Tag: solar system

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NASA Voyager 1’s Data Anomaly Said Fixed

A critical system aboard the probe was sending garbled data about its status. Engineers have fixed the issue but are still seeking the root cause.

Engineers have repaired an issue affecting data from NASA’s Voyager 1 spacecraft. Earlier this year, the probe’s attitude articulation and control system (AACS), which keeps Voyager 1’s antenna pointed at Earth, began sending garbled information about its health and activities to mission controllers, despite operating normally. The rest of the probe also appeared healthy as it continued to gather and return science data.


The team has since located the source of the garbled information: The AACS had started sending the telemetry data through an onboard computer known to have stopped working years ago, and the computer corrupted the information.


Suzanne Dodd, Voyager’s project manager, said that when they suspected this was the issue, they opted to try a low-risk solution: commanding the AACS to resume sending the data to the right computer.


Engineers don’t yet know why the AACS started routing telemetry data to the incorrect computer, but it likely received a faulty command generated by another onboard computer. If that’s the case, it would indicate there is an issue somewhere else on the spacecraft. The team will continue to search for that underlying issue, but they don’t think it is a threat to the long-term health of Voyager 1.


“We’re happy to have the telemetry back,” said Dodd. “We’ll do a full memory readout of the AACS and look at everything it’s been doing. That will help us try to diagnose the problem that caused the telemetry issue in the first place. So we’re cautiously optimistic, but we still have more investigating to do.”


Voyager 1 and Voyager 2 have been exploring our solar system for 45 years. Both probes are now in interstellar space, the region outside the heliopause, or the bubble of energetic particles and magnetic fields from the Sun.
For more information about the Voyager spacecraft, visit: https://www.nasa.gov/voyager


https://www.jpl.nasa.gov/news/engineers-solve-data-glitch-on-nasas-voyager-1

AR Issue #57

Project Stardust

by William Henry

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Saturn’s Rings Left by Missing Moon?

By Jennifer Chu

Swirling around the planet’s equator, the rings of Saturn are a dead giveaway that the planet is spinning at a tilt. The belted giant rotates at a 26.7-degree angle relative to the plane in which it orbits the sun. Astronomers have long suspected that this tilt comes from gravitational interactions with its neighbor Neptune, as Saturn’s tilt precesses, like a spinning top, at nearly the same rate as the orbit of Neptune.

But a new modeling study by astronomers at MIT and elsewhere has found that, while the two planets may have once been in sync, Saturn has since escaped Neptune’s pull. What was responsible for this planetary realignment? The team has one meticulously tested hypothesis: a missing moon. (https://www.science.org/doi/10.1126/science.abn1234)
In a new study appearing in Science, the team proposes that Saturn, which today hosts 83 moons, once harbored at least one more, an extra satellite that they name ‘Chrysalis.’ Together with its siblings, the researchers suggest, Chrysalis orbited Saturn for several billion years, pulling and tugging on the planet in a way that kept its tilt, or “obliquity,” in resonance with Neptune. 

But around 160 million years ago, the team estimates, Chrysalis became unstable and came too close to its planet in a grazing encounter that pulled the satellite apart. The loss of the moon was enough to remove Saturn from Neptune’s grasp and leave it with the present-day tilt.

What’s more, the researchers surmise, while most of Chrysalis’ shattered body may have made impact with Saturn, a fraction of its fragments could have remained suspended in orbit, eventually breaking into small icy chunks to form the planet’s signature rings.

The missing satellite, therefore, could explain two longstanding mysteries: Saturn’s present-day tilt and the age of its rings, which were previously estimated to be about 100 million years old—much younger than the planet itself.
“Just like a butterfly’s chrysalis, this satellite was long dormant and suddenly became active, and the rings emerged,” says Jack Wisdom, professor of planetary sciences at MIT and lead author of the new study.

The study’s co-authors include Rola Dbouk at MIT, Burkhard Militzer of the University of California at Berkeley, William Hubbard at the University of Arizona, Francis Nimmo and Brynna Downey of the University of California at Santa Cruz, and Richard French of Wellesley College.

In the early 2000s, scientists put forward the idea that Saturn’s tilted axis is a result of the planet being trapped in a resonance, or gravitational association, with Neptune. But observations taken by NASA’s Cassini spacecraft, which orbited Saturn from 2004 to 2017, put a new twist on the problem. Scientists found that Titan, Saturn’s largest satellite, was migrating away from Saturn at a faster clip than expected, at a rate of about 11 centimeters per year. Titan’s fast migration, and its gravitational pull, led scientists to conclude that the moon was likely responsible for tilting and keeping Saturn in resonance with Neptune.

But this explanation hinges on one major unknown: Saturn’s moment of inertia, which is how mass is distributed in the planet’s interior. Saturn’s tilt could behave differently, depending on whether matter is more concentrated at its core or toward the surface.

“To make progress on the problem, we had to determine the moment of inertia of Saturn,” Wisdom says.

In their new study, Wisdom and his colleagues looked to pin down Saturn’s moment of inertia using some of the last observations taken by Cassini in its “Grand Finale,” a phase of the mission during which the spacecraft made an extremely close approach to precisely map the gravitational field around the entire planet.  The gravitational field can be used to determine the distribution of mass in the planet.


This research was supported, in part, by NASA and the National Science Foundation.

https://news.mit.edu/2022/saturn-rings-tilt-missing-moon-0915

AR Issue #74
Crystal Saturn

by Martin Ruggles

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Zircon from Mars Shows Asteroid Hit

Curtin University researchers studying a Martian meteorite have found the first evidence of high-intensity damage caused by asteroid impact, in findings that have implications for understanding when conditions suitable for life may have existed on early Mars.

Published in leading journal Science Advances, the research examined grains of the mineral zircon in Martian meteorite NWA 7034. The meteorite, colloquially known as ‘Black Beauty’, is a rare sample of the surface of Mars. The original 320-gram rock was found in northern Africa and first reported in 2013.

Lead author Morgan Cox, a PhD candidate from Curtin’s Space Science and Technology Centre (SSTC) in the School of Earth and Planetary Sciences, described the meteorite as a collection of broken rock fragments and minerals, mostly basalt, that solidified and became a rock over time. A zircon found inside the meteorite preserves evidence of damage that only occurs during large meteorite impacts.

“This grain is truly a one-off gift from the Red Planet. High-pressure shock deformation has not previously been found in any minerals from Black Beauty. This discovery of shock damage in a 4.45 billion-year-old Martian zircon provides new evidence of dynamic processes that affected the surface of early Mars,” Ms Cox said.

“The type of shock damage in the Martian zircon involves ‘twinning’, and has been reported from all of the biggest impact sites on Earth, including the one in Mexico that killed off the dinosaurs, as well as the Moon, but not previously from Mars.”

Co-author Dr Aaron Cavosie, also from Curtin’s SSTC, said the occurrence of zircon grains in the Black Beauty meteorite provided physical evidence of large impacts on early Mars, and had implications for the habitability of the young planet.

“Prior studies of zircon in Martian meteorites proposed that conditions suitable for life may have existed by 4.2 billion years ago based on the absence of definitive shock damage” Dr Cavosie said.

“Mars remained subject to impact bombardment after this time, on the scale known to cause mass extinctions on Earth. The zircon we describe provides evidence of such impacts, and highlights the possibility that the habitability window may have occurred later than previously thought, perhaps coinciding with evidence for liquid water on Mars by 3.9 to 3.7 billion years ago.”

The research team also included collaborators from The University of Western Australia and the University of Glasgow.

The full research paper, ‘Impact and habitability scenarios for early Mars revisited based on a 4.45-Ga shocked zircon in regolith breccia’ can be found online here.

Issue #79
Life in the Solar System