Richard Lawrence - The Mammoth Book of Space Exploration and Disaster

A couple of weeks later, Gilruth and Webb were aboard one of NASA’s R4Ds when over the radio the president was addressing Congress, pledging NASA to a lunar expedition. Gilruth was “aghast.” He looked at Webb, who knew all about it. In his special message to Congress, delivered on May 25, 1961, President Kennedy set out his vision on a number of “urgent national needs,” one of them the conquest of space. In a resonant call to arms, the president asked the nation to “commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth.” No other space project, Kennedy declared, would be “more impressive to mankind, or more important for the long-range exploration of space.”

Glenn’s flight had been launched by the Mercury Atlas 6 (MA-6) which carried 122 tons of kerosene and liquid oxygen, more than four times the fuel load of the Redstone rockets which had powered Shepard and Grissom’s sub-orbital flights. Scott Carpenter had been the back-up to Glenn, who had left the face plate of his helmet open on re-entry. At the formal inquiry he was cleared of the charge of panicking. Deke Slayton was scheduled to make the next orbital flight but during a G force test in August 1959 it had been noticed that his heartbeat was erratic. In January 1962 an Airforce cardiologist recommended that he should be grounded and Carpenter was given the next flight, designated MA-7. Carpenter named his capsule Aurora 7.

Carpenter’s daughter, Kris Stoever, was six years old at the time and later helped her father write his account. Carpenter’s wife’s name was Rene. Kris Stoever:

Finally, at a little after seven forty-five, the great Atlas engine were fired, sending out billows of steam, flames, dust, smoke, fumes and heat. At this signal, all four Carpenter children abandoned their posts in front of the television, where all three networks were covering the launch live, and dashed out to the beach. Already the pale morning sky was streaked with contrails, and in the distance they could see the Atlas lifting off. Against the low slant of the sun, Rene saw the Atlas streak into the sky and then disappear.

Just before liftoff, Scott had been thinking about his grandfather, Vic Noxon. “At last I’ll know the great secret,” the old man had told Dr Gilbert on a golden Sunday morning on the Front Range. He was dying. He knew he was dying. He wasn’t afraid. Scott was confident that May morning, like his Grandpa Noxon, that everything was going to be all right – that this experience so long anticipated had finally arrived. As the rocket engines began to rumble and vibrate beneath him, he became preternaturally alert to the many sounds and sensations of liftoff.

There was surprisingly little vibration, although the engines made a big racket and he felt the rocket swaying as it rose. The ride was gentler than he expected. He looked out his window, placed directly overhead, to see the escape tower streaking away like a scalded cat. One especially odd thing, for one accustomed to level flight after the required climb, was to see the altimeter reach seventy, eighty, then ninety thousand feet and yet know that he was still going straight up.

No one noticed at the time – there was no dial to measure its functioning – but the capsule’s pitch horizon scanner (PHS) had already started malfunctioning. The Mercury capsule was chockfull of automatic navigational instruments, among them the PHS, which does just what the name implies: it scans the horizon for the purposes of maintaining, automatically, the pitch attitude of the capsule. For MA-7, however, the PHS immediately began feeding erroneous data into the Automatic Stabilization and Control System (ASCS), or autopilot. When this erroneous data was fed into the ASCS, the autopilot responded, as designed, to fire the pitch thruster to correct the perceived error. This in turn caused the spacecraft to spew precious fuel from the automatic tanks. Fuel was a finite commodity.

Forty seconds after tower separation, the pitch horizon scanner was already 18 degrees in error. It was indicating a nose-up attitude, or angle, of plus-17 degrees while the gyro on the Atlas showed pitch to have been minus 0.5. By the time of spacecraft separation, the pitch gyro aboard the capsule had “slaved” to the malfunctioning pitch-scanner output and was in error by about 20 degrees. NASA later found that the error would persist, intermittently, to greater and lesser degrees, throughout the three-orbit flight, with near-calamitous effect as MA-7 readied for reentry less than five hours later.

At the moment, Scott was focused on the gravitational forces, which peaked at a relatively gentle 8 Gs. He marvelled at the intense silence, but then experienced an even greater sensation of weightlessness. At five minutes, nine seconds into the flight, he reported to Gus listening as Capcom at Cape Canaveral: “I am weightless! – and starting the fly-by-wire turnaround.”

The sensation was so exhilarating, his report to the ground was more of a spontaneous and joyful exclamation than the routine report he had expected to make. The fly-by-wire manual controls were exquisitely responsive and quickly placed the Mercury capsule into a backward-flying position for the beginning of Scott’s first circumnavigation of the earth. John had accomplished this maneuver on autopilot, as specified by his flight plan, causing the system to expend more than four pounds of fuel in the process. In the fly-by-wire control mode, it could be done using only 1.6 pounds.

The three-axis control stick (or hand controller) designed for Mercury was a nifty device that allowed the pilot to fly the capsule in either the “manual proportional” or “fly-by-wire” (“wire” here meaning electrical) systems. The manual proportional system required minute adjustments of the control stick – of perhaps 2 or 3 degrees – to activate the one-pound thrusters. Fore and aft movements controlled pitch, which is the up or down angle of the spacecraft, side-to-side movements controlled roll. The pilot could control or change the direction left or right, by twisting the control stick – a hand control that replaced the old rudder pedals used in airplanes The MA-7 flight plan specified only limited use of the ASCS.

Gus Grissom, as Capcom, gave Carpenter the good news: “We have a Go, with a seven-orbit capability.” Carpenter replied: “Roger. Sweet words.”

Carpenter described:

Sweet words indeed. With the completion of the turnaround maneuver, I pitched the capsule nose down, 34 degrees, to retroattitude, and reported what to me was an astounding sight. From earth-orbit altitude I had the moon in the center of my window, a spent booster tumbling slowly away, and looming beneath me the African continent. But the flight plan was lurking, so from underneath the instrument panel I pulled out my crib sheets for the flight plan written out on three 3 x 5 index cards, and Velcroed for easy viewing. I could just slap them up on a nearby surface, in this case the hatch, covered with corresponding swaths of Velcro. Each card provided a crucial minute-by-minute schedule of in-flight activities for each orbit. They gave times over ground stations and continents, when and how long to use what type of control systems, when to begin and end spacecraft maneuvers, what observations and reports to make on which experiments. In short, they told me, and the capcoms, who had copies, what I was supposed to be doing every second of the flight – every detail of which had been worked out, timed, and approved before liftoff. A brief investigation of these cards is enough to suggest constant pilot activity. But to get the best appreciation of just how busy we all were during those early flights, read the voice communication reports between the capcoms and the astronaut.