Tim Peake, 43, has become the first Briton to walk in space after he ventured out of the ISS to help repair a broken power unit from 12.55 GMT on Friday.
The official name for a space walk is called an Extra-Vehicular Activity (EVA).
Major Peake, writing on his blog, said he felt ‘exhilarated’ by the prospect of walking in space, but said: ‘I have no time to dwell on these emotions.
‘The six hours and 30 minutes we will work on the Space Station’s hull are meticulously planned and Tim and I need to execute each step methodically.
‘Spacewalks, like many critical operations, operate on the buddy-buddy system.
‘Tim and I will constantly be checking each other and relying on each other for assistance if something should go wrong.’
Many British famous faces are watching right now and are giving Peake good luck wishes.
— David Cameron (@David_Cameron) January 15, 2016
— The Who (@TheWho) January 15, 2016
— Paul McCartney (@PaulMcCartney) January 15, 2016
— Tim Peake (@astro_timpeake) January 14, 2016