“Mark one minute, Houston,” Jones reported. “Five nautical miles in altitude, twenty-three nautical miles downrange, velocity twenty-three hundred feet per second.”
“Roger, Lightning. You’ve passed through Max Q. Looking good to throttle engines back to one hundred percent.”
“Roger, throttling up,” responded Kessler.
“One minute and forty-five seconds, Lightning.”
“Roger,” acknowledged Kessler.
“Looking good, Lightning. Mark one minute, fifty-five seconds. Twenty-one miles high, five thousand feet per second. Initiate Solid Rocket Booster separation.”
“Roger, Houston. Starting SRB sep.”
Kessler watched the pyrotechnic display as both SRBs simultaneously separated from the sides of the external tank.
“Confirm separation, Lightning.”
“Smooth as glass, Houston, smooth as glass.”
“Good, Lightning. Two minutes, fifteen seconds. Press for MECO.”
“Roger, Houston. Press for MECO,” acknowledged Kessler as Lightning’s on-board guidance system converged, steering Lightning for its precise window in space for Main Engine Cut-Off. Lightning was now thirty-five nautical miles high.
“Okay, Houston, the engines are coming down and looking good,” reported Jones as he monitored the main engines’ status on the control panel to his left.
Lightning rose higher and higher as its speed blasted past six thousand feet per second. The communications link between the orbiter and Houston switched from NASA’s ground-tracking stations to one of three satellites from the Tracking and Data Relay Satellite System in geosynchronous orbit 22,000 miles above the Earth. Lightning’s data, acquired by the five-thousand-pound satellite, was transmitted to the EDRSS ground station at White Sands, New Mexico, where it was relayed to Johnson Space Center.
“Lightning, Houston. You’re looking good at three minutes.”
“Roger, copy looking good at three.”
The sky began to darken. The colorful blue of just a minute earlier had turned into one of a less vivid hue, as the orbiter scurried through the Earth’s stratosphere at nearly ten times the speed of sound. Kessler had only been exposed to a maximum of three Gs during Max Q. Quite a contrast from his days as a naval aviator when pulling seven or eight Gs in a twisting, turning F-14D Tomcat was an everyday occurrence.
“Mark three minutes, fifty-five seconds, Lightning. Mark negative return. Repeat, negative return. You’re a go for space!”
“Roger, Houston.” Kessler eyed the instruments. Fifty-eight miles high at eight thousand feet per second. He looked over at Jones, who smiled and gave him a thumbs-up. He stared at Jones for one more second before he felt a strange vibration. Something he had never felt before. Lightning began to tremble.
“Houston, Lightning here. I think we’ve got a—”
His words were cut short by a powerful blast. It shook the entire vessel. Images of Challenger’s explosion flickered in front of his eyes as what was once a clear view of the cosmos was suddenly engulfed in a ball of flames. Kessler felt momentarily disoriented. He wasn’t sure what had gone wrong.
“SSME failure! SSME failure!” screamed Jones.
“Shut it down, Lightning!Shut down number-one SSME now, NOW!”
Kessler reached with his right hand for one of three covered switches located in the middle of the wide center console. He lifted the cover and shut off number-one Space Shuttle Main Engine as they left the wrathful flames behind and free space was in plain view once more. “Number-one SSME off.”
“Lightning, you are to press to ATO! Repeat, press to ATO!”
Kessler frowned. There were four abort modes for the space shuttle. The first was to simply return to the launch site, but at this altitude and speed, that option was no longer available. The second abort mode was called TAL, for Transoceanic Abort Landing to a landing strip at either Zaragoza or Moron Air Bases in Spain, but a powerful storm had all but closed those bases. The third abort mode was called AOA, or Abort Once Around, meaning the shuttle was unable to reach a stable enough orbit but had enough speed to circle the Earth once and then land. The fourth, and preferred option was to Abort to Orbit, or ATO, and it was used when the shuttle could not achieve its desired orbit but could reach a lower stable orbit. Given Lightning’s current speed and altitude, and the fact that two of its SSME engines continued to provide plenty of thrust, NASA was opting for ATO, which was actually the preferred of the abort options.
“Roger, press to ATO,” he finally responded.
Kessler rotated the abort mode switch to the ATO position and depressed the abort push button, initiating the computerized programs that would manage the abort. He then throttled up the two remaining main engines to 109 percent. He felt the light kick and nodded approvingly.
“Houston, Lightning,” Kessler said. “Sixty miles altitude, five hundred miles downrange, velocity twenty thousand feet per second. What the hell happened?”
“Can’t tell for sure, Lightning. Computers are running diagnostics on number-one SSME.”
“Press to MECO in one minute, thirty seconds. Systems remain nominal,” he reported, referring to Main Engine Cut Off, the moment he would shut off the two remaining engines, which he was keeping burning for a little longer to reach a reasonable orbit.
“Roger, we copy, Lightning.”
Everything appeared normal once more, but Kessler knew that could be deceiving. The explosion could have loosened some of the heat-resistant tiles that protected the orbiter from the extreme temperatures during re-entry. He was not that concerned about losing tiles on the upper fuselage, but it would be critical if tiles underneath were missing, where temperatures would reach over two thousand degrees during Earth re-entry.
“Houston, MECO in fifteen seconds.”
“Roger, Lightning.”
“MECO in five… four… three… two… one… MECO! Seventy miles at twenty-seven thousand feet per second,” Kessler called out as both operational main engines shut down. He then proceeded to prepare Lightning for External Tank separation.
“Five seconds for ET sep. Four… three… two… one… we have ET sep.” Kessler performed an evasive maneuver by moving below and beyond, and translating to the north of the External Tank. He watched it moving away from the side window. He relaxed. They would reach orbit. A low orbit, but nevertheless an orbit. With their current speed he estimated Lightning would achieve an egg-shaped orbit of 140 by 110 miles, the balance point between the Earth’s gravitational pull force and Lightning’s centrifugal force.
“Lightning, Houston here. We just double-checked all computer outputs before launch. All systems showed nominal.”
“So what do we do now?”
“You’re in low Earth orbit. OMS burn in fifty-three minutes, ten seconds.”
The two Orbital Maneuvering System engines would be used to reach a more stable orbit. Each OMS was powered by highly pressurized helium reaching a titanium-layered tank filled with 4500 pounds of hydrazine, and another tank packed with an oxidizer. The helium gas — performing the same role as an SSME turbopump — would force both propellant and oxidizer through an array of pipes and valves leading to the combustion chamber. The chemicals would then ignite on contact in a hypergolic reaction, generating a combined thrust of twelve thousand pounds.