{"id":9267,"date":"2024-06-17T14:01:19","date_gmt":"2024-06-17T18:01:19","guid":{"rendered":"https:\/\/spaceandplanetarynewswire.com\/?p=9267"},"modified":"2024-06-17T14:01:19","modified_gmt":"2024-06-17T18:01:19","slug":"the-hubble-telescope-has-shifted-into-one-gyro-mode-after-months-of-technical-issues-%e2%88%92-an-aerospace-engineering-expert-explains","status":"publish","type":"post","link":"https:\/\/spaceandplanetarynewswire.com\/?p=9267","title":{"rendered":"The Hubble Telescope Has Shifted into One-Gyro Mode After Months of Technical Issues \u2212 an Aerospace Engineering Expert Explains"},"content":{"rendered":"
The Hubble Space Telescope is nearing its 35th birthday. NASA via AP<\/figcaption><\/figure>\n

Imagine keeping a laser beam trained on a dime that\u2019s 200 miles away. Now imagine doing that continuously for 24 hours, while riding a merry-go-round. Seem difficult? Well, that\u2019s basically what the Hubble Space Telescope does.<\/p>\n

After months of technical issues, NASA announced June 4 that Hubble would shift into one-gyroscope mode<\/a>. This essentially means that the telescope will have to rely on just one of the several gyroscopes \u2013 devices that measure an object\u2019s orientation in space \u2013 it normally uses to track and follow objects in space.<\/p>\n

Named after astronomer Edwin Hubble<\/a>, the Hubble telescope launched in 1990 into low Earth orbit. Here, it\u2019s above Earth\u2019s atmosphere, which interferes with the observations from Earth-based telescopes. During its three decades of operation, it has provided us with stunning pictures of distant galaxies<\/a> and allowed scientists to look closer to the beginning of the universe.<\/p>\n

Hubble takes clear, high-resolution pictures<\/a> of stars billions of light years away. To collect enough photons \u2013 light \u201cparticles\u201d<\/a> \u2013 for a high-quality picture, it essentially acts as a very low-speed camera. It keeps its aperture<\/a> \u2013 that is, the opening in the lens that lets light pass through \u2013 open for up to 24 hours to take a single picture.<\/p>\n

Anyone who has taken a photo at a low shutter speed knows how difficult it is to avoid ending up with a blurry image. Hubble takes this to an extreme. It needs to stay pointed at the same distant point in space with an accuracy<\/a> within a few milliarcseconds \u2013 where one milliarcsecond equals one 3,600,000th of a degree \u2013 for up to 24 hours. And it needs to keep this accuracy while orbiting the Earth at 17,000 miles per hour (27,000 kilometers per hour) through extreme heat and cold.<\/p>\n

To keep track of its target and generate clear pictures, Hubble uses what aerospace engineers like me call attitude control systems. All spacecraft and aircraft have an attitude control system to help them point in the right direction.<\/p>\n

What\u2019s a gyro, anyway?<\/strong><\/p>\n

An attitude control system consists of a suite of sensors<\/a> measuring the orientation of the spacecraft, a set of actuators \u2013 thrusters, reaction wheels or control moment gyroscopes \u2013 that move the spacecraft around, and a flight computer. The flight computer takes the measurements from the sensors and generates the commands for the actuators.<\/p>\n

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\"A
The gyros work in tandem with fine guidance sensors and reaction wheels to control the telescope\u2019s orientation in space. NASA\/STSci<\/figcaption><\/figure><\/figure>\n

A gyroscope<\/a> is a device that measures an object\u2019s attitude, or orientation in space. In other words, it measures how much the object has rotated from some fixed point. For Hubble to know where it\u2019s pointing to take a picture, it has to know where it is in space. It needs at least three gyros \u2013 one per axis.<\/p>\n

Hubble initially had six gyros: three main ones and three more as extras. But after more than 30 years in orbit, four of the gyros have failed<\/a> from complications related to aging.<\/p>\n

From the two remaining gyros, NASA has reserved one as a backup, so Hubble is now operating with a single gyro<\/a>. But if you need at least three gyros \u2013 one per axis \u2013 to know where you are, how can Hubble figure out where it is with only one gyro?<\/p>\n