Sunday, 2 October 2016

Spacecrafts Engines Can be Fueled By Water: Revolutionary Step

Scientists led by NASA’s previous chief technologist are hopeful to launch a satellite carrying water as the source of its fuel. The scientists from Cornell University, led by Mason Peck, wants their device to become the first shoebox-sized 'CubeSat' to orbit the Moon while explaining the potential of water as a source of spacecraft fuel. It’s not dangerous, water is a stable substance that’s comparatively common even in space, but could also find better use here on Earth as we search for replacements to fossil fuels.

NASA/Northrop Grumman/William Furlong

while we build a warp drive or some other high-tech propulsion system, space travel is expected to depend mostly on the kind of propellant-based rockets we use today. These work by firing gas out of the tail of the vehicle in a way that, thanks to the laws of physics, thrusts it forward. Such propellant systems for satellites must be lightweight and carry a lot of energy in a small space (high energy density) so that constantly pack a powerful punch over the many years, or even decades, that the craft is in orbit.

Safety too is of major concern. Filling energy into a minor volume and mass in the form of a fuel means even the slimmest issue can have calamitous consequences, as we saw with the recent SpaceX rocket explosion. Putting satellites in orbit with any form of insecure fuel on board could influence disaster for costly hardware or even inferior, human life. Water is a way around this matter because it is basically an energy transporter rather than a fuel. The Cornell squad is not planning to use water itself as a propellant but to rather use electricity from solar panels to divide (split) the water into hydrogen and oxygen and use them as the fuel.

The two gasses, when re-combined and burned maybe will explode, leaving out the energy that they took throughout the splitting process. This combustion of gasses can be used to move the satellite forward, gaining speed or changing its position in orbit of whichever chosen planet or moon is the target. Solar panels, with high consistency and no moving fragments, are preferably suited to operate in zero gravity and in the risky environments of space, generating current from sunlight and letting the satellite to actively engage in its mission.

Usually, this energy is stored in batteries. But the Cornell team wants to use it to produce their fuel source by splitting the on-board water. The planned process, known as electrolysis, includes running a current through a water sample generally containing some soluble electrolyte. This breaks down the water into oxygen and hydrogen, which are released discretely at the two electrodes.

On Earth, gravity would then be used to separate the gasses so they can be collected and used. In the zero gravity of space, still, the satellite has to use centrifugal forces from its spin to separate the gasses from the solution. Electrolysis has been used in space before to deliver oxygen supplies for manned space missions without the necessity for high-pressure oxygen-storing tanks, for example on the International Space Station (ISS) . But instead of directing water into space in heavy loads on rockets, we could also one day mine it from the Moon or asteroids.

If the novel method of using both the hydrogen and oxygen for satellite fuel proves effective, we could have a prepared source of it waiting for us in space. This means it could form how we power at least various spacecraft of the future. As is often the situation, progresses in space technology are pushing ideas that are likely to support and overcome major energy problems here on Earth. Electricity is actually difficult to store and, as we raise our renewable energy supplies, we need to safeguard the supply and demand.

The Wind and the grids farms are really unproductive forms of renewable energy, not because of difficulties with the generating technology however because we often can’t do anything valuable with the energy that they produce. The electricity grid fights at times of high production and short energy need. The answer, as in outer space propulsion, could include using extra electricity to split water into hydrogen and oxygen. This harvests a storable, transportable product in the form of hydrogen fuel.

When the energy is necessary, it can be released by re-combining it with oxygen from the atmosphere. This can also be done in a fuel cell to harvest electricity again, or by burning it in a combustion engine or a hydrogen gas burner. Welsh startup strong River-simple, with major car builders Toyota and Volkswagen, is by this time producing hydrogen fuel-cell cars. So if the hydrogen is created from solar energy in the same method as Cornell’s satellite, this space technology could become part of your everyday life faster than you consider.

Charles W. Dunnill, Senior Lecturer in Energy, Swansea University and Robert Phillips, PhD. Student in Renewable Energy Storage, Swansea University.

This article was originally published written on The Conversation.

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