Italian Paolo Nespoli, 54, has spent 174 days in space across two missions, travelling into Earth orbit on both NASA’s Space Shuttle and the Russian Soyuz spacecraft. We asked what it’s like to live in space, how it felt to witness the Space Shuttle docked to the ISS and more in our exclusive interview.

How It Works: Why did you decide to become an astronaut?

Paolo Nespoli: Ever since I was a little boy I wanted to become an astronaut. I was inspired by the Apollo missions, though not really Apollo 11. I was more interested in the later missions where they drove the rovers on the moon. I thought it was fascinating, with the astronauts jumping and driving around on the surface. Life was kind of different after that. I was drafted into the Italian army (they still had the draft back then) then figured out that I could make it as an astronaut. I applied twice to the European Space Agency (ESA) and didn’t make it, but on the third selection I made the cut.

HIW: Your first mission to space was on board STS-120. What was it like going to space for the first time?

PN: I was selected fairly young and got to fly after just nine years of training, which is somewhat of a short time to wait compared to many. People asked if I was scared but I wasn’t really. I’d trained so much, I knew what to expect. Feeling the acceleration in the Space Shuttle was amazing. The first couple of minutes it really shakes you. However, I was scared in space, because we’d trained for years and we only had 15 days to complete our mission. All I kept thinking to myself was, ‘You better not mess this up. People have been working on this for years!’ The fear of failure was the scariest thing about going into space.

HIW: What was the hardest part of going to space?

PN: I didn’t mind it so much in space, but my body felt really old when I came back to Earth; the gravity was so intense. I was fine in space, but I’m not exceptional or a superhero. Of the seven Shuttle crew members and three on the Soyuz I was the worst coming back by far. The micro-gravity environment does a lot to your body. You lose a lot of calcium in space; your bones and muscles can get quite weak.

HIW: How did you ensure your body stayed in shape? How did you adapt to life in space?

PN: We’d do about two hours of physical fitness every day. I would say you come back in better shape [in terms of fitness]. Doing two hours of exercise every day for six months, I came back with more muscles and less fat than when I left.

We did about one hour of cardiovascular exercise on a treadmill and another hour of resistance exercise. Obviously, you can’t lift weights in space, so a machine simulates the strain of lifting as on Earth.

There’s no training to prepare your body for its loss of balance. You get nausea and all sorts of things. Your skeleton also stretches (I was five or six centimetres taller than on Earth), and so muscles keep their strength but they are of a different length. Your body’s equilibrium shifts, and when you come back to Earth the muscles start contracting again, but they cannot find the equilibrium point so easily. I remember shaking constantly. Also I could be sitting and feel totally tired. Coming back to Earth is definitely the hardest aspect of being in space – for me, anyway!

On the station, you are isolated and confined, with only a few other people to talk to. You can’t just go out in the evening and see people. For some reason I discovered that whatever I was doing I was seeing pizzas all over the place, such as in clouds when looking at Earth. Freud would probably have a lot to say about that! I thought the food on the station was decent but far away from what an Italian would say is delicious. It was very good from a nutritional point of view, but a little horrific for an Italian. Maybe I was craving pizza because of food like that, or maybe I was just associating pizza with going out with friends and having a beer, maybe that is what I was missing. You are in isolation up there, and there are a lot of things you can’t do, a lot of things which aren’t normal.

Sometimes you forget that you’re in space. It takes about a month and a half before you get out of your ‘Earth habits’, getting used to space, doing things in a different way. For example, we had a table in one of the nodes for eating in the evening. That table had been there for years. It was horizontal in respect to the floor of the deck, because that’s how a table is on Earth. It was protruding a lot, and you’d often hit it when going past. One day I was looking at it and I thought, ‘There must be a way to do this better. Why is this table parallel to the deck, when there’s no gravity?’ You use Velcro to stick things to the table anyway so that they don’t float away, so why not have it at an angle, like a technical drawing table? I kind of tilted it up a little bit, then more, and more, until finally, if you look at it now, it’s tilted at a steep angle because you don’t need a horizontal table and it’s much more out of the way. It was there for ten years before somebody thought to move it!

I would say that it is an environment that is closed, isolated and confined. At first, when I was told I would spend six months on the station before the mission, I thought, ‘Oh my God, six months, are you out of your mind?’ Looking back I realised that I did not have the time to do everything I wanted, like taking more pictures, looking at Earth, playing around more, calling people, doing video clips. You end up doing things up there that make sense, time flies and everything is nice, but you wish you could have done more.

HIW: What was your favourite aspect of living in space?

PN: I loved taking pictures, looking at the Earth and [re]discovering it. It was very enjoyable. You just go to the window and there you have it – a great and gorgeous view. However, when you go to the window randomly, more often than not you’re just going to see an ocean with clouds. It’s nice and blue, but that’s about it. Sometimes you see a piece of land going by and it’s not so recognisable. It’s not easy to figure out what’s what, except Italy! When you start talking about the UK and Ireland it gets complicated because of the angle, cloud coverage, time of day and sun reflection, etc. In the beginning you try to figure out where you are without using the software that tells us, but little by little you start to know what’s going on. By the second/third/fourth months you look out the window and you know where you are – the continent, information, features that are there that you might want to take pictures of, or if it’s boring you might spend a few minutes on something else.

I started using more and more powerful lenses to capture some interesting details that I could see from up there. First I tried to see the Egyptian pyramids, the Great Wall of China, and other landmarks. I wanted to see an aircraft carrier at sea, some volcanoes, special islands, and then I started looking around randomly, taking pictures of things that were astonishing and different. I had this feeling that I was a scientist peering down a microscope that allowed me to take pictures of this small sphere rotating below, discovering microscopic things. I’d look at the pictures and realise that those things were 20 kilometres [12.4 miles] in diameter. You can’t really see things that are any smaller than that.

I became really interested in taking photos of landmarks and countries. I started using social media like Twitter and Flickr because I thought those things were interesting. I decided to start tweeting them to see what people thought. That turned out to be a pretty good source of enjoyment: finding something special and tweeting it to people, asking them for quizzes or riddles from space and seeing all the comments. It turned out to be a very enjoyable way to spend time, letting everybody participate in this adventure.

HIW: Were you asked to take the pictures by NASA or the ESA?

PN: I wasn’t asked to do it by NASA or the ESA. Some of the other astronauts had done it before me. I was not the first. Several of them told me that it was enjoyable. I did not tweet before I went into space because I don’t have much time to do it. I see some people go around with phones all day, typing what they are doing, clicking, clicking, clicking, but I have so many things to do. However, in space it worked out pretty well. Sometimes when I was taking pictures I was asking for help from ESA to identify what I was looking at. Other times I would guess but sometimes I would make a mistake, and people would correct me, so I learned that it was better to verify what I was seeing before half of the world thinks, ‘What is that stupid astronaut doing up there?!’ One of the first weeks I was up I tweeted a picture of a European city and really thought it was London… Turns out it was Paris. How can you make a mistake between London and Paris? It was beyond me. But in space, you travel so fast that you pass by so quickly, and you only have a few seconds to snap a picture. You have no time to research, so mistakes do happen.

HIW: Did it feel like you were travelling at 17,000mph?

PN: Well, it depends. If you are above an ocean, for example, which happened often, it doesn’t look like you are going very fast. But if you want to take a picture of something specific, then you understand how precise you need to be. I’m always on space time now. When I’m at home in the evening, and I look outside and see a sunset or moon. I see a nice picture and think, ‘Okay, I’m going to get my camera and I’ll take a picture in 30 minutes’. In space if you see the moon and you like it, you better take that picture in the next ten seconds because [otherwise] it’s gone. A good sunset is eight seconds and you think, ‘Oh, that’s a nice sunset, I’ll just get my camera… Holy cow, I need a picture now, where’s that camera!’ If you take out the card or wrong lens, then it’s gone. [This is how I mainly perceived speed on the ISS.]

You don’t feel anything physically on the ISS or the Soyuz capsule though. I remember when we detached from the station on Soyuz coming back to Earth, there is a moment in which the engine fires and you slow down and go into the atmosphere, and the capsule breaks up into three pieces. You are in the middle, the only one that gets to Earth; the others burn up in the atmosphere. At that point you are tumbling, finishing with a braking burn. The capsule has separated and you are waiting to be captured by the atmosphere. Then you look outside and realise you’re tumbling. It’s not a nice feeling. Are we supposed to be tumbling, you think. If you don’t look outside you don’t feel it, even at mach 25.

Astronauts Jack Schmitt and Gene Cernan break into song during the Apollo 17 mission of December 1972.

9. Bunny hopping on the moon

Gene Cernan discovers a new and easier way to get around on the Moon during the Apollo 17 mission by jumping with two feet rather than more traditional walking methods.

8. Alan Shepard plays golf

Becoming the first and only person to play golf on the Moon, Alan Shepard takes a couple of shots during the Apollo 14 mission.

7. Armstrong and Aldrin unveil lunar plaque

Neil Armstrong and Edwin “Buzz” Aldrin unveil a plaque left behind on the Apollo 11 mission, which finishes by stating: “We came in peace for all mankind.”

6. Hammer throw

Astronaut Jack Schmitt throws his geology hammer into the distance before Apollo 17 takes off after pleading for permission.

5. Galileo proved corrrect

During the Apollo 15 mission, commander David Scott drops a hammer and feather simultaneously to show that, in a vacuum, all objects fall at the same speed with an absence of air resistance, proving Galileo’s hypothesis.

4. Astronaut takes a tumble

Proving just how difficult it is to cope with the Moon’s weak gravity whilst wearing top-heavy space suits, Jack Schmitt has a couple of falls during the Apollo 17 mission before being called “twinkletoes” by mission control.

3. On board a lunar rover

Astronaut John Young takes the lunar rover out for a spin on the surface of the Moon during the Apollo 16 mission of April 1972. Although only designed to reach about 8mph (13kph), Young unofficially holds the Lunar Land Speed Record of 11mph (18kph).

2. First man on the Moon

Neil Armstrong becomes the first human to set foot on another celestial body at 0256 GMT on 21 July 1969. Many people believe that he fluffed his famous lines as he stepped on to the surface, missing out the “a” as he proclaimed it was “one small step for [a] man, one giant leap for mankind.” However, listen closely and you can almost make out an “a” just after he said “for”, and Armstrong later insisted that he did say “a man”. What do you think?

1. Last humans on the Moon

Marking the end of NASA’s missions to the Moon, the ascent stage of Apollo 17′s Lunar Module takes off on 14 December 1972. On board were Harrison “Jack” Schmitt and Eugene “Gene” Cernan, the last humans to set foot on the Moon. The footage was taken by a camera on the lunar rover left behind on the surface, tracked manually by mission control on Earth.

No one knows for sure, but we can make estimates based on the expected age of the universe and the motions of galaxies throughout the universe. The universe itself is expanding, but not in the way a balloon expands. The expansion is taking place throughout the universe, where space-time itself is being stretched outwards. Whereas a balloon pushes its edges out as it expands, the universe is also pushing its insides outwards as well, but there is no centre of the universe, so everything is moving away from everything else. It’s a bit like baking a ball of dough; the entire dough expands and grows, not just its edges.

However, based on our knowledge of how old the universe is, roughly 14 billion years, we can observe a theoretical ‘edge’ of the visible universe about 14 billion light years away from us. This is the furthest distance we can see, as light that might be further away has not had time to reach us yet. Thus, we can say that the visible universe has a diameter of 28 billion light years, 14 billion light years in either direction from Earth. However, what’s beyond this distance is unknown. The 28 billion diameter visible universe we can observe could be just a tiny fraction of a much larger universe, or perhaps just one in a system of many universes.

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Asteroids and comets are both remnants of the early formation of the solar system 4.5 billion years ago. As of August 2011, there were less than 4,500 known comets in the solar system, compared to over 550,000 known asteroids (although there are thought to be many millions more).

Asteroids are composed of rocky material and metals, while comets are made of ice. As a result, asteroids formed nearer the Sun than comets, because ice could not remain solid at a close distance. Comets that formed further out and later approached the Sun lose material with each orbit because the ice melts, forming a tail behind the body. Asteroids, on the other hand, do not lose material, and thus do not have a tail. Comets are often found in large elongated orbits extending outwards up to 50,000 times the distance from the Earth to the Sun. By comparison, Neptune – the furthest planet of the solar system – is just 30 times further from the Sun than the Earth.

Concurrently, asteroids are usually found following a circular orbit around the Sun and they tend to group together in belts, such as the asteroid belt found between Jupiter and Mars, which was formed when the gravitational pull of Jupiter prevented the asteroids from forming into another planet.

A hypernova, also known as a collapsar, is an extremely energetic supernova. The two are not to be confused, even if their formation is very similar. In a supernova, a star shears off its outer matter but leaves a new star at its centre, often a neutron star. In a hypernova, the force of the explosion tears the inner star apart too. Hypernovas occur in stars with a mass greater than 30 times that of our Sun. Like in a supernova, as the star runs out of fuel it can no longer support itself under its own gravity. It collapses and subsequently explodes, sending out matter in all directions. This releases more energy in seconds than our Sun will in its entire 10 billion-year lifetime.

Hypernovas are incredibly rare. In fact, the rate of hypernovas occurring in the entire Milky Way is estimated to be one every million years, making the observation of the celestial explosions particularly difficult. Twenty-five million light years from Earth in another galaxy astronomers have found what appear to be the remnants of a giant hypernova, providing new information about these huge explosions, but currently there are several theories as to what actually causes them. One school of thought is that a massive star rotating at a very high speed or encased in a powerful magnetic field explodes, ripping apart the inner core. Alternatively, a hypernova could be the result of two stars in a binary system colliding with each other, merging into one gigantic mass and subsequently exploding.

The result is clear, however. A black hole is produced and a huge amount of energy is released in the form of a gamma-ray burst, one of the brightest known events in the universe. In fact, a hypernova releases several million times more light than all of the Milky Way’s stars put together.

In the image above a massive star (30+ solar masses) collapses to form a rotating black hole emitting twin energetic jets, surrounded by an accretion disc of debris. The star is subsequently torn apart by vigorous winds of newly formed isotope 56Ni blowing off the accretion disc, and shock waves produced as the jets plough through the stellar material. The hypernova, whose luminosity is powered by the radioactive decay of 56Ni, is the result of the explosion of the star.

The larger of Mars’s two moons (the other being Deimos), Phobos is not circular in appearance like most other moons in the solar system. At its largest extreme it is 26 kilometres (16 miles) across, but only 18 kilometres (11 miles) across at its shortest.

Eons of meteoroid impacts have given Phobos a rather battered appearance, with dark trails resulting from landslides marking the steep slopes of the large craters on its surface, in addition to a host of smaller craters.

The moon is tidally locked to Mars, and its close proximity to the Red Planet – an average distance of 9,378 kilometres (5,828 miles) above its surface – means that half of the moon has a temperature of -4°C (25°F), while in contrast, the far outward-facing side can drop as low as -112°C (-170°F).

The largest feature on this Martian moon is the Stickney Crater (above), a ten-kilometre (six-mile)-wide crater caused by an impact from a large meteoroid. The crater is full of fine dust and debris, suggesting that boulders slide down its sloped walls and settle further down in the basin.

Phobos is moving 20m (66ft) closer to the Red Planet every 100 years and is expected to crash into the surface of Mars or burn up in its atmosphere within the next 10 million years.

Images courtesy of NASA/JPL

Planets have moons because early in their formation they were introduced to other space- faring rocks that either crashed into the planet and threw off debris, or were trapped in the gravitational pull of the planet. Over billions of years the orbits of these rocks (or debris), now under the influence of the planet’s gravity, were squashed into a spherical shape that kept them encircling their host planet.

To visualise how a moon becomes ensnared, imagine the earth is a ball placed on a floating sheet of frictionless paper (to represent gravity). The ball depresses the paper and if you roll a coin (to represent a moon) around this depressed area at a fast enough speed, it will circle the ball indefinitely.

So, why don’t moons have their own moons? The answer is that the planet they are orbiting has a much stronger gravitational pull, so over time it would selfishly take other objects in as another moon for itself.

The Mars500 mission was an important study to ascertain the mental and physical strain on humans in closed isolation on a long-haul trip to Mars. The mission was a join project between the ESA and Russian Institute for Biomedical Problems, beginning on 3 June 2010 and culminating on 4 November 2011. In it, six candidates (three Russians, two Europeans and one Chinese) were sealed in an isolation chamber for 520 days, the approximate journey time for a real mission to and from the Red Planet.

The isolation facility they were held in was based in Moscow and consisted of five modules; three to replicate the spacecraft (where the volunteers spent the majority of their time), one to replicate the Mars-lander astronauts would travel in to the surface and another to simulate the Martian surface, with a total combined area of 550 m³ (19,423 ft³).

To accurately simulate a mission to Mars, the volunteers were subjected to the same conditions that would be apparent for astronauts making the trip for real. For example, all communications outside the pod were given a time delay, ranging from one-minute when near “Earth” to 20 minutes at “Mars”, while the crew were also given a diet identical to that of astronauts on board the International Space Station.

The volunteers carried out the same tasks that astronauts would in a real-life Mars trip, including simulating a Martian landing and performing experiments. The participants were able to talk to friends and family via video link at various points in the mission, albeit with the aforementioned time delay.

With the mission finished, future astronauts making the long-haul trip to our neighbouring planet will have useful knowledge of the conditions they might expect when being in isolation for such a long period of time and at such a great distance from home.

Mars500 images courtesy of ESA