Between the third and fourth minutes of powered flight, Endeavor, riding heads down beneath her half-dry external tank, accelerated from 4.6 to 6.3 times the speed of sound as she climbed from 43 to 63 nautical miles high. Her nose slowly dropped toward the sea, a clearly curved blue line when viewed upside down by the two fliers behind their six windows.
“Endeavor is press to MECO at four minutes.”
“Thanks, Flight. Go in the sky.”
The ship now carried sufficient energy to reach her main engine cut-off goal should one main engine fail early. Endeavor screamed past 65 nautical miles in altitude, where her gray carbon-carbon composite nose cap glowed a dull red from the intense heat of high speed air friction.
“Press to ATO at 4 plus 20.”
“Copy that, Flight. Pulling three G’s and we’re real tight up here.”
“And from the ground too, Will.”
Should Shuttle lose an engine now, she could still struggle upward to execute an Abort to Orbit, or ATO.
“Negative return at 04 plus 26.”
“Roger, Flight. Then we’ll go forward!”
“Do that, Jack.”
Endeavor was now too high and too far out to sea to turn around to shoot an emergency landing on Cape Canaveral’s runway.
For the next several seconds, the crew rode the most dangerous part of their ascent in terms of abort options. An engine failure during this brief period leaves them too far out over the Atlantic to return to the Cape and too slow to coast to an emergency landing in Europe. Main engine failure now would reduce the 1.2 billion-dollar ship to only a banner headline in the morning newspaper.
“And you’re press to Rota, Endeavor.”
Leaving behind them the momentary No Man’s Land of their abort options, Shuttle can now make an emergency landing if she blows only one main engine. She could use two surviving engines to reach the U.S. Navy air station at Rota, Spain, on the far side of the Atlantic.
Endeavor rode her blue flames into the black, airless sky. Only blue ocean, upside down, can be seen outside the flightdeck windows. The pilots are pressed into their seats by forces which triple their body weight.
“At 06 plus 05, Endeavor is single-engine Rota.”
“Copy, Flight. We’re Go at six minutes five seconds.”
Even with a failure in two of her three main engines, Shuttle now carried enough speed to reach an emergency landing in Rota, Spain, without getting her feet wet.
In the cockpit of white lights and three green television screens on the forward instrument panel, there is absolutely no noise, no vibration, and no feeling of movement. Only the acceleration load of 3 G’s tells the inverted crew that they are in motion hanging by their lap belts.
“Single engine press to MECO at 06 plus 50, Endeavor.”
“Roger, Flight. Good news!”
Shuttle could now make a fragile orbit even if she should lose two of her three main engines. Endeavor pressed onward, upside down, 68 nautical miles above the mid-Atlantic.
Far below and behind, 7 minutes and 13 seconds into the flight, the two SRB’s splashed into the chill sea close to the booster recovery ship USS Mercury.
“Throttles down!” the Aircraft Commander called.
“Copy, AC. You’re Go from here.”
The flight computers automatically reduced the power on each main engine from 104 percent to 68 percent for the final sprint into space. This would reduce the structural strain of an abrupt burn-out when the SSME’s completed their eight and one-half minutes of furious work.
The inertial measurement units sought out their keyhole in the velvet black sky. The primary, on-board computers found their invisible target.
“MECO at 08 plus 33!”
“We see it, Endeavor. Main engine cut-off. Energy state looks right on, Endeavor.”
Instantly, the engines stopped and the fliers floated weightlessly against their seat belts. Jacob Enright immediately grabbed the glareshield on the dashboard before his face. He was seized by the pilots’ somatogravic illusion of pitching forward, head-over-heels, when the forward acceleration suddenly stopped with main engine burn-out.
Riding straight and level upside down, 900 statute miles east of Pad 39-A, 70 nautical miles into the black sky, Endeavor’s engines are quiet. Eight and one-half minutes aloft, the 100-ton bird with the nearly empty external tank attached to her belly coasts bottoms-up at the velocity of five miles per second. Even with her engines stilled, Endeavor still climbed upward at a rate of 220 feet per second. The two pilots were weightless in Zero-G and they could feel their faces become puffy and swollen as blood begins to pool in their cheeks. Their earth-borne circulatory systems did not know what to do with their blood when heart and veins do not have to work against gravity’s pull. Tiny pools of blood collected within the hair-fine capillaries of the crew’s faces. Weightlessness also increased the fluid pressure inside their eyeballs by 25 percent: an unsolved problem which could mean blindness on long flights to the planets.
In the excruciating sunlight of the black sky, where no stars shine in daytime, Endeavor glided silently, nose forward, wings level and belly up. The brown external tank was still bolted to Shuttle’s underside.
“Major Mode 104 now running. Mother likes it. We’re looking at digitals of 80 by 13.”
“Copy, Jack. We see 104 in the computers and we concur with an orbit of 80 by 13 nautical miles. LOS momentarily at Bermuda. AOS Madrid in ten minutes. You are Go for OMS-1 burn at 10 plus 34. First sunset at 32 minutes out… Configure LOS Bermuda…”
Nine minutes from the still hot and steaming Pad 39, almost 1,000 miles behind them, Endeavor coasted out of radio range with the Bermuda Island tracking station.
Endeavor’s preliminary orbit with a high point of 80 nautical miles and a low point of 13 miles was an illusion of orbital physics. Shuttle carried sufficient energy to whirl around the blue planet in this lopsided orbit for years before gravity’s immutable tug cracks the delicate balance between the ship’s velocity and her 100-ton mass. But in reality, the planet’s gossamer envelope of air would wrench Endeavor from an orbit so low within an hour. More kinetic energy must be added to Endeavor to hoist her higher if she is to keep her aluminum toes from tripping over the atmosphere’s fiery fingers. With the external tank nearly dry and the three main engines quiet and cooling, Endeavor must ignite her two powerful OMS engines tucked in her tail to raise the orbit to a survivable energy state. The OMS-1 rocket maneuver would loft Shuttle into a slightly safer, higher orbit 10½ minutes into the flight, in mid-Atlantic out of earshot of any tracking station. Another OMS firing, OMS-2, in half an hour would finish the job of inserting Endeavor into a safe orbit. But first, Shuttle must cast off the external tank which glistens with frost in the burning daylight under the ship’s inverted belly. The flight computers are programmed to disconnect the ET.
“Attitude hold, Skipper,” Enright called 8 minutes 50 seconds into his first ride into space.
“Mother has it, Number One,” the command pilot replied. “Auto sep… ET away!”
Automatically, explosive charges detonated without sound in the airless blackness. The three support brackets holding the ET to Shuttle ruptured. As the brown tank drifted upward into the sky away from the belly-up Shuttle, Endeavor’s reaction control system’s small jets fired automatically for five seconds. The little jets pushed Endeavor downward and away from the freed external tank.
“ET free. Evasive maneuver complete. Delta-V at 4 feet per second, Jack.”
The upside-down pilots could not see the ET rise away from Endeavor as Shuttle slipped downward at a rate of four feet per second. The green television screen read out confirmation of ET separation.