♫ Spaceman, I always wanted you to go into space, man! ♫

After nearly five hours in space, British astronaut Tim Peake completed his first spacewalk, at 17:31 GMT on Friday 15 January.  Intended to last over six hours, the space walk was cut short after his US colleague Tim Kopra reported a water leak in his helmet.

Major Tim is currently on a six-month mission to the space station for the European Space Agency.  The UK astronaut described his first space walk as “exhilarating”, and posted a selfie on Twitter (top image) saying the feat would be “etched in my memory forever”.

That was despite being told to return to the International Space Station (ISS) just four hours into a six and half hour mission to repair a broken power unit and lay new cabling.  Earlier, Major Peake told of his pride in stepping into space with the Union Jack on his space suit, saying it was ‘a privilege’ and ‘a proud moment.”

A moment, Tim Peake spent many months preparing for…

 

Working under Pressure and Avoiding the “Bends”

The astronauts need to ‘pre-breathe’ before any spacewalk.  Inside the ISS, the astronauts live in air at pressures similar to on Earth.  Outside, however, there is no air pressure, so astronauts wear spacesuits to keep safe.

Operating a spacesuit at normal air pressure is impractical as it creates large pressure differences between the inside of the spacesuit and the vacuum of space.  Just as passenger jets operate at reduced air pressure, so do the spacesuits worn by astronauts.

By reducing the pressure differences between the inside and the outside, both jumbo jets and spacesuits do not need to be so heavy and cumbersome to withstand the pressure.

For the astronauts, the lower pressure also makes it easier to move their arms and legs in the spacesuit.  The disadvantage to working in lower pressure, however, is that as you transition from high to lower pressure is that the normal nitrogen in your blood can form dangerous bubbles inside.

This is a very serious condition known as decompression sickness or ‘the bends’.  Scuba divers are at risk as they return to the sea surface after spending time deep underwater (at high pressure compared to sea level).

Astronauts go through a similar process, leaving their higher pressure environment leaving their higher pressure environment inside the ISS for the lower pressure spacesuit.  An effective way to stop the nitrogen from causing problems is by removing it altogether.

This is what Tim and Tim had to do prior to their space walk.

By breathing pure oxygen for two hours, their bodies no longer have any nitrogen.  The astronauts do some light exercise to help speed up the process, as well as continue preparing for the spacewalk.

 

The Two Tims

It all happened under the watchful eye and guidance of NASA astronaut Scott Kelly.  The two Tims – Tim Kopra and Tim Peake – set off on their walk.

The Union Jack ‘flew’ officially space for the first time yesterday, and David Cameron commended the astronaut for ‘making history’.  The flag could be seen clearly on the British astronaut’s shoulder as Major Peake exited from a hatch on the ISS on a tricky six hour mission.

It was the 192nd spacewalk.  Watching from the window of the ISS, American Kelly said:

“It’s really cool to see that Union Jack in space.  The Union Jack has explored all over the World, now it’s exploring space.”

Before the recall, the spacewalk was running ahead of schedule.  It had been timed to the minute, so that the power unit could be removed in darkness, when there was no chance that solar rays on the ISS panels could spark a short circuit.

Major Peake and Colonel Kopra slowly made their way over the main strut of the space station to a faulty power unit some 200 feet from the hatch.  The power unit linked to the solar panels had short-circuited on November 13th.  The ISS had not been running on full power since then.

They had to wait for a ‘working eclipse’ to give them 31 minutes of darkness to work in, with the unit only illuminated by their head torches.  The broken regulator box was replaced with a spare power unit, nicknamed “Dusty”, which arrived in 1999 on the ISS.

 

Four hours and 10 minutes into the space walk

Major Tim Peake’s historic first spacewalk ended abruptly on Friday night, when water started to pool in his crewmate’s helmet, forcing NASA to call for an immediate termination of the technical mission:

“Guys, you can start opening your cuff checklists to page seven; we are in a terminate case.”

Mission Control

 

Around 15ml of fluid was found in Tim Kopra’s helmet and its absorbent padding was swollen with liquid, which is thought to have leaked from the cooling system.

Although the duo were able to complete successfully their main job of replacing a faulty electrical unit that regulates power from the station’s solar panels, other scheduled work, including routing many metres of cables for new docking ports, had to be left for future spacewalks.

“All’s well that ends well,” said mission commentator Rob Navias.  He said it was a “safe and successful end” to the spacewalk, if a bit early.

 

Not the first experience of a water leak in a spacesuit

Meanwhile, Italian astronaut Luca Parmitano – who also suffered a water leak in his helmet on a spacewalk in 2013 – tweeted his congratulations.

Mission controllers are gathering evidence on what might have caused the bubble of water to form inside Tim Kopra’s helmet.  Station commander Scott Kelly is helping the astronauts inside the equipment room of the ISS.

Tim Kopra’s suit and helmet will be tested and suitably analysed.  The temperature of the water gives one clue, as cold water suggests it came from some sort of leak inside the space suit, rather than sweat or condensation.

 

All’s Well That Ends Well

This is the third time that astronauts have reported water inside their helmets.  In 2013, a spacewalk was abandoned after less than an hour when Parmitano’s helmet began filling with fluid.  The astronaut said he feared he would drown after his nose became blocked.

An inquiry found a similar leak, caused by a blocked filter, had occurred on an earlier mission although it had not affected the spacewalk.

Last February, Nasa’s Terry Virts also reported water in his helmet. In a video captured by his crewmates he was seen making visible ripples by blowing on the water.