Hubble in safe mode, down to two gyroscopes

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The end might be near: The Hubble Space Telescope went into safe mode this weekend when one of its three working gyroscopes failed.

Hubble has six gyroscopes, all of which were replaced by spacewalking astronauts during a servicing mission in May 2009. The telescope needs three working gyroscopes to “ensure optimal efficiency,” mission team members have written, and the failure brings that number down to two (if the “problematic” one that had been off can’t be brought back online).

But that doesn’t mean it’s time to panic. Hubble can do good science with two gyroscopes, or even one, astrophysicist Grant Tremblay, of the Harvard-Smithsonian Center for Astrophysics, said via Twitter Sunday.

While it is true that Hubble can do science on one or two gyroscopes, in that mode it will no longer be able to take the sharp spectacular pictures that represent its great glory.

Hubble was launched in 1990, fixed in 1993, and has been the most successful science robot ever launched. Scientists had hoped, when they made the James Webb Space Telescope their priority in the very early 2000s that both would be in space and operating to provide top notch science data, with Hubble working in visible wavelengths and Webb in the infrared. Webb’s endless delays and cost overruns has now probably made that impossible.

Worse, there are no plans to build a replacement for Hubble. For the first time since 1993, the human race will no longer be able to see, with our own eyes, the universe sharply.



  • born01930

    How about this for a publicity stunt…SpaceX offers to fix Hubble from Dragon…NASA provides the gyroscopes and pool time for training since they should already have the mockup. No need to service ISS first, go fix Hubble

  • Diane Wilson

    The ESO Very Large Telescope in the Atacama desert has achieved first light with adaptive optics and interferometry, and can achieve image sharpness that equals or exceeds Hubble. It uses four 8.1 meter mirrors, and smaller, 1.8 meter mirrors for interferometry. In addition, construction is under way for the Extremely Large Telescope that will have a 40 meter mirror, and is supposed to equal or exceed the optical resolution of JWST. First light is planned for 2024.

    Best of all, these can be serviced from the ground.

  • Diane Wilson: The problem with ground-based telescopes using adaptive optics is that they can only observe very small fields sharply. With Hubble gone we will no longer have its wide field capabilities.

    Moreover, except for Keck all the giant ground-based telescopes built in the past two decades have had serious technical problems, unexpected by their designers or builders, and have thus produced disappointing results. (I have written about his for Sky & Telescope: see their January 2015 issue.)

    The simple fact is that it is much more cost effective for astronomers to build an optical space telescope. They get much more bang for the buck. We are losing this now.

  • David

    While sending a Dragon to update the Hubble sounds like a neat concept, it’s not even remotely realistic. Dragon isn’t currently set to spend that much time occupied on orbit, there are no outside handholds or such for EVA, there is no mechanism to grapple the Hubble, and perhaps most importantly, there is no provision for EVA capable suits, opening the capsule to vacuum, etc. Starliner has all the same issues. Orion could handle the on-orbit time, but still has all the other issues.

  • born01930


    Maybe it is a pipe dream but it seems like an adapter node for the Dragon (ala Apollo-Soyuz) that can take a vacuum, have handholds and a small grappler could be built. I am no rocket engineer which is obvious…the hardest part may be the environmental control for Dragon. Do you know how long it is supposed to be rated for staying aloft?

  • born01930: My rough memory is that Dragon and Starliner are only rated for about a week in orbit, unattached to ISS.

    They are not designed to do this, and making it possible is far harder than you imagine. In fact, right now a robotic mission to Hubble might make more sense. Some NASA engineers proposed this back in the mid-2000s, when then-NASA administrator Sean O’Keefe canceled the last shuttle servicing mission. Then it didn’t make sense, as the technology and engineering was not far enough advanced. Today such a mission is very conceivable, at a reasonable cost.

  • wayne

    “The Hubble Space Telescope and the Visionaries Who Built It”
    Explorer’s Club, June 30, 2008

    (this should have a lot more Views!)

  • wayne: I’ve said this before, but it simply isn’t that good a lecture on my part. Too long. Better people read the book.

  • Wodun

    The MEV or the spin-off products could possibly solve this problem.

  • Kyle

    How about they detach the Canadarm2 and module from ISS and ferry it over to Hubble with a dragon

  • wayne

    Writing Hubble Telescope History:
    Q&A with Author Robert Zimmerman
    April 22, 2015

  • Richard

    Isn’t WFIRST supposed to be the de facto replacement for Hubble? I mean, assuming it survives the budget cutters’ axe?

  • Richard: WFIRST stands for Wide Field Infrared Space Telescope. It is not designed to provide optical observations. It, like Webb, is not a replacement for Hubble in the slightest.

  • Kyle

    Does the Air Force’s X-37B have a robot arm? Or perhaps it could send a robot to fix it. How big are these gyroscopes?

  • pzatchok

    A MEV style system could and would work great.

    But I do not think the Hubble has available hard points that are robotically accessible.

    But maybe a simple clamp on system could be assembled inside a year? Or at least something to boost it to a higher orbit to save it for latter repairs.

  • Chris Cresta

    It’s too bad that the unused spy satellite with the Hubble grade mirror that was one of two gifted to NASA (the other one being used for WFIRST) couldn’t be turned into a Hubble replacement.

  • Edward

    Kyle asked: “How about they detach the Canadarm2 and module from ISS and ferry it over to Hubble with a dragon

    Their orbits are very different. Hubble is at about 20 degree inclination, and the ISS is about 60 degrees. The delta v needed to change 40 degrees of inclination is more than half the orbital speed, which means that would take more than 4 km/sec of delta v. Then another similar delta v to return it.

    We have known that Hubble was eventually doomed, but NASA and Congress have not been eager to prepare another rescue attempt in advance of this event, even with the possibility of borrowing the mysterious X-37B (or is the Air Force unwilling to lend it out?). I think that we have to acknowledge and accept the sad fact that Hubble will eventually or soon be relegated to reduced-science mode, at least for the foreseeable future.

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