In nine short minutes yesterday morning, Mike Fincke made the day of 15 middle and high school students as the orbiting astronaut answered their questions over a radio link to Upper St. Clair High School.

Fincke, an Emsworth native who has been aboard the International Space Station since April, chatted with students over a radio connection established by two amateur radio groups, the Wireless Association of the South Hills and Washington Amateur Communications.

"I was just so excited that we actually made contact," said Pat Palazzolo, the coordinating teacher who had worked up until 3 a.m. to prepare for the event. The date for the exchange had been postponed several times over a period of weeks, she noted.

School doesn't start until Monday in Upper St. Clair, but Palazzolo said she had no trouble finding students -- eight boys and seven girls from the high school and from Fort Couch and Boyce middle schools -- willing to come to the high school on their last day of summer vacation.

"He was wonderful with the kids," she said of Fincke. They had submitted questions in advance to NASA but, because of the time crunch, only nine of the 15 students had a chance to ask a question.

"That was the tough part," she said.

Most of the questions had to do with what it's like to walk in space, what's difficult about living in the space station and what stars look like from orbit.

But they didn't get a chance to ask Fincke, whose wife gave birth to their second child about two months after he went into space, the question that Palazzolo found most intriguing: "Do you think giving birth in zero-G would be easier or more difficult than on Earth?"

The chat was part of a space-to-students program called Amateur Radio on the International Space Station, a joint effort of NASA, the American Radio Relay League and the Radio Amateur Satellite Corp. A 1984 Upper St. Clair graduate, Lesley Retallick Lee, works at Johnson Space Center in Houston and encouraged Fincke to talk with students from the district.

Fincke and his space station partner and commander, Cosmonaut Gennady Padalko, are preparing for the final space walk of their six-month expedition. They will open the hatch at 12:50 p.m. on Friday.

During a planned six-hour excursion, the pair will replace a coolant regulation valve for a system that controls the temperature of equipment on the Russian segments of the space station. They also will install several antennas that will be used as navigation aids for docking of the new Automated Transfer Vehicle. That unmanned cargo ship, built by the European Space Agency, will make its maiden flight to the station next year.

During a press briefing yesterday, Paul Boehm, the expedition's lead extravehicular activity officer, said Fincke has apparently succeeded at repairing the balky cooling system of one of the station's American space suits. The cooling problem has forced Fincke and Padalka to use only the station's Russian space suits during their space walks.

Fincke and Padalka are scheduled to be replaced by a fresh crew and to return to Earth aboard a Soyuz spacecraft in late October.