What happened to the structure used in the Shuttle payload bay that the Hubble was launched up with?
Quote from: Targeteer on 10/08/2018 03:12 amAren't there two types of gyros? Motion and rate? Which is this one?Control Moment Gyroscope (CMG) and they each control fine guidance sensors. The others are Rate Gyro Assembly (RGA) and control rate sensors assemblies for inertial navigationAs for HST's size only combined gyros are need and are called simply just Reaction Wheels. As for ISS CMG's must operate separately from RGA's for them to serve a spacecraft mass that size correctly without burning out its motors for each axis.
Aren't there two types of gyros? Motion and rate? Which is this one?
Quote from: tyrred on 10/08/2018 08:37 am.Could HST rescue possibly be a job for BFS?Sure.If we weit for BFS-crew, and BFSpacesuit, getting to hubble is pretty easy.They can then 'just' do a servicing mission and replace the gyros.(Or even fetch the gyros, repair, put them back).The questions are the cost of spinning up production for new gyros, and the fact the telescope is really quite old.There are other subsystems that are seriously showing their age, to the point that it might be sensible if everything was ideal to lift more instruments.Automated approaches likely could be done some 3-4 years earlier, depending - and in principle BFS could recover it entire, for repair on earth.Does any hardware remain on the ground in flight condition?
.Could HST rescue possibly be a job for BFS?
Maybe someone can ask the folks at Hawthorne a price estimate for replacement hardware for the HST. They seem to make less costly hardware quicker then everyone else.
Quote from: Zed_Noir on 10/09/2018 09:21 amMaybe someone can ask the folks at Hawthorne a price estimate for replacement hardware for the HST. They seem to make less costly hardware quicker then everyone else.That is, if nothing else, a political non-starter. Almost every single bit of NASA and the existing contractors would be strongly lobbying against such a thing, as if they pull it off, or appear likely to pull it off, it has a catastrophic impact on funding.Launching flight hardware made by 'the usual suspects' lets people keep to the internal narrative that SpaceX is good at rockets, and NASA plays a vital and irreplaceable role in complex space hardware. It also allows a slower transition between business as usual and the future.(I agree with the vital, not so much the irreplacable part)
Quote from: IanThePineapple on 10/08/2018 08:09 pmQuote from: Lee Jay on 10/08/2018 08:03 pmI'm not up on the details, but wouldn't an obvious way to fix Hubble be to launch WFIRST?It's nowhere near ready though.Yeah, I know, but is there much that Hubble can do that WFIRST can't? Same aperture, same resolving power (I think?) same, seeing (perfect), just much higher productivity (dramatically wider field of view). And maybe Hubble can be nursed along for a few more years like Keppler was (different approach, obviously) until the gap to WFIRST could be reduced a good bit.Wouldn't that make more sense than a rescue mission?
Quote from: Lee Jay on 10/08/2018 08:03 pmI'm not up on the details, but wouldn't an obvious way to fix Hubble be to launch WFIRST?It's nowhere near ready though.
I'm not up on the details, but wouldn't an obvious way to fix Hubble be to launch WFIRST?
NASA makes progress on fixing Hubble gyroby Jeff Foust — October 22, 2018KNOXVILLE, Tenn. — Engineers have made progress correcting a faulty gyro on the Hubble Space Telescope, making NASA optimistic the space telescope can resume normal operations in the near future.
Oct 22, 2018Hubble Moving Closer to Normal Science OperationsNASA took great strides last week to press into service a Hubble Space Telescope backup gyroscope (gyro) that was incorrectly returning extremely high rotation rates. The backup gyro was turned on after the spacecraft entered safe mode due to a failed gyro on Friday, Oct. 5. The rotation rates produced by the backup gyro have since reduced and are now within an expected range. Additional tests will be performed to ensure Hubble can return to science operations with this gyro.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.A wheel inside the gyro spins at a constant rate of 19,200 revolutions per minute. This wheel is mounted in a sealed cylinder, called a float, which is suspended in a thick fluid. Electricity is carried to the motor by thin wires, approximately the size of a human hair, that are immersed in the fluid. Electronics within the gyro detect very small movements of the axis of the wheel and communicate this information to Hubble’s central computer. These gyros have two modes — high and low. High mode is a coarse mode used to measure large rotation rates when the spacecraft turns across the sky from one target to the next. Low mode is a precision mode used to measure finer rotations when the spacecraft locks onto a target and needs to stay very still. In an attempt to correct the erroneously high rates produced by the backup gyro, the Hubble operations team executed a running restart of the gyro on Oct. 16. This procedure turned the gyro off for one second, and then restarted it before the wheel spun down. The intention was to clear any faults that may have occurred during startup on Oct. 6, after the gyro had been off for more than 7.5 years. However, the resulting data showed no improvement in the gyro’s performance. On Oct. 18, the Hubble operations team 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-center 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. Following the Oct. 18 maneuvers, the team noticed a significant reduction in the high rates, allowing rates to be measured in low mode for brief periods of time. On Oct. 19, the operations team commanded Hubble to perform additional maneuvers and gyro mode switches, which appear to have cleared the issue. Gyro rates now look normal in both high and low mode. Hubble then executed additional maneuvers to make sure that the gyro remained stable within operational limits as the spacecraft moved. The team saw no problems and continued to observe the gyro through the weekend to ensure that it remained stable. The Hubble operations 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.Hubble is managed and operated at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.For more information about Hubble, visit:www.nasa.gov/hubble
Unfortunately, the process may be flawed, too. In 2014, the Space Telescope Science Institute noticed a pattern: In more than a dozen review cycles since 2001, proposals led by men consistently did better than proposals led by women. The Institute’s leadership wondered whether the way they assessed proposals had something to do with it; under the current system, reviewers know the identities of applicants—including their gender—but applicants don’t know the identities of reviewers. It’s a standard setup in the sciences, from telescope proposals to paper submissions, but perhaps it had allowed subtle biases to creep in.This year, the institute decided to conduct a double-blind review of Hubble proposals, which hid nearly all information about applicants, including gender, from reviewers. Of the 351 male-led proposals, 28 were picked. Of the 138 female-led proposals, 12 were chosen. That translates into an 8.7 percent success rate for female researchers, and 8 percent for male researchers.Under the new review system, the disparity that Hubble’s decision-makers had seen year after year had disappeared.Priyamvada Natarajan, a theoretical physicist at Yale who led the effort, said she was surprised at the outcome. “I was ready to see a small change, but not complete parity,” she said.But she wasn’t surprised that the years-long pattern had been broken. Research has found ample evidence that men and women are evaluated differently in the same settings, and the Hubble program is no different, she said.
More problems for the Hubble https://twitter.com/NASAHubble/status/1082857056225259520