Maggie Aderin-Pocock on asteroid impacts – and how we can avoid them
With not one but two asteroid missions currently in progress, interest in these celestial bodies has been rising.
This week, as The Sky at Night delves into the science of these missions we talk to Maggie Aderin-Pocock about what it takes to get to an asteroid, what they can tell us about our own origins and why we need to be keeping an eye on them.
Both missions have the same aim, to sample the asteroid before returning back to Earth with their precious cargo. While this is not the first time this has been done (Japanese scientists managed it back in 2010), the volume of rock to be returned from the asteroids will be unprecedented.
There are a number of reasons why scientists want to bring physical bits of asteroid down to Earth, despite the incredible complexity it adds to a mission.
Largely, it comes down to the simple fact that scientists will be able to use much more sophisticated technology - and carry out far more detailed analysis - on these samples in labs on Earth.
'The space industry is very good at
'The joy of a sample return is that we don't have to do any of that. Labs across the world will get these samples and examine them in great detail, giving us the best analysis we've ever had of what asteroids are made of. It should reveal a lot about our own origins.'
Asteroids are some of the oldest bodies in our solar system, formed when the planets were only just beginning to come together as the Sun formed at the
This means that asteroids can act as a window into the early solar system. As the origin of most of the water that is currently on Earth, they could even help answer questions about how life kicked off on our young planet.
While both these missions to rendezvous with asteroids involve innovative science, the technology that actually makes up the spacecraft is often deceptively simple.
'Most people think that we're using cutting edge technology and the latest equipment, but
Scientists need to use slightly older technology to be certain that a piece of equipment won't fail.
'When we build a spacecraft or satellite, we generally use equipment that has been tried and tested. You don't want to send out a £300 million satellite that then doesn't work because we didn’t test it enough,' says Maggie.
'We put the satellites through
Each component is tested on its own, subjected to vacuums, extremes of temperature and vibrations, before the modules are pieced together. 'Once we've built the spacecraft, we then need to know that everything interacts and sits happily together,' says Maggie, 'so we do similar tests but on a larger scale.'
It is not just for the esoteric reasons that we
Asteroid impacts are not a rare event. Scientists have predicted that a meteorite between 30 and 50
'History tells us an asteroid impact is a significant risk,' explains Maggie. 'We know asteroids can have a huge impact on life on Earth - after all the dinosaurs are thought to have gone extinct due to one.
The reason why Bennu was chosen by NASA to visit is
Every six years or so, Bennu passes within 300,000
During the day small asteroids absorb the Sun's heat, which at night is then emitted as radiation, this gives the
While this is thought to have a limited impact on larger asteroids, for smaller asteroids the Yarkovsky effect can be quite significant. With Bennu it is thought to have shifted the asteroid's position by 185
The chance that this will cause Bennu to hit Earth remains incredibly slim, but that may not be the case with all Near-Earth Objects.
For that reason, one of the aims
When it comes to assessing the impact risk of any asteroid, figuring out exactly what orbit it is in and how this might change is critical, giving scientists an advanced warning. When it comes to the potential threat of asteroids, time is of the essence.
'The sooner you
'If the asteroid is a long way out, for example, then a small push is enough to move it out of
With both the OSIRIS-REx and Hayabusa2 missions still in their early days, anticipation – and nervousness - is growing. Within the next few months, as the spacecraft start sending more data back to Earth, experts will begin to get glimpses of what to expect over the coming years.
And when asteroids inevitably head for Earth, scientists are hoping to be ready for them.
With the impact from an asteroid long overdue, NASA has been drawing up plans for how they might deal with the imminent threat of a rogue asteroid heading for Earth. This includes the Asteroid Impact and Deflection Assessment (AIDA) mission, tentatively scheduled to launch in 2020.
The space agency hopes to send a spacecraft to Didymos, a large asteroid which has a smaller one orbiting around it, and then slam the craft into the little 'moon'. This will allow scientists to measure what effect this impact might have on the small asteroid's path. It will also inform scientists about the feasibility of doing something similar, if an asteroid were to make a beeline for Earth.
It means that species of the future will hopefully avoid the same fate as the dinosaurs.