Later this month, a small satellite pushes a ride on a SpaceX Falcon Heavy rocket for the world's first demonstration of "green" satellite propellant in space. The satellite was fueled by the AFM-315, which Air Force first developed more than 20 years ago as a replacement for the typical satellite juice selection, hydrazine. If successful, the AFM-315 can make satellite more efficient, satellite deployment time less than weeks to day, and greatly reduce safety requirements for storing and handling gasoline of satellite, a good for people and the environment. Looking at the future, scientists working on gasoline say it has a big role in helping to get satellite operations out of the ground.
Hydrazine is a variability of fuel that destroys your day-and maybe your life-if you're exposed to it. To fuel a satellite you need a lot of safety infrastructure, including pressurized full-body "SCAPE suit" just to handle things. On the other hand, AFM-315 is more toxic than caffeine, so you need a lab coat and pump. "We are literally sitting in a room next to a plastic jug when we are fueling the satellite," says Chris McLean, an engineer at Ball Aerospace and the project led to the NASA's Green Propellant Infusion Mission.
Unlike hydrazine, which is a uniformity of water, AFM-315 is thick. But its fuel density will increase the "mile per gallon" delivered to a satellite by 50 percent, compared to the same amount of hydrazine.
McLean claims one of the largest selling AFM-315 after safety is the fact that it does not freeze. AFM-315 is a liquid salt, which means at very low temperatures, it is subject to moving glass instead. It changes gasoline into a brittle, solid glass mirror, but it does not cause gasoline expansion like frozen water or hydrazine. This feature prevents fuel lines and storage containers from cracking under stress. Additionally, moving its glass is very low, so gasoline does not have to be heated on satellite-a big suck on other missions. McLean said it would do more power available for other instruments or satellite systems, which could open new possibilities for missions on other planets.
But for all its benefits, the journey from the conception of AFM-315 has been a long one. Originally developed by the Air Force Research Laboratory in 1998 as an alternative satellite fuel, McLean said that its use was limited due to its high temperature burns, nearly twice as hydrazine. Exotic and expensive materials are needed to prevent satellite damage. In late 2000, the cost of manufacturing manufacturing systems that could handle heat from the AFM-315 was low enough to make it feasible, but no company would be risking fueling their satellites with experimental propellant. If the AFM-315 is to be widely adopted by the satellite industry, McLean says, it should prove itself to the orbit. Thus, NASA's Green Infusion Propellant Mission was born.
Previously launched in late 2015, the mission of the greenhouse was caught in delays to enter the development of the SpaceX Falcon Heavy rocket. On June 24 it is scheduled to fly on Falcon Heavy's second mission run with several other payloads, including an atomic clock tested for deep space navigation.
The green propellant satellite bus was built by Ball Aerospace and equipped with four 1-newton thrusters and a 22-newton thruster to be used to test the AFM-315 propellant. During his 13-month mission, it will use thrusters to perform orbital maneuvers, such as lowering its orbit and changing its attitude or preference, in order to test the propellant's performance.
McLean claims that there are already customers who are interested in using the green propellant if the demonstration flight is getting stronger. This means that the satellites can fly missions to operate around the Earth as soon as 18 months after the presentation. Looking forward to the future, McLean said that the AFM-315 is especially useful for exploring the cold regions of the solar system, such as the Martian poles. It looks like the Red Planet gets a bit more green.
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