700 pounds of liquid oxygen spewed out through the cooling center main engine. When this was completed, 1,700 pounds of unused liquid hydrogen would be dumped into space through the umbilical vent on the starboard side of Endeavor’s tail. Helium gas would then flood the frigid fuel lines to drive out any traces of unburned propellants to avert an explosion in Shuttle’s bowels.
“Shutdown!” the AC called as Mother pulled the plug on the two OMS rockets after 87 seconds. “Looks good, Jack. Delta-V right on at 165 for an orbit of 132 by 57 nautical miles. On our way now, Buddy!”
Endeavor, well clear of the tumbling external tank, climbed toward her higher, safer orbit in pursuit of LACE. Their new orbit’s low point of 57 nautical miles was still fatally low. But the OMS-2 burn in 28 minutes would fix that.
“MPS inerting routine is continuing, Skipper. Major Mode 105 now running.”
“Roger, Number One. Douche ’er out, Jack.”
The cleansing of the Main Propulsion System would continue for another ten minutes.
“Close your doors, Jack.”
The copilot anxiously watched five lights on the cluttered instrument panels at his right side.
“ET umbilical doors closed and latched, Skipper.”
Enright pushed five lighted pushbuttons which confirmed that two large doors had closed and sealed on the underside of the rear of Endeavor’s black wings. Through these two doors in the ship’s belly, the ET’s 17-inch-wide pipes had passed into Shuttle’s insides to feed propellants from the ET into Shuttle’s three main engines, which remain permanently attached to the ship’s square tail section. Failure to seal the doors, each four feet square, would spell doom during re-entry’s searing heat.
“OPS-2, Major Mode 205, running in the GPC.”
“ ’Kay, Skipper.”
“And at 15 minutes out, let’s secure the APU’s, Jack.”
Endeavor coasted silently on her back above the middle of the cold North Atlantic. From this height, the hazy blue horizon of the sea was 957 statute miles distant from the forward cockpit’s six large triple-paned windows. Creeping toward them over the far eastern horizon, the islands of the Azores emerged from the planet’s fuzzy, curved edge. The upside-down crew could have seen the small islands but for the haze at the Earth’s distant comer and the achingly white sun directly overhead where it was noon in mid-Atlantic.
“APU shutdown, Skipper. My side, Panel Right-Two: APU coolant pumps, Loops A and B, off. APU automatic shutdown to inhibit. Hydraulic circulation pumps One, Two, and Three, off. Ignition switches lever-locked off, off and off. Fuel tank valves lever-locked close, close and close. APU controller power One, Two, and Three, lever-locked off. Okay, Skip, three auxiliary power units secured.”
With Endeavor’s three main engines cooling, and with the wings’ elevons and the tail’s rudder not needed until re-entry and landing, the ship’s three hydraulic systems were put to bed for two days.
Directly beneath Endeavor, the seven small islands of the Azores glowed blue-green in a sparkling sea.
“God! Looky there, Skipper!” Enright pressed his helmet to his side window. The tiny islands glistened in sunlight, where under Shuttle it was 2 p.m. on a sunny winter day. Shuttle’s clocks set on Houston time read 9:15 a.m.
“Endeavor, Endeavor: Houston remote, Madrid local. We have solid S-band lockup at sixteen minutes. How do you read?”
Enright started as his reverie was broken by the crackling radio in his ears. After crossing the Atlantic from one end to the other in 16 minutes without radio traffic from Earth, it was easy to forget that a legion of technicians far below were anxious to invade Endeavor’s weightless privacy as the ship hurtled eastward and crossed a new time zone every four minutes.
“With you, Houston,” a Kentucky voice drawled 780 miles west of the Spanish coastline, a distance to be flown in only 2½ minutes.
“Okay, Endeavor. We’re getting a good solid downlink from you. We see Major Mode 202 running for rendezvous with your target. You’re clear to run GPC Number One for GNC functions, GPC Two for rendezvous, and GPC Three for systems maintenance in Major Mode 801. Computers Four and Five to standby in Major Mode 106. We show your target at range 206 miles and closing. Slight out-of-plane error of point 0-0-7-5 degree. Your OMS-2 burn will therefore be a combination mid-course correction with the programmed Delta-V and a plane change. No need to induce a nodal crossing with the target vehicle. Your OMS-2 burn pad follows: TIG at 40 minutes 51 seconds; Delta velocity plus 151 point 9 and 03 feet per second plus Y; BT of 91 seconds. Backroom boys are Go for a closed loop solution for an ‘M equals One’ rendezvous. And we have some SM data for you when you’re ready.”
“Okay, Houston,” the Mission Commander called. Both pilots flew headsdown over the North Atlantic toward the west coast of Morocco. They rode in their bulky orange pressure suits but without their gloves. Inside their helmets with the laser-proof visors in position, two microphone booms reached to their slightly swollen lips, puffy from only 18 minutes of weightless spaceflight.
“ ’Kay, Houston. Understand Go for on-board rendezvous solution. Super. Copy OMS-2 burn at 40 minutes plus 51 seconds; burn time 91 seconds; velocity change 151 point niner feet per second with half a mile plane adjustment. What do you have for systems management?”
“Endeavor: Houston by Madrid. We want you to go to Loop Mode on the signal processor. And we recommend going to water Loop One on the ARS. Inhibit water Loop 2. We show you carrying a tad excess heat in the freon loop. Keep an eye on flash evaporators. We don’t see any problem at this time in keeping the bay doors closed until your first pass Stateside. But we may have you initiate PTC over Australia.”
“Understand, Flight. Water Loop One up, Two down. Let us know about the passive thermal control. We would rather not be in rotisserie mode when we shoot the TPI.”