The controller was intuitive; moving it up or down made her pitch, her feet tipping up; left or right gave her a yaw, a sideways tilt. She twisted the handle, and made herself roll about an axis through her head to her feet.

The payload bay rotated around her.

“It’s heavy,” she said. “I can feel the unit’s inertia as I roll.”

“You mass more than seven hundred pounds, suit and all, Paula.”

She blipped the RCS thrusters again, and slowed her roll. She finished up facing Lamb, where he clung to the aft cabin bulkhead. She pushed her left-hand controller, which drove her forward and back. There was a gentle shove, and her drifting slowed.

The MMU seemed to be working well, but its scuffs and scorch marks showed its age. And things most definitely did not feel the same, up here, as in the tethered sims on the ground. When she started moving, she just kept on going, until she stopped herself. She was in a frictionless, three-dimensional environment, like a huge ice-rink, where Newton’s laws held sway in their bare simplicity.

No wonder the Station assembly has proceeded so slowly, she thought. We just aren’t evolved for this environment.

“Okay, Paula,” Lamb called. “You ready for your one small step?”

No, she thought.

“Let’s do it.”

“Houston, EV2 is preparing to leave the payload bay.”

“We copy, Tom.”

Benacerraf tipped herself up so she was facing Earth, with the orbiter behind her.

Earth, before her, was immense, overwhelming. The overall impression was of blue sea and white clouds, the white of an intensity that hurt her eyes. When she looked towards the horizon she could see the atmosphere, a thin blue shell around the planet.