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Hubble Returns To Normal Functioning Soon: NASA

After the engineering tests have been completed, Hubble is expected to soon return to normal science operations, NASA stated

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US shutdown delays space missions but NASA not grounded: Report,

NASA has brought Hubble Space Telescope’s seven-year old backup gyroscope (gyro) back to life, after the spacecraft entered safe mode due to a failed gyro earlier this month, the US space agency said on Tuesday.

A gyro is a device that measures the speed at which the spacecraft is turning and is needed to help Hubble turn and lock on to new targets.

Hubble’s backup gyro, which had been off for more than 7.5 years, was incorrectly returning extremely high rotation rates, NASA said in a statement.

Hubble
The Hubble Telescope hovering in space. Wikimedia Commons

This gyro was turned on after the spacecraft entered safe mode due to a failed gyro on October 5.

Additional tests will be performed to ensure Hubble can return to science operations with this gyro, NASA said.

To correct high rotation rates, the Hubble team executed a running restart of the gyro on October 16.

This procedure turned the gyro off for one second, and then restarted it before the wheel spun down.

However, the data showed no improvement in the gyro’s performance.

Hubble Telescope. red dwarf
This gyro was turned on after the spacecraft entered safe mode due to a failed gyro on October 5. Flickr

The team, then on October 18, commanded a series of spacecraft maneuvers, or turns, in opposite directions to attempt to clear any blockage that may have caused the float to be off-centre and produce the exceedingly high rates.

During each maneuver, the gyro was switched from high mode to low mode to dislodge any blockage that may have accumulated around the float.

They noticed a significant reduction in the high rates, allowing rates to be measured in low mode for brief periods of time.

On October 19, the team again commanded Hubble to perform additional maneuvers and gyro mode switches, which appear to have cleared the issue.

NASA mars, UAE, Hubble
The planet Mars is shown May 12, 2016 in this NASA Hubble Space Telescope view when it was 50 million miles from Earth. VOA

The rotation rates produced by the backup gyro have since reduced and are now within an expected range, NASA noted.

Also Read: New Gamma-Ray Collection Named After Hulk, Godzilla: NASA

The team plans to execute a series of tests to evaluate the performance of the gyro under conditions similar to those encountered during routine science observations, including moving to targets, locking on to a target, and performing precision pointing.

After these engineering tests have been completed, Hubble is expected to soon return to normal science operations, NASA stated. (IANS)

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Asteroids Are Falling On Earth’s Surface Twice As Often: Study

This enhanced impact rate poses a threat for the next mass extinction event.

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Asteroids
This Dec. 29, 1968, photo made available by NASA shows craters on the moon. For the past 290 million years, giant rocks from space have been crashing into Earth more than twice as often as they did in the previous 700 million years, according to a new study. VOA

Giant rocks from space are falling from the sky more than they used to, but don’t worry.

For the past 290 million years, large asteroids have been crashing into Earth more than twice as often as they did in the previous 700 million years, according to a new study in Thursday’s journal Science.

But no need to cast a wary glance up. Asteroids still only smack Earth on average every million or few million years, even with the increased crash rate. NASA’s list of potential big space rock crashes shows no pending major threats. The biggest known risk is a 4,200-foot (1.3-km) wide asteroid with a 99.988 percent chance that it will miss Earth when it whizzes very near here in 861 years.

Tell that to the dinosaurs. Most scientists think dinosaurs and a lot of other species went extinct after a huge space rock crashed into Central America about 65 million years ago.

Earth, Asteroids
Taurids meteor shower lights up the sky. The risk of asteroids hitting the Earth has grown over the years. Wikimedia

“It’s just a game of probabilities,” said study lead author Sara Mazrouei, a University of Toronto planetary scientist. “These events are still rare and far between that I’m not too worried about it.”

Mazrouei and colleagues in the United Kingdom and United States compiled a list of impact craters on Earth and the moon that were larger than 12 miles (20 km) wide and came up with the dates of them. It takes a space rock that’s half a mile (800 meters) wide to create holes that big.

The team counted 29 craters that were no older than 290 million years and nine between 291 million years and 650 million years old.

But we can see relatively few big craters on Earth because the planet is more than 70 percent ocean and past glaciers smoothed out some holes, said University of Toronto planetary scientist Rebecca Ghent, a study co-author.

Earth, Asteroids
These rocks were rare survivors from a very different time on Earth. Pixabay

Extrapolating for what can’t be seen brings the total to about 260 space crashes on Earth in the last 290 million years. Adding in other factors, the science team determined that the current space crash rate is 2.6 times more than the previous 700 million years.

Craters older than 650 million years are mostly wiped off on Earth by glacial forces so the scientists used impact craters on the nearby moon as a stand-in for holes between 650 million and 1 billion years old. The moon is a good guide for estimating Earth crashes, because it is close enough to be in the same bombardment path and its craters last longer.

Mixed reactions

So what happened nearly 300 million years ago?

“Perhaps an asteroid family was broken up in the asteroid belt,” Mazrouei speculated. The space rocks then headed toward the Earth and moon, and the planet got slightly more because it is a bigger target and it has higher gravity, Ghent said.

Oldest known asteroid family
An asteroid family. Wikimedia

Outside scientists are split about the research. Jay Melosh at Purdue said he found the number of craters too small to come to a reasonable conclusion, but Harvard’s Avi Loeb said the case was convincing.

Also Read: Newly Discovered Super-Earth Exoplanet May Sustain Primitive Life

Humans might not have emerged without mass extinctions from space rocks about 250 million and 65 million years ago, Loeb said in an email, adding, “but this enhanced impact rate poses a threat for the next mass extinction event, which we should watch for and attempt to avoid with the aid of technology.”

“This demonstrates how arbitrary and fragile human life is,” Loeb wrote. (VOA)