Technicians were already assembling the threader when Henry arrived in ED ready-one. The inside of the dome was the same triple-level layout as a free-fall space station; with Haumea’s minimal gravity it made maneuvering large machinery a lot easier. The central deck was the assembly area for threaders. Henry smiled inside his helmet as he saw the six-meter one being prepared; the big machines always delighted him.

The core of this one was the pair of six-meter portals, currently pressed together so tightly they formed a single disk of molecular circuitry a meter and a half thick. Nine robot arms were carefully integrating an elegant egg-shaped frame of brushed aluminum ovals around them, containing a multitude of mechanical components and actuators, wound with power cables and data fibers.

Henry clicked his space suit boots into the floor grid, holding himself in place while the technicians glided around the growing threader like curious fish investigating a shining reef. He watched the process advance while the voices of the crew back in Gylgen babbled away in his ears.

Once the first part of the threader was complete, a similar, smaller version was attached to its front end, then finally an even smaller edition was attached to the end of that. The three together resembled a bizarre Russian doll mechanism caught in mid-separation.

“Henry, we’re ready for you,” the lead technician said.

Henry picked up the second of the two suitcases he’d brought with him from Brixton. He kicked off the floor and floated easily through the air to the threader. To stop he grabbed one of the ceiling handholds, and maneuvered himself back to vertical relative to the decking. Working in zero gee, constantly having to manipulate your whole body mass with a single arm, built muscle bulk like no gym exercise ever could. All space workers developed upper bodies like pro swimmers. And because portal doors meant everyone went back home to Earth at the end of shift, nobody suffered the kind of calcium loss and muscle wastage early astronauts were plagued with on long-duration flights.

He opened the suitcase and took out the circular thirty-centimeter portal. It locked into place on the front of the threader. “Integration complete,” he reported.

“Reading it,” Fitz said. “Running threader procedure checks. You are go to egress the ventlock.”

The magnetic monorail grip on the bottom of the threader powered up, propelling it along one of several rails on the deck. Henry waited until it went past, then grasped one of the curving aluminum ribs at the back and let it tow him along. The rail led down a passageway to the largest ventchamber on Haumea.

As soon as it was inside the cylindrical metal cave, the inner door slid shut and sealed with a fast succession of metallic clunks. The threader extended ten legs, which engaged with loading pins on the chamber floor.

“In position,” Henry said. He looked up, checking the outer door above the threader. A ring of amber caution lights was flashing around the heavy-duty hydraulic actuators.