Hubble Space Telescope image of supernova 1994D in galaxy NGC 4526.

Hubble Trouble – NASA Working to Patch Their Ageing Space Telescope

Guest essay by Eric Worrall

Perhaps if they trimmed the climate budget NASA scientists might not have to spend so much time struggling with the ageing Hubble platform.

Operations Underway to Restore Payload Computer on NASA’s Hubble Space Telescope

The Hubble Space Telescope is deployed on April 25, 1990 from the space shuttle Discovery. Avoiding distortions of the atmosphere, Hubble has an unobstructed view peering to planets, stars and galaxies, some more than 13.4 billion light years away.Credits: NASA/Smithsonian Institution/Lockheed Corporation

July 15, 2021 – NASA Begins Switch to Backup Spacecraft Hardware

Today, NASA began a switch to backup spacecraft hardware on Hubble in response to an ongoing problem with its payload computer. This will be a multi-day event. If successful, the next step will be for science instruments to be brought back into operation.

July 14, 2021 – ​NASA Identifies Possible Cause of Hubble Computer Problem

NASA has identified the possible cause of the payload computer problem that suspended Hubble Space Telescope science operations on June 13. The telescope itself and science instruments remain healthy and in a safe configuration.

The payload computer resides in the Science Instrument Command and Data Handling (SI C&DH) unit. It controls, coordinates, and monitors Hubble’s science instruments. When the payload computer halted, Hubble’s science instruments were automatically placed into a safe configuration. A series of multi-day tests, which included attempts to restart and reconfigure the computer and the backup computer, were not successful, but the information gathered from those activities has led the Hubble team to determine that the possible cause of the problem is in the Power Control Unit (PCU).

The PCU also resides on the SI C&DH unit. It ensures a steady voltage supply to the payload computer’s hardware. The PCU contains a power regulator that provides a constant five volts of electricity to the payload computer and its memory. A secondary protection circuit senses the voltage levels leaving the power regulator. If the voltage falls below or exceeds allowable levels, this secondary circuit tells the payload computer that it should cease operations. The team’s analysis suggests that either the voltage level from the regulator is outside of acceptable levels (thereby tripping the secondary protection circuit), or the secondary protection circuit has degraded over time and is stuck in this inhibit state.

Because no ground commands were able to reset the PCU, the Hubble team will be switching over to the backup side of the SI C&DH unit that contains the backup PCU. All testing of procedures for the switch and associated reviews have been completed, and NASA management has given approval to proceed. The switch will begin Thursday, July 15, and, if successful, it will take several days to completely return the observatory to normal science operations.

The team performed a similar switch in 2008, which allowed Hubble to continue normal science operations after a Command Unit/Science Data Formatter (CU/SDF) module, another part of the SI C&DH, failed. A servicing mission in 2009 then replaced the entire SI C&DH unit, including the faulty CU/SDF module, with the SI C&DH unit currently in use.

Launched in 1990, Hubble has been observing the universe for over 31 years. It has taken over 1.5 million observations of the universe, and over 18,000 scientific papers have been published with its data. It has contributed to some of the most significant discoveries of our cosmos, including the accelerating expansion of the universe, the evolution of galaxies over time, and the first atmospheric studies of planets beyond our solar system. Read more about some of Hubble’s greatest scientific discoveries.

Read more:

NASA has pulled off some remarkable feats over the years, like re-establishing communication with their lost IMAGE mission after an amateur astronomer stumbled across it while scanning the night sky. IMAGE was believed lost in 2007, due to a suspected power supply failure.

So it seems entirely possible they will get Hubble operational again. Eventually.

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July 16, 2021 2:39 am

Meanwhile NASA’s Sea Level Change Science Team is keeping an eagle eye on the wobbly moon exacerbating climate change-
Moon wobble to exacerbate climate change flooding effects in next lunar cycle, NASA warns (
Hubble bubble toil and trouble!

The Saint
Reply to  observa
July 16, 2021 9:19 am

I thought the Webb Telescope was the replacement/upgrade for the Hubble Telescope. I guess not.

Reply to  The Saint
July 16, 2021 9:59 am

I believe the Webb telescope is concentrating on the infra-red spectrum.

Joel O'Bryan
Reply to  MarkW
July 16, 2021 1:31 pm

And parked a million miles from Earth, the Webb has to work correctly without any chance of repair.

Reply to  Joel O'Bryan
July 16, 2021 2:17 pm

The Webb telescope should be renamed the When telescope.

Its launch data has been receding faster than commercial applications of nuclear fusion.

It’s not correct to call it a replacement for Hubble since it’s spec and mission are very different.

Michael S. Kelly
Reply to  Greg
July 16, 2021 10:16 pm

Yep, JWST is principally an infrared observatory. It has a huge aperture, though, and will have amazing resolution for an IR scope.

If it works, that is. It has the most complex self-deployment sequence of any spacecraft, ever. That sequence won’t occur until the scope is in it’s Sun-Earth L-2 orbital position – so far away that we can’t reach it for repairs. At least right now.

Dave Akin, of the University of Maryland Space Systems Laboratory, had developed space robotic servicing systems, and had demonstrated their capability to perform all of the repairs and servicing functions Shuttle astronauts had previously done on Hubble. But when Mike Griffin became NASA Administrator in 2005, he waived that away, and proclaimed that any future Hubble servicing had to be done by astronauts (which they did in 2009, for the last time). Griffin was presiding over the post-Columbia return to flight at the time, so his position was kind of understandable.

I would bet that Akin, along with some other people I know, could get together a robotic repair mission For JWST. And with $10 billion worth of space telescope at stake, I think NASA would be able to find the cash to do it.

(This was actually a reply to MarkW)

Last edited 1 year ago by Michael S. Kelly
July 16, 2021 2:49 am

Nasa’s priorities appear to be Whitehouse incumbent dependent. With Obama it was Earth, with Trump it was the moon and beyond, now it’s Earth again.

…budget proposal offers NASA’s Earth science program, which received $2 billion in fiscal year 2021, an increase of $250 million, or 12.5%. The document stated that the additional funding would be used “to initiate the next generation of Earth-observing satellites to study pressing climate science questions,” NASA and the new urgency of climate change – SpaceNews

How much longer will they be hitching a ride? Once, they could have sent a man (or woman!) to fix it.

Last edited 1 year ago by strativarius
Reply to  fretslider
July 16, 2021 5:41 am

No, once they boosted it into a higher orbit, there has been no way to get any mechanics to it. There has also never been any rocket tug which could haul its orbit down for repairs and boost it back up afterwards.

All that could have been developed of course, but that capability has never existed.

Reply to  Felix
July 16, 2021 6:18 am

That orbit is decaying…

Reply to  Felix
July 16, 2021 7:54 am

I don’t see why a Crew Dragon couldn’t be sent to fly in close formation with spare parts to be installed by spacewalks. Of course, it would be a novel use of the Crew Dragon, but it doesn’t seem impossible. While it’s too innovative to be considered by NASA, I wonder if Musk would suggest it if the Hubble becomes inoperable.

Daryl M
Reply to  NickSJ
July 16, 2021 8:26 am

It’s not possible for a Crew Dragon or a Cargo Dragon to reach the Hubble orbit.

Reply to  Daryl M
July 16, 2021 8:54 am

Based on conversations over at from a few years ago, it’s quite possible for a Falcon 9 to boost Crew Dragon (or Cargo Dragon) to the Hubble orbit (altitude ~340 miles, so slightly higher than the ISS; inclination 28.47 degrees, so closer to SpaceX’s Boca Chica launch site of 26 degrees north latitude than to ISS’s 55 degree inclination).

The problem, surprisingly (well, it surprises me) is that you can’t do an EVA from Crew Dragon. It doesn’t have an airlock (when it connects to the ISS, it connects directly to the ISS, i.e. air pressure diff is zero); cabin electronics etc. are not vacuum-rated, and you probably couldn’t fit through the hatch wearing an EVA suit. You’d have to create some kind of EVA/ airlock module to attach to the Dragon, in which the astronauts could change into the EVA suits, which would provide support for their suits, and which would have a sufficiently large hatch at the other end. The Dragon XL (designed for lunar orbit missions) has some, but not all, of these capabilities.

Finally, back in 2010 SpaceX did a study of exactly such an HST servicing mission, see here:;topic=28805.0;attach=395606;sess=0

Reply to  mcswelll
July 16, 2021 10:01 am

Carrying an EVA module would probably make the Dragon to heavy to reach Hubble’s orbit.

Reply to  MarkW
July 16, 2021 10:48 am

That’s why there is a Falcon Heavy!

Reply to  PCman999
July 16, 2021 10:54 am

and you know, why bother? I remember in the initial run up and hype to the Hubble launch (and huge subsequent embarrassment resulting from the near-sighted telescope), that Hubble cost a billion dollars – which was also the real launch cost for the space shuttle! But even now, why bother worrying about fixing Hubble? Design and build a much better replacement for the Hubble (same or larger spectrum range) and launch it. Scientists will be able to then have more telescope time and a better instrument with the latest in CPU power.

Reply to  PCman999
July 16, 2021 11:06 am

Before the trolls/nags come out: Hubble was originally supposed to be about $400 mil, cost about $4B by the time it launched, but I remember the 1 billion dollar figure, probably the only number known (or revealed) by the time of the launch.

Tom Abbott
Reply to  PCman999
July 16, 2021 2:21 pm

I just watched a special on the Hubble Telescope on the Science Channel (recorded).

The program described all the amazing things Hubble has discovered during its lifetime.

The Hubble has been serviced four times using the Space Shuttle.

The last servicing mission, number four, was initially cancelled because NASA considered it too dangerous after the Space Shuttle Columbia crashed.

But the public didn’t like that idea, and started sending NASA thousands of letters and emails asking that Hubble be saved. And NASA finally gave in and scheduled the Hubble repair mission.

When the mission to the Hubble was launched in 2009, NASA had a second Space Shuttle sitting ready on the launch pad just in case something happened to the first space shuttle that would leave them stranded in space, and the second shuttle was there to go to the rescue. Fortunately, that was not necessary.

When they repaired Hubble for the fourth time, there came a point where the astronaut stripped a bolt he was trying to undo, and this stripped bolt could have caused the entire mission to fail.

After considering the situation for a while, NASA suggested that the astronaut use brute force to remove the grab-bar the bolt was holding. The astronaut jerked on it and it came loose! And the mission was saved. Sometimes it takes a hammer.

Let’s see, the Musk Heavy-Lift rocket could put a crew capsule at Hubble’s orbit.

No airlock on the crew capsule. Well, they could fly to the Hubble, get dressed in their spacesuits and then evacuate the air out of the crew capsule, exit the vehicle, do their repairs, return to the crew capsule, shut the door, and refill the cabin with air.

See if you can work that out, Elon.

A LOT of astronomer’s jobs are on the line if the Hubble doesn’t get repaired.

The NASA Hubble tv special claimed that the fourth repair mission would be the last, but I think they need to do it at least one more time. Otherwise, NASA is going to get a lot of nasty letters from the Hubble fans around the world.

Reply to  Tom Abbott
July 16, 2021 6:22 pm

I was about to disagree with you about having the second shuttle on standby, but you’re right:

Re evacuating the crew capsule: Apparently some electronics (and other controls, and probably things like food and water and the toilet) are certified to operate in a vacuum, some are not. (I’m guessing it’s a heat dissipation thing, although maybe also gas trapped inside some components, which might rupture the casing under a pressure differential.) And apparently certifying the crew capsule for operation with a vacuum inside is non-trivial. Also, the exit hatch is too small to get through while wearing a space suit (think of the backpack, if nothing else).

All that said, I’m sure Elon (and SpaceX) would love to be given this job (and the $ that would go with it, not to mention the additional capabilities).

Tom Abbott
Reply to  mcswelll
July 17, 2021 4:40 am

“I was about to disagree with you about having the second shuttle on standby, but you’re right”

I had forgotten about that myself, until I saw that NASA video about it, and there, right on the screen, you could see both Space Shuttles sitting there ready for launch on two different launch pads.

NASA was afraid that some of the shuttle protective covering would come off, which was what caused the Columbia to burn up in the atmosphere upon re-entry, and they were going to inspect the Space Shuttle after it got to orbit, and if it was damaged in the launch, then they would send the second shuttle to rescue them.

Tom Abbott
Reply to  PCman999
July 16, 2021 2:04 pm

That’s right. Get that big one doing some work! 🙂

Reply to  MarkW
July 16, 2021 4:39 pm

Probably, but it could be a two-rocket mission: one to launch the Crew Dragon, the other to launch the EVA module, then a docking in the vicinity of the Hubble. I realize this is getting complicated, but it’s not impossible. The most difficult part might be the design and certification of the EVA module.

Gregg Eshelman
Reply to  mcswelll
July 16, 2021 7:40 pm

What’s needed is a permanent, movable, ‘service station’ put in orbit. Give it engines and refillable fuel tanks so it can change orbits. Give it a decently sized crew area and a place to hold parts for repairs and mount two or three robot arms. One could be fitted with whatever fixture is required to grab the satellite for the current repair job and the other arm(s) with the foot holding fixtures often used with the Canadarm in the Shuttles.

After some missions trying service jobs with free flying astronauts and satellites, NASA figured out it was far easier to put fixtures in the cargo bay to attach the “bird” to then connect the astronaut’s feet to the Canadarm. Then the astronaut didn’t have to make any effort to stay put relative to the job and when installing and removing threaded fasteners didn’t require special torque canceling tools. They could hold the tool and brace against the torque with their feet while not bothering with the torque trying to twist the satellite the other way.

So a roving service station would grab onto the fixture on the base of Hubble (installed by one of the repair missions) to position itself in the ideal location for the other arms and astronauts to reach it.

Job done, drop the service station down to a lower orbit and dock with a Dragon for crew return to Earth. That dragon could also be bringing tools, parts, fixtures, fuel and supplies along with another crew for another repair job.

Reply to  Gregg Eshelman
July 16, 2021 9:04 pm

You can trust your car to the system with the star. Gotta love it!

(Back to the Future II)

Tom Abbott
Reply to  Gregg Eshelman
July 17, 2021 4:57 am

“What’s needed is a permanent, movable, ‘service station’ put in orbit. Give it engines and refillable fuel tanks so it can change orbits.”

That exactly right! A space station-type module attached to an engine/propellant module would work just fine.

The need for an orbital tranfer vehicle is obvious. We need to be able to repair the Hubble in the future and we will need it for future repairs to the James Webb Space Telescope soon to be launched. And for a lot of other things I can think of right now.

And any commercial activity in space is going to need orbital transfer vehicles to carry out their business. We have a private company intending to put artificial-gravity space stations in orbit in the next five years. They’ll need a method to get around up there.

NASA has been dragging its feet on orbital transfer vehicles for too long. They will need them to go back and forth in low-Earth orbit, and they will need them to transfer people and equipment to and from the Moon powered by water ice mined there.

I like the “Flying Tea Kettle” model for an orbital transfer vehicle. No need to separate the hydrogen from the oxygen to provide propellant from the Moon water, just take the water as it is and heat it up to the point it turns to steam and then you can steam all over the Earth/Moon system. KISS. 🙂

Reply to  Tom Abbott
July 17, 2021 9:13 am

As a former steam propulsion plant engineer (on a Navy destroyer), I love it!

Of course you can’t use fossil-fuel powered boilers to provide the steam (nothing to do with climate change–if you’re going to burn fuel in a rocket, you might as well send it out the rocket engine, rather than losing energy by heating water). Solar energy might provide the heating capacity near the Sun, but further out in the solar system you’d need nuclear power. NASA actually has a couple small contracts out for designs for nuclear propulsion:

This IMHO is where NASA should be: not getting payloads up to LEO, which SpaceX can handle, while NASA should be figuring out how to get astronauts around the solar system.

Speaking of LEO, maybe Boeing can get their act together for getting people to the ISS; the latest is that the second unmanned test flight of their crew capsule was postponed yet again, now scheduled for the end of this month–more than a year and a half after their last botched attempt.

Tom Abbott
Reply to  mcswelll
July 17, 2021 12:31 pm

“Solar energy might provide the heating capacity near the Sun”

That would work.

We could buy power off the Chicoms when they put their Solar Power Satellite in orbit around 2030 (so they claim).

I would prefer that NASA beat them to it, build their own Solar Power Satellite, and then we could buy power off the U.S.instead.

We could power all sorts of orbital transfer vehicles and other things with a Solar Power Satellite.

NASA needs to start thinking ahead. The Chicoms are thinking big. The U.S. needs to think bigger.

Reply to  Gregg Eshelman
July 17, 2021 10:35 am

Designing the space station to be moved is stupid.
Do you have any idea how much fuel you would need to move an entire station? Not to mention the need to strengthen the station to be able to withstand repeated orbit changes?
If you want to service satellites in orbit, having orbital shuttles is a much better way to do it.

Reply to  MarkW
July 17, 2021 8:47 pm

Gregg said service station, not space station. A robot-equipped, and maybe airlock equipped, satellite with docking capability so a manned ship like the SpaceX crew ship that doesn’t have built-in airlock could dock with it, allowing EVAs in support of human repair efforts if need be.

Doesn’t have to be very big, although granted, orbit changes–particularly changes in orbital inclination–can require a lot of power, so it might carry a lot of fuel and oxidizer (and you have to ensure those don’t evaporate while it’s waiting around). But given that it’s already in orbit, and you don’t have to boost it up from the ground, and you’re not in a hurry (missions can be planned months or even a year ahead), it might be that a low thrust high impulse engine could get it there. Maybe even an ion engine, in which case the evaporation problem should be easier to solve (no oxidizer needed).

But yes, it’s possible that it might be cheaper to launch the mission from the ground. Some things–repair parts, say–would have to be ground launched and transferred via rendezvous. I think it would take an engineering study to see whether this makes sense, but it’s intriguing.

Tom Abbott
Reply to  mcswelll
July 17, 2021 4:43 am

It looks like Musk will have more time to work on a Hubble repair as it seems NASA has managed to get the Hubble back in operation by switching to a back-up set of instruments.

NASA thinks it will take a few days to get everything back online.

Reply to  Tom Abbott
July 17, 2021 9:00 am

Good news! Of course that means there is no longer any backup for whatever system they had to substitute. Time to think about what happens the next time there’s a failure: 1) Count it as a loss, 2) Launch a new (and probably better) telescope with similar capabilities (JWST has mostly complementary capabilities), or 3) Come up with a new repair method, of which several possibilities have been mentioned here (and of course in other forums).

If it were me, I’d go with option (3), because the HST (and the JWST) aren’t the only satellites that would benefit from this. Plus you could use it to safely de-orbit dead un-repairable satellites, like the Chinese booster, although you’d probably need a re-fueling capability. (When the repair vehicle did a burn to de-orbit another satellite, it would need to do a second burn to return itself to a safe orbit. Not to mention that changing orbit–particularly changing the inclination of an orbit–takes a lot of fuel.)

Reply to  mcswelll
July 17, 2021 10:33 am

I suspect that the design, building and certifying of an EVA module would take longer than the Hubble has left.

Reply to  MarkW
July 17, 2021 8:58 pm

Might could be, at the speed of government. But the real question is how fast Hubble’s orbit is decaying. Should some part fail next year, the repair could wait a few more years for design/ building/ certification, so long as Hubble doesn’t come down in the mean time. I can’t find any recent projections, but as of a few years ago they were estimating orbital decay in the 2030s, which *ought* to be enough for the module.

Also, if Hubble’s orbit decays too much before then, an attempt would be made to attach a rocket to bring it down in a controlled fashion, somewhere out at sea. But if that rocket could bring it down, it could also lift it into a higher orbit. So the orbital decay problem may be a non-problem.

And before someone questions whether the cost of building an EVA module (plus the other costs of a manned mission) are too much, realize that developing the capability of in-orbit repair would make it possible to repair any LEO satellite that was designed to be reparable (and with a larger booster, geosynchronous satellites too). Heck, we could even retrieve Vanguard I and put it in the Smithsonian.

The Saint
Reply to  NickSJ
July 16, 2021 9:24 am

China might steal the tools before an astronaut could get there to use them if they were just left floating in space.

Reply to  fretslider
July 16, 2021 6:02 am

NASA’s is and will always be a political beast. It’s priorities are determined by the party in power. They are the ones who set the budget.

Reply to  MarkW
July 16, 2021 6:12 am

For any excitement now you have to look to Musk’s firework factory in Boca Chica.

Tom Abbott
Reply to  fretslider
July 17, 2021 4:58 am

Yes, Musk is on the cutting edge if anyone is.

Giordano Milton
July 16, 2021 4:39 am

NASA can still do serious work, but much of the focus for the many-many-many managers is on maintaining headcount (jobs). It’s become (mostly) just another bureaucratic monster.

July 16, 2021 6:01 am

As much as I despise the time and money that NASA is wasting on the global warming scam, it’s not a lack of money that is hampering the work on the Hubble.
Unless we take one of the Shuttle’s out of mothballs and send it back into orbit, switching to backup systems is the only option for keeping Hubble operational. When those back ups in turn fail, Hubble will be dead.

None of our current or planned vehicles have the capability to service the Hubble.

July 16, 2021 6:14 am

How much would Nasa save if they fired Gavin Schmidt?

July 16, 2021 6:18 am

I am just amazed it is working still at all.

D. J. Hawkins
Reply to  2hotel9
July 16, 2021 6:39 am

Anyone know what the original planned mission duration was supposed to be? I can’t seem to find it anywhere.

Reply to  D. J. Hawkins
July 16, 2021 6:58 am

There were 4 or 5 Shuttle missions to service the Hubble. I believe it was either the last mission, or the one before that, included a space walk to service the Hubble.

Reply to  D. J. Hawkins
July 16, 2021 7:01 am

I don’t recall ever hearing a timeline for it. Certainly well past it’s use by date. 😉

Reply to  2hotel9
July 16, 2021 10:07 am

I don’t know if they bothered trying to calculate an initial life expectancy, since the Hubble was designed to repairable in space.

Tom Abbott
Reply to  MarkW
July 17, 2021 5:01 am

They not only repaired Hubble, they added several new instruments to its collection over time.

Reply to  D. J. Hawkins
July 16, 2021 2:24 pm

I seem to remember it was 5y but I could be confabulating.

Reply to  Greg
July 17, 2021 10:37 am

I thought that was Star Trek.

July 16, 2021 6:47 am

If they were really interested in saving the Earth and people they would be supporting NASA to protect the Earth from a Manhattan size rock.

Orbiting telescopes have many uses and no one has to make up what those uses are.

Reply to  Olen
July 16, 2021 8:57 am

The HST is a nice telescope, but it’s not what you’d use to search for asteroids. What you want for a search is s.t. with a wide field of view, so you can conduct a search. Otherwise it’s like looking through a soda straw.

Once you found a dangerous asteroid, you might study it with the HST.

Rory Forbes
Reply to  mcswelll
July 16, 2021 10:47 am

I believe they already have a solar orbiting, wide angle instrument in planning. It’s designed specifically to locate and track objects roughly to the scale of the Chelyabinsk meteorite. There is a Nova program specifically on that.

July 16, 2021 7:41 am

A new one is going up this year too.

Reply to  Ossqss
July 16, 2021 9:04 am

True, but it would be nice to have both a telescope that looks in the visible and UV (HST) and one that looks in the IR (JWST). (There is some overlap: HST sees down into the near IR, while JWST looks up to around red or yellow.)

Also, there is more than one land-based giant telescope, and there are plenty of astronomers clamoring for their use. I would bet that if HST and JWST were both working, they would both be thoroughly used.

Jeff Labute
Reply to  mcswelll
July 16, 2021 10:23 am

Despite being mostly IR (plus visible red up to yellow), you can surprising see a lot of new details a visible range telescope would miss.

Reply to  Jeff Labute
July 16, 2021 6:46 pm

Agreed, Jeff. And I imagine there are lots of things you can only see in the UV. So it would be awfully nice to keep both HST and JWST working for a long time, as I imagine we all agree.

FWIW, there’s been a huge amount of progress since Hubble was conceived and launched in adaptive optics, that allow earth-bound telescopes to reach almost the resolution of Hubble despite the atmosphere. But the atmosphere does prevent them from seeing very well at some wavelengths.

Joel O'Bryan
July 16, 2021 1:30 pm

Like all of us, Hubble is getting older and more fault prone. To expect it or us to live forever is irrational.

Tom Abbott
Reply to  Joel O'Bryan
July 17, 2021 5:13 am

But, we want Hubble and ourselves to live as long as possible. 🙂

Jesse Brown
July 21, 2021 3:28 am

Interesting discussion. Back in oh, I guess it was 1980-81 I started as a test tech at Fairchild Space and Defense Co in Germantown, Md, working on environmental testing of the Remote Interface Unit(RIU) and the CU/SDF for Hubble.

Fairchild designed and manufactured the SI&DH module that Hubble uses. This module was also used on a number of other NASA science satellites conceived, built and launched in the 80s and early 90s – TOPEX, Solar Max, Landsat and a number of classified NRO birds. Eventually I took over the Final Test Dept which tested each individual “black box” (they were actual black boxes) before they were integrated into the SI&DH Module.

We all knew we were participating in history. I don’t think anyone ever expected the Hubble to last this long (none of the other birds are still flying). The original CU/SDF was based, if memory serves, on a 70s Intel 8088 CPU. That was replaced with i486 tech on one of the servicing missions years later. All of the units in the SI&DH were dual redundant thank the stars.

NASA decided in the 90s to move in another direction architecturally from the SI&DH. Sadly that meant the end of Fairchild Space Co. and it’s sister Defense company (making targeting modules for the F-14 fighter). The plant beside I-270 in Germantown has been demolished to make way for condos or some such and all the brilliant engineers and technicians who helped make those satellites have passed away or are retired now (as I am). Heady days. Fond memories.

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