"Imagine walking around with your eyes closed in a fishbowl. Really, that's what was going on ... It's just a very uncomfortable feeling to be with your face underwater for all that time," he said.
Parmitano, a former test pilot, said he was lucky to get back inside so quickly. He figures there was three pounds of water floating inside his helmet when his crewmates yanked it off; that's nearly a half-gallon.
NASA managers have said Parmitano could have choked or drowned, and praised his calmness during the ordeal.
Parmitano's colleagues grabbed towels to mop his bald head once the one-hour spacewalk ended. Some water bubbles escaped and floated away.
The astronauts as well as engineers in Houston are still trying to figure out what went wrong. Parmitano's drink bag has been ruled out. The only other possibility is the cooling system for his suit. Parmitano said his long underwear, containing water tubes, appears to be fine.
"I'm sure that they will find both the problem and the solution," Parmitano said.
Parmitano became Italy's first spacewalker last week. His spacesuit functioned perfectly the first time around. Tuesday's excursion was a continuation of the maintenance work, none of which was urgent.
The trouble began barely an hour into Spacewalk 2.
Parmitano said he felt cold water on the back of his head. Within a few minutes, he felt it covering his ears.
"The water kept trickling until it completely covered my eyes and my nose," Parmitano said.
The sun was setting as the spacewalkers made their way back, making it harder to maneuver in the darkness.
"All those things sort of came together at the perfect storm, so to speak, for us to deal with," Cassidy told TV reporters.
Cassidy said the space station crew reviewed the spacewalk procedures in advance and discussed possible emergencies.
"But lo and behold, what happened was not one of those items that we discussed," said Cassidy, 43, a former Navy Seal.
"My own gut feeling," Cassidy said, "I knew it was time to end it when I saw the water creeping around his communications cap, kind of right by his eyelid. I knew that was a significant amount of water to be in a helmet, and it was time to go in."
Parmitano was low key as he recounted the experience. Once the helmet came off, he said, "that was the end of it".
Spare spacesuits are on board in the event of a space station emergency. NASA wants to be certain the problem is isolated to Parmitano's suit before sending any more astronauts outside.
- AP