Meteors are some of nature's most spectacular moments to see as they dash through Earth's atmosphere. Mankind is catching up as the artificial shooting star project Sky Canvas attempt to recreate colourful cosmic showers. Using miniature satellites that will shoot special alloy ball bearings, the shower can be created to order over any spot on Earth for a spectacular fireball display and to help better understand how to dispose of space debris.
The Solar System is a very untidy place, even after billions of years, it is still cluttered with debris from its creation – some on the scale of dwarf planets and others the size of dust motes. One particular source of debris are the comets that are periodically disrupted from their ancient nesting grounds in the Kuiper and Oort belt, only to plummet into the inner Solar System.
Sky Canvas is backed by Japan's ALE Company and other partners and aims to create artificial meteors a bit closer to home. Instead of lassoing comets, the project uses a mini-satellite placed in a sun-synchronous orbit. It is a high-polar orbit that is set at an angle and altitude that allows the satellite to fly over a specific spot on Earth at exactly the same time each day. It is a technique used by spy satellites to ensure that their targets are always in full daylight while being photographed, but for Sky Canvas, it is to make sure the meteors arrive on cue.
In order to produce the bright plasma emissions caused by the heat of re-entry that make meteors visible from the ground as streaks of light, the satellite carries up to 300 pellets – one centimetre in diameter and made of special metal alloys. It is confidential to know what these alloys are made of, but they include different elements to cause the artificial shooting star to burn in different colours.
Once in proper orbit, the pellets are released and it hits the atmosphere at about one second intervals over a period of roughly eight minutes. If the weather over the targeted area is poor, the satellite has an abort function to prevent spoiling the show.
These pellets will burn up at an altitude between 60 and 80 km where it will glow with a brightness of magnitude -0.86 or about that of the star Aldebaran. This will make the artificial shower visible over an area of 200 km in diameter at a cost of $16,000 (US) per meteor. The satellite itself will burn up in the atmosphere due to orbital decay in two to four years.
According to ALE, the artificial meteors can also be used for scientific research. The pellets are released in a controlled fashion and their incidence, velocity and materials are known. This makes them very useful to compare to natural meteors to understand more about their characteristics by providing a baseline of comparison. This will allow scientists to better understand Earth's upper atmosphere.
The first test of the system is expected in 2019 with the first display over Hiroshima, Japan in the middle of that year.
The video below introduces Sky Canvas.