Fishing for Space Junk

Fishing for Space Junk

The Japanese space agency, JAXA, announced that next month it will pilot its ‘electrodynamic tether’ for the first time. It is one of the possible solutions suggested to deal with the increasing number of space debris. Nearly a million pieces of spacecraft, satellites and other astronautic equipment speed round our planet, posing devastating consequences. An object just 10 centimetres across could ‘catastrophically damage’ a satellite and a piece just 1 centimetre across could disable a spacecraft; the Kessler Syndrome is the worst-case scenario – it refers to the collision between pieces of junk that would ultimately result in more and more debris.

JAXA aims to use a ‘debris-catching net’ - a 700 metre long mesh of aluminium and steel wires that hangs tethered from an unmanned spacecraft. The net is fitted with sensors that detect light changes resulting from reflections off small pieces of debris, the net then aligns itself accordingly so that it can attract the waste material. The electrical current flowing through the wires induces an electromagnetic field that attracts the debris and pushes the net away from the Earth’s magnetic field. Once enough junk has been collected, the spacecraft and net and made to slow down so they burn up as they enter Earth’s atmosphere.

JAXA claims the main advantage is the net’s simplicity. It’s lightweight and doesn’t require propellant to move, and JAXA hopes to build a 10 kilometre version to capture satellites that no longer have use. However not everybody is so confident. One concern is that the spacecraft will take too long to de-orbit and others fear that the net may ‘run into operational satellites’. A JAXA spokesperson also warned that ‘there is a possibility of the tether being severed by debris of micrometeoroids’.

Using a net is just one of many proposed solutions to the space junk issue. European company EADS Astrium wants to give satellites built in ‘sails’ to act as an orbital brake, dragging them into Earth’s atmosphere; whilst a team in Switzerland is currently building a robot, CleanSpaceOne, that will sweep up junk by deploying jellyfish like grippers to collect the target. Boeing on the other hand wants to send up a rocket that could dispel the debris with jets of gas and other companies want to use lasers to clear the debris. 

Space debris surrounding Earth

Source: New Scientist

Stardust - The Fountain of Life

Stardust - The Fountain of Life

The dust grains that travel through our solar system contain the vital components needed to form water. Similar dust grains are thought to be found all over the universe and this bodes well for the existence of life in other galaxies. Hope Ishii commented on the discovery, saying ‘it is a thrilling possibility that this influx of dust on…solar system bodies has acted as a continuous rainfall of little reaction vessels containing both the water and organics needed for the… origin of life’. This magic stardust is a result of many processes, though primarily the breakup of comets.

Particles extracted from the Earth’s stratosphere were found to contain minuscule pockets of water. The reason for this phenomenon is the product of a reaction between dust and solar wind. The dust is made mostly of silicates, which contain oxygen - as it travels through space; it meets the solar wind which is a stream of charged particles, including high energy hydrogen ions, ejected from the sun’s atmosphere. When the two collide, hydrogen and oxygen combine to form water.

Of course, this can’t solely account for the sheer mass of water that covers Earth today; a more probable origin is saturated asteroids that hit Earth billions of years ago. Nonetheless, the water producing reaction is likely to happen all over the cosmos wherever there is a star present. Furthermore, the interplanetary dust contains organic carbon which, too, is fundamental for life. If stardust contains carbon and water, ‘the essentials of life could be present in solar systems anywhere in the universe and raining down on their planets’.

Source: New Scientist