The massive spacecraft headed for Jupiter’s moon Europa uses four large interaction wheels to help keep it oriented.
Just as NASA’s Mars rover relies on durability Wheels To get around the Red Planet and do science, some orbiters also rely on wheels — in this case, reaction wheelsTo stay pointed in the right direction. Engineers and technicians at NASA’s Jet Propulsion Laboratory in Southern California recently installed four reaction wheels on the Europa Clipper, which it will rely on during its journey on Jupiter’s icy moon Europa.
As a NASA spacecraft hurtles through deep space, glides into orbit around Jupiter, and collects science observations while flying dozens of times by Europa, the wheels spin the probe so its antennas can communicate with Earth and its science instruments, including cameras, .
Two feet wide and made of steel, aluminum, and titanium, the wheels spin quickly to generate a torque that causes the probe to spin in the opposite direction. Isaac Newton’s third law of motion also applies in deep space and explains the basic phenomenon: for every action there is an equal and opposite reaction. Reaction wheels cause the spacecraft to react to the motion of the wheels spinning.
Here’s one way to visualize how reaction wheels work: Imagine you’re sitting in a swivel chair and your feet are off the ground so that you can spin freely. If you move your torso in one direction, the chair and your legs will rotate in the opposite direction. Reaction wheels work the same way: since the reaction wheel motor accelerates the metal wheel in one direction, the spacecraft experiences acceleration in the opposite direction.
Without these reaction wheels, Europa Clipper will not be able to conduct its science investigations when it reaches the Jupiter system in 2030 after its launch in 2024. Scientists believe that Europa harbors a vast inner ocean that may have conditions suitable for life support. The spacecraft will collect data on the moon’s atmosphere, surface, and interior—information that will help scientists learn more about the ocean, ice shell, and possible plumes that might spew groundwater into space.
During its orbits around Jupiter, the Europa Clipper will rely on reaction wheels to help it perform thousands of turns, or “failures.” Although spacecraft can perform some of those maneuvers with thrusters, their thrusters need fuel—a limited resource on the orbiter. The reaction wheels will run on electricity provided by the spacecraft’s massive solar arrays.
The trade-off is that reaction wheels run slowly. It will take the Europa Clipper’s reaction wheels about 90 minutes to rotate the vehicle 180 degrees – a motion so gradual that from a distance it is almost imperceptible to the human eye. The rotation of the spacecraft will be three times slower than the minute hand on the clock.
Also, it can wear out over time. It happened on NASA’s Dawn spacecraft, which required engineers to figure out how to spin the thrusters with available fuel. To remedy this, the engineers installed four wheels on the Europa Clipper even though only three wheels were needed for maneuvering. They take turns on whichever three wheels are running until wear and tear. This leaves them with a “spare” wheel in case one fails.
Fitting the wheels was one of the latest steps in the phase known as the assembly, test and launch operations. Science instruments continue to arrive at JPL to be added to the spacecraft. After that, a variety of tests will be performed, such as Space ship It is moving towards its launch period in October 2024. After traveling more than 1.8 billion miles (2.9 billion km), the Europa Clipper will be ready to begin unearthing the secrets of this icy world.
the quote: NASA’s Europa Clipper Gets Its Wheels for Deep Space Travel (2022, November 23) Retrieved November 23, 2022 from https://phys.org/news/2022-11-nasa-europa-clipper-wheels-deep.html
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