It's back to Earth with a bump for our Tim

The astronaut, from Chichester, will undock from the International Space Station (ISS) he has called home for the last six months at around 6.30am, and step out of his travel capsule on to Kazakhstan soil just four hours later.

Tim is looking forward to “having the feeling of gravity pull me down on to a comfy mattress” after sleeping weightless in a sleeping bag for six months.

On a recent blog sent down from the ISS, Tim explained that a good night’s sleep would be one of the things he wanted to enjoy first upon his return to Earth.

He said: “I strap my sleeping bag loosely to the wall and then zip myself into it and let myself float. I find it easy to sleep in space but it's probably not as good quality sleep as I get on Earth.

“It's sometimes hard to get your arms into a comfortable position - I normally just fold them across my chest.

“I am actually looking forward to sleeping in a proper bed again and having the feeling of gravity pull me down into a comfy mattress."

He blasted off into space in December as the first Briton to be employed as an astronaut by the European Space Agency.

During his six month mission Major Tim has racked up a series of “firsts” including sending the first Hogmanay and “God Save the Queen” messages to earth, being the first person to receive an Honour while in space, and being the first Briton to undertake a spacewalk.

He has also undertaken research into the effects of space o the human body, and broken records including setting the fastest marathon time ever run in space.

He is not the first Brit in space - that title was taken by Helen Sharman in 1991 when she visited the Mir space station as part of a privately-financed Russian mission.

Major Tim's Soyuz TMA-19M capsule will release its clamps and drift away from the International Space Station at 6.30am British time, and its fiery re-entry will experience speeds of 28,000kph and temperatures in excess of 1600 degrees C before parachutes and landing rockets ensure a soft landing shortly after 10am.

The mission he and crewmates Tim Kopra from NASA and Russian cosmonaut Yuri Malenchenko have undertaken has been named Principia - after Isaac Newton’s seminal work on the laws of motion and gravity.

COUNTDOWN TO A LANDING SIMILAR TO A CAR CRASH

ONE hundred and eighty five days ago, a Russian spacecraft designed in the 1960s blasted off from Kazakhstan carrying a helicopter pilot from Chichester into the history books.

At 10.30am tomorrow, all being well, Major Tim Peake will step out of a tiny capsule and, on a barren steppe in central Asia, his foot will touch the soil of planet Earth for the first time in six months.

Since arriving aboard the International Space Station (ISS) with two crewmates, he has walked in space and completed a marathon while travelling more than 73 million miles as the station has hurtled round the planet in an orbit 220 miles above the surface of the Earth.

But his short, fast journey back, which begins at 3.30am tomorrow, will represent one of the fiercest challenges he has faced yet.

In the early hours of the morning, Major Peake and his crewmates – Tim Kopra from Nasa and Russian cosmonaut Yuri Malenchenko – will bid farewell to ISS colleagues and board the tiny Soyez TMA-19M capsule.

Measuring just 7.3ft long and 7.1ft wide it will be a tight squeeze as the door locks shut at approximately 3am BST, followed by an uncomfortable wait before undocking from the ISS at 6.30am.

While inside and still attached to the station, the crew will check the integrity of the craft and “salt load” their bodies. In space the body holds less water so they will take on additional supplies and salts to prevent the risk of arriving on Earth seriously dehydrated.

Once the re-entry module undocks from the station, Moscow Mission Control will start issuing directions from the ground, starting with the command to float free for 20 metres before firing a controlled 15-second “separation burn” to begin the descent.

At that point the journey to the surface of the planet begins but even with two hours of orbiting the Earth to reduce speed the trip should still take less than four hours and peak at speeds in excess of 28,000km/h (around 25 times the speed of sound).

During the course of the journey the Soyuz will separate into three parts, with the orbital and service modules burning up on re-entry in the denser layers of Earth’s atmosphere roughly halfway through the trip.

The descent module then turns to position its heat shield towards the direction of re-entry, allowing it to use the friction of the atmosphere itself to slow its descent – the friction of which will generate temperatures of 1,600°C.

Once re-entry begins, at an altitude of about 120km, that top speed will reduce dramatically and the crew will be pushed back into their seats with a g-force of four to five g.

The heat will be so intense that the air around the craft will be transformed into an entirely different state of matter: plasma.

Major Peake, from Chichester, explained: “This means we feel four to five times our own body weight and during this time the plasma around our spacecraft will prevent us from communications with mission control and the ground search and rescue team.”

Once the craft reaches 10km above sea level, parachutes will reduce the speed from 864km/h to 324 km/h.

The Soyuz will descend at an angle of 30º to cool, then the main parachute shifts it to a straight vertical descent.

At the last moment, retrorockets fire before touchdown to limit the impact to around 5 km/h which some have still compared to the impact of a small car accident.

Major Tim and his fellow astronauts will be in custom-fitted seats designed to minimise the shock of impact.

Once the tiny pod is safely on the ground, the crew will raise a communication antenna to help rescue teams track down their precise location – although usually search and rescue teams are already on-site to retrieve the space voyagers.

Despite the microgravity generated by the ISS’s orbital velocity and his own efforts including frequent runs strapped down to a treadmill, After the lengthy stay in space and brutal return trip, Tim Peake will be weak and exhausted when the hatch finally opens and he sees direct sunlight for the first time since before Christmas.

So as relentlessly positive and inspiring as this has been, it is worth betting Tim will be pleased to feel the sun on his face and the Earth beneath his feet once again.

TWENTY THINGS MAJOR PEAKE HAS ACHIEVED WHILE IN SPACE...

1 Other Brits have been to space but Major Tim Peake is the first British or UK-born person to fly to space without either a private contract or foreign citizenship.

2 He was the first British astronaut to do a spacewalk – the January mission was cut short after water began to pool in a crewmate’s helmet but it was chalked up as a success after repairing solar panels and returning the station to full power.

3 The spacewalk was the first time the Union Jack, which was sewn on to Major Peake’s spacesuit , officially “flew” in space.

4 Major Peake set an unlikely record in space as the world’s fastest extraterrestrial marathon runner. He ran on a treadmill to coincide with the London Marathon in April, finishing in a time of three hours, 35 minutes and 21 seconds.

5 He is the first person to deliver a “God Save The Queen” message from space.

6 Earlier this month he was made a Companion of the Order of St Michael and St George, making him the first person in history to be named in the Queen’s Birthday Honours while in space.

7 Major Peake didn’t sever ties with the planet while orbiting 220 miles (400km) above our heads, he was the first person to remotely manoeuvre a rover on Earth from the ISS – an exercise in preparing scientists and astronauts to control vehicle on Mars.

8 He also managed to stay in touch with family and colleagues back home – although not always successfully. In December he dialled a wrong number and caused confusion by saying “Hello is this planet Earth?”.

9 He and his crewmates Tim Kopra and Yuri Malenchenko were aboard the international station – first launched in 1998 – when it made its 100,000th orbit of the Earth

10 Among the more lighthearted experiments carried out by the record-breaking astronaut was a film of him tumbling head over heels spinning around 80 times to discover whether you can get dizzy in space. The answer? “Definitely.”

11 Before he ever blasted off from a Kazakh launchpad, former helicopter pilot Major Peake underwent 28 months of training which included piloting the Soyuz spacecraft and a 12-day underwater mission as an “aquanaut” to learn get him acclimatise.

12 During launch, the crew maintained the tradition of each choosing three songs to play: Major Peake chose Queen’s Don’t Stop Me Now, U2’s Beautiful Day and Coldplay’s A Sky Full Of Stars.

13 He sent a Happy New Year message back to the UK which was broadcast on the BBC.

14 The goals of his mission, which he completed, included studies of asthma and immunity as well as attempts to grow human blood vessel cells.

15 He also lent a hand to repairing the station’s ageing infrastructure, including the toilets.

16 The space age collided with the information age when Major Peake took part in the first “Facebook Live” broadcast from space, joining the social network’s founder Mark Zuckerberg to answer questions.

17 As if being the first flag-flying Brit in space wasn’t enough, Major Peake earned his children’s approval when presenting a global success award to singer Adele at the Brit Awards in February, saying “My kid is going to think I’m so cool.”

18 He introduced children to the wonders of space by playing water ping pong in space while hurtling above the atmosphere at 17,000mph.

19 His confirmed return date of June 18 has extended his original mission duration by almost two weeks, taking his space trip past the six-month mark

20 Travelling that fast for that long means Major Peake has travelled around 73 million miles in space.