Is This The Oldest Still-Working Geostationary Satellite?

The LES-5 spacecraft
The LES-5 spacecraft

Regular followers of space news will know that when satellites or space probes reach the end of their life, they either are de-orbited in a fiery re-entry, or they stay lifeless in orbit, often in a safe graveyard orbit where they are unlikely to harm other craft. Sometimes these deactivated satellites spring back into life, and there is a dedicated band of enthusiasts who seek out these oddities. Dead satellite finder extraordinaire [Scott Tilley] has turned up a particularly unusual one, a craft that is quite likely to be the oldest still-working geostationary satellite.

LES-5 is an experimental satellite built by MIT’s Lincoln Labs, launched in 1967, and used to test military UHF communications in a geosynchronous orbit. It had an active life into the early 1970s after which it was placed in a graveyard orbital slot for redundant craft. It’s lain forgotten ever since, until this month when [Scott]  found its beacon transmitting on 236.75 MHz. The Twitter thread is an extremely interesting glimpse into the satellite finder’s art, as first he’s not certain at all that it is LES-5 so he waits for its solar eclipse to identify its exact position.

Whether anything on the craft can find another use today is not certain, as he finds no evidence of its transponder. Still, that something is working again 53 years after its launch is a testament to the quality of its construction. Should its transponder be reactivated again it’s not impossible that people might find illicit uses for it, after all that’s not the first time this has happened.

39 thoughts on “Is This The Oldest Still-Working Geostationary Satellite?

    1. while causing major problems when first introduced do you have any evidence other than 35 year old second hand rumours handed down by grumpy old farts, cause now that we got past oh 1990, it seems to be doing just fine…

      1. do you remember all the dead 1st-gen Xbox 360s that turned into a lucrative business for home-based repair services? that was due to the lead-free, brittle solder used to mount the CPU cracking and separating under the shear stresses of dissimilar thermal expansion between the CPU and motherboard. they were generally repaired using more-ductile leaded solder and I did not hear about any ever having a recurrence of the sheared solder problem

          1. I think you meant Wistron (the design engineers) and/or Flextronics and Celestica (all 3 were manufacturers)

            But isn’t that the point you missed? If 80% of the world can’t get your product (lead free solder) to work, perhaps the problem is with your product and not with everything and everyone else.

            This is further evidenced by the fact the designs did not change at all to fix the problem, using a different lead free solder made later specifically to address the problems with it, is what fixed the problems.

          1. It isn’t a “minor engineering problem” to people who crash their cars because their throttle got stuck to 100%.

            The difficulty is that the tin whiskers can take months to 10 years to grow, and they will not conduct by default. You need a certain breakdown voltage before the insulating layer over the whisker breaks, and the whisker will melt down beyond a certain voltage, so it’s rather an intermittent failure that is beyond the usual warranty of the product and can’t be reliably detected using standard measures like a multimeter. In other words, it’s hard to prove that they will occur, and even if they do there’s little incentive to fix the problem because the failure rate exceeds the designated EOL of most products out there.

          1. Lead completely suppresses tin whisker formation in solders AND stops the development of tin pest. That’s why it was used. Now both problems have returned.

    2. Yeah, yeah. We get it. But it’s a worthwhile trade. Which would you rather have, obsolete satellites from the fifties or a life without tons of ambient lead poisoning? People bitched and moaned about the ban on leaded gas too. Tin whiskers are not a significant problem in the world at all. Way overblown, kind of like the danger of sharks or something.

      And I doubt its longevity is really explained by the solder used. Probably has far more to do with very large components and good design practices.

      1. “…or a life without tons of ambient lead poisoning? ”

        The effort of reducing lead in components and solder worldwide has resulted in the equivalent of a few hundred PbA car batteries being tossed in the environment every year. Batteries are exempt from RoHS.

      2. From what I’ve seen of the population pre and post lead ban, I’ll take the lead poisoning. Lack of lead in the environment actually seems to be a detriment to human development.

      3. “tons of ambient lead poisoning”

        From leaded solder? You have got to be kidding.

        And you compare it with leaded gasoline? Do you have any concept of magnitude?

        Even if leaded solder was still used in everything today no doubt it would be statistically insignificant compared to lead from other sources such as batteries. And neither is anything at all compared to what leaded gasoline was.

        Not to mention the fact that the rosins required for use with lead-free soldering are particularly nasty themselves.

        A better solution would be to keep leaded solder but encourage responsible recycling of electronic devices. Also encouraging manufacturing devices which last longer, consumers to keep them longer and programmers to support older devices.

        People go through cellphones, tablets and even laptops today like they are dixie cups. It is sickening. It’s a far bigger problem than leaded solder ever was. If you haven’t noticed any devices failing early due to solder issues it’s probably because you don’t keep things long enough.

      4. “a life without tons of ambient lead poisoning?”

        This is the type of thinking that comes from significantly overvaluing zero vs. some minuscule non-zero risk level.

        We got almost all of the benefit from the first 90% of the solution, and almost all of the downside from the last 10%. But still the entirety of the benefit is used to justify that downside.

    1. go play some kerbal space program. a sat in GSO is not going to just ‘fall out of orbit’, it requires way more dV than a sat’s stationkeeping budget can provide. the graveyard orbit is well-documented so it’s safe from active sats being placed there, and is close enough that a sat being retired will have enough dV left to get there

      1. Also in short, stuff that falls round the planet in 24 hours, thus remaining in about the same position over the surface is a lot higher than stuff that falls around the earth in 2 hours and is subject to a tiny tiny bit of drag due to the really thin wisps of atmosphere that are up there… eventually that drag slows it down enough that it can’t keep missing the planet so it moves towards it more, where the atmosphere is fractionally thicker and it slows more.. You may concur from this that stuff falling around the planet higher up is moving faster, with exponentially less of the thin wisps of atmosphere to slow it down it will take thousands of years of tidal forces to do the job unless acted on by a force, like its thrusters. Yes, it needs power to get down again.

    2. Look into orbital mechanics and the energies involved and you’ll understand why. These satellites aren’t in LEO, but quite far away. It takes a lot of energy to get them up there and it takes a lot of energy to get them back down again, especially considering they don’t suffer the drag satellites in LEO do. It’s just not very feasible. Once we have technology which dramatically chances the efficiency of sending mass to space we could consider deorbiting geostationary satellites, but that would require something other than chemical rockets. At this point that is nothing but a fantasy.

    3. It is a matter of fuel management. In order to get the full service, the satellite owners, FCC and ITU require satellites to be flown to the graveyard rather than using fuel and navigation they don’t have for a controlled re entry burn up. Keep in mind they are way up there and there are hundreds if not thousands of lower orbit military and commercial MEOs and LEOs to navigate around.
      Generally the “satellite” communications stuff is powered by solar forever. The satellites use fuel (in a tank) to fly a figure 8 to compensate for Earth wobble and after running low on this fuel operate for years slightly relocated from the original orbital position using fuel only to maintain orbital location as a non geostationary satellite where connected Earth stations have to motorize their dishes to track them. Once below a certain fuel level they are required to relocate to the graveyard while they are still controllable. The primary reason satellites are retired is because there is a technical improvement and replaced with a better satellite and not because they fail. When they lose station keeping fuel or lose control and drift it turns into a disaster as they slow down and cross other satellite locations and wipe out major comms as they interfere with other transponders. As a reference AMC 9. Yes the graveyard is a best option for when satellites deplete the station keeping fuel. My guess is that most satellites in the graveyard would work just fine but they’re turned off. Very few satellites actually quit working it’s just someone comes up with more sensitive amplifiers with better noise figures, more power, better third order intercept and linearity. Satellite companies get very serious about single dB improvement specs.

      1. It’s been quite a few years since I sat through my satellite controller courses (31S 1C) but as I recall, the avg orbit for a geostationary object is just about 4e4 km out. As to why use graveyards? You could probably design a burn that would eventually bring it back into the atmosphere, but it would use all of your fuel doing it. The last thing you want is a school is sized object careening through hundreds of billions of dollars of multinational assets while not under power. No one is willing to take that kind of risk. You could blind yourself, start a war, or ground the entire industry for decades.

    4. GEO is a different beast. Way too high to just decay and burn up, and there’s plenty of space up there. Nothing’s gonna cause a traffic jam in a graveyard orbit that high, even if we kept putting birds up there for centuries.

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