He tried to put the problems aside. He was still flying, still in shape. And, no matter what was happening to the MH96, he had a program to work through, a whole series of experiments for NASA and the USAF.

One minute forty-one.

He activated the solar spectrum measurement gadget and the micrometeorite collector in his left wing pod.

Suddenly, the MH96 control system’s gains shot up to 90 percent, for no apparent reason, and the automatic RCS cut back in.

He checked his instruments. Like most experimental aircraft, the X-15’s cockpit had a primitive, hand-made feel, with rivets and wires showing. Well, it seemed he had full control ability for the first time since entering his ballistic flight path. He welcomed the return, but he was unnerved, all over again. What next?

He had very little confidence left in the battered old bird. Maybe she knows it’s her last flight; maybe she’d prefer a blaze of glory to a few decades rusting in some museum.

He would soon be going over the top, the peak of his trajectory, at 260,000 feet.

It was time to begin the precision attitude tracking work required for the solar spectrum measurement. He needed a nose-down pitch, and a yaw to the left. He was already flying at almost a zero-degree angle of attack, but was yawing a little to the right, and rolling off to the right as well. So he fired his wing-mounted roll control thruster for two seconds to bring his wings level, and his yaw control thruster to bring the X-15’s nose around to the left. The X-15 was like a gimbaled platform, hanging in the air, twisting this way and that in response to his commands. To stop the left roll he fired another rocket -

He was still rolling, too far to the left. Christ. What now?

The MH96 had failed again, and had cut out the automatic RCS, just as he was completing his maneuver.

He continued to rotate. To compensate he held his right roll control for eight more seconds. But the air was so thin that his aerodynamic controls were degraded, and the response was sluggish. He fired his manual RCS yaw rockets.

He could feel sweat pooling under his eyes; one problem after another was hitting him, blam blam blam.

Suddenly the MH96 cut back in with its automatic RCS. That stopped his yaw, short of the correct heading. Stone fired his manual yaw again; this time as he approached the reference heading the yaw was countered by the automatics, apparently correctly — but the damn thing cut out again, and he yawed past the reference.

And, on top of that, his roll attitude indicator ball was rotating. He had started rolling to the left again. He tried to wrestle that back with three short pulses on the manual roll RCS, but he overshot, and started a roll to the right…