Spacewalking astronauts took extra safety precautions on Saturday to avoid getting toxic ammonia on their suits.
The spacewalk on Saturday was to rearrange the International Space Station plumbing but the astronauts had to be careful to avoid the coolant still lingering in the lines.
Victor Glover and Mike Hopkins had no trouble removing and venting old jumper cables to remove the ammonia.
But there was so much of it that Mission Control worried the frozen white flakes could have gotten on their suits.
Hopkins was surprised at the amount of ammonia unleashed into the vacuum of space. "There's more than I thought," he told flight controllers.
Even though the stream of ammonia was directed away from the astronauts and the space station, Hopkins said some icy crystals may have contacted his helmet.
Mission Control said it would do inspections as a result. The astronauts' first suit check found nothing amiss: "Looks clean," Hopkins said.
NASA did not want any ammonia getting inside the space station and contaminating the cabin atmosphere.
Mission Control said the astronauts had already spent enough time in the sunlight to bake off any ammonia residue from their suits about four hours into the spacewalk.
But Glover later complained of eye irritation, saying his right eye was watering. He then quickly assured Mission Control that blinking seemed to help.
Once the ammonia hoses were emptied, the astronauts moved one of them to a more central location near the NASA hatch, in case it's needed on the opposite end of the station. The ammonia jumper cables were added years ago following a cooling system leak.
The hose work should have been completed during a spacewalk a week ago, but was put off along with other odd jobs when power upgrades took longer than expected.
There were other chores on Saturday including replacing an antenna, rerouting cables and tightening connections on a European experiment platform.
Saturday's spacewalk got started almost an hour late. It was the sixth spacewalk and the last for this U.S.-Russian-Japanese crew of seven. All but one was led by NASA.