Famously flawed, it is 30 years since the Hubble Space Telescope was launched

Mirror

I think you have your urban myths crossed.

The mirror was made by PE on the same production line as the keyhole spy satelites - the Hubble being optically a keyhole facing up.

The polishing was 70s technology so if the polishing machine was computer controlled it was only for very small values of "computer". The shape fsck-up as nothing to do with the computer it was pure user error.

Kodak had bid to make a pair of mirrors so to have a backup if anything went wrong in polishing.

Although if they had used the same standard testing technique as PE and made the same mistake any error would have equally applied to both. The polishing technique had nothing to do with the error.

The big failing was PE not to have done a very simple test of the mirror to show any gross error - it relied on having a single super precise test that it did wrong. And then made a super precise mirror to the wrong shape. The lesson is that it's often worth doing a quick and dirty back of the envelope measurement/calculation before trusting the 10decimal place answer from the super precise machine with the flashing lights

They didn't do this test because of time constraints, although ironically Hubble then sat in storage for years after the challenger accident.

The missus and I went down to Florida to watch the launch of Atlantis on STS-125, the final Hubble service mission. It was cool seeing two Shuttles ready for flight. (Endeavour was prepped for a rescue, because Atlantis couldn't reach the ISS from Hubble's orbit if necessary.) The launch was awesome.

Interestingly, STS-125 was the only Shuttle mission ever to launch early. NASA bumped it up a day, because keeping Endeavour ready to launch was expensive. It cost me a fortune to change our travel plans at the last minute to make it to the Cape in time for the launch.

For those who can access the BBC iplayer there was an edition of Horizon last night (24th April BBC2 9PM) well worth a watch, as it covered all the servicing missions.

Memories...

Hubble's reflector was actually quite a hassle even before launch. First the alignment system didn't work and Perkin-Elmer had to subcontract that part of the project to a specialty instrumentation maker that hadn't worked on a telescope since Landsat (my old employer). Then during the years-long launch delay, some of the other contractors lost blueprints that turned out to be important for the repair. (Fortunately we still had those.)

One story I heard from a co-worker who was our main point of contact with Lockheed is that there was a physically separate design office tasked with re-creating the subsystems that couldn't be copied from Lockheed's military satellites, without the benefit of being able to look at blueprints or talk to the engineers at the other office. Sounded like fun...

Pretty incredible

This thing has been up there since I was in high school. Meanwhile, code that has not been touched for a couple of years probably does not work anymore. Heck, there are many programming languages that have been created and have become obsolete since that time.

Going Forward

Hubble captured the public's imagination and also made science appear more accessible. The telescope has been a remarkable success and it's longevity a real tribute to the designers and engineers that built and run it. Crucially the design allowed the telescope to be serviced so that critical components could be replaced in the event of failure and instruments upgraded as technology improved. You then look at the abominations that have followed with the James Webb Telescope and some of the other proposals that are being put forward. None are replacements and I don't see how any are going to deliver the value and public interest Hubble has. The JWST should have been canned years ago, it is just a bottomless pit of money and complexity. It's position at L2 means that it was designed not to be serviced, even if we developed something in the future that could get there.

Currently all the main space telescopes are either retired or are in the later stages of their expected life. The JWST appears to have been a giant ego trip/willy waving exercise by NASA to show how clever they are. The reality is that it is making them look incompetent.

I hope, simply from a money perspective that NASA do get the JWST up and working so that some science comes back but I am not overly optimistic.

"For the costs involved in flying a Shuttle every time"

Really? With the costs overruns to build a new telescope every time - and they would have not been identical due to new tech becoming available - and the need to design a launcher that a a time didn't exist, and would have took the same time and costs of SLS? Moreover - how much experience about operating in space was gathered by the repair missions? What about the risks in returning to the Moon or flying to Mars?