This post is about space tourism, which means ordinary people travelling into space for leisure purposes and paying to do so. This is a subject which has always been of great interest to me and although the market is very small at the moment I think it will grow over the coming decades. With the proposed launch of Virgin Galactic’s SpaceShip Two later this year, it is a topic which is likely to be in the headlines.
The stuff of science fiction
Even since as a child I read the the novels of British author Arthur C Clarke (1917-2008) I have been fascinated by the idea of space tourism.
As I mentioned in my post on 27 June, “Living on the Moon”, I am particularly fond of “A Fall of Moondust” . It was written in 1961, but set in the 2050s. In the novel the Moon has been already been colonised, and it is visited by tourists from Earth. One of its attractions is a cruise, in a specially designed boat, across one of the maria, or lunar seas, which is filled with an extremely fine and very dry dust which flows like water.
Arthur C Clarke author of “A Fall of Moondust”
Sadly, I think that the chances of frequent tourist visits to the Moon by the 2050s are zero. However, I think that in the future there will be a large growth in space tourism and in the next few decades more ordinary people will be venturing into space.
What do we mean by ‘going into space’ ?
One question we need to think about what talking about space tourism is: what do we actually mean by ‘going into space’? Where does the Earth’s atmosphere end and space begin? This is a question to which there are no hard and fast answers. As we get higher up, the atmosphere gets gradually thinner and thinner and very gradually merges into interplanetary space, but there is no clear line where the Earth’s atmosphere ends and space begins. Most people would agree that:
- a jet airliner flying at 35,000 feet in altitude (10.6 km) is not in space, even though a human would be dead at that altitude without supplemental oxygen, and
- the International Space Station (ISS) which orbits around 400 km above the Earth’s surface is in space.
The diagram below shows a number of key altitudes above the surface of the Earth.
Various Key Altitudes
- The summit of Mount Everest -8.8 km. At this point the air pressure is only one third of that at sea level and even a fit young person acclimatised to altitude could not survive for more than 30 minutes without extra oxygen.
- A jet airliner -10.6 km. This is the height at which a jet airliner flies on a long journey. The air pressure at this height is around 27% of that at sea level and a human would be dead within minutes from lack of oxygen.
- Concorde -18.3 km. This is maximum altitude at which the supersonic aeroplane Concorde could travel. Indeed Concorde, which is sadly is no longer in service, could travel at twice the speed of sound and was advertised as travelling ‘on the edge of space’. At this altitude the air pressure is around 6% that of sea level and the air is so thin the the sky is dark blue in daytime. At this pressure the boiling point of water is around body temperature so that any exposed liquids in the eyes, mouth throat and the lining of the lungs will literally boil away. To prevent this happening, a human would need to be enclosed in a pressurised space suit to survive.
- The manned balloon flight record -39 km. This the altitude record set by the Austrian skydiver Felix Baumgartner in August 2012. When the balloon reached this altitude, he jumped out wearing a space suit. On his descent he reached a speed faster than the speed of sound in free fall before his parachutes opened to slow him down – hence his nickname name Fearless Felix.
- Aurora 100 km to 200 km. Aurora are caused by high speed electrically charged particles from the Sun hitting the Earth’s upper atmosphere, at altitudes of 100 km upwards, causing it to glow. Incidentally, Mrs Geek and I are hoping for a sight of the Aurora Borealis, more commonly known as the Northern Lights, when we visit Finland in September, as they are rarely visible in England. The chance of this is actually pretty low, as we will be in Helsinki and they are seen more often further north, but we live in hope.
- Low Earth orbit -160 km to 2000 km. 160 km is the lowest altitude at which a satellite can remain in orbit. At this altitude, a satellite would be slowed by air resistance, caused by traces of the Earth’s atmosphere, which means it would lose energy and spiral down to Earth within a day. As we get higher than this the atmosphere continues to get thinner and thinner and satellites are slowed less and less by air resistance, enabling them to stay in orbit longer. The International Space Station, which orbits at an altitude of 400 km, loses altitude at the rate of around 2 km per month and rocket motors attached to the station or on visiting spacecraft need to be used a few times a year to lift it higher up, thus maintaining its orbit and preventing it from crashing down to Earth.
- Medium Earth orbit -above 2000 km. Above 2000 km the traces of the Earth’s atmosphere are negligible and a satellite will remain in orbit indefinitely.
So where exactly does space begin?
The Fédération Aéronautique Internationale (FAI), the international body setting standards and keeping records in the field of aeronautics and astronautics defines space as starting 100 km above the surface of the Earth. As you can see, this is a very conveniently rounded number, which strongly suggests that it is somewhat arbitrary. At this altitude the air pressure is around 0.00003% of that at sea level, which is too low for a conventional aeroplane to fly. Although this pressure is very low, it is still high enough to cause so much air resistance that a satellite could not orbit. The thin air would cause it to burn up like a meteorite.
So, space travel means travel to beyond 100 km above the earth. So far, the only space tourists are the few who have been carried into space in the Russian Soyuz spacecraft. The first of these was the American investment manager Dennis Tito who in 2001 traveled on a Soyuz to the ISS and returned 7 days later.
Dennis Tito (left) with his fellow crewmates in his Soyuz capsule- Image in public domain
He paid $20 million for his trip and had to undergo months of tough cosmonaut training in Russia. He was followed by six other space tourists. The last of them, Guy Laliberté, the Canadian founder of Cirque du Soleil, paid $40 million for a 11 day stay in space in 2009.
At the moment, because of the high cost and physical demands of getting into orbit, space tourism is only open to those who are super-rich and able to undergo the necessary training and preparation. Not only is true demand therefore very small, but supply is also very limited indeed. The Russian space agency is – so far – the only organisation with the capacity and willingness to put space tourists into orbit.
NASA never allowed paying space tourists on the space shuttle and, following the retirement of the space shuttle in 2011, America has no capability of putting a human into space. Rather than NASA developing their own spacecraft to do so, the contract to ferry astronauts to and from the ISS will be put out to private corporations. The Dragon 2 spacecraft developed by the SpaceX company is the leading contender to win the contact.
Although initially its primary purpose will be to ferry astronauts to and from the space station, removing the reliance on Russia, it is likely that SpaceX will eventually sell seats on a Dragon 2 orbital flight to space tourists. SpaceX plan to charge NASA $140,000,000, or $20,000,000 per seat if the maximum crew of 7 is aboard.
For a number of years the Virgin Galactic group have been developing the suborbital space plane called SpaceShip Two. This is planned to offers space tourists a much cheaper “taster” of space tourism. Launched from an aeroplane, it is a small plane with a rocket motor rather than a jet engine, which will take eight people up to just beyond the 100 km line thus – just about – qualifying as travel into space. During the flight the passengers will experience weightlessness for around 5 minutes and will be above the 100 km boundary for a couple of minutes. Virgin Galactic eventually plan to have a fleet of five SpaceShip Twos, each seating six passengers, which will fly multiple times a day. Although a definite date for the first flight has not yet been released, it is likely to be later this year or early next year. There is a waiting list of over 500 people for SpaceShip Two flights, each of whom has already paid a $20,000 deposit. At $250,000 for a seat it is hardly cheap, and is well beyond the budget of most ordinary people -including Mr and Mrs Geek. This works out at around $ 7.5 million for for each hour spent in in space! Nevertheless, as competitors emerge and Virgin Galactic build more spacecraft the price may come down – but I doubt it will be within the reach of ordinary people.
Virgin Galactic Space Ship Two in testing -Image provided by Jeff Foust
In my next post I will say more about SpaceShip Two and discuss what being a space tourist would really be like.