The fragments of Virgin Galactic’s SpaceShipTwo now littering the Mojave desert in California are a grim reminder of one of the harshest facts in modern aeronautics: that attempting to travel beyond our atmosphere can be a punishingly dangerous activity.
Those who seek to slip the surly bonds of Earth take their lives in their hands each time they climb into their capsules or spaceships. Engineers may argue that they have developed safe, foolproof spacecraft and launchers, but the wreckage of SpaceShipTwo suggests such claims remain premature.
US astronomer and writer Carl Sagan once said: “If we are to send people into space, it must be for a very good reason – and with a realistic understanding that almost certainly we will lose lives.”
To date, 18 US and Soviet astronauts have died in space accidents, and even more during training. This latter group includes Yuri Gagarin, the first human in space, who died in 1968 during a routine jet exercise while preparing for his second flight into space.
Two key threats face those who fly in space: gravity and air, or rather lack of air. The latter problem killed Georgy Dobrovolsky, Viktor Patsayev and Vladislav Volkov when a faulty valve vented the air in their Soyuz capsule as it began re-entry in June 1971. When a recovery team opened its main hatch, they found all three had suffocated.
However, it is the problem of overcoming gravity that makes space travel particularly dangerous, and this issue has beset astronautics from the first days of manned spaceflight. To reach gravitational freedom in Earth orbit, a craft must reach speeds of thousands of miles per hour, and to date this has been achieved only by igniting powerful combinations of fuel and liquid oxygen, or by using solid propellents to create mighty, fiery upthrusts. Most manned missions have therefore involved astronauts perching themselves on top of towers of high explosives in the hope that these ingredients will ignite in a controllable manner.
In general, things did go well – until the space shuttle was developed in 1980s. Strapped to the side (instead of being perched on top) of giant tanks of hydrogen and oxygen, and then fitted with two solid state booster rockets, the space shuttle became the most dangerous mode of transport ever built. On 28 January 1986, the shuttle Challenger was destroyed shortly after take-off when flames from a solid booster caused its liquid fuel tanks to explode. All seven people on board were killed.
Then, in February 2003, the shuttle Columbia disintegrated over Texas as it returned home, an accident that was traced to damage caused by debris falling on to the shuttle from a fuel tank during launch two weeks earlier. Again, all seven on board were killed.
America’s three remaining shuttles were retired in 2011. Since then, Nasa has pursued a policy of using private launch companies such as Space X – owned by PayPal billionaire Elon Musk – and Orbital Sciences Corporation. So far, only their unmanned rockets have been used, mainly to send supplies to the International Space Station. Last week Orbital came unstuck when one its Antares rockets, destined for the ISS, exploded seconds after lift-off, destroying 2,250 kg of equipment. The company nevertheless remains buoyant about its prospects, while Space X continues to promote ambitious plans to fly humans into orbit on its Dragon spacecraft.
Both these companies use relatively standard rocket technology. But Richard Branson’s Virgin Galactic has adopted a very different, relatively low-tech approach, based on a system developed by US designer Burt Rutan.
Strapped to the belly of a jet-powered mother ship, the Virgin Galactic Spaceplane would be lifted to an altitude of 15km. There it would be released and its rocket engine ignited, sending it soaring up at more than 4,000km an hour. The six passengers would have six or seven minutes to float round the cabin in zero gravity before the ship began to arc downwards.
This system has one key advantage: the craft would already be 15km high and travelling at jet speeds when the rocket motor was ignited. Rutan used powdered rubber and nitrous oxide as fuel – a simple, easily controlled mix, it has been claimed. But in May, Virgin Galactic announced that SpaceShipTwo would switch to a polyamide-based fuel. Scaled Composites, the company building the spaceship for Virgin Galactic, had extensively tested the new fuel formulation on the ground, the company insisted at the time. Nevertheless, there is considerable speculation that the new fuel lies at the heart of last week’s tragic accident.
Whatever the cause, there is no doubt hopes that we stand at the threshold of cheap access to space have had a serious blow. Virgin Galactic’s technology was supposed to cut through the complexities of standard rocketry and make space flight simple. The pieces of its spaceplane that are spread over the Mojave desert show this goal is far from realisation. The dream may not be dead, but it is certainly a lot dimmer today.
STARGAZING
Some of the planet’s highest-profile celebrities have paid between £125,000 and £157,000 for a seat on Virgin Galactic’s two-hour suborbital flight. Among them are Justin Bieber and fellow pop stars Lady Gaga, who has reportedly been asked to perform live on the aircraft, and Katy Perry, whose latest headlines documented her decision to dress up as a giant Cheeto for Halloween.
Perry’s former husband, Russell Brand, who is currently attempting to rouse followers to ignite a global revolution, has also been named among the 700 individuals to have spent a total of £50m on ticket deposits, though it can probably be presumed that Brand and Perry will not be on the same flight.
Two people who almost certainly will be travelling together are Angelina Jolie and Brad Pitt, who between them have appeared in more than 70 films, although none with an intergalactic theme.
Among the other Hollywood luminaries to have reserved tickets are Tom Hanks, who starred in Apollo 13, about the aborted 1970 lunar mission, and Leonardo DiCaprio. Other US celebrities to have signed up include actor-turned-tech investor Ashton Kutcher, and socialite Paris Hilton.
Ashley Cowburn
