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Chandra X-ray Observatory back at work after gyroscrope troubles caused it to shut down

NASA has said its Chandra space telescope has returned to normal operation following a major technical problems.

Chandra automatically went into so-called safe mode last Wednesday, because of a gyroscope problem.

Hubble and Kepler have had similar malfunctions in the past weeks – with Kepler still out of action.  

 

This illustration made available by NASA shows the Chandra X-ray Observatory. On Friday, Oct. 12, 2018, the space agency said that the telescope automatically went into so-called safe mode on Wednesday, possibly because of a gyroscope problem.

WHAT IS ‘SAFE MODE’

When Chandra automatically entered safe mode, the telescope’s instruments are put into a safe configuration.

Critical hardware is swapped to back-up units, the spacecraft points so that the solar panels get maximum sunlight, and the mirrors point away from the Sun.

‘On the evening of October 21, Chandra returned to science observations after the team successfully carried out a procedure to enable a new gyroscope configuration for the spacecraft,’ NASA said.

The team initiated a set of maneuvers to change the pointing and orientation of the spacecraft to confirm that the gyroscopes were behaving as expected.

‘During the coming week, scientists will collect spacecraft data to fine-tune the performance for the new gyroscope configuration,’ it added. 

‘As a final step, the team will uplink a software patch to apply any necessary adjustments to the on-board computer.’ 

The safe mode was caused by a glitch in one of Chandra’s gyroscopes resulting in a 3-second period of bad data that in turn led the on-board computer to calculate an incorrect value for the spacecraft momentum. 

The erroneous momentum indication then triggered the safe mode. 

All of NASA’s orbiting observatories are old: Hubble is 28, while Chandra is 19, and Kepler is 10.

Earlier this week NASA said ‘The Kepler spacecraft has transitioned to its no-fuel-use sleep mode. 

‘The Kepler team is currently evaluating possible next steps.’ 

NASA says it’s coincidental both went ‘asleep’ within a week of one another.  

An astronomer who works on Chandra, Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics, a few weeks ago that ‘Chandra decided that if Hubble could have a little vacation, it wanted one, too.’

‘At approximately 1355 GMT on October 10, 2018, NASA’s Chandra X-ray Observatory entered Safe Mode, where the telescope’s instruments are put into a safe configuration, critical hardware is swapped to back-up units, the spacecraft points so that the solar panels get maximum sunlight, and the mirrors point away from the Sun,’ NASA said.

‘Analysis of available data indicates the transition to safe mode was nominal, i.e., consistent with normal behavior for such an event. 

‘All systems functioned as expected and the scientific instruments are safe. The cause of the Safe Mode transition is currently under investigation.’

The Hubble Space Telescope was been sidelined by a serious pointing problem.

NASA announced that one of Hubble’s gyroscopes failed last Friday.

As a result, Hubble is in so-called safe mode with non-essential systems turned off, putting all science observations on hold.

Most of the giant Hubble Space Telescope can be seen as it is suspended in space by Discovery's Remote Manipulator System (RMS) following the deployment of part of its solar panels and antennae. The Hubble Space Telescope has been sidelined by a pointing system failure.

Most of the giant Hubble Space Telescope can be seen as it is suspended in space by Discovery’s Remote Manipulator System (RMS) following the deployment of part of its solar panels and antennae. The Hubble Space Telescope has been sidelined by a pointing system failure.

WHAT IS THE PROBLEM WITH HUBBLE? 

Hubble entered safe mode after one of the three gyroscopes (gyros) actively being used to point and steady the telescope failed.

Hubble has six gyroscopes, all of which were replaced by spacewalking astronauts during a servicing mission in May 2009. 

The telescope needs three working gyroscopes to ‘ensure optimal efficiency.’

The latest failure brings that number down to two (if the ‘problematic’ one that had been off can’t be brought back online)

 

NASA says mission controllers are working to restore the 28-year-old telescope.

Gyroscopes are needed to keep Hubble pointed in the right direction during observations. 

‘It’s true. Very stressful weekend,’ Rachel Osten, Hubble’s deputy mission head at the Space Telescope Science Institute in Baltimore, said on Twitter. 

‘Right now HST is in safe mode while we figure out what to do. 

‘Another gyro failed. 

‘First step is try to bring back the last gyro, which had been off, and is being problematic.’ 

Launched in 1990, Hubble has had trouble with its gyroscopes before. 

Spacewalking shuttle astronauts replaced all six in 2009. 

The telescope could work with as few as one or two gyroscopes, although that leaves little room for additional breakdowns.

Olsten confirmed the problem would not mean the end of Hubble.

‘Not really scary, we knew it was coming. 

WHAT ARE THE PILLARS OF CREATION? 

The original Hubble Space Telescope image of the famous Pillars of Creation was taken two decades ago and immediately became one of its most famous and evocative pictures.

The jutting structures, along with the nearby star cluster, NGC 6611, are parts of a star formation region called the Eagle Nebula, also known as Messier 16 or M16. 

The nebula and its associated objects are located about 7000 light-years away in the constellation of Serpens (The Serpent).

The Pillars of Creation are a classic example of the column-like shapes that develop in the giant clouds of gas and dust that are the birthplaces of new stars. 

The columns arise when immense, freshly formed blue–white O and B stars give off intense ultraviolet radiation and stellar winds that blow away less dense materials from their vicinity.

Denser pockets of gas and dust, however, can resist this erosion for longer. 

Behind such thicker dust pockets, material is shielded from the harsh, withering glare of O and B stars. 

This shielding creates dark ‘tails’ or ‘elephant trunks’, which we see as the dusky body of a pillar, that point away from the brilliant stars.

 

‘The gyro lasted about six months longer than we thought it would (almost pulled the plug on it back in the spring). 

‘We’ll work through the issues and be back.’

Even with one gyro working , Hubble will still be able to take part in science, NASA confirmed.

‘There isn’t much difference between 2- and 1, and it buys lots of extra observing time. Which the Astro community wants desperately.’

Astronomers use the orbiting observatory to peer deep into the cosmos, revealing faraway solar systems as well as galaxies and black holes. 

WHAT IS THE HUBBLE SPACE TELESCOPE?

The Hubble telescope was launched on April 24, 1990, via the space shuttle Discovery from Kennedy Space Centre in Florida.

It is named after famed astronomer Edwin Hubble who was born in Missouri in 1889.

He is arguably most famous for discovering that the universe is expanding and the rate at which is does so – now coined the Hubble constant. 

Hubble has made more than 1.3 million observations since its mission began in 1990 and helped publish more than 15,000 scientific papers.

The Hubble telescope is named after Edwin Hubble who was responsible for coming up with the Hubble constant and is one of the greatest astronomers of all-time

The Hubble telescope is named after Edwin Hubble who was responsible for coming up with the Hubble constant and is one of the greatest astronomers of all-time

It orbits Earth at a speed of about 17,000 mph in low Earth orbit at about 340 miles in altitude.

Hubble has the pointing accuracy of .007 arc seconds, which is like being able to shine a laser beam focused on Franklin D. Roosevelt’s head on a dime roughly 200 miles away.

Hubble’s primary mirror is 2.4 meters (7 feet, 10.5 inches) across and in total is 13.3 meters (43.5 feet) long – the length of a large school bus.

 

Read more at DailyMail.co.uk


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