NASA is testing the use of a new green fuel for spacecraft of all sizes. To replace toxic hydrazine, which it has used since the 1960s, NASA is using a less polluting propellant and new technological tools to work together.
A little over a year since launch, the Green Propellant Infusion Mission (GPIM) showed that a never-before-used propellant and propulsion system do work as intended. This result led to the conclusion that both resources are practical options for upcoming missions, according to La Opinion de Murcia.
The GPIM set out to test a monopropellant, a chemical propellant that can burn by itself without the need for a separate oxidizer. This propellant is called Advanced Spacecraft Energetic Non-Toxic (Ascent). Formerly known as AF-M315E, the U.S. Airforce Research Laboratory created the propellant at the Edwards Air Force Base in California. It is considered as an alternative to monopropellant hydrazine.
“This is the first time in 50 years NASA tested a new, high-performing monopropellant in space,” said Tim Smith, GPIM mission manager at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “It has the potential to supplement or even replace hydrazine, which spacecraft have used since the 1960s.”
Based at Marshall, NASA’s Technology Demonstration Mission (TDM) program manages the mission.
GPIM’s effective demonstration of the propellant paved the way for NASA’s acceptance of ASCENT in new missions. The next NASA mission to use ASCENT will be Lunar Flashlight. The small spacecraft, which aims to provide clear-cut information about the presence of water deposits inside craters, will launch as a secondary payload on Artemis I, the first integrated flight test of NASA’s Orion spacecraft and Space Launch System (SLS) rocket.
Despite being pink in color, ASCENT is considered “green” for its significantly reduced toxicity compared to hydrazine, which requires protective suits and rigorous propellant loading processing procedures. It is safer to store and use, requiring minimal personal protective equipment such as lab coats, goggles, and gloves. Furthermore, hydrazine can cause cancer.
In addition to being easier and less expensive to handle here on Earth, when loading a spacecraft with propellant, for example, ASCENT will allow spacecraft to travel farther or operate longer with less propellant in their tank, given its higher performance.
How they got to this conclusion
To test the propellant on a small spacecraft, the GPIM team had to develop hardware and systems compatible with the liquid.
Aerojet Rocketdyne of Redmond, Washington, designed and built the five thrusters onboard GPIM. Aerojet Rocketdyne and Ball Aerospace of Boulder, Colorado, co-designed the other elements of the propulsion system.
While in orbit, GPIM tested the propellant and propulsion system, including the thrusters, tanks, and valves, by conducting a planned series of orbital maneuvers. Attitude control maneuvers, the process of maintaining stable control of a satellite, and orbit lowering demonstrated the propellant’s pre-mission projected performance, showing a 50% increase in gas mileage for the spacecraft compared to hydrazine.
On the other hand, Smith believes that, on the basis of the nearly completed technology objectives, the mission indicated that both Ascent and the compatible propellant system are good alternatives for NASA and the commercial space travel industry.
The GPIM is close to mission completion and the spacecraft has concluded a series of de-orbiting deorbit burns. Approximately seven burns will lower the orbit to about 110 miles (180 kilometers) and deplete the propellant tank. The small spacecraft will burn up in Earth’s atmosphere upon reentry, anticipated in late September 2020.
Damages caused by hydrazine
Hydrazine is a colorless and oily liquid that releases vapors when exposed to air. Its uses include fuel for aircraft, missiles, spacecraft and satellite. However, hydrazine is highly toxic and dangerously unstable.
According to the U.S. Agency for toxic Substances and Disease Registry (ATSDR), small amounts of hydrazine and dimethylhydrazine have been found in tobacco products. This means that people that chew or smoke tobacco, and even the ones that breathe the smoke, are exposed to small amounts of these substances.
A strong exposition to hydrazine can cause irritation of the eyes, nose, and the throat; dizziness, nausea, pulmonary edema, seizures, and even a coma.
It can also cause severe damages to the liver, kidneys, and the nervous system and even cause lung cancer and cancer in the nasal cavity, as well as liver tumors.
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