Gehrels/Swift space telescope enters safe mode
The Neil Gehrels Swift observatory ceased science observations and entered safe mode on January 18, 2021, when one of its six reaction wheels experienced a failure.
It appears the other five reaction wheels, which function as gyroscopes to point the telescope accurately, are working properly. If engineers can’t recover the lost wheel, the telescope will still be able to operate with no problems.
Swift was launch seventeen years ago in order to solve the mystery of gamma ray bursts, which it did most successful. The man who most made the observatory possible, its principal scientist, Neil Gehrels, passed away in 2017, and to honor his memory the telescope was then named after him.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The Neil Gehrels Swift observatory ceased science observations and entered safe mode on January 18, 2021, when one of its six reaction wheels experienced a failure.
It appears the other five reaction wheels, which function as gyroscopes to point the telescope accurately, are working properly. If engineers can’t recover the lost wheel, the telescope will still be able to operate with no problems.
Swift was launch seventeen years ago in order to solve the mystery of gamma ray bursts, which it did most successful. The man who most made the observatory possible, its principal scientist, Neil Gehrels, passed away in 2017, and to honor his memory the telescope was then named after him.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
By my rough count that is around 9 reaction wheel failures since 1997.
Gary M. Reaction wheels are moving parts that, though the technology has improved, still fails to keep them running as long as one would like. Hubble’s six for example were replaced multiple times, including all six during the last servicing mission in 2009, and 12 years later it now sits with only three working, with at least one of those three questionable.
These last Hubble gyroscopes actually have done extremely well, lasting as long as they have.
This might provide some background–
Scott Manley (2018)
“Scientists May Have Figured Out Why So Many Spacecraft Were Failing”
https://youtu.be/KibT-PEMHUU
7:09
“In the last 20 years it’s been surprisingly common for space probes to end missions early because reaction wheels have failed, moreover there’s been a large number of failures associated with a specific supplier – Ithaco. ”
In the YT description Manely links to a PDF study done by United Technologies entitled:
“A Newly Discovered Branch of the fault Tree Explaining Systemic Reaction Wheel Failure and Anomalies “
“the mystery of gamma ray bursts, which it did most successful. ” As a test, I entered the quoted text into a Gmail message. Gmail underlined “successful”. Clicking on the underlined word results in an offer to change it to “successfully”. When did Gmail go beyond simple spell checking?
Willi – in Gmail’s settings, there are toggles for spell check, grammar suggestions, and autocorrect. Don’t know for sure when they were added.