[ExI] The Thirty Meter Telescope is now officially dead

John Clark johnkclark at gmail.com
Sun Dec 22 10:48:30 UTC 2019

On Sat, Dec 21, 2019 at 5:36 PM Adrian Tymes via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

*> Heck, with the team & tools I have available to me (via CubeCab) right
> now...the TMT's budget was about $2B to put together, right?  I dare say
> that I could put together a thirty meter diameter telescope, in low Earth
> orbit (thus, above all the atmospheric distortions), for $200M: a tenth the
> budget of the TMT.(This would be a synthetic aperture array,*

I doubt that that very very very much.

> *$100M in launch costs, leaving the remaining $100M for development,*

Launch costs are not the issue! Synthetic aperture is not going to help you
when it comes to equalling the light gathering power of the thirty meter
telescope, you're still going to need 707 square meters of PRECISION
optical surfaces, nobody has ever made a optical array anywhere close to
that even on the ground much less in space. Synthetic aperture works well
for radio wavelengths but it's really hard to do for optics, it's been done
a few times with the 2 Keck telescopes in Hawaii but only with the help of
many tons of precision equipment and even then it only worked in one
dimension not 2 needed for a picture. In 2005 money was approved to improve
things and add 4 much smaller 1.8 meter telescopes that wouldn't have added
much light gathering power but would have allowed the much improved
interferometer to resolve Neptune sized planets around nearby stars. The 4
telescopes were actually built but they never made it to the top of the
mountain, they were stopped by, you guessed it, Hawaiian protestors, they
feared the invisible man on the mountain wouldn't like it. The super
interferometer project officially died in 2012 although it was moribund
long before that.

Another problem with a space based system is that all those precise optical
surfaces are going to have to be flying in orbits far far more precise than
anything ever flown before, so you can't put them in low earth orbit due to
atmospheric drag. There is no way you're going to overcome all these
problems with just 100 million.

 John K Clark
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