Hubble Telescope Hit By Mechanical Failure (bbc.com)

The Hubble Space Telescope is operating with only essential functions after it lost one of the gyroscopes needed to point the spacecraft. From a report: The observatory, described as one of the most important scientific instruments ever created, was placed in "safe mode" over the weekend, while scientists try to fix the problem. Hubble had been operating with four of its six gyroscopes when one of them failed on Friday. The telescope was launched in 1990. After the gyro failure at the weekend, controllers tried to switch on a different one, but that was found to be malfunctioning. That leaves Hubble with only two fully functional gyros. At any given time, Hubble needs three of its gyroscopes to work for optimal efficiency.

Comments

Re:Ouch

[rickb928]

A service call to Hubble is out of scope for the first several SpaceX manned launches. It doesn't provide the same capabilities as the Shuttle at all.

But Elon might actually offer a solution, or at least offer to offer one.

Ground based telescopes with adaptive optics

[PeterM from Berkeley]

Do we really need Hubble that badly anymore?
Apparently adaptive optics technology is allowing ground-based telescopes to surpass Hubble's capability.
https://www.airspacemag.com/sp...

Rather than firing up an expensive space mission (I remember each shuttle mission was $500M), would it genuinely be better to just take that money and build or retrofit a ground-based telescope with adaptive optics? A telescope that you could easily maintain thereafter?

This doesn't help with wavelengths of light that don't go through Earth's atmosphere, but that's not what Hubble does. Seems like we could do without Hubble nowadays.

--PeterM

Re:Ground based telescopes with adaptive optics

[Immerman]

One of the biggest advantages that an orbital telescope can provide (beyond avoiding atmospheric distortion) is a stationary platform for targetting distant objects and long exposures. Any telescope on Earth is rotating at a constant rate of 1 revolution per day, as well as being plagued by the many vibrations traveling through the Earth itself. You can build it on a moving platform so that servos keep it focused on a specific point in the sky, at least while that point is above the horizon, but then you introduce all the vibrations of the tracking mechanism, which makes it impossible to take clear images of fine detail. Rather like trying to use a high-power telescope while holding it in your hands - all you'll ever be able to see is a blur.

An orbital telescope though stays focused where you point it. It orbits the planet, but the parallax from that is irrelevant over long interstellar distances, and it only takes a little help from vibration-damped precision gyroscopes to keep gravitational fluctuations, solar wind, etc. from causing it to start spinning.

Re:Ouch

[bobbied]

Doing another maintenance run on the Hubble is probably beyond the spec/capabilities of the first manned SpaceX launch, currently planned for mid 2019.

I fear you are correct. Hubble was/is at the extreme limits of the shuttle system's ability and the last trip was risky enough that they almost didn't do it. Now we have no shuttle.

I don't doubt Space X could engineer some solution to service Hubble, but the timeframe it would take to develop the capability is likely to be longer than the scheduled replacement's arrival. To do this Hubble service thing, you need to first catch it in orbit (the shuttle used an astronaut on the robot arm for this) so you can work on it, then open it up and move around some large chunks of delicate gear from some kind of cargo area.

Given the age of Hubble, the cost of such a rescue mission and the projected replacement of the system already scheduled, I'm guessing they use Hubble as best they can with what's left that is still working. It's been a great achievement, but I don't think it's worth it at this point to try and fix the thing. Besides, we all knew the day would come when Hubble would work no more. It's sad, but the time may be closer than we would like to admit.