Space debris—fragments of old satellites and rockets that remain in space—poses an epic threat to satellites and spacecrafts currently in orbit. Proposals to eliminate it have so far included everything from harpoons to lasers.
Singapore-based startup Astroscale has a different idea. It reckons it could use a satellite equipped with a specially configured adhesive—whose chemical structure the company is keeping secret—to trap and destroy rogue bits of space waste. The contraption would basically work a bit like flypaper. As well as working on grabbing space debris, the startup is also working on tracking space waste.
"In March, after a series of tests, we finally made a glue that manages to trap bits of space debris while withstanding harsh space environments," said Miki Ito, an engineer and president of Astroscale's Japan office, in a meeting room above the company's research and development lab.
Astroscale has been testing its secret glue by subjecting it to radiation and extreme temperature fluctuations in simulated space environments. It's intended for the company's newest satellite, ADRAS 1, which weighs up to 120 kg and is being readied for a 2018 launch. The satellite features two components: The design of its base part, dubbed "Mother," is inspired by the Hodoyoshi-3 and -4 satellites that were launched into space by the Japanese Space Agency (JAXA) in 2014, while a part dubbed "Boy" sits on top of the Mother component and is designed to separate once in space. Boy contains the pad coated with the special glue that will allow it to latch onto pieces of space junk bigger than 10 cm, much in the same way that a spider pounces and immobilizes a bug.
ADRAS 1, explained Ito, possesses three key functions. First, its onboard sensors allow it to autonomously detect and make its way toward a piece of space debris. The capturing process sees Boy separate from Mother, stick out its adhesive pad, and pull in the piece of space debris. Lastly, Boy deorbits, re-entering the Earth's atmosphere with the aim of destroying both itself and the debris. The intense air drag and high temperatures as it penetrates the Earth's atmosphere cause both the satellite and the space debris it contains to burn up, explained Ait-Mohammed Nori, an engineer at Astroscale.
Space is a notoriously hostile environment, with spacecrafts and satellites subjected to cosmic radiation, unfiltered solar light, and severe temperature fluctuations. According to Ito, it took a good few months of testing to get the glue strong enough to withstand these typical space challenges.
The satellite's construction is carried out in the Japan's office's basement, which is sealed off to visitors. Testing is done in collaboration with nine universities.
Astroscale secured up to $35 million in March 2016, but the company would have to have to make an army of ADRAS 1 satellites if it's going to fight the space debris problem en masse, as each Boy can only take out one piece of space junk (it'll focus on tackling particularly dangerous pieces).
Mother will deorbit itself within 25 years, and during that period, it will observe Earth and send back data related to its propulsion system, for example. For the moment, Astroscale is still in the testing stage, and Ito said its 2018 space mission is intended to prove that the concept can work and be expanded in the future.
In the meantime, the team is also working on launching IDEA OSG 1, a smaller 380 mm by 600 mm satellite weighing 20 kg, which is being made to collect data on just how many small particles of debris there could be up in space. It will be launched in early 2017 and will spend roughly two years up in orbit.
"There's no data on how much space debris measuring between 0.1 mm and 10 cm there is up in space, because we can't see it from Earth," Ito said. "IDEA OSG 1 will be used to collect data on particles of space debris which can't be tracked from Earth."
IDEA OSG 1 has thin polyimide sheets with conductive lines replete with small signal power. Once debris hits the sheet, it breaks up the conductive lines, causing the signal—monitored from Earth by the team—to change. The goal of the mission is to allow Astroscale to collect a sample of the miniscule particles of space debris over a two-year period, and to come up with an estimate of just how many of these small space waste fragments are in Lower Earth Orbit.
Ultimately, Astroscale's mission is twofold. The company asserts it wants to tackle the human-caused problem of space debris in order to ease the dangers for space missions, and to promote more interest in space among younger generations of kids in Asia.
"The companies that are investing in us in Japan aren't really doing it for profit," explained Ito. "They want to be part of something that will benefit the world, and getting rid of human-caused space debris will ensure the safety of future space missions."
Cool Japan is a column about the quirky and serious happenings in the Japanese scientific, technological and cultural realms. It covers the unknown, the mainstream, and the otherwise interesting developments in Japan.