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I'm sure it cannot because I've never heard it suggested even on the pretty imaginative space flight communities on line. But the question is why, what makes it a bad idea.

Some orbital data I find on Wikipedia:

Altitude: ISS 220-435 km, HST 569 km, diff 134-349 km

Inclination: ISS 51.6 degrees, HST 28.5 degrees, diff 23.1 degrees

Could the energy of the higher altitude of HST together with its remaining rocket fuel be enough to dock with the ISS? Could the ISS be refueled enough to reach an orbit to meet HST half way or further?

AFAIK the HST has no conventional docking ability, it needs to be grabbed by a robotic arm. And ISS is the only thing which has that capability (the "Canadarm"), if even that is suitable for this purpose. Implementing such a contraption on Dragon or Cygnus or ATV or Soyuz would take longer than the HST can survive.

Would it be a meaningful investment to save the Hubble Space telescope any further? Or is it too aged to be used as an optical platform for upgraded instruments? And would its operations be hurt by joining orbits with the ISS?

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The altitude difference is minor compared to the plane change. Even 23 degrees of plane change would require a prohibitively large change in velocity

2 * 7.5 km/s * sin(23 degrees / 2) = 3.0 km/s

In reality the plane change required is greater than 23 degrees, because the two orbits don't have the same right ascension of ascending node.

Hubble actually has no propulsive capability at all, but for comparison a typical earth orbiting satellite might have a 200 m/s delta-V capacity; Shuttle with full OMS tanks had approx 300 m/s.

It would be even less practical to move the ISS - far heavier, so far more impulse required for the same delta V. In a lower inclination orbit, the ISS could not be reached by crew and cargo vehicles launched from Baikonur.

Even disregarding those factors, if Hubble were docked to the ISS, it would be useless because

  1. Pointing control and stability of the station are insufficient for long astronomical exposures.
  2. Outgassing from the various activities on the ISS would contaminate the optics.
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    $\begingroup$ The wrong right ascension isn't as big of a deal, as if you line things up right it takes care of itself. And for a one time event, I'm sure they would like it up. RA drifts with time. $\endgroup$
    – PearsonArtPhoto ♦
    Jul 7, 2014 at 22:22
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    $\begingroup$ The station is also subject to vibrations (due to people moving around within, experiments, machinery), which would be transmitted to the HST via the docking mechanism and mess up the observations. $\endgroup$
    – Hobbes
    Jul 9, 2014 at 8:20
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    $\begingroup$ Who cares about operating it? We just want to store it for a future reboost. $\endgroup$
    – Joshua
    Nov 9, 2015 at 21:29

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