update: I've just read these intriguing first sentence in the recently published (and paywalled) Aviation Weekly article No Second Chances On Webb Telescope Deployment:

NASA has no plans to service the $8.7 billion James Webb Space Telescope (JWST), but it has not completely closed the door on the idea as it prepares a rigorous series of tests designed to ensure in-space repairs will not be needed. When the 6.5-m (21-ft.) telescope launches to the Sun-Earth Lagrange point (L2) in 2018, its launch interface ring will carry optical targets that could be sought out by a servicing robot’s machine vision as it approaches to attach itself in order to make ...* (my emphasis)

The Hubble Space Telescope (HST) was robotically deployed from the Space Shuttle under direct local control by the astronauts on the shuttle. There were five further service missions using the shuttle using a combination of work by astronauts in suits and astronaut-controlled robotic maneuvers. The HST was designed (at least in part) for servicing - in some cases modules could be pulled out of racks and updated or replaced, for example.

It's possible the James Webb Space Telescope (JWST) might have some features like that, but probably not to the same extent as the HST, since 1) it will be much farther away and there is not currently any manned or robotic mission activity to earth-moon (or any) libration points, and 2) the design is optimized for things like weight, reliability, performance and thermal management, rather than easy access. Since it is designd for infrared wavelengths, a substantial fraction of the systems must be maintained at low temperature.

There are several answer given to the question The JWST - What happens if/when it breaks?. Interestingly all of the answers only address service by astronauts. Now the NASA Satellite Servicing Capabilities Office, has announced and described the Restore-L mission - a first test and demonstration of completely robotic service and/or repair.

The answers and comments associated with question What satellites did the Shuttle retrieve from orbit? contain references to on-orbit repairs to satellites (presumably) in LEO carried out by astronauts using the shuttle's robotic arm Canadarm 1. But I'm not sure if those satellites were serviceable by design or luck, and this comment speaks to that.

Thus my question: Besides HST, JWST and stations, are there any examples of satellites designed for service in space?

Let's exclude all past/present/future space stations and anything else that has been designed specifically for astronaut activity.

I've tried to use the infinitive form for the question, so the answer can include past, present, and future satellites, but let's keep it near-future and well-planned, and exclude the hypotheticals.

The Educational Outreach page of the NASA Satellite Servicing Capabilities Office shows a YouTube video which contains an animation of robotic satellite repair. For more discussion see Is Landsat-7's propellant resupply port “robot-ready”? (Restore-L mission) and associated answers. Here is a GIF reconstructed from frames of the video:

enter image description here

  • 1
    $\begingroup$ pretty much most commercial satellites... $\endgroup$
    – SF.
    Jun 27, 2016 at 0:43
  • $\begingroup$ @SF. tell me more! $\endgroup$
    – uhoh
    Jun 27, 2016 at 1:29
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    $\begingroup$ I believe you'll learn more than I know by following the same path as me but more thoroughly. Follow this list for all repair missions, then research these in-depth. I was focusing on recovery from orbit, but got sidetracked by STS-49 which was a heroic repair attempt; the satellite refused mooring attempts. Once moored, replacement of the whole engine was a breeze. $\endgroup$
    – SF.
    Jun 27, 2016 at 6:02
  • $\begingroup$ @SF. I always enjoy a good read about SX events and the human drama behind the raw data. Thanks for the leads! $\endgroup$
    – uhoh
    Jun 27, 2016 at 6:24

2 Answers 2


A family of spacecraft in the 1980s were designed around the Multi-mission Modular Spacecraft (MMS) bus. This bus was designed specifically to allow for retrieval and repair of the spacecraft by the Space Shuttle. (reference)

As far as I know, the only MMS-based satellite that was actually repaired by a Shuttle mission was the Solar Maximum Mission. This spacecraft was disabled by failures in its electrical system, and was retrieved and repaired (not without some associated drama) by Shuttle mission STS-41C.

enter image description here

Incidentally, 41-C was a prime example of an ambitious pre-Challenger accident Shuttle mission, featuring an untethered EVA by an astronaut flying the Manned Maneuvering Unit, near-real-time replanning of robotics operations, and deployment of a science satellite, the Long Duration Exposure Facility. It was also the first mission to fly a "direct insertion" ascent, obviating the need for an OMS-1 burn.

Quite a bit of footage from this mission showing the capture and repair is included in the early IMAX film The Dream is Alive.

  • 1
    $\begingroup$ It's so great to look at astronauts in space and hear Walter Cronkite's voice again - beautiful! What's an OMS-1 burn? $\endgroup$
    – uhoh
    Nov 10, 2016 at 3:18
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    $\begingroup$ From the shuttle press reference: Normally, two thrusting maneuvers using the two orbital maneuvering system engines at the aft end of the orbiter are used in a two-step thrusting sequence: to complete insertion into Earth orbit and to circularize the spacecraft's orbit. The orbital maneuvering system engines are also used on orbit for any major velocity changes. In the event of a direct-insertion mission, only one orbital maneuvering system thrusting sequence is used. $\endgroup$ Nov 10, 2016 at 3:22
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    $\begingroup$ That's too bad. Will see if I can turn up another link. $\endgroup$ Jun 11, 2018 at 11:54
  • 1
    $\begingroup$ Replaced video link. Thanks for the heads-up. $\endgroup$ Jun 11, 2018 at 12:25
  • 2
    $\begingroup$ Two strikes and I give up. $\endgroup$ Aug 27, 2019 at 11:54

Unlike Hubble, JWST is not designed for service.

The only preparation for servicing are the targets on the launcher interface ring. Those are just some stickers they can add to the surfaces around the interface ring, so that's trivial to do. All the difficult work hasn't been done.

There are no big access doors for easily swapping instruments (unlike on Hubble), for example. No handholds for astronauts to grab.

The launcher interface ring is not a docking ring. It's just a sturdy piece of metal that a servicing mission might be able to grab with a fixture that has to be custom-designed for such a mission.

From the only time those targets were mentioned:

After some confusion at the briefing, though, NASA officials didn’t entirely rule out the possibility that it could be serviced in some kind, but suggested it was highly unlikely. Ochs said that Webb’s launch interface ring, which connects the spacecraft to the launch vehicles, will have targets added to aid in any docking by a future spacecraft. “I think the story we have to tell, the record of performance that we have, should stand us in good stead,” Bolden said.

At the same time, they suggested any servicing would be unlikely. “There’s no plans for anything needing servicing for the mission,” said Eric Smith, the Webb program manager at NASA headquarters. “If the unthinkable happens and we have to do something, it would require an entire design effort for such a mission. At that time, the agency would have to make a decision about whether it’s worth going up there.” It would, he said, depend on exactly what went wrong with the spacecraft and the feasibility, and cost, of repairing it.

(emphasis mine)

NASA does not consider JWST to be serviceable:

Because Webb, like virtually every satellite ever constructed, will not be serviceable it employs an extensive seven year integration and test program to exercise the system and uncover any issues prior to launch so they might be remedied. Unlike Hubble, which orbits roughly 350 miles above the surface of Earth and was therefore accessible by the Space Shuttle, Webb will orbit the second Lagrange point (L2), which is roughly 1,000,000 miles from Earth. There is currently no servicing capability that can be used for missions orbiting L2, and therefore the Webb mission design does not rely upon a servicing option.

  • $\begingroup$ Your answer is quite well sourced and I am sure everything is correct. But I have a completely indefensible hunch that they have left some unofficial "trap door" or "easter-egg" for some kind of service or maintenance, just in case. I know I am wrong, one doesn't mess with a frozen design to add undocumented features intentionally of course. We'll have to wait a few decades and see... $\endgroup$
    – uhoh
    Jun 21, 2018 at 16:58
  • $\begingroup$ Specifically, I wonder if the propellant and coolant filling ports are in a particularly accessible location. $\endgroup$
    – ikrase
    Feb 23, 2020 at 23:01

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