Laser Bees
Laser Bees refer to a proposed method of asteroid deflection that leverages small satellites equipped with lasers to redirect potentially hazardous asteroids away from Earth. This innovative concept emerged from research at the Universities of Strathclyde and Glasgow, where scientists aimed to utilize laser ablation—a process that heats the surface of an asteroid to create plumes of gas that can alter its trajectory. The idea evolved from earlier designs using mirrors to focus sunlight, which proved less effective than direct laser applications.
By surrounding an asteroid with a swarm of these laser-equipped satellites, researchers believe they could generate a strong, overlapping beam of laser light to manipulate the asteroid's path. This method is considered advantageous because it relies on the asteroid's own material for propulsion, potentially avoiding the creation of dangerous debris that could result from more explosive methods. While the approach shows promise, challenges remain, particularly regarding the effectiveness against larger asteroids and the management of ejecta—material released during the ablation process. Overall, Laser Bees represent a forward-thinking strategy in planetary defense, complementing ongoing efforts to monitor and mitigate the risks posed by near-Earth objects.
Laser Bees
FIELDS OF STUDY: Asteroid Impact Avoidance; Space Technology; Aerospace Engineering
ABSTRACT: A laser bee is a type of small spacecraft with a powerful built-in laser. Scientists are studying whether lasers from a number of these crafts can be aimed at an Earth-bound asteroid to cause it to change course. Laser bees could be an important way to protect Earth from a direct hit by an asteroid.
Danger of Asteroid Impacts
In mid-February 2013, people in the area of Chelyabinsk, Russia, were jolted when an asteroid exploded above them. The blast rattled buildings, broke windows, and injured more than a thousand people. This relatively small asteroid (17 meters, or about 56 feet in diameter) was the most powerful such collision with Earth’s atmosphere since 1908. It drew much attention to the efforts to develop better ways to detect and redirect asteroids that could strike Earth.
Even before that incident, researchers were aware of the danger to Earth from a close approach by an asteroid. Many scientists believe that a large asteroid of about 9.7 kilometers (5.9 miles) in diameter struck Earth in the Yucatan Peninsula in southeastern Mexico 65 million years ago. Such an impact caused catastrophic changes that resulted in the extinction of the dinosaurs. For several decades, scientists have been considering ways to prevent such a mass extinction event from recurring. Some proposals called for the use of nuclear devices or other explosives to destroy Earth-bound asteroids. However, others recognized that this could possibly create many smaller asteroids that could still cause massive destruction.
The idea of rerouting an oncoming asteroid to avoid Earth came to be seen as more feasible. One proposed method considered satellites that would use their own gravity to nudge the asteroid into a different course over time. Others put forth the use of explosive devices to knock the approaching asteroid off course. Another idea involved the use of a swarm of relatively tiny satellites equipped with mirrors to reflect sunlight onto the asteroid’s surface. The vaporization caused by these mirror bees would, in theory, change the asteroid’s orbit by creating propulsive jets of gas from the asteroid’s surface.
As scientists explored the mirror bee concept, they quickly found that equipping each spacecraft with a laser, not a mirror, was more effective. Some scientists consider these laser bees to be the safest, most cost effective, and quickest way to prevent a direct hit on Earth by an asteroid.
Small Satellites, Big Effect
In 2008, researchers at the Universities of Strathclyde and Glasgow in Scotland began conducting work on the use of ablation to deflect an asteroid. Ablation is the process by which erosion removes material from an object. In theory, heating the surface of an asteroid would cause a gas plume to be ejected. This could act as a thruster, changing the course of the object in space. A change in its weight would also alter its trajectory slightly, so given enough time and distance, it could pass harmlessly by.
The Scottish team, led by Massimiliano Vasile (b. 1970), investigated the use of swarms of small satellites to create ablation. Of nine different types of possible defense methods they evaluated, the "bee swarm" approach promised to be the fastest and most effective, short of using nuclear warheads. At first the project was based on using an effect like that of using a magnifying glass to start a fire. The initial experiments tested the use of satellites equipped with mirrors to focus sunlight on the surface of an asteroid. The focused energy would cause the asteroid to superheat and undergo sublimation (direct transition from solid to gas) in a selected area. This should release a jet of gas and material from the asteroid with enough force to propel it onto a course that would not cross paths with Earth.
These mirror bee satellites were promising, but the researchers soon discovered that satellites equipped with lasers could be even more effective and precise. They would also be simpler to set up, without requiring precise alignment with the sun. By surrounding a threatening asteroid with swarms of these small laser bees, scientists could direct repeated laser blasts to carefully manipulate the asteroid’s course.
Process Details
The experiments by the Scottish researchers were carried out in a laboratory, not in space with real asteroids. However, they checked results against computer models and hold that the method should work in a real-life planetary defense situation. They propose that a small fleet of laser-carrying satellites would be deployed as soon as a threatening asteroid was in range. These laser bees would fly alongside the asteroid in a pattern designed to maximize the effectiveness of the laser blasts. The number of bees and their flight pattern would be set based on the size of the asteroid, its composition, and how much warning scientists have of its approach. Using a swarm of laser bees gives the scientists the most flexibility in attacking the asteroid and the greatest potential for generating a strong, overlapping beam of laser light to initiate redirection.
The laser bees would be directed to shoot the laser beam at a spot calculated to create the best opportunity to propel the asteroid in a different direction. The energy from the laser would heat the surface of the asteroid. This would convert the solid material into a gas that would act much like fuel does in a rocket, with the escaping gas pushing against the solid surface to propel it through space, but at lower speed. The low thrust would still be enough to move the asteroid off a collision course with Earth.
The process was tested in laboratory conditions by directing lasers at rocks in a vacuum chamber. This provided valuable insight into the amount of gas released. Scientists working on the laser bee project also identified the possible issue of debris called "ejecta" being released along with the gas during laser ablation. Scientists are studying ejecta to determine its impact on the diversion outcome in a real-life scenario and to find ways to mitigate it.
One advantage of this approach is that the small craft can be more easily deployed in the event of an asteroid approach. The unmanned satellites do not require astronauts to undertake a risky mission. Ablation also does not create large amounts of debris that could still pose a threat to Earth, which exploding an oncoming asteroid might do. The laser bee process also uses the asteroid itself as a fuel source for redirection, simplifying the deployment of the asteroid diversion mission.
Possible drawbacks include the possibility that larger asteroids might be more difficult to deflect with laser bees and some uncertainty about possible contamination by ejecta.
The research at the Universities of Strathclyde and Glasgow was supported by the nonprofit Planetary Society, founded in 1980 by space experts including Carl Sagan (1934–1996). The Planetary Society works to train and support amateur astronomers to detect and monitor asteroids and space debris. The organization believes the monumental task cannot be undertaken by professionals alone. The researchers are working to develop the best practices for deflecting and possibly exploiting asteroids.
Importance of Asteroid Detection
On the day of the Chelyabinsk asteroid incident in 2013, scientists had their eyes on a much larger asteroid that was expected to pass near Earth but not pose any threat. The smaller space body that struck the atmosphere over Chelyabinsk was undetected until it hit. Fortunately, many smaller asteroids (which are classified as meteors once they enter Earth’s atmosphere) are destroyed by the atmosphere and never reach Earth’s surface. But some are large enough to cause a great deal of destruction.
Scientists had detected more than twenty-nine thousand near-Earth asteroids (NEAs) as of 2022. Many are considered potential hazards. These could pose a threat to Earth because they are fairly close to the planet or its orbit. But they have been studied enough that scientists can predict their paths and determine that they do not pose an imminent threat for at least one hundred years. Undetected asteroids pose the greatest risk.
National Aeronautics and Space Administration's (NASA) and other agencies’ asteroid watch programs constantly monitor space for any approaching threats and would alert world leaders of any danger. These organizations include the Planetary Defence Coordination Office at NASA, the International Asteroid Warning Network, and the Space Missions Planning Advisory Group. Researchers continue to seek ways to prevent an asteroid strike; for example, in 2021 NASA launched a spacecraft as part of its Double Asteroid Redirection Test (DART). In 2022 China announced it was developing an asteroid deflection test as well. No laser bee launches were being planned at that time. In addition, researchers are studying NEOs to determine the makeup of these asteroids and help refine the processes for deflecting or removing them from Earth’s path.
Principal Terms
- asteroid: a small, rocky space object that orbits another larger celestial body such as the sun or a planet. Asteroids are categorized by their orbits.
- laser: stands for "light amplification by stimulated emission of radiation"; a device that creates a steady beam of visible radiation by stimulating electronic, ionic, or molecular particles to a higher energy level, causing them to emit some of that energy.
- mirror bee: a small spacecraft equipped with mirrors intended to reflect and focus the sun’s light on a specific spot on an asteroid, which would superheat and explode. This would release a plume of gas that would act much like a propulsion system to redirect the asteroid. The mirror bee idea was the precursor to laser bees.
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