With his feet wedged into the foot restraints, Enright let his body float backward until he was nearly horizontal in the open bay. His heavily gloved hands floated before his helmet. The two safety divers floated at his elbows. Behind them, two NASA utility divers straddled each ledge of the 15-foot-wide shuttle bay.
“Okay, Chief. All set down here.” Enright peered over his neckring at the dials and controls strapped to his small chestpack. As with the helmet he would wear in space during extravehicular activity, the bottom portion of his clear faceplate on the helmet was optically ground to magnify the chestpack dials under his chin. “Air at 28 PSI, suit inlet temp at 65, outlet at 75 degrees, nitrogen at 2500 PSI each tank. Don’t feel any fish inside the suit. Real snug here, Chief, and ready to engage the MMU.”
“Copy, Jack,” the deck chief replied into his microphone headset from behind his poolside console. “Go for MMU activation.”
At the chiefs side, Colonel Parker scanned the console’s digital numerics relaying Enright’s pulse and suit temperatures from the water.
In space, the MMU maneuvers about by 24 compressed nitrogen jets. But in the water simulation, the MMU scoots around propelled by water jets. Enright’s nitrogen gauge on the chestpack was one more simulation, one more meter to read too high or too low, one more caution-and-warning light to flash in simulated catastrophe.
“ ’Kay, Chief,” the speaker crackled. “Powering up.”
Strapping the 300-pound MMU to one’s back, a pilot nestles his behind into it. Like sitting in Grandfather’s great chair, the pilot becomes part of the MMU.
A boxy wing projected from the upper corners of the MMU outward along each side of Enright’s helmet. Each of the eye-level booms contained forward-shining work lights. A tiny thruster nozzle was positioned on each wing, level with the pilot’s jaw. In space, each small jet fires nitrogen gas with one and a half pounds of thrust to maneuver the pilot in a backflip. Two similar nozzles faced outward from the side of each neck-level projection. These thrusters maneuvered the pilot either sideways or in a slow roll, clockwise or counter-clockwise. At the outside of each of Enright’s knees, two matching wings projected from the base of the MMU backpack. Each of these pods contains one knee-level, forward-thrusting jet and two outside-thrusting jets. One jet in each of the head wings and in each of the knee-level wings points backward.
“Telescoping arms deployed,” Enright called from 35 feet under water. From beneath each armpit, he adjusted an arm-length boom which locked into place under each of his arms. These booms fit the length of the space suit’s arms. The pilot cradled each of his forearms upon the white arms of the MMU which projected nearly perpendicular from the backpack. At the end of each arm, Enright grabbed a T-shaped control handle between his gloved fingers.
“Rotation Hand Controller engaged.” Enright’s right hand flicked the switch, energizing the MMU’s right-arm control handle. This handle would control his in-place attitude. By firing the water jets with the handle in his right hand, his wrist movements would “pitch” him forward or backward, “roll” him clockwise or counter-clockwise, or “yaw” his heels sideways left or right.
“THC engaged,” Enright called topside.
“Understand Translational Hand Controller activated,” the chief confirmed. In his gloved left hand, Enright gripped the translational T-handle which would activate the MMU’s jets to shove him through the water upward or downward, left or right, and forward or backward.
One of the divers slowly circled Enright and carefully touched the pilot’s helmet neckring and hoses locked to the suit from the PLSS — the Portable Life Support System backpack permanently attached to the suit’s upper torso. The PLSS pack was nestled inside the MMU backpack as it would be in space. The diver gave Enright a wet thumbs-up sign.
“Ready, Chief,” Enright radioed over his single umbilical line, which reached to the surface and to the deck chiefs console. There would be no such safety tether in space. Colonel Parker’s face moved from the console’s dials and caution lights to the shimmering image of his sunken partner.
“Go to secure the flying grapple fixture, Jack.”
“Rogo, Chief.”
The four watchful divers gave Enright room to twist his cumbersome body attached to the bay’s foot restraints.
Gently, the submerged astronaut leaned toward a breadbox-sized fixture mounted on a tubular brace in front of his position. Facing the chest-high structure, the pilot carefully grabbed the grapple device in his gloves. He pulled his body toward it until he aligned his chestpack with the device’s corners. The grapple fixture snapped into place upon Enright’s chestpack brackets.
“Grapple fixture secured,” Enright called. “Coming free.”
Enright pushed a release lever atop the grapple unit, and the fixture parted from its bay support stand.
“See you free, Jack,” the chief confirmed.
Flexing his weighted ankles, Enright straightened his body. Each of his weighted arms found the MMU’s forearm cradles. Each of his gloved hands clutched a T-handle.
“And we’re flying,” Enright called as his left hand moved the THC handle. Water jets squirted from the base of the MMU.
“TVC direct, Chief.”
“Copy, Thrust Vector Control to direct, Jack.”
The jets thrusted upward as long as Enright pushed the left-hand T-handle upward. The pilot rose. Ten feet above the open bay’s floor, Enright fired downward-shooting jets behind his ears. The flier stopped and floated near two windows in the submerged simulated flightdeck.
“You’re a tad out of my field, Jack,” the wall speaker crackled with a garbled, water-filled voice. The diver behind the windows in the rear of the boilerplate shuttle flightdeck peered through the window which faced aft into the open bay. “Only have your feet, Jack.”
“Okay. Comin’ down.” With a downward push on the THC handle, Enright dropped 12 inches and arrested his descent with a brief burst from the downward-thrusting jets beside his knees.
“Gotcha now, Jack,” the diver gurgled behind his window.
“RHC checkout,” Enright called. Topside, the deck chief touched the digital readout of Enright’s pulse. Colonel Parker followed the chiefs fingers. The numbers read 80.
“Copy, Jack. Stay cool.”
The pilot twisted the T-handle to the right. Two water jets beside his left ear and two jets beside his right knee squirted outward. Slowly, without moving off, Enright’s body rotated counter-clockwise as viewed from the window he faced.
“RHC Go in roll.”
“Got it, Jack,” the chief radioed.
Moving his right hand in the opposite direction, Enright’s rotation stopped. He was upside down in the water and motionless.
Pushing his right-hand T-handle sideways, Enright executed a half circle and ended up standing on his head.
“You’re upside down,” the pilot radioed to the diver he could see behind the aft flightdeck window.
“No. You are, Jack” came a garbled voice with a stream of shimmering bubbles.
“Roger that. Rollin’ aft.” The white space suit rotated on its head until the pilot faced the shuttle’s submerged tail at the far end of the open bay. He stopped his rotation and then pitched rightside up with small movements of his right hand on the T-handle.
“RCS real tight, Chief.”
“Copy, Jack. Reaction Control Systems Go. Clear to translate to the target, Jack.”
The black object floating beside the open payload bay hung by cables reaching out of the water to an overhead derrick. Silently, on the deck chiefs command, the support cables flexed and the sunken cylinder began a slow rotation in place beside the shuttle mockup.