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How do engineers take care of the Hubble Space Telescope while it's in space?

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Hey guys, meet Patti Hanson. She works on the Hubble Space Telescope project.

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Today, we're at NASA Goddard Space Flight Center in Greenbelt, Maryland.

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Okay, Patti, so far we've learned about algebra, optics, telescopes, and a little about the Hubble Space Telescope.

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Now, what is NASA Goddard doing to protect the Hubble while it's orbiting around the Earth?

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Yeah, and how do engineers like you use algebra in your jobs?

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Whoa, those are a lot of questions.

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Here at Goddard, we're actually the servicing part of the Hubble Space Telescope project.

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We actually prepare scientific instruments, computers, tape recorders to go up on the shuttle, rendezvous with Hubble,

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and perform servicing of the telescope.

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Astronauts go out into the payload bay, get the new equipment out of carriers,

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and install it on the telescope, and we bring the old hardware home.

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Now, when we're getting ready for a servicing mission, we have our instruments in our clean room.

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And in the clean room, we want to make sure we control contamination by having everyone get dressed in what we call bunny suits.

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And you'll see that everybody in the clean room is dressed head to toe in white.

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What this does is it controls all the contamination from your clothing, which is lint, your hair.

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We don't want any dropped hairs on our science instruments.

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And our skin flakes.

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Here on Hubble, we're really worried about both particulate and molecular contamination accumulating on the primary and secondary mirrors.

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Particulate contamination is like a fine layer of dust that scatters the light

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and doesn't allow it to transmit through the optic and gather into the detector very well.

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Molecular contamination is a thin film similar to the condensation that you see on this mirror when I squirt it with the nitrogen cleaner.

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This doesn't allow the light to be transmitted very well through the optic.

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Okay, Van, to get back to your question about how I use algebra in my job,

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is that I have an end-of-life requirement for the amount of contamination I can accumulate on flight optics.

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Now, for Hubble, that's the primary and secondary mirrors.

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End-of-life is the amount of contamination that we can accumulate from the time it was launched

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until the time that we no longer expect to take science.

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And for Hubble, that's 20 years.

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So you're saying that in 20 years, you will accumulate some type of contamination on Hubble's mirrors?

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That is correct.

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Okay.

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And what we do is we take periodic measurements and we compare that to our end-of-life requirement.

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Okay, let's look at the algebra Patty is talking about.

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NASA engineers know the total amount of contamination on the Hubble has to be less than 5 percent

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or the telescope won't work the way it should.

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Before Hubble was launched, three measurements for contamination were taken.

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The first was 8 tenths of a percent.

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The second was 6 tenths of a percent.

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And the third was 1 tenth of a percent.

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The total amount of contamination on the Hubble consists of the amount of contamination measured on Earth

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plus the amount of contamination that it collects on orbit.

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If we substitute the values we know into the inequality,

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we find that the amount of contamination the Hubble can collect on orbit has to be less than 3.5 percent.

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Using algebra, you can see that we have plenty of on-orbit margin left

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to accumulate contamination on both the primary and secondary optics.

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Hey, check it.

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Did you know that the Hubble Space Telescope is about the same size as this school bus?

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This is where all of the data from the Hubble Space Telescope is continuously being collected.

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Back in 1995, NASA Goddard collected images from the Hubble Deep Field.

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A few thousand never-before-seen galaxies are visible in this deepest-ever view of the universe.