Vanguard 1 holds the record for being in space longer than any other man-made object, along with the upper stage of its booster. It was launched on March 17, 1958, but was last heard from in May of 1964.

What still-orbiting satellite that is still transmitting a signal holds the record as oldest?

Are there any older-still satellites from which we could potentially get a signal if they were reactivated (such as Prospero)?

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    $\begingroup$ Related: What is the oldest artificial satellite still in use? $\endgroup$ – TildalWave Mar 15 '14 at 21:54
  • $\begingroup$ I liked the pre-edit version of this question because Finally, what’s the oldest satellite that still (at least partially) is fulfilling its mission design has an interesting answer. I guess I'll add it to that other question. $\endgroup$ – David Hammen Mar 15 '14 at 22:08
  • $\begingroup$ @DavidHammen I see, the answer to the other question does not fulfill the mission design spec. $\endgroup$ – Jerard Puckett Mar 15 '14 at 22:15

Transit 5B-5 a.k.a. Oscar 2 (not to confuse with OSCAR ham radio satellites), part of the Transit / Navsat navigational satellite program was launched 51 years ago on Dec. 13th 1964 and its telemetry transmitter is still transmitting on 136.650 MHz when it's passing through sunlight. It's not operational anymore (in fact it quit its job 19 days after launch) but it's most likely the oldest piece of space scrap that's still kind of "active".

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    $\begingroup$ Can you add a link showing (or at least saying) that the beacon is still transmitting? Thanks! $\endgroup$ – uhoh Jul 28 '16 at 4:37
  • $\begingroup$ Until more is posted, there is this answer! $\endgroup$ – uhoh Apr 19 '17 at 11:20

As far as I'm aware, this distinction belongs to Pioneer 6, which was the first spacecraft launched from the set of Pioneer 6, 7, 8, & 9 probes on December 16, 1965. Whether it's still functional and contactable at this very moment, I'm not sure. Pioneer 7 & 8 are supposedly still functional.

Pioneer 6 was last contacted on December 8, 2000. Nearly 15 years ago - and it exchanged communications with ground control for approximately 2 hours. You might be looking for something a bit more recent, however.

In that case, Wikipedia claims that Voyager 2 is both the oldest functioning and operational spacecraft, which launched on August 20, 1977 - thus it has been operational continuously for over 37 years, and it is expected to remain operational until at least 2025.

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    $\begingroup$ The question was clearly about orbital satellites; all your examples are deep space probes that do not orbit anything, as far as I am aware $\endgroup$ – raptortech97 Mar 10 '15 at 2:19
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    $\begingroup$ @raptortech97. Well, then the question needs clarification, as the Pioneers orbit the sun and Voyager 2 orbits the Milky Way. "Earth orbit" was not specified. $\endgroup$ – ReactingToAngularVues Mar 10 '15 at 3:13
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    $\begingroup$ Let Voyager 1 finish one orbit around the galaxy and then we'll be able to tell if it really is in its orbit :) With all that dark matter we don't quite understand "orbits the Milky Way" is not nearly as sure as we thought when launching Voyager 1. $\endgroup$ – SF. Dec 5 '15 at 17:55
  • $\begingroup$ @SF.: Voyager 1 does not possess enough energy to climb out of the Milky Way's gravity well, and its escape velocity relative to the sun is puny compared the the total delta v required. It could no more escape than the sun could. $\endgroup$ – Joshua Dec 10 '17 at 19:04

I know the Oscar 7 satellite, launched in 1974 is still working, be it while only in sun. There's reports from December of 2016 that contacts are still being made through it.

Reports of Amateur satellite contacts are posted here: http://www.amsat.org/status/ and there are frequent "Heard" entries for AO-7 this week.

  • $\begingroup$ Can you add some links to back this up? $\endgroup$ – Jan Doggen Apr 19 '17 at 7:34
  • $\begingroup$ @JanDoggen I've added a sentence. Seems to be beeping away nicely. I can't tell if it is the transponder repeating signals from HAMs on Earth, or if it is only the beacon that is being heard. $\endgroup$ – uhoh Apr 19 '17 at 10:09

Perhaps it is the courier 1b? Launched in 1960, the last information on the satellite published c 2009 lists the nav beacon as still transmitting.

Additionally, it might actually be theoretically possible to contact. With the batteries long dead, the solar cells might do a reboot allowing the satellite to be recontacted...?

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    $\begingroup$ Can you add a link showing (or at least saying) that it's beacon was still transmitting in 2009? Thanks! $\endgroup$ – uhoh Jul 28 '16 at 4:37

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