Last year, Odyssey looked as if it might be running out of gas: Calculations suggested its hydrazine fuel was much lower than expected.
For more than 20 years, NASAs Mars Odyssey orbiter has actually been studying the Martian surface area. In 2006, the missions Thermal Emission Imaging System instrument caught this image of sand dunes creeping throughout the flooring of a location called Bunge Crater. Credit: NASA/JPL-Caltech/ASU
Odyssey released in 2001 with nearly 500 pounds (225.3 kgs) of hydrazine propellant. One method to determine Odysseys fuel is to apply heat to the spacecrafts two propellant tanks and see how long they take to reach a particular temperature.
That is, in reality, what appeared to accompany a fuel quote performed on Odyssey in the summer of 2021. The mathematics seemed to reveal that about 11 pounds (5 kilograms) of propellant remained readily available– less than the missions modeling had predicted. Another estimate in January 2022 suggested just 6 pounds (2.8 kgs) of hydrazine remained.
If the figures were precise, Odyssey would be operating on empty in less than a year. Either the spacecraft had actually experienced some kind of failure, like a leak, or something was off in the teams measurements.
Months of testing and extreme investigation ensued. After studying the mystery of the “missing” fuel, objective engineers have learned brand-new aspects of how the aging spacecrafts complex fuel system behaves in flight. Their conclusion: The orbiter ought to in fact have enough to last at least through the end of 2025.
NASAs 2001 Mars Odyssey orbiter is portrayed in this illustration. The objective group spent the majority of 2021 assessing just how much propellant is left on the orbiter, concluding it has enough to remain active through at least 2025. Credit: NASA/JPL-Caltech
How Odyssey Uses Hydrazine
Odyssey doesnt require a lot of hydrazine to get by on any offered day. Solar panels power its systems, while 3 strategically placed response wheels assist the orbiter point its science instruments at the Martian surface area. As the response wheels spin inside the spacecraft bus, or body, they develop torque that causes Odyssey to move in the opposite direction.
” These reaction wheels have to interact to preserve the spacecrafts pointing,” stated Odysseys objective supervisor, Jared Call of NASAs Jet Propulsion Laboratory in Southern California. “But with Odyssey completing a complete loop every orbit, you need a way to discharge the increasing momentum.”
Thats where Odysseys hydrazine comes in. The spacecrafts thrusters launch this propellant in small, calculated bursts to counter the reaction wheels structure momentum.
Teamwork
When the groups estimations showed that their propellant supply was lower than expected, engineers at JPL got to work with those at Lockheed Martin Space, which built Odyssey, maintains mission operations, and provides spacecraft engineering assistance.
” First, we had to validate the spacecraft was OK,” said Joseph Hunt, Odysseys task manager at JPL. “After eliminating the possibility of a leak or that we were burning more fuel than approximated, we began looking at our measuring procedure.”
The team concurred that they needed some fresh eyes to evaluate the circumstance. They generated Boris Yendler, an outside consultant who likewise specializes in spacecraft propellant estimation.
Like all spacecraft, Odyssey relies on heating systems to keep various parts, consisting of the fuel tanks, working in the cold of area. Yendler wondered whether heat was being contributed to the propellant from some other source on the spacecraft, complicating the fuel measurement. After lots of experimentation, the team confirmed that was the case: Heaters along a fuel line linking the tanks were warming them faster than anticipated, making it seem as if the tanks were nearly empty.
” Our technique of measurement was great. The problem was that the fluid characteristics occurring on board Odyssey are more complex than we thought,” Call said.
After figuring out how much heat wasnt being represented in their computations, the team concluded that Odyssey has about 9 pounds (4 kgs) of hydrazine left. Its enough to last the objective for a few more years. The number might change as the group works to refine the measurements and improve their precision, the team is resting simpler now that they better comprehend their spacecraft.
” Its a little like our procedure for clinical discovery,” Call stated. “You check out an engineering system not understanding what youll discover. And the longer you look, the more you find that you didnt anticipate.”
NASAs Mars Odyssey spacecraft passes above Mars south pole in this artists principle illustration. Considering that NASA introduced the 2001 Mars Odyssey Orbiter to the Red Planet almost 22 years back, the spacecraft has looped around Mars more than 94,000 times. Their work has actually assisted Odyssey develop a clinical tradition: The spacecraft has mapped minerals across the Martian surface area, permitting researchers to better understand the worlds history. One way to measure Odysseys fuel is to apply heat to the spacecrafts two propellant tanks and view how long they take to reach a specific temperature. Like all spacecraft, Odyssey relies on heating systems to keep numerous parts, including the fuel tanks, working in the cold of area.
NASAs Mars Odyssey spacecraft passes above Mars south pole in this artists concept illustration. The spacecraft has been orbiting Mars because October 24, 2001. Credit: NASA/JPL-Caltech
Measuring the fuel supply on Odyssey, a decades-old spacecraft without a fuel gauge, is no easy task.
Because NASA introduced the 2001 Mars Odyssey Orbiter to the Red Planet nearly 22 years earlier, the spacecraft has actually looped around Mars more than 94,000 times. Thats about the equivalent of 1.37 billion miles (2.21 billion kilometers), a range that has actually needed incredibly careful management of the spacecrafts fuel supply. This feat is all the more outstanding offered that Odyssey has no fuel gauge; engineers have needed to rely on math rather.
Their work has actually assisted Odyssey construct a clinical legacy: The spacecraft has actually mapped minerals throughout the Martian surface, allowing scientists to better comprehend the planets history. Odyssey is also amongst a small constellation of orbiters that communicates data back to Earth from NASAs landers and rovers (almost 150 gigabytes to date, and counting).
