As we suspected, the NASA Hubble team has decided to operate Hubble henceforth in single gyro mode.
There are some limitations in this mode - Hubble will need more time to slew and lock onto a science target and won't have as much flexibility as to where it can observe at any given time.
The other healthy gyro will be kept as a spare. Hubble now has 4 failed gyros.
The team expects to resume science operations again by mid-June.
Modern spacecraft like JWST use a newer type of gyroscope - the "Hemispherical Resonator Gyroscope" (HRG). It uses a quartz hemisphere vibrating at its resonant frequency in a vacuum; the hemisphere's rate of motion is sensed by the interaction between the hemisphere and sensing electrodes on the HRG housing.
There are no moving parts, flexible leads or bearings.
Extremely reliable but high mfg complexity.
MTBF = 10 million hours!
Note that gyros are used to accurately determine Hubble's pointing direction. Telescope movement is done using reaction wheels and magnetic torquers.
In one-gyro mode, Hubble supplements info from the gyro with info from its magnetometers, sun sensors, star trackers and fine guidance sensors + some nifty software processing. It's a slower process but once Hubble is on target, pointing accuracy is comparable to that of 3-gyro mode.
Hubble's gyros contain a wheel spinning at 19,200 rpm on gas bearings. The wheel is mounted in a sealed cylinder, which floats in a thick fluid. The gyro’s motor is powered via hair-thin wires that traverse this fluid.
Rotations of the spacecraft cause tiny movements of the axis of the wheel, which are measured and fed to Hubble’s flight computer.
Hubble's gyros were the most accurate in the world in their time. But prone to failure ...
The #Hubble gyros are very interesting to me. They apparently contain a thick sauce, er, sorry, liquid inside a wrapper of pida, no – titanium, yes titanium. There are onions, or rather wires that go through the garlic sauce, I mean liquid, and those are at continual risk.
Someone should investigate, and I'll gladly volunteer.
NASA confirms that #Hubble will switch to one-gyroscope mode after the increasingly erratic behavior of gyro 3 caused the observatory to repeatedly go into safe mode.
Hubble will continue doing great science, but with somewhat reduced efficiency. It will need more time to slew and lock onto science targets. There is also a limit to the fraction of the sky it can observe at any one time (although it will have access to the full sky over the course of a year).
I'm glad that switching #Hubble to single-gyro pointing was not necessary until now; because the telescope did important observations of the #DARTMission impact and its aftermath through last year.
Here are the much anticipated 10 images taken by the Euclid "Dark Matter Hunter" space telescope.
The images and accompanying papers were presented today at a gathering by the Euclid Consortium. We have seen the first image before.
These are part of the Euclid Early Release Observation program. The first results from Euclid’s wide and deep main surveys will take until fall, first cosmology papers at least until late 2025.
Here are two more infrared images of the reflection nebula Messier 78 - a wide angle shot from the ESO VISTA telescope (FOV = 1.65°) and one from the Hubble Space Telescope.
Note that HST WFC3/IR camera has a Field of View of 0.038°, which is 19x smaller than that of Euclid (0.772°) and a detector size of 1kx1k vs 8kx8k for Euclid. Hence its image covers a much smaller section of M78 and is at lower resolution.
Let's celebrate #AstronomyDay with this image taken today by Mars rover Perseverance's SHERLOC Autofocus and Context Imager (ACI).
This is the first such image of a rock sample since Dec 16, 2023, when the dust cover of the camera and laser spectroscopy instrument got stuck. It is still stuck, but in an open position and its auto-focus mechanism is nonoperational.
The camera took a sequence of images from different distances; the middle ones are in focus.
Les milliardaires techbros libertariens sont vraiment la plaie de l'humanité.
Les déchets volants de Musk pourrissent les images scientifiques de Hubble 😱
It is 15 years since human hands touched NASA's Hubble Space Telescope for the last time. Michael Good (on the end of the shuttle's Remote Manipulator System) works to refurbish and upgrade NASA's Hubble Space Telescope during Servicing Mission 4. Image credit NASA Today, more than three decades after its launch in 1990, Hubble continues to send stunning images back to Earth and conduct groundbreaking science.
#OTD in 2009, the final #Hubble servicing mission launched. SM4 had an ambitious list of tasks designed to bring Hubble to the apex of its scientific capabilities and ensure it would operate for many years to come. (1/3) 🧵
An asteroid wanders through this image of galaxy UGC 12158 captured by the Hubble Space Telescope. Hubble took multiple exposures of the galaxy, causing the foreground asteroid to appear as a series of bright white dashes. The curved path is due to parallax as Hubble orbits the Earth.
I came across this delightful video this afternoon when going through some old slides and paused what I was doing to watch the whole thing.
Here is a supercut of 18 astronomy visualizations from @spacetelescope, using computer simulations and Hubble images to create 3D flythroughs of objects in space.
I just love this image - it highlights why we need all the different telescopes: each of them looks at the same object in different ways. And only when working together a complete image emerges.
Here, #Euclid's wide field is combined with #Hubble's zoom-in and #JWST sharpest IR image we ever obtained, allowing us to study how radiation interacts with interstellar matter.