Peake, who arrived at the space station last month, is part of a six-month mission and has the distinction of being the first British astronaut to live at the International Space Station - and he would have been the first to take a spacewalk.
Mr Kopra had reported a high carbon dioxide reading in his spacesuit earlier in the outing, but felt no symptoms, and mission control decided the alarm was due to a faulty sensor.
Kopra said the glob of liquid was about four inches long and two inches high (10 by five centimeters). Indeed, Kopra took time to thank everyone for their help as the air lock was pressurized.
The International Space Station called off a spacewalk planned for Thursday afternoon because of a water leak in the helmets of the crewmembers tasked with carrying it out.
Crew member Scott Kelly photographed Major Peake's gloves for "future reference and inspection", the ESA said, before his helmet was removed too.
Back then, Italian astronaut Luca Parmitano's helmet and suit filed between one and one and a-half liters of water. The suit was refurbished following the 2013 incident.
Chief astronaut Chris Cassidy, who was Parmitano's partner during the aborted 2013 spacewalk, said the cold temperature of the water indicated a leak from somewhere in the spacesuit's backpack, which contains a cooling system.
Before the spacewalk, Peake tweeted: "Popping outside for a walk tomorrow".
"The risk of high-voltage sparks means the job must be completed as the Station flies through Earth's shadow, giving them around 30 minutes to swap the failed unit for a spare", NASA said. The eight solar panels, which feed electricity into the station, should now be fully operational.
The ISS circles the Earth every 90 minutes, spending 31 of those minutes on each pass in the dark.
Mission Control said the spare - dubbed Dusty for its 17-year tenure in orbit - appeared to be working properly.
Engineers suspect the original unit suffered an internal electrical short. Luckily, both of them in that time had already completed their primary objective of the spacewalk, which was to restore a lost power channel to normal operations. The action unfolded on the far reaches of the space station.
Peake received a bounty of well wishes as he became the first spacewalker to wear the Union Jack on his suit. It's explored all over the world.
Former NFL player Lawrence Phillips found dead in prison cell
Considered by many as the definition of wasted potential, a life littered with poor choices comes to a sad conclusion. Phillips appeared in eight games for Calgary, rushing for 486 yards and a TD before being released.
