Moscow ? It was a sickening feeling the NASA chief hoped never to experience again, certainly not three months later.

But when communication was lost just minutes before the touchdown of the Russian capsule returning three men from the international space station, Sean O’Keefe relived the morning of the Columbia disaster all over again.

He shuddered just thinking about it Monday.

“God, it was just unbelievable is what it was,” O’Keefe told The Associated Press.

Unlike the Columbia accident in February, when NASA knew within minutes the shuttle had broken apart over Texas and all seven astronauts were dead, Sunday’s gut-wrenching search dragged on for two hours.

“It was high anxiety, there’s no doubt about that,” said O’Keefe, who watched the events unfold from Russia’s Mission Control outside Moscow.

O’Keefe was overcome with emotion when astronauts Kenneth Bowersox and Donald Pettit and cosmonaut Nikolai Budarin finally were found safe in Kazakhstan, nearly 300 miles from where the Soyuz spacecraft should have landed.

NASA will participate in the investigation into why the Soyuz capsule went into a steep ballistic entry, exposed the crew to twice the usual gravity forces and landed so far off target. A commission of mostly Russian aerospace engineers was created Monday to look into the matter.

This new Soyuz model, made roomier at NASA’s request to accommodate larger astronauts, was making its first test flight for re-entry.

On Sunday, the head of Soyuz maker Energiya, Yuri Semyonov, said on Russian television that one of the Americans on board hit the wrong button.

Then on Monday, Semyonov was quoted as saying that one version of the account had Budarin — an experienced flight engineer, but not a pilot — pushing the button that engaged the ballistic entry. He said the cosmonaut assured him he did not touch anything. A Soyuz descent is almost entirely automated.

Bowersox said the computer readouts shifted suddenly from a normal re-entry to a ballistic one. The only way to manually trigger that is to press a button on a handle, and Budarin had that button covered so that it would not be pressed accidentally, the astronaut said.

“We don’t think we did anything to cause that to happen,” Bowersox said in a NASA interview broadcast Monday.