Now a system designed to make sure Hubble doesn't happen again is being used to build better contact lenses, and to ensure more accurate laser surgery. It's one of many ways in which NASA technology spins off into new consumer products--but it's one of few that stems, at least in part, from one of the space agency's biggest blunders.
The Hubble Space Telescope, arguably the greatest observatory ever conceived, is one of the crowning achievements of modern science. But its first days in space were not exactly proud. Back in the 1980s, the company contracted to build Hubble's primary mirror didn't have a way to test its own testing equipment, and it was ultimately used improperly, resulting in a misshapen mirror.
The now-legendary saga stemmed from a positioning rod in a tool called a "null corrector," used to create an optical template, kind of like a map for how to grind the telescope's 96-inch primary mirror. Other tests were not considered accurate enough to measure the mirror's perfect angle, so mirror-maker Perkin Elmer Corp. set out to design a perfect null corrector. A rod in this null corrector was installed upside down, changing the angle at which its locator-beam reflected light. The rod looked like it was higher than it really was--objects in the mirror may be closer than they appear, if you will. When workers changed the mirror grinding to compensate for this, the result was a 1.3-millimeter error in the curvature of the mirror.
Hubble suffered from a spherical aberration, which means light reflecting off the edge of the mirror focuses on a different point from the light reflecting off its center. NASA engineers were able to figure out how it happened, and three years after Hubble's launch, spacewalking astronauts installed corrective optics that fixed the problem.
That won't be possible for Hubble's successor, the James Webb Space Telescope. Parked in a gravitational three-way among Earth, the moon and the sun, the JWST's perch 1 million miles from home will never be accessible for space-based repairs. It's got to be right the first time; it needs a perfect map for grinding a perfect mirror. That's where Dan Neal comes in.
The JWST is so big, its primary mirror is actually 18 separate beryllium hexagons that come together to form one big, shiny surface. Each segment was cast in a rough shape, machined and then ground to perfection. The segments start with a few thousandths of an inch of deviation, but must be ground to optical tolerances, with fractions of a micron in variation, Neal explained.
"There's a metrology gap. You can measure something larger with mechanical means, but when you need to get to 0.1 micron — that's going from 40 microns of error to 0.1," he said. "The measurement techniques don't exist for something in between, so we had to invent those."
That configuration of gold-coated beryllium mirrors is beautiful in that light... I sure do hope they manage to get it deployed without any problems. It's just a shame it would be able to last longer than they project once we do get it up there. Especially for the price.
This is why government funding of space and other cutting edge research is important. The technologies invented to solve some of the problems encountered en route trickles down to products that change our lives and contribute to maintaining America's technological edge.
Cost overruns will always be probable just as you will fall down when learning to ride a bike for the first time. It is very difficult to cost something you have never done before with technologies that have yet to be invented. America needs conviction to stand behind education and science rather than just Wall Street. People cry foul when there is a cost overrun at NASA but a trillion dollar wall street bailout is fine.
Unlike what some people including (unfortunately) politicians think, space exploration is much more than just playing space cowboys. ..... Saying funding NASA is waste of public money is like Sarah Palin saying that she will support autism research but will ban wasteful expenditure like research on fruit flies....
This same tech is available today to create prescription eyeglass lenses which offer near-perfect correction for higher order aberrations. For instance, visual artifacts such as halos, haze and starbursts around bright lights at night (even with 20/20 vision) are all caused by slight deformations in the lens of the eye. One such eyeglass lens system is made by Zeiss called iScription. It uses the same wavefront exam to determine the corrective lens and then the lenses are computer machined to a level of precision well beyond standard glasses. They cost a bit more and the shops offering them are few and far between (due to the equipment required) but it's well worth it if you have those kinds of issues and don't want or can't afford custom lasik.
If you think Christine`s story is surprising,, in the last month mother in-law actually earned $9546 working a 20 hour week from their apartment and their co-worker's mother-in-law`s neighbour was doing this for 10-months and earnt over $9546 part-time at their labtop. use the guide from this site.... <strong>BIT40.ℂOM</strong>
until I saw the draft saying $9856, I didn't believe that...my... best friend woz truly bringing home money part-time on their apple laptop.. there uncles cousin has been doing this 4 only 6 months and resantly paid the dept on their apartment and purchased a brand new Bugatti Veyron. this is where I went, <strong>-- Buzz80.ℂOM</strong>