On November 5, a mile-wide asteroid silently tumbled through interplanetary space. At closest approach to Earth, some 6.5 million kilometres away (or 17 times the Earth-moon distance), the Goldstone Observatory in the Mojave Desert, California, captured radar images of the space rock. As part of NASA’s Near-Earth Object Observations Program, Goldstone is part of an international network of observatories – collectively known as “Spaceguard” – charged with detecting and monitoring asteroid threats to our planet. Although asteroid 2007 PA8’s orbit is well-known and isn’t considered to be an immediate threat to life on Earth, it is classified as a “near-Earth asteroid” – one of 848 known asteroids over one kilometre wide that drift close to Earth during their journey around the Sun.
The 2007 PA8 flyby was totally overshadowed by world events, however, and struggled to make the headlines. Indeed, asteroid flybys are routine, but to astronomers, the photo opportunity provided invaluable data for our ongoing work to characterise this persistent threat to our way of life.
Playing political asteroids
While the interplanetary interloper buzzed our planet, a more Earthly event was unfolding: The US was about to go to the polls to vote for their next commander-in-chief on November 6. From the perspective of cosmic events, politics and democracy may seem petty, but the one policy that the majority of the US electorate had little idea about was President Barack Obama’s instigation of sending a manned NASA mission to visit an asteroid by 2025.
During the George W Bush era, such a plan was rarely spoken of. Under the Shuttle replacement programme – known as Constellation – the primary motivation was to send man back to the Moon. Eventually, Constellation would have formed the foundation for a human mission to Mars. However, in 2009, the Democratic president was sworn in and Obama called for an inquiry into the expensive Constellation Programme. The Augustine Commission found the new rocket system to be woefully under-funded and behind schedule. The plan, by enlarge, was cancelled.
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But one component of Constellation was saved, a multipurpose deep space capsule called Orion. NASA’s next crewed spacecraft wouldn’t be a winged shuttle; it would be a high-tech version of capsules that have historically been so effective at getting humans into space and returning them through the superheated fury of atmospheric reentry. NASA is developing the Orion MultiPurpose Crew Vehicle, not as a part of Constellation, but as a part of a new programme – the monster Space Launch System (SLS).
Although the SLS has been controversial, it is considered to be a more cost-effective solution to the US human spaceflight problem. The SLS, in addition to NASA’s continuing support of private cargo and human launch capabilities, is a two-pronged approach of weaning NASA off its dependence on foreign space agencies to put their astronauts into orbit, whilst spearheading NASA’s aim of pushing the envelope of human spaceflight. Since the 30-year old Space Shuttles were retired in 2011, NASA has been relying on Russia to launch its astronauts to the International Space Station (ISS) – a situation that is reprehensible to many.
Private companies such as SpaceX and Orbital Sciences Corp are now working under NASA contracts to build a commercial space infrastructure, to eventually wean the US off its dependence on foreign launch capabilities, while the SLS will travel beyond low-Earth orbit, sending astronauts to an asteroid and, once again, form the backbone of a mission to Mars by the mid-2030s.
That’s the plan, anyhow.
But this new NASA mission is very much an Obama administration-driven mission, one that would likely have been (at best) modified or (at worst) scrapped by the new Romney administration. Although Republican presidential nominee Mitt Romney was vague on details for his plans for NASA, it is likely that the importance of a manned asteroid mission would have been sidelined in favour of using SLS to land astronauts back on the Moon (pretty much in line with Bush’s pre-2008 Constellation plan). As it turns out, we’ll likely never know what shape NASA would have taken with Romney at the reins.
But to re-prioritise NASA as a lunar-driven agency would have been a political move and would have ignored a constant threat to our planet no matter who is leader of the USA. That threat is, of course, a planetary collision with a big old scary chunk of asteroid.
It’s a question of when
Although there’s no way any scientist can predict when, exactly, we will hit by a large asteroid, we know that Earth gets hit by large asteroids on short geological timescales. The Tunguska event, for example, flattened a region of Siberia the area of Moscow (2,150 square kilometres) in 1908 – it is thought to have been an asteroid that slammed into an under-populated part of the world, exploding above the ground and destroying a forested region in Siberia. Although estimates vary, the Tunguska meteoroid is thought to have been less than 100 metres wide. When compared with 2007 PA8’s 1.6 kilometre dimensions, the Tunguska meteoroid was tiny. But to one forest in Siberia, the impact of that “small” asteroid was nothing less than cataclysmic.
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And guess what? Statistics suggest that Earth gets hit by one Tunguska-sized space rock every 100 to 200 years. This means that there’s a pretty good chance that in my lifetime, I will be witness to another Tunguska-sized event. Here’s to hoping I’m not living near the impact site. This isn’t a question of if; it’s a question of when.
During a recent TEDx presentation by former NASA astronaut Ed Lu of the B612 Foundation, he succinctly summarised the situation: “Asteroids are nature’s way of saying: How’s that space programme coming?”
Lu used Tunguska as an example and a motivation for improved detection and monitoring of errant asteroids. Although big asteroids like 2007 PA8 get a lot of attention (as, let’s face it, if one of those monsters hit us it will be devastation on a global scale), it is believed that 93 percent of near-Earth asteroids over 1 kilometre wide have been discovered. Things become a lot less certain when talking about sub-kilometre asteroids that are small enough to go undetected, yet large enough to destroy huge metropolitan areas. This is the motivation for the B612’s plan to fund, build and launch (atop a SpaceX Falcon 9 rocket, by the way) their own asteroid-hunting space telescope by 2018.
So what’s all this got to do with Obama winning the US presidential election?
One may think that we understand the nature of asteroids and what they are made of, but asteroid science is in its infancy. If we discovered an asteroid on a collision course, although we may have some really good ideas as to what to do with it (in theory), we don’t have the in-space infrastructure already in place to physically do anything about it. Of course, it depends on how much notice we have. If we have years to decades, one can imagine a global effort to deal with the threat. But say if the impact is only months or weeks away? That’s no time at all to develop the necessary hardware to intercept the asteroid and steer it away (or blow it up). The “let’s nuke it” Hollywood style probably wouldn’t be the best option either.
Currently, there isn’t a specific asteroid threat, so it seems prudent to learn as much as we can in preparation for such an event. We’ve sent robotic missions to study asteroids up-close (the Japanese have even retrieved samples from an asteroid’s surface) and there are plans for more. But NASA’s plan to send astronauts on a daring deep-space mission to an asteroid could hold the key to any future asteroid deflection effort. Not only would astronauts be able to carry out invaluable science, critical docking/landing techniques in the microgravity environment may help NASA develop a plan for confronting an asteroid on a collision course with Earth.
But the problem with a politics-driven space agency is that its priorities wax and wane depending on which political party is in the White House. Any future effort to set up an asteroid deflection infrastructure would need many years of planning, funding and implementation. Changes in government can seriously disrupt this work.
So now the US has four more years under an Obama administration and NASA’s course appears to be safely on its way to an astronaut rendezvous with an asteroid by 2025. Let’s hope it stays that way, our future may depend on it.
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