Top ten spacecraft

Douglas Adams, in The Hitchhikers' Guide to the Galaxy, wrote "Space is big -- really big -- you just won't believe how vastly, hugely mind-bogglingly big it is. You may think it's a long way down the road to the chemist, but that's just peanuts to space."

Space's roominess is good news for us rapidly multiplying humans, because it seems logical that we should one day want to expand into our solar system -- and possibly further. But because of our frail and squishy bodies we need some heavyweight protection to leave the cosy home comforts of our bijou atmosphere, and great ingenuity to even have a look around. This list celebrates the best spacecraft -- those that have taken us to new places or brought us information about what's out there.

So sit back, cool your jets and point your telescope at ten of the most magnificent achievements in the history of human-kind's exploration of our little bit of the universe. We know there will be some disagreement about our selection, but then it wouldn't be the Internet if there weren't constant arguments about virtually everything. -Ian Morris

10. Mars Express/Beagle 2
Squeaking into the top ten through patriotism rather than any real spacefaring merit, Beagle 2 was a British innovation that could have made a significant contribution to our understanding of Mars. If it hadn't broken into a million pieces.

Britain has never had any sort of manned space programme, but that hasn't stopped us from being as enthusiastic about all things spacey as our trans-Atlantic cousins. In 2003 it looked like we might get our chance at being a part of something special when Beagle 2 was scheduled to land on the surface of Mars, having been conveyed there on the ESA's Mars Express. The mission was conceived by Professor Colin Pillinger, who instantly became the UK's favourite mad, whiskery scientist.

As we all know, Beagle 2 was destroyed by Decepticons on the surface of Mars. Had it survived, it was to send back detailed information about the surface of everyone's favourite red planet, and tell us about what sort of life might have been there in the past. A jolly good try, nonetheless.

Photo credit: ESA

9. Vanguard 1
Not content with littering the planet, humans are rapidly filling up the skies. We need a plan to clear our junk up, and Vanguard 1 is the perfect reminder that the problem isn't just going to go away.

At 50 years old this year, Vanguard isn't the most remarkable piece of technology, but it is the oldest. Vanguard was the fourth artificial satellite to be placed in orbit and is now one of an estimated 12,000 pieces of non-operational space-junk that are larger than an orange. It's also deeply worrying -- if you spend any time in space at all -- that there are a further 100,000 objects in space that we have no way of tracking.

Space junk is a problem that's worsening too, with more and more things being launched into space, and then eventually abandoned. The Chinese have also conducted experiments to destroy satellites in orbit, and in so doing have created space debris on a massive scale.

Vanguard also holds the much more prestigious honour of being the first satellite to use solar power. It managed to send data for six years after its battery died.

Photo credit: NASA

8. Prospero X-3
The Prospero deserves some love, because its arrival in orbit made Britain the sixth nation to successfully use a domestically created rocket to deliver a payload to low Earth orbit. Okay, we're grasping at straws. We even had to take it to Australia to launch it.

Prospero was a fairly simple device, really just a sideline of the UK's Black Arrow missile research project. It had some solar cells to test, and a tape player, which played 730 times before giving up the ghost. The satellite also contained an FM transmitter that supposedly still broadcasts on 137.560MHz, although it was officially deactivated in 1996.

The satellite is still in orbit, and was apparently last heard transmitting an FM signal in 2006. It has an expected orbital life-span of some 100 years. Which means it won't be destroyed by the ravages of re-entry until around 2073.

Photo credit: artq55 via flickr (licence: cc-by-sa-2.0)

7. Mir
Living in space is the dream of every dorky child from San Diego to Ipswich, and it's a dream that doesn't die when you reach adulthood.

As much as the ISS is the space station for now, it wasn't the first and we think Mir needs to be credited because it was remarkable for so many reasons. Firstly, it was constructed over a period of ten years, starting with the core module, and then bolting new bits on the side.

Mir also holds the record for the continuous manned presence in space, just a few days short of ten years. Between 5 September 1989 and 28 August 1999 there were always people on board the station -- much of the junk in space is their daily garbage. It travelled 3.6 billion kilometres in its lifetime.

At the end of its life there were plans to exploit Mir for space tourism, and run it like a hotel for the mega-rich in orbit. It proved too expensive to fix all the problems with ageing components, however, and on 23 March 2001 the 124-tonne space station was de-orbited and burned up in the atmosphere.

Photo credit: NASA

6. Apollo 11
It's probably the most obvious choice on this list, but the simple fact is Apollo 11 was the first mission to put a man on the Moon. The Moon, man! The Moon!

The problem these days is that science-fiction TV shows and movies have spoilt us. We assume that messing around in space is as easy as it looks in Star Trek. But the fact is, humans are pathetically weak and require a ludicrous amount of molly-coddling in order to stay alive.

Apollo 11 not only managed to keep its crew alive, plonk them on the surface of the Moon and take off again, it also returned them safely to the surface of the Earth so they could tell us how amazing the view is up there and make us all sick with jealousy.

Photo credit: NASA

5. Pioneer 10
As humans we want to learn about the world around us. But the world is pretty much all discovered -- apart from the sea, but that's cold and wet -- so the next step is a voyage through the solar system to really get a sense of how insignificant we are.

Pioneer 10 was the first spacecraft to travel through the asteroid belt, and is the first artificial object to leave the solar system (although there's considerable debate about what constitutes leaving the solar system).

Originally designed to report on the asteroid belt, Pioneer 10 is powered by a radioisotope thermoelectric generator, mounted some distance away from the body of the craft, to prevent messing up the instrumentation.

The last time we spoke to Pioneer 10 was on 23 January 2003, and conversation had all but dried up by then. With Pioneer unprepared to discuss such things as telemetry, it barely acknowledged our existence, as it travelled on to bigger and better things. In 2 million years or so, Pioneer 10 will reach Aldebaran, by which time it will be nothing but a flying memorial to a planet Earth long since destroyed by mutant camels.

Photo credit: NASA

4. Vostok 1
Despite successfully sending animals into space, no one knew what would happen to the first cosmonaut, so Yuri Gagarin must have had some iron-clad danglies to risk leaving the atmosphere. Plus it was one hell of a technical feat.

No list of the top spacecraft would be complete without the one that started manned space exploration. The Vostok 1 was the vessel that put the first human in space, and Earth orbit too.

No one knew how weightlessness would affect Gagarin, so he wasn't allowed any control of the Vostok, although in an emergency situation there was a code that could be used to unlock the controls. He was, essentially, at the mercy of a computer program with nothing to do except take notes and write a postcard to his mum.

The launch of Vostok wasn't entirely without trauma. Although Gagarin didn't know it at the time, the second stage of the rocket burned for longer than it was supposed to, putting him in a different orbit. That would have meant that if the braking engine didn't fire, he wouldn't have had enough oxygen to return to Earth.

In the end though, after a 108-minute journey, Gagarin returned to the atmostphere, ejected from the re-entry module, became a global superstar and best of all, really annoyed the Americans.

Photo credit: NASA

3. Manned manoeuvring unit
Like Gagarin, Bruce McCandless must have some rock-solid goolies. Would you push off into outer space with only a gas-filled rocket pack strapped to your back? McCandless did, so we salute him and the device he used.

Not so much a spacecraft as an extra-vehicular device, but when it's the only thing that's going to allow you to get back to your extraterrestrial conveyance, we think you'll afford it the same respect as any other.

The MMU got its debut on 7 February 1984 when McCandless used it and was made famous by two photographs taken on 12 February, when McCandless used it to put a distance of 97m between himself and Columbia.

Propulsion was provided by nitrogen pumped out of 24 nozzles at the rear of the MMU, and it could run for around 6 hours, depending on what the astronaut was up to. NASA retired the manoeuvring unit in 1986, after the Challenger disaster, because it was deemed too risky -- many of the jobs it would be used for had been cancelled for safety reasons anyway. Astronauts now stay tethered to their craft, and you can hardly blame them.

Photo credit: NASA

2. Space Shuttle orbiter
Every wannabe astronaut in the world looks at the Shuttle as their ticket to space. Sure, it's had its fair share of problems, but it's still an amazing spacecraft.

There are people who argue that the orbiter is a gigantic waste of time and money. And to some extent they are right, because re-usable spacecraft aren't particularly practical and don't offer massive advantages over single use craft.

But that said, it's still fair to say the Shuttle is a marvel of engineering, and has almost certainly done a huge amount to inspire children worldwide to imagine flying to space.

The Shuttle will make its last scheduled flight in 2010, to the International Space Station. This mission isn't guaranteed, though, so the end might come earlier for the Shuttle. But in its life, the five shuttles -- Columbia, Challenger, Discovery, Atlantis and Endeavour -- have spent more than 1,100 days in flight over 120 missions. Collectively they have orbited the planet nearly 18,000 times, deployed 66 satellites and docked with ISS and Mir 32 times. By the time it is retired, the Shuttle is expected to have cost the US government a total of $174bn.

As useful as the Shuttle has been, it hasn't been without human cost. In total, 14 astronauts have been killed in Space Shuttle disasters, in two separate accidents -- the launch of the Challenger in 1986 and the re-entry of the Columbia in 2003.

Photo credit: NASA

1. Voyager 2
No spacecraft has achieved more than Voyager 2. It has taught us about the solar system, been to planets it wasn't scheduled to go to and it's never once asked for overtime or a Christmas bonus. It's what we call a trouper. We salute you Voyager 2, and wish you the best for the eternity you'll be wandering across the universe.

Voyager 2 is described as the most productive space probe yet to be deployed. Launched in 1977, it is now more than 9.7 billion miles away from Earth. In its 31-year life Voyager 2 has done far more than it was designed to, visiting Jupiter, Neptune, Saturn and Uranus and finally becoming an interstellar probe.

Voyager 2 is made up of over 65,000 components, has transmitted more than 582GB of data back to Earth and weighs three-quarters of a tonne, but operates on just 400W of power.

It continues to work, even today, thanks to a nuclear power source that won't become totally depleted until 2025. Even once the probe does finally shut down its last electrical system, it could continue to be of use -- if an alien race encounters it. Voyager has a golden disc on-board that contains information about mankind, Earth and a selection of music from across our planet. If extra-terrestrial life forms discover it, and are somehow able to work out what we're banging on about, they may decide to pay us a visit. At the very least, as long as it doesn't collide with anything, Voyager could tell a tale of the Earth long after we're all dead and gone.

Photo credit: NASA