Hubble gyro manufacturer

Question

I have been trying to find information on Hubble's gyros. So far all I have found is that they are rotating mass rate gyros with gas bearings and that the were the most accurate available when installed (according to NASA).

Does anybody know what organization manufactured the Hubble gyros? And anything about their heritage? Are they still manufactured (just curious, it seems unlikely there will be a chance to replace the ones onboard)? As far as I know, nobody still makes rotating mass gyros for space applications. I have checked websites for Honeywell and Northrup Grumman and found nothing.

Answer 1

Does anybody know what organization manufactured the Hubble gyros?

Erin Anne's answer is on the money

Originally, Bendix Guidance Systems Division of Bendix Corporation built the RSU's. As of 2009, they were replaced entirely with newly manufactured units made by L-3 Communications.

(To clarify, of the three RSU's installed in 2009, each containing two gyros, two were newly manufactured by L-3, and a backup Bendix-manufactured unit, refurbished by L-3 was installed instead when one of the new ones failed to seat properly)

TL;DR:

So I would like to add to that, the following notes (and not as an answer):

Found on page: https://asd.gsfc.nasa.gov/archive/sm4/multimedia/gallery2_gyro.html

The label is partially visible, and with the title "Space Telescope Rate Sensor Unit", is the logo for Bendix (Guidance Systems Division) bottom left:

Bendix GSD product photo of the unit for HST:

Contractors for HST (From: NASA Hubble Space Telescope Reference Guide):

Equipment: Rate Gyro Assembly, Contractor: Bendix

And finally, a ref for Bendix: https://en.wikipedia.org/wiki/Bendix_Corporation

And anything about their heritage?

research has shown the heritage goes back to Saturn, and at least looking to build upon Skylab's CMG experience. In general Bendix's involvement, with guidance systems, has an even longer history that predates the modern space industry.

Recommendations for improvements over Skylab CMG's:

During the 4 year period from 1970 to 1973 the Bendix Guidance Systems Division (BGSD) of the Bendix Corporation developed and delivered to Marshall Space Flight Center (MSFC) several items of advanced Control Moment Gyro (CMG) prototype and breadboard equipment for MSFC evaluation

https://ntrs.nasa.gov/api/citations/19750006025/downloads/19750006025.pdf

1985, "Accommodation of Astrophysical Instruments in the Space Station System"

https://ntrs.nasa.gov/api/citations/19860003891/downloads/19860003891.pdf

(through mergers in the 1980s, Bendix became a Honeywell brand; following further changes, the Bendix name is now related to the automotive industry only)

Are they still manufactured ? As far as I know, nobody still makes rotating mass gyros for space applications.

Specific to the HST RSU's, at some point L-3 Communications took over the contract for responsibility of the RSU's. Under this company, they manufactured new RSU's with modifications, for the 2009 SM4 STS-125 mission. Following a merger, this company became L3Harris Technologies, Inc.

It seems that technology has marched on, with spinning mass mechanical gyros having given way to ring laser gyros (and other types) for the space industry. Honeywell still list mass mechanical gyros as one of their key technologies.

https://aerospace.honeywell.com/us/en/products-and-services/product/hardware-and-systems/space/inertial-navigation-and-control-assembly

https://aerospace.honeywell.com/us/en/products-and-services/product/hardware-and-systems/sensors/gg1320an-digital-ring-laser-gyroscope

Modern RGA:

The ISS for example mounts two (one a spare) Honeywell GG1320AF RGA's with three RLG's inside each.

Additional (RE: STS-125, SM4):

https://asd.gsfc.nasa.gov/archive/sm4/technology/sm4_gyros.html

https://ses.gsfc.nasa.gov/ses_data_2009/091006_Whipple.pdf

https://asd.gsfc.nasa.gov/archive/sm4/multimedia/gallery2.html

https://science.nasa.gov/mission/hubble/observatory/missions-to-hubble/servicing-mission-4/servicing-mission-4-engineering-components/

https://www.slideserve.com/monte/sts-125-hubble-space-telescope-hst-servicing-mission-4-sm4-overview

https://nara.getarchive.net/media/s125e007519-sts-125-view-of-a-hst-rsu-taken-during-eva2-edba26

https://www.nasa.gov/wp-content/uploads/2012/06/327688main_09_sm4_media_guide_rev1.pdf

https://www.cbsnews.com/network/news/space/srh/SRH_125_low.pdf

https://www.nasaspaceflight.com/2009/05/sts-125-moves-into-eva-2-fd5-opens-with-tps-quick-look/

after successfully installing the replacement RSU2, RSU1 failed to seat and bolt into position. While RSU3 successfully took the place of RSU1, the plan moved to placing the new RSU1 in RSU3’s position also proved to be problematic.

With the issue confirmed to be with RSU1 itself, the spacewalkers were informed to move to a backup plan of installing an old unit from the Contingency ORU Protective Enclosure (COPE), into the remaining postion. This also seemed to be “wobbling” on the installation plate, before success was finally forthcoming via a successful attempt to bolt the spare RSU in place. Hubble now has two new RSUs, and one spare, successfully installed.

https://www.stsci.edu/files/live/sites/www/files/home/hst/about/space-telescope-users-committee/presentations-and-documentation/_documents/2015_nov/hstmo-update.pdf

The 2009 replacement of the RSU's:

The new RSU's were manufactured by L-3 Communications, and differed from previous RSU's in mainly two areas: the first with regards to a component that facilitates the transfer of electricity and data inside the gyro. Over time, the flex leads begin to corrode and can physically bend or break. Over three decades, Hubble had eight out of 22 gyros fail due to a corroded flex lead. With the new Enhanced Flex Leads (EFL), the flex lead is coated with a protective barrier to slow degradation caused by the fluid in which it floats. From this point on, the previous components were referred to as Standard Flex Leads (SFL).

The second area was that in previous gyros there was a build-up of particles and lubricant between the shaft and the rotor resulting in a transient load torque and a momentary disruption in the spin motor phase. Gyros that failed due to rotor restriction tended to have shaft-to-rotor spacing on the low end of tolerance. Tolerance was modified to ensure greater spacing.

https://science.nasa.gov/mission/hubble/observatory/design/hubble-one-gyro-mode/

This is from 2015. Beyond this point it is difficult to find further info on new, if any, construction of such units.

Answer 2

I think they were made by Bendix. Here's why:

Performance Characterization of the Hubble Space Telescope Rate Gyro Assembly has two authors, Weinstein and Slater, attributed to Allied Bendix Aerospace Corp, Guidance Systems Division, Teterboro NJ.

That prompted me to look to see if Bendix claimed them anywhere, and I got Scale Factor and Noise Performance Tests of the Bendix Corporation Rate Gyro Assembly, a 1980 report from the 6585th Test Group at Holloman Air Force Base, NM. Quoting the foreward:

This report documents the results of scale factor and noise performance tests of the three Bendix Corporation Rate Integrating Gyroscopes which were part of a Rate Gyro Assembly (RGA) to be used on the Space Telescope Pointing and Control System. Two gyros were standard Bendix models, while the third used a low-viscosity rotation fluid.

It's not airtight but the overlapping terminology, timeframe, and the contributions of the Bendix authors to the Hubble Space Telescope document are all quite suggestive.

The gyro assemblies must be bespoke, because Enhanced versions were provided to deal with some of the ongoing issues. I can't find any evidence that they were manufactured for further space telescopes, though obviously that isn't conclusive.