Review Point

Gravity’s Embrace

A former space shuttle Columbia astronaut remembers the joys and perils of returning to Earth. By Jim Pawelczyk ’82

The beauty of the Earth from space and the thrill of microgravity are privileges not easily relinquished. So the day you come home from space is intensely bittersweet. Re-entry signals the end to a mission that has been the focus of your life for months or years. You know the people you’ve grown close to—your crew and a fabulously devoted mission team—will soon go their separate ways.

But the homecoming is eagerly anticipated. While I fondly remember my time aboard Columbia, I’ll never forget that first hug from my kids.

Re-entry, of course, isn’t just emotional—the ride itself is surreal in a physical sense. Flying backward and upside down on the descent to Earth places the shuttle and its contents in a state of free fall, balancing centrifugal force against the pull of gravity. So delicate is this poise that a few minutes’ firing of the shuttle’s maneuvering engines, which slows the vehicle’s speed about 1 percent, is enough to drop it from orbit. From this point, it takes less than an hour to come home.

Slowing a 100-ton spacecraft from a speed of 5 miles per second to land on a three-mile strip of concrete is no easy task. For most of re-entry computers fly the shuttle, first flipping it in a handspring so that its underside settles into the cushion of atmosphere beneath. Like a slalom skier on a steep slope, the shuttle shifts from side to side, using the thickening atmosphere to reduce speed.

In a fantastic swap that Newton would appreciate, velocity is traded for heat as the shuttle slows thousands of miles per hour in a matter of minutes. Temperatures approach 3,000 degrees on the nose and leading edges of the wings.

The shuttle takes on a fiery glow, a dragon’s breath of plasma dancing along its back. Inside, crews enjoy the light show in 75-degree comfort. It’s a relative term for people cinched into straight-back seats and clad in 86 pounds of gear, including inflatable compression pants designed to protect bodies weakened from days without feeling gravity’s relentless pull.

As gravity captures the craft, what should seem natural is decidedly unnatural: Items that have floated for days begin to sink. Laughter erupts as my microgravity shovel pass becomes a sinker, leaving a notebook on the floor instead of in my crewmate’s hand. The force builds steadily, never exceeding Earth’s gravity by more than 50 percent, but after 16 days in free fall it feels like a bad experiment with super glue.

During re-entry the shuttle evolves from a spacecraft to a glider. This is the technical marvel of the space shuttle in all its glory. Control jets give way to wing flaps; computer control gives way to the commander’s gloved hand. Double sonic booms announce your arrival over Florida.

Tragically, coming home was different for seven astronauts on the morning of February 1. I imagine they enjoyed Columbia’s special look; the distinctive black chines that flare to form the upper part of Columbia’s wing were unique among the space shuttles. They offered a touch of dignity, I think. Inside, the foot-snagging switches that occasionally embarrass rookie astronauts are a different story.

But I’m certain they looked forward to coming home, humbled to have had the chance to explore space and advance science for our nation and humanity. And now, sadly, their home resides only in our thoughts, hearts, and prayers.

Jim Pawelczyk ’82 is an assistant professor of physiology and kinesiology at the Pennsylvania State University. He served as a payload specialist astronaut on the space shuttle Columbia in 1998. A version of this essay originally appeared in The New York Times.