NASA wants to find an asteroid, capture it, bring it towards us and send it into an orbit around our Moon. This isnБЂ™t a plot for a new Hollywood Blockbuster starring Bruce Willis, this is an idea that NASA is seeking funding for. It is hoped that this venture will advance the knowledge of asteroids, and give us ways to defend Earth from asteroid crashes.
Illustration of how NASA could capture an asteroid
(image credit: NASA)
What is an asteroid would be the first question! Well, an asteroid is described as a minor planet orbiting the Sun. However, unlike the planets, asteroids are typically smaller. The largest known asteroid is Ceres which is 580 miles (930km) in diameter. The majority of the asteroids in the solar system are found in the БЂњasteroid beltБЂќ which is located between Mars and Jupiter. Our understanding of asteroids has been derived from three main sources: Earth-based remote sensing, data from the Galileo probe flybys, and laboratory analysis of meteorites.
Photo of asteroid Ida and its moon Dactyl taken from the Galileo spacecraft
(image credit: NASA)
Many bodies have struck Earth and the Moon in the past, and this is evident from the many craters that were formed which are easily visible, especially on the MoonБЂ™s surface. One widely accepted theory blames an asteroid impact 65million years ago for mass extinction of life, including the dinosaurs. Many asteroids come close to the Earth and ones that come within 1.3 AU (121million miles/195 million km) of the Sun are known as Earth-approaching or near-Earth asteroids (NEAs).
Never mind an asteroid, look what happens when a 45 m meteorite hits the Earth. This is the 1 mile wide and 570ft deep crater created.
On June 30, 1908, a small asteroid 330 feet (100 meters) in diameter exploded over the remote region of Tunguska in Siberia, devastating more than half a million acres of forest. On March 23, 1989, an asteroid 0.25 miles (0.4km) wide came within 400,000 miles (640,000km) of Earth. Scientists estimated that Earth and the asteroid had passed the same point in space just six hours apartБЂ¦. a close shave! If the asteroid had impacted it would have created the largest explosion in recorded history, 12 times as powerful as the Tsar Bomba, the most powerful nuclear bomb ever exploded. But if you think that was close, fast-forward to 15 February 15, 2013, when an asteroid passed approximately 17,200 miles (27,700km) above the surface of Earth. This was closer than satellites in geosynchronous orbit.
So you can see why NASA feels it is essential to understand these bodies of rock, mainly because we know very little about them, and in certain circumstancesб NEAБЂ™s are only detected at the last minute. Take, for example, the Chelyabinsk event which occurred on 15 February, 2013. Shortly after dawn a meteor travelling at 34,000 mph descended above the Russian city. The object had not been detected before atmospheric entry with the dazzling lights of the meteor said to be bright enough to cast moving shadows during the morning daylight in Chelyabinsk. The meteor was observed from Sverdlovsk, Tyumen, Orenburg Oblasts, the Republic of Bashkortostan, and in Kazakhstan. Eyewitnesses also reported at how they felt intense heat from the fireball.
This photograph shows the meteor streaking through the sky above Chelyabinsk, Russia, on Feb. 15, 2013
(Image credit: NASA / M. Ahmetvaleev)
Around 1,500 people were injured, two seriously with most of the injuries caused by indirect effects, rather than the meteor hitting them itself. The majority of injuries were due to broken glass from windows that was blown apart when the shock wave arrived. With an estimated initial mass of 11,000 tonnes, and measuring approximately 17 to 20 meters across, the Chelyabinsk meteor is the largest object to have entered Earth’s atmosphere since the 1908 Tunguska event, and it is the only meteor known to have resulted in a large number of injuries. The meteor was quite small compared to some of the objects out there that could potentially hit the Earth, thus if we understood asteroids it could be potentially life-saving!
So what exactly is NASA planning to do? Well according to Charles Bolden, NASA Administrator, the agency is БЂњdeveloping a first-ever mission to identify, capture and relocate an asteroid. This mission represents an unprecedented technological feat that will lead to new scientific discoveries and technological capabilities and help protect our home planet.”
Basically an unmanned spacecraft with a giant telescoping opening would fly to the asteroid, draw it in, and secure it inside the spacecraft. The craft would then fly back towards the Earth and put the asteroid into a steady orbit around the Moon. NASA would then organise to fly astronauts to the asteroid for research missions. They could break off pieces of the asteroid to bring back to Earth for study. Learning what asteroids are made of “could help us understand the origins of the solar system and inform decisions about how to conduct missions to distant planetary bodies,” NASA believes. This mission could start as soon as the early 2020s with NASA already simulating an asteroid mission to figure out how astronauts might undertake a spacewalk on it.
БЂњThe plan combines the science of mining an asteroid, along with developing ways to deflect one, along with providing a place to develop ways we can go to MarsБЂќ according to U.S. Senator Bill Nelson, a Florida Democrat. It could also be the first step in establishing a commercial enterprise in deep space. This enterprise could lower the cost of space exploration by using energy and raw materials from the Sun, asteroids, and the Moon. In fact two private space-mining firms have already announced plans to potentially drill asteroids for water and valuable metals. Delving into an asteroid could be very lucrative when you learn that a typical 79-foot metallic asteroid could hold 33,000 tons of extractable metals, including бё35 million in platinum alone. A 23-foot carbonaceous asteroid can hold 24,000 gallons of water which is useful for generating fuel and oxygen. This could be useful as later missions could utilise this material instead of having to pay to launch water into space.
Artist’s concept of an astronaut performing a tethered manoeuvre at an asteroid.
(Image credit: NASA)
Another very useful reason to tow an asteroid back towards Earth would be that it could be used as a stop-off point for future missions to Mars. NASA administrator Charles Bolden says, БЂњThis mission allows us to better develop our technology and systems to explore farther than we’ve ever been before – to an asteroid and to Mars – places that humanity has dreamed about БЂ¦ but has had no hope of ever attainingБЂќ.
Artist’s concept of an astronaut gathering samples on the surface of Mars.
(image credit: NASA)
The plan sounds audacious, and to be honest it does sound like a screenplay from an upcoming Steven Spielberg movie. But this is a plan that could help us understand asteroids better, it could help us learn how to protect ourselves against them, and for certain interested parties it could make them quite a lot of money! Expect to see a lot more about this in the coming months and years. What do you think? Can NASA lasso an asteroid back to Earth?
(Article by Sinead McNicholl, Education Support Officer)
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