Atmospheric mining  Atmospheric mining is the process of extracting valuable materials or other non-renewable resources from the atmosphere. Due to the abundance of hydrogen and helium in the outer planets of the Solar System, atmospheric mining may be easier than mining terrestrial surfaces. Atmospheric mining of outer planets has not yet begun. There is some consensus that gas should be mined from gas planets, but this would be difficult with current technology; however Uranus and Neptune would be the easiest planets to mine for gas due to their smaller gravity well. Jupiter and Saturn are closer with respect to Earth, but Jupiter has a lot of gravity and a powerful magnetosphere to contend with, and it could be difficult navigating through the rings of Saturn. Also, Earth's atmosphere can be mined for carbon dioxide to produce fuel and to reduce the levels of greenhouse gas in the atmosphere. Hydrogen may fuel chemical and nuclear propulsion. Helium-3 may fuel nuclear propulsion. Methane may fuel chemical propulsion. Carbon dioxide mining on Earth will reduce the level of greenhouse gases and can also produce fuel. The carbon extracted could be used to produce other materials such as plastics, which unlike fuel would have much greater potential to keep the carbon from returning to the atmosphere especially if the final products were intended to be durable and for long-term use. Hydrogen and helium are abundant in outer planets. An aerostat would be a buoyant station in the atmosphere that gathers and stores gases. A vehicle would transfer the gases from the aerostat to an orbital station above the planet. A scooper would be a vehicle that gathers and transfers gases from the atmosphere to an orbital station. A Skyhook (structure) is similar to a space elevator, such a device would be used to pump gas to an orbital propellant depot. A cruiser would be a vehicle in the atmosphere that gathers and stores gases. A smaller vehicle would transfer the gases from the cruiser to an orbital station.