ota+@ANDREW.CMU.EDU (Ted Anderson) (01/26/89)
From the Tuesday January 24, 1989 New York Times, page 22 reproduces without
permission and without comment.
"Weather Satellite Dies of 'Old Age'"
Washington, Jan 23 (AP) - A satellite that provided cloud pictures for
television weather forecasts failed Saturday, depriving customers of views of
the Western United States, officials said.
The failure occurred aboard GEOS-6, a National Oceanographic and Atmospheric
Administration satellite that was launched in April 1983, said Milton Mortman, a
shift supervisor at the agency's satellite operations control center.
"It's just old age," he said.
Al Brown, a meteorologist at the National Weather Service, said weather
map-making would be little affected because forecasters rely most on data
gathered from the ground.
He said partial pictures can be provided from a companion satellite, GEOS-7,
which covers the Eastern United States.
"Eventually we will move the eastern satellite over so it can cover the entire
country," Mr. Brown said. Mr. Mortman said that maneuver would be completed
around Feb. 21.
Until the satellite is moved, weather watching will also be augmented by other
existing satellites operated by NOAA and by satellites from the European and
Japanese space agencies, said Thomas N. Pyke Jr., NOAA's assistant administrator
for satellite and information services.
NOAA said GEOS-7 would perform double duty for about 18 months, until the next
GEOS satellite is expected to be ready for launching.mmm@cup.portal.com (Mark Robert Thorson) (02/02/89)
In the Jan 31 issue of the San Jose Mercury-News, page 1E, there is a story on the failure of GOES-6 which reveals the following information: "The aging GOES-6 satellite, which for over five years has snapped weather pictures day and night, was forced into retirement 10 days ago when a crucial light bulb in one of its components burnt out." and later: "But some satellites have suffered repeated problems with the light bulbs in an instrument the satellite uses to keep itself oriented." A light bulb? I'm surprised. That's like hearing a piece of string broke or a rubber band snapped. Does anybody have more specific information on what this lightbulb was being used for? While I'm on the subject of crudely-built satellites, you may be interested to know there is a twin of the Telstar satellite in the main lobby of Bell Labs, Murray Hill, New Jersey. When I first saw this thing, I was amazed how klugey it looked. It looks like it's held together by solder. There is sort of a little museum there. The first transistor is there, as well as an old copy of the NY Times which has the first description of negative-feedback amplifiers scribbled in the margin. There are a number of automated displays, where you push a button and a demonstration takes place. About half the displays are out-of-order! What a great advertisement for AT&T!
henry@utzoo.uucp (Henry Spencer) (02/09/89)
In article <14215@cup.portal.com> mmm@cup.portal.com (Mark Robert Thorson) writes: >"But some satellites have suffered repeated problems with the light bulbs in >an instrument the satellite uses to keep itself oriented." > >A light bulb? I'm surprised. That's like hearing a piece of string broke >or a rubber band snapped. Does anybody have more specific information on >what this lightbulb was being used for? As I recall, it's part of a sensor that encodes the position of rotating parts in the satellite's scanner system. Those bulbs are a notorious reliability problem that is being designed out of more recent satellites; even putting several of them in each encoder for redundancy hasn't brought their reliability up to acceptable levels. -- Allegedly heard aboard Mir: "A | Henry Spencer at U of Toronto Zoology toast to comrade Van Allen!!" | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
sw@whuts.ATT.COM (WARMINK) (02/09/89)
In article <1989Feb9.013228.965@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > As I recall, it's part of a sensor that encodes the position of rotating > parts in the satellite's scanner system. Those bulbs are a notorious > reliability problem that is being designed out of more recent satellites; There must be a good reason why LEDs weren't used - 6 years plus isn't that long ago...anybody know why not? -- ------------------------------------------------------------------------------ "PENTAGON OFFICIALS ARE CONCERNED ABOUT | Stuart Warmink, Interface Systems AN ANTIMATTER SHORTAGE" ("WHAT'S NEW") | <att!>whuts!sw Whippany NJ USA -----------> My opinions are not necessarily those of my employer <-----------
frank@ut-emx.UUCP (Frank Abernathy) (02/10/89)
In article <5352@whuts.ATT.COM>, sw@whuts.ATT.COM (WARMINK) writes: > In article <1989Feb9.013228.965@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > > As I recall, it's part of a sensor that encodes the position of rotating > > parts in the satellite's scanner system. Those bulbs are a notorious > > reliability problem that is being designed out of more recent satellites; > > There must be a good reason why LEDs weren't used - 6 years plus isn't that > long ago...anybody know why not? > My understanding is they emit RF in the GHZ range. That's also why they aren't usually employed in ECM equipment. (But, as usual, I'm probably wrong. :^) )
henry@utzoo.uucp (Henry Spencer) (02/11/89)
In article <5352@whuts.ATT.COM> sw@whuts.ATT.COM (WARMINK) writes: >> ... Those bulbs are a notorious >> reliability problem that is being designed out of more recent satellites... > >There must be a good reason why LEDs weren't used - 6 years plus isn't that >long ago...anybody know why not? Semiconductors can take quite a while to become space-qualified, and there is considerable reluctance to change a design that seems to work all right. I think it was only in the last few years that it was understood that the bulbs were a systematic weakness. Also, don't forget that the bird may have been built well before it was launched -- it's not uncommon to build a batch of satellites and then keep the last few on the ground until they're needed. The more recent encoder designs do use LEDs. -- The Earth is our mother; | Henry Spencer at U of Toronto Zoology our nine months are up. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
marcus@illusion.UUCP (Marcus Hall) (02/11/89)
In article <5352@whuts.ATT.COM> sw@whuts.ATT.COM (WARMINK) writes: >There must be a good reason why LEDs weren't used - 6 years plus isn't that >long ago...anybody know why not? On the most recent, GEOS-7, the 4 encoder light bulbs were replaced with two bulbs and two LEDs. It would seem that this would be done out of some concern that the LEDs might fail, so there are some light bulbs included. On the other hand, the LEDs might work fine, in which case two of them should outlast the light bulbs. I haven't heard anything about it, so I guess that everything is working fine. Thus, I would expect all subsequent GEOS to use LEDs. marcus hall marcus@illusion.UUCP