Later this month, a small satellite will run on a SpaceX Falcon Heavy rocket for the world's first "green" satellite spacecraft demonstration. The satellite is powered by AFM-315, which the Air Force first developed more than 20 years ago as an alternative to the typical satellite evening, hydrazine. If successful, the AFM-315 would make the satellites much more efficient, reduce the time of satellite integration from week to day, and drastically reduce the security requirements for storage and management of satellite fuel, a blessing for humans and the environment. Given the future, scientists working on the fuel say it will play a major role in helping extraterrestrial satellite operations from the ground.
Hydrazine is a volatile fuel that destroys your day ̵
Unlike hydrazine, which has a consistency similar to water, AFM-315 is viscous. However, its fuel density would increase "miles per gallon" delivered to a satellite by 50 percent compared to the same volume of hydrazine.
McLean says one of AFM-315's largest after-sales outlets is the fact that it does not freeze. AFM-315 is a liquid salt, which means that at extremely low temperatures it undergoes a glass transition instead. This turns the fuel into a brittle, glass-like solid, but it does not expand the fuel as frozen water or hydrazine. This attribute prevents fuel lines and storage containers from breaking under stress. Moreover, its glass transition point is extremely low, so the fuel does not need to be heated on the satellite – a great force sucks for other tasks. McLean says this will make more power available to other instruments or systems on the satellite, which could open up new opportunities for missions to other planets.
But for all its benefits, the AFM-315's journey from fertilization to launch has been a long one. First developed by the Air Force Research Laboratory in 1998 as an alternative satellite fuel, McLean says it found limited use due to the high combustion temperature, which was about twice as high as hydrazine. This required exotic and expensive materials to prevent the satellite from being damaged. By the end of the 21st century, the cost of manufacturing propulsion systems that could handle the heat of the AFM-315 was low enough to allow use, but no company wanted to risk burning their satellites with an experimental fuel. If the AFM-315 was ever to be widely adopted by the satellite industry, McLean says, it would have to prove itself in orbit. Thus, NASA's Green Infusion Propellant Mission was born.
Originally slated to be launched at the end of 2015, the green fuel mission was captured in the delays that plagued the development of SpaceX Falcon Heavy rocket. On June 24, it is planned to fly on Falcon Heavy's other operational missions together with several other payloads, including an atomic clock that is being tested for deep space navigation.
The satellite bus with green fuel was developed by Ball Aerospace and is equipped with four 1-newton thrusters and a 22-newton thruster that will be used to test AFM-315 propellants. During its 13-month mission, it will be used to perform orbital maneuvers, lowering its orbit and changing its setting or tilt, to test the fuel performance.
McLean says there are already customers interested in using the green fuel if the demonstration flight goes well. This means that satellites could fly operational missions around the world as soon as 18 months after the demonstration. Looking forward to the future, McLean AFM-315 says can be particularly useful for exploring the solar system's cold areas, such as the Marspole. It looks like the red planet became a little more green.
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