Drop in Pressure Aborts Spacewalk

CAPE CANAVERAL, Fla. —  Two astronauts who stepped out of the International Space Station for a risky spacewalk were quickly ordered back in Thursday when mission control spotted a pressure drop in one man’s oxygen tanks.

NASA said the astronauts were never in danger. They were safely in the pressurized confines of the orbiting complex within minutes and reported that they were feeling fine.

The spacewalk -- a crucial effort to replace a circuit breaker -- was put off until Tuesday at the earliest. Flight controllers said they needed to understand what went wrong before sending astronaut Mike Fincke and cosmonaut Gennady Padalka back out.

Fincke had just popped the hatch and floated outside when the words came from Russian mission control: “You need to return. Something is not right.”

Mission control informed them that the pressure in Fincke’s primary oxygen bottle was falling rapidly. They sealed the hatch less than 15 minutes after opening it and repressurized the Russian airlock.

Fincke and Padalka were using a combination of U.S. and Russian gear and carrying a spare circuit breaker. The new breaker is needed to restore power to one of the gyroscopes that help keep the space station stable and pointed in the right direction.