Magnetic manipulation against space waste

New technology to solve space debris problem

The space debris problem It becomes more urgent. between suggested solutions To scatter potentially dangerous space debris from afar, or to slow damaged satellites in uncontrolled rotation in order to repair them, there are magnetic manipulation. In particular, proposed by the University of Utah exploits induced currents by moving magnetic fields in the metal pieces that make up space debris.

They call it space junk, but it looks more like a hail of bullets than anything else. 27,000 debris, the size of tennis balls traveling up to 28,000 kilometers per hour: a lot of it will be above our heads, according to NASA. And this (from) the download – you read the Media Inaf, the online newsletter of the National Institute of Astrophysics – Risks of causing significant damage to satellites or spacecraft that are still operating.

As on Earth, the problem of garbage becomes more and more stressful as the population increases (objects orbiting space, in the case of space). The problem, in this case, is understanding how to manipulate it appropriatelyAnd – and perhaps – how to restore them where the damage can be repaired. A study published in Nature has discovered a new way to deflect orbital debris without touching it by using a rotating magnet.

Magnetic processing is precisely the advantage of being able to do it offline, to avoid dangerous and destructive collisions between the manipulator object and the target. This concept is well proven and even has up to six degrees of freedom of motion in the case of ferromagnetic materials. However, in the case of space debris, the metal that composes it is a conductor of electricity but does not contain an appreciable amount of ferromagnetic material.

When metallic debris is exposed to a time-varying magnetic field, the electrons spin inward in circular motions, generating eddy currents that interact with the magnetic field itself. In the new study, scientists prove that this feature is physical It allows manipulation with six degrees of freedom, for objects conducting by rotating magnetism: the process turns debris into a true electromagnet, so its motion can be controlled remotely.

The idea of ​​using induced magnetic currents to move objects in space is not new, but until now it was limited to only one degree of freedom, such as horizontal thrust..

Using multiple magnetic field sources in a coordinated fashion, the researchers figured out how to move objects with six degrees of motion, including rotation.. “What we wanted to do was manipulate it, not just push it, just like we do on Earth,” says Jake J. Abbott, professor of mechanical engineering at the University of Utah and leader of the team that created this new method. “This form of skillful manipulation has never happened before.”

With this new technology, it would be possible, for example, to stop a damaged satellite in an uncontrolled rotation to repair it, a maneuver that would be risky under normal conditions. “You have to take this crazy object floating in space, and put it in a position where it can be fixed with a robotic arm,” Abbott explains. “But if it gets out of control, it can break the robot’s arm, creating more debris.”

This method also allows you to Handling especially fragile items. While a robotic arm can damage an object through the use of excessive force, these magnets will apply a softer force to the entire object so that no sections are damaged. To test the new technique—Media Inaf continues—the team used a series of magnets to move a copper ball on a plastic raft in a water tank (the best way to simulate slow objects in microgravity). The magnets not only moved the ball into a square, but were also able to rotate it.

“NASA tracks thousands of space debris the same way air traffic controllers track planes. “You have to know exactly where it is to avoid accidentally bumping into it,” Abbott says. “The US government and the governments of the world know this problem because there are more and more things piling up with each passing day.”

Jupiter’s ‘red spot’ is now less mysterious

New mysteries have been revealed about Jupiter’s famous ‘red spot’. Jupiter’s Great Red Spot is actually an anti-eddy storm with ‘trapped’ depth The new results were obtained from measurements of the planet’s gravity by NASA’s Juno probe and revealed, in a study published in the journal Science, that Jupiter’s Great Red Spot, although very large, is not as deep as he had imagined. This discovery could explain the reasons for their development and possible disappearance.

“The results of our study testify that the mass of the storm is equal to about half of the entire Earth’s atmosphere and under all the waters of the Mediterranean Sea, and the Great Red Spot represents as an object very similar to a very large disk. (its smaller size is approximately equal to the diameter of the Earth) but rather thin, with characteristics Similar to those of the largest terrestrial storms.

Sapienza researchers remember that Jupiter is the largest planet in the solar system, with a radius of 71,492 kilometers at the equator, and composed mainly of hydrogen and helium and for this reason it is known as a ‘gas giant’. The Great Red Dot is perhaps the most famous feature on the planetGiandomenico Cassini may have discovered an anti-eddy storm in 1665. This day resembles an oval with a size of about 16,000 x 12,000 km, making it the largest storm in the solar system, albeit in the past 100 years, for reasons that are still unknown. .

The Great Red Spot still brings with it many questions: One of those factors has to do with the depth at which this storm is sinking into Jupiter. The Juno probe, built by NASA with an important Italian contribution, answered this as well as other questions about the size of the nucleus. During two upper operations near Jupiter (February and July 2019), NASA’s Juno mission (in orbit around Jupiter since July 5, 2016 to study the formation mechanisms, internal structure, magnetosphere and atmosphere of the gas giant) first observed closely the Great Red Spot . Since the interior of the planet cannot be directly observed, accurate measurements of its gravitational field are used to understand its internal structure, which is an expression of the distribution of mass within the planet.

Measurements of the planet’s gravitational field showed that strong winds from east to west (with speeds of up to 360 km / h), which can be seen by tracking the movement of clouds, are pushing to a depth of about 3000 km. Today, new research, funded in part by the Italian Space Agency (ASI) and coordinated by Marzia Baresi, a former doctoral student at Sapienza and now a postdoctoral at Caltech/JetPropulsion Laboratory, along with an international group of any part explains Daniele Durante. Luciano Ice from the Department of Mechanical and Aerospace Engineering at Sapienza How is it done instead The great red machine wind has a somewhat limited vertical penetration depth, equal to about 300 km, much less than the winds blowing in the visible beams of the planet.

The results of the work were published in the journal Science. With a very eccentric orbit, the Juno probe managed to get very close to the gas giant, at an altitude of 4-5 thousand km above the clouds: at these distances it is possible to have a high sensitivity to the gravitational acceleration exerted by structures mainly from the planet’s atmosphere.

The probe used the KaT radio science instrument – Ka-Band Translator, created by Thales Alenia Space-I with funding from the Italian Space Agency – the heart of the experiment that made it possible to determine the vertical extension of the Great Red Spot. The Great Red Spot imperceptibly disturbed Juno’s orbit, but the maximum measurement accuracy (up to 0.01 mm/sec) made it possible to capture the very weak gravitational signal and thus estimate the depth at about 300 km.

“Juno’s measurements – concludes Luciano Ice from the Department of Mechanical and Aerospace Engineering at Sapienza University in Rome – have provided a third dimension to the phenomenon of Jupiter’s atmosphere that has attracted the attention of many of us, as well as astronomers for more than three hundred years, showing that it is certainly a superficial storm Widespread, but very shallow. This new procedure will help to understand its nature, evolution, and possible disappearance.”