It is probably every rookie astronaut’s nightmare, and probably even a veteran astronaut’s nightmare…scratch that it’s probably every single astronaut’s biggest fear that their spacecraft is destroyed whilst out on a space walk and they are stranded in space completely alone with no way of contacting Earth! Well that just describes the synopsis for Alfonso Cuarón’s upcoming film Gravity! Due out in October 2013 this ‘out of this world’ film will star Sandra Bullock as the newbie astronaut embarking on her very first shuttle mission and George Clooney as the veteran accompanying her on his final space voyage before retirement. (With a set up like this it is kind of inevitable that it wasn’t going to go smoothly!) After nasty space debris rips through the pair’s Shuttle spacecraft we see them stranded alone in space awaiting whatever fate the dark, vast universe has in store for them! But what does it have in store? What are the realistic dangers of space travel? Let’s find out, to both spoil the plot before October rolls around and also see what potential hazards await us on those future space holidays we all hope becomes normal practice in the not so distant future!
Space debris is a growing problem with space travel. Space debris can be literally anything, from tiny flecks of paint, a metal bolt right up to a fully-sized defunct satellite. Over 2000 satellites have been launched into space since the first, Sputnik in 1957. But unlike Sputnik, which returned to Earth when it re-entered the atmosphere after three short months in orbit, some have refused to come home, such as the US Vanguard 1 satellite which is the oldest satellite still orbiting in Earth’s low orbit after its launch in 1958. But these are usually big objects that can be easily spotted, right? Well imagine the mess if two satellites collided! Two big and easy to spot and track objects now turn into thousands of hazardous pieces ranging in size from big to too tiny to track! In Earth’s orbit now there are roughly 21 000 pieces of space trash bigger than 4 inches (10 cm); approximately 500 000 between 1cm and 10cm and millions smaller than 1cm! You may think it doesn’t matter having all these tiny pieces of space debris floating about but you would be very wrong. They could be lethal! These tiny scary pieces of trash are “floating” at roughly 4 miles per second (6.6 km/s) , turning a tiny fleck of paint into the equivalent of a pound coin hurtling at a speed of 60 mph (100 km/h)! Back in 1983 the Space Shuttle Challenger felt the wrath of an angry paint fleck on their window but still managed to return home from this mission with the damage. So imagine the damage it could do to the all-important space suits Sandra Bullock and George Clooney will be floating about in! Could a fleck of paint bring a quick end to Gravity?
Not only is man-made space debris a very worrying issue, but so are the natural space debris including meteoroids and micrometeoroids! Meteoroids are pieces of rock and metal floating through space which are often left over pieces of rock from the formation of the Solar System. Micrometeoroids are even smaller pieces of meteoroids, often weighing less than a gram. They may sound small but they cause much of the weathering that happens in space and when these particles all gang up and create high speed cosmic dust clouds, things can get nasty! NASA’s Mariner 10 satellite ran into one of these formidable cosmic clouds which resulted in part of its insulation being ripped off and the impact of the cloud being so great it changed the trajectory of the spacecraft! Imagine an astronaut caught up in such a scary cloud and wonder if a space suit could withstand what a heavy duty satellite couldn’t.
The importance of an undamaged space suit!
Space is a crazy place where in the shadow you could freeze to death in seconds and boil in the sunlight the next! Your space suit is vital in keeping you alive making it a mini space ship itself. It regulates the body’s temperature to cancel the hot and cold temperatures outside, and even the astronaut’s own body heat building up inside it, it using layers of insulation and a cooling system. Near Earth space itself is about -180˚C so it is extremely cold! (Space is a vacuum, so just to be clear, this this temperature of objects in the shade.) But when in direct light from our sizzling Sun it is an eye watering 115˚C. So space walks can be fine in space for a short period of time but, if say there’s a glitch in the space suits’ cooling system or a tear happens from a piece of space debris hitting the suits, things could go fatally wrong!
Not only is the space suit keeping your temperature regulated it is allowing you to breathe in space! Space is a vacuum and obviously we are unable to breathe in it without the aid of a space suit. An average life span for a tank of oxygen is between 6 – 8 hours so that gives little time to be found if you get knocked away, not a good time frame to be working with for Mr Clooney or Ms Bullock!
If you find you’re extremely interested in the importance of the space suit click here for a recent interesting article on the Astronotes blog!
Radiation/ Cosmic Rays
A very big problem for humans and space travel is the risk of radiation. On Earth we are protected by the planet’s natural radiation shield, the magnetic field that surrounds our world which blocks out 99.9 percent of the harmful radiation from the Sun and deep space. But what will happen to us if we leave the Earth’s protection and float freely in the vastness of space or visit another body in the Solar System?
Radiation is obviously not healthy for humans. In space radiation is in the form of subatomic particles that can come from the Sun and further out in the Universe including the Milky Way Galaxy and even beyond. They are moving at high speeds and can rip through our DNA molecules causing damage or splitting within them which can lead to cancer and other diseases. So although Hollywood would put this forward as a method to become a member of The Fantastic Four I doubt the ability to stretch or turn invisible is what is in store for Sandra Bullock in ‘Gravity!’
Radiation in space has recently found its way on to the news as it is confirmed to be a big problem for sending humans to Mars and could set space travel to the Martian world back somewhat if a faster method of travel is not developed. Confirmation of high levels of radiation was verified with data collected by the space flight of the Mars Curiosity rover to the rusty Red Planet. It has been revealed that the level of radiation that astronauts will be exposed to could raise their chances of cancer! On Earth we are exposed to roughly 3 millisieverts of radiation per year. In the International Space Station astronauts stationed there for the average of six months will be exposed to roughly 100 millisieverts of radiation. A roundtrip mission to Mars, not including time for exploration of the planet, would expose potential Martian astronauts to 662 millisieverts of radiation, which is scary considering in an astronaut’s career their cap is supposed to be 1,000 milliseverts! And bear in mind that they have the protection of a space vehicle to shield some amount of radiation, if you left floating about in the harshness of space all that’s between you and cosmic rays is your space suit and that is not a comforting prospect! Accumulating dangerous doses of radiation would be hazards to crews on any long endurance mission, so any plans to voyage to asteroids or work on a Moon base must factor in some kind of shielding to protect the delicate humans.
Launch and Re-entry
One of the most dangerous places for an astronaut is the launch and re-entry of their rocket. A lot of rocket fuel for reaction mass and energy is required to attain even a low Earth orbit. The spacecraft needs to get up to least 7 miles per second or 25 000 miles per hour, which is a very scary and dangerous speed. Proof of such a thing is the Challenger disaster of 1986 when a Space Shuttle blew apart 73 seconds into its launch costing the lives of all seven members of its crew.
Some may argue that the re-entry of a spacecraft is even more dangerous. The friction of air on the rocket would cause the rocket to burn up like a meteor and be destroyed in seconds, so spacecraft have been designed to allow them to re-enter the atmosphere slowly by gradually circling downward. Now this has not always ran smoothly with Columbia disintegrating during its return to Earth in 2003 after a small part of the Shuttle Orbiter’s wing was damaged on launch. It affected the vehicle’s thermal protection system which ought to have shielded it from the massive amounts of heat which resulted in a further seven astronauts’ deaths. So even if George Clooney and Sandra Bullock’s characters are miraculously rescued from floating away in space they will probably have their fingers crossed for that scary re-entry through Earth’s atmosphere!
When thinking about the scariness of space, moon dust is not exactly top of the ‘terrible foe’ pile but it’s much more hazardous than you may realise. The Moon, as you know, has no liquid water so the dust on the Moon’s parched plains has the consistency of flour (which allowed the footprints to be made). This fine powder can stick to all it touches and can find its way in to all the creases and seams of your space suit. This dust is made of tiny jagged grains, so it is also rough like sandpaper so can do some damage. Imagine breathing the stuff in, each breath a million tiny daggers, and the damage it can do to your lungs! Over time, the dust would clog them up and eventually kill you and it probably wouldn’t need huge amounts to do so! Apollo 17’s crew learnt their lesson of how dangerous moon dust is back in 1972. So eager to leave the surface, Jack Schmitt and Eugene Cernan forgot to brush the dust off their boots before re-entering their space capsule. Now they knew how annoying this dust could be throughout their mission as it clogged up their suits and they then were stuck with it on their journey home. The dust was immediately airborne and Schmitt soon complained of congestion and something like that of ‘lunar hay fever’! It was too small an amount to hurt them too much and after a day the symptoms subsided but a lesson was learned… fear lunar dust! If we ever return to the Moon to stay, the intrepid pioneers will need to take great care to guard against this subtle hazard.
A big issue for me personally is something a little simple and could completely ruin the credibility of the film entirely and give away the ending if they stick to reality and not fantasy. Space is weightless! In the worst possible case, if Sandra Bullock’s character is sent hurtling through space by the time another Shuttle is fueled, manned and sent up she will never be caught up with. Even a slight nudge would send her flying through space never to slow down unless she got hit or blocked by another object i.e. Newton’s First Law of Motion. So putting it into figures say after the huge accident and Sandra Bullock’s character is sent hurtling through space at roughly 24 000 miles per hour on top of her orbital velocity, she will have exceeded the Earth’s escape velocity! Say it takes Earth a week to send a rescue mission to retrieve her by the time they are up there she is millions of miles away (not that the Space Shuttle could have matched this velocity in the first place! It is a very scary thought and perhaps why the movies tag line is ‘Don’t let go’…..because you will end up flying through space forever!
So hopefully this has not put you off the prospect of a future holiday to the Moon and or becoming an astronaut but I am sure it has given you an even deeper respect and admiration for the dangers astronauts face to advance our knowledge of this vast and scary Universe!
(Article by Kerry Scullion, Education Support Officer)