Speaking from the International Space Station, he said life in orbit “was absolutely spectacular”.
He arrived at the space platform on Tuesday after blasting off from Kazakhstan on a Soyuz rocket.
During a live link-up, he did a backwards somersault and said he was surprised how quickly his body had adapted to weightlessness.
How dark space is
“But I am amazed how quickly my body has adapted,” he added.
“On my second day I woke up feeling ready to go to work and I have had no problems since.”
The first professional British astronaut said the most unexpected thing was “the blackness of space”.
“We always talk about seeing the view of planet Earth and how beautiful it is and you come to expect that.
“But what people don’t mention that much is when you look in the opposite direction and you see how dark space is.
“It is just the blackest black and that was a real surprise to me.”
And he said one of the questions he gets asked the most is what the space station smells like.
“It is certainly not unpleasant – it is a kind of metallic smell but not chemically or bad in any way. It is quite distinctive,” he said.
He said on Christmas day he would be missing friends and family but at least he would be able to orbit the Earth 16 times and look down on the planet.
It’s not every day that you get to talk to an astronaut in orbit. But as the International Space Station slid above Europe this afternoon, I was among a group of journalists invited to Europe’s astronaut training centre in Cologne to ask questions.
We had been warned to avoid small talk because of the inevitable confusion that can be caused by a three-second delay – as the signals bounce from ISS to distant satellites to remote ground stations and back again. But after a while we all got used to it. I wanted to know if he had suffered from space sickness, like many new astronauts – his first 24 hours had been “rough” he told me but now he was fine.
Another question was about how he was sleeping – and he said he was happy not to tether his sleeping bag to a wall but to drift around instead. Did his tea taste different? That came from someone on Twitter. OK, he said.
And, as our time drew to a close, the experience of chatting to someone in orbit started to feel a little less abnormal. I almost forgot that Tim was hurtling through space. Until he was asked to try a somersault, which he did enthusiastically but badly.
Mr Peake said he would be working out in space on Friday afternoon to get some exercise.
According to the European Space Agency, he has a number of tasks to perform, including unpacking cargo and taking part in an experiment looking at the effects of microgravity on the bone marrow.
Mr Peake is among six crew members living and working in space.
They include US station commander Scott Kelly, who is spending a year on board the ISS.
Earlier, in tweets he said he had enjoyed some home comforts such as tea and a bacon sandwich.
In a tweet, mentioning the Nasa astronaut, the 43-year-old from Chichester in Sussex said: “What makes a good leader? @StationCDRKelly having a hot bacon sarnie waiting as my 1st meal on #ISS. Boy that tasted good! #Principia.”
And he added: “1st 48hrs on ISS – busy but incredible. Amazing how fast the body adapts to new environment. Found my tea … life is good!”
The former Army aviator and helicopter test pilot also received messages of support from the Queen and Sir Elton John after the successful launch and docking on Tuesday.
He tweeted singer Sir Elton John from space, quoting his famous song Rocket Man, in response to a good luck message.
And he tweeted the Queen from space after Buckingham Palace’s twitter account posted a good luck letter from the monarch.