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UAHuntsville group reaches milestone in tests for the biggest space telescope

research scope

HUNTSVILLE, Ala. (July 24, 2011) -- The mirrors that Dr. James Hadaway and his associates will soon test for NASA's next great space observatory look pretty much like he thought they should look 15 years ago.

Dr. James Hadaway is shown inside the vacuum chamber at NASA's X-Ray and Cryogenic Facility with six mirrors destined for the James Webb Space Telescope. (Jake Lewis, Ball Aerospace & Technologies Corp.)

Scheduled to arrive at NASA's Marshall Space Flight Center 's X-ray and Cryogenic Facility (XRCF) on Monday, July 25, six gold-coated mirrors for the James Webb Space Telescope (JWST) must be tested at temperatures mimicking the extreme environment of space ions to ensure that the mirrors will be smooth and focused when they are put to work most of a million miles from Earth.

A principal research scientist at the University of Alabama in Huntsville's Center for Applied Optics, Hadaway leads the optical testing of the Webb telescope's 18 primary mirrors. Subcontractors through Ball Aerospace, he and Dr. Patrick Reardon are part of a team working to insure that the Webb telescope sees everything it should see. The observatory was designed to look at stars and galaxies on the distant edges of the universe.

Dr. James Hadaway, left, and Dr. Patrick Reardon are with the instruments they use to test primary telescope mirrors for the James Webb Space Telescope. (Phillip Gentry, Catalytic PR)
The mirrors arriving this week are the second of three sets. The first six mirrors all passed their tests in April and May, despite MSFC losing electric power following the April 27 tornadoes.

"We had six mirrors in the vacuum chamber and we were at the cold temperature -- 45 Kelvin (about 378° F below zero) -- and we had finished measurements on three mirrors by that Wednesday afternoon," recalled Hadaway. "It was a pretty critical time. It takes a lot to get and keep these mirrors cold.

"We knew something bad was happening outside, but we had to focus on what we were doing."

UAHuntsville's optical measurement team headed for home about 5:30 that afternoon, just before the power went out at MSFC. That included power to the (XRCF) where the mirror testing is done.

"Fortunately, the XRCF has a diesel generator to keep things running in a power outage," Hadaway said. "That night they e-mailed us, 'We're still good,' so for the next three days we were out there taking data. They only had enough power for the instruments and to maintain the chamber, so by Saturday it was up to 85 inside the building. But we ended up getting all of our data as planned, on budget and on schedule.

"The real story on this is the people who run the (XRCF) ) facility. They're the ones who did the heroic job, arranging for enough diesel fuel, liquid nitrogen, liquid helium and all the other things needed to keep us running. They did a great job of keeping everything going."

Once they are cooled to the temperature of deep space, the extraordinarily smooth mirrors have to be warmed slowly over a period of several days to avoid damage, distortion or condensation, which could leave behind deposits on the polished gold surface.

Hadaway has been part of the Webb telescope program from its beginning, when he led the optical design team that came up with the initial layout for the telescope. With a mirror that is about seven times bigger than the mirror on the Hubble Space Telescope, the Webb will collect infrared radiation (energy that our bodies sense as heat) from the most distant stars and galaxies ever viewed.

"The final optical design is basically the same as my original design," Hadaway said. "The optics weren't too difficult to design. The hard part was making lightweight mirrors that will survive launch loads and then deploy properly." The mirror development team led by Ball Aerospace included UAHuntsville, Brush Wellman of Elmore, Ohio, Axsys Technologies of Cullman and L-3 Tinsley of Richmond, Calif.,

The next step would be building and testing mirrors, starting with engineering mockups and continuing with flight hardware.

What would have been routinely challenging was complicated by the observatory's working environment. Infrared energy includes the same wavelengths created when sunlight warms a spacecraft. To avoid polluting weak infrared radiation from galaxies on the edges of the universe with heat absorbed from sunlight, the Webb telescope will be shaded from the sun. Sitting in that shade, the mirrors will operate at temperatures about 45 degrees Celsius above absolute zero.

When the mission was proposed, no one knew how telescope mirrors built on Earth at room temperatures might bend and distort at temperatures that cold. During a meeting at NASA's Marshall Space Flight Center, officials wondered where they might find someone with the special knowledge and skills needed to organize and conduct a mirror testing program under those extreme conditions.

Hadaway stuck up his hand.

"We can do that," he said. After working with NASA to develop specialized mirrors used for X-ray telescopes, Hadaway was confident the CAO team could develop the tools needed to test mirrors designed to collect energy at the other end of the electromagnetic spectrum.

A house-sized cryogenic chamber in the XRCF, a facility built for testing the Chandra X-ray Observatory's optics, was adapted for testing Webb mirrors at extremely cold temperatures.

Using techniques that they developed, "we measured to see how each mirror deforms when it 'goes cold,'" Hadaway said. "We send what we find to Tinsley Laboratories in Richmond, California, which polishes opposite distortions into the mirrors. If it was a bump when it was cold, they polish in a hole. Now it looks bad at room temperature, but it's perfect in the cold."

Perfect? The average imperfection allowed is the height of about 200 hydrogen atoms.

Testing mirrors in a massive insulated chamber requires Hadaway and his team to be flexible. "If it gets cold at 3 a.m., you go in at 3 a.m.," he said. "You go when they're cold. We try to work with the guys at Marshall so things work out in the daytime, but you just have to be there when it's time."

The mirror-testing program is scheduled to end by the end of this year, although Hadaway expects to be involved in the Webb telescope's ongoing testing, development and preparations for a possible launch in 2015. In the 15 years he has been involved in the program, Hadaway's team has received more than $5 million in NASA funding to support UAHuntsville's work.

"I was part of this program from day one," he said. "My goal is to be there when it's on orbit and certified to be operational."

 

For more information,
contact Ray Garner
256.824.6397
(256.UAH.NEWS)
ray.garner@uah.edu

Journey to the center of…the Moon!

UAHuntsville ‘Wormbot’ captures first place 

 

HUNTSVILLE, Ala. (May 10, 2011 ) — The students enrolled in Dr. Christina Carmen’s senior design class in the Mechanical and Aerospace Engineering Department at The University of Alabama in Huntsville had the option of choosing from 10 projects.

But for Bradley Boaz, Charles Boyles, Emory Eledui, Ben Gasser, Joshua Johnson, Ben Long, and Nathan Toy, it was the Lunar Wormbot that seemed to offer the best opportunity for a unique, real-world experience.


Their hunch and their hard work paid off. The team captured first place in the prestigious NASA Exploration Systems Mission Directorate (ESMD) Systems Engineering Paper Competition. UAHuntsville won the contest ahead of second place Temple University and Old Dominion, which finished third. Past winners of this competition include MIT in 2010, Virginia Tech in 2009 and Georgia Tech in 2008.

The team won $3,500 for their effort and has been invited to the last space shuttle launch, now scheduled for June 28. And, while they are down there, they will do further testing on the Wormbot at the Kennedy Space Center.

 “I wanted a senior design project that was outside the ordinary and something big,” says Eledui, “and the Lunar Wormbot proved to be just that.”

Just what is the Lunar Wormbot? Carmen describes it as a robot designed to drill into the lunar surface (or regolith) and extract samples that can be returned to Earth for study. She herself learned of the project during a fellowship at NASA’s Marshall Space Flight Center (MSFC) last summer.

“I was talking to some MSFC engineers about my senior design class, which is called product realization,” says Carmen. “They brought up the Lunar Wormbot, which was started at the National Space Science and Technology Center by Dr. Jessica Gaskin. I thought it would make a great senior design project.”

The students were also enthusiastic, but as Johnson candidly points out, “most of us are seniors and have a lot of other things going on, so we wanted to minimize our design.” They decided to concentrate on just one subsystem – the locomotion. “We focused on how it’s going to get from point A to point B,” he says.

The team wanted something that would be both effective and energy efficient. After careful research and analysis, they opted to have the Wormbot’s locomotion simulate the burrowing of – you guessed it – a worm. “That way you, can fire one segment at a time, reducing the overall power requirement,” says Gasser. “The auger, or drill, head would be moving constantly, but the rest would be inching down like a worm.”

The eventual goal, Gasser explains, “is for the Wormbot to go down 15 meters. But for our immediate goal, we’re looking to see how far down it will go and whether or not there are any corrections needed. After that, the ideal is to get the Wormbot submerged.”

Carmen points out that the team is not building the version that will actually be used on the lunar surface; rather, they’re building a ground-based Wormbot that can be used for testing here on Earth. To that end, the team will head down to Kennedy Space Center (KSC) in late June to test their design on KSC’s lunar regolith test bed.

“The KSC test bed is the closest simulation of lunar regolith on Earth – it’s made to test things like lunar rovers,” says Johnson. “Sand just doesn’t describe the properties of regolith and how abrasive and incredibly bad it is. Imagine sand is like a softball, whereas regolith would be like holding a shard of glass.”

The challenge is figuring out how to protect the Wormbot’s internal electrical and mechanical components from the erosive effects of this environment. “We’ve looked at several different types of polymers, but even those are somewhat limited as far as what’s readily available,” says Eledui. “So because of our budget constraints, we’re looking at leather. In short, it’s cheap, flexible, and resistant to abrasion.”

If that sounds like an out-of-the box idea, that’s because it is.

“Initially, we thought of protective clothing. Top-quality motorcycle clothing is leather-based,” says Gasser. “And since abrasion is one of our main considerations, leather turned out to be a very good product.”

But coming up with a design solution and actually fabricating it are two different things. The team is currently having difficulty with parts procurement, which Gasser says “isn’t going well. Most parts aren’t locally available.” Moreover, the team needs to get parts – specifically the Wormbot’s auger head – from Louisiana Tech University, whose sister team there is responsible for “the design and optimization of the auger as well as the sampling segment,” says Johnson.

Carmen said “there will be some continuation of the project after the official end of the semester to finish the Wormbot.” But whereas for most students any extension of the school year would be cause for complaint, that is hardly the case for this dedicated group of proto-engineers, all of whom recognize and appreciate this one-of-a-kind opportunity.

“There’s no way that I would have been able to get an experience like this without Dr. Carmen,” says Eledui. “It’s allowed me to see the whole idea of engineering, from the start of a concept that wasn’t fully fleshed out, though refining the design, to turning the design into actual parts you can see and that work. I didn’t just read about it or hear someone tell me about it; I got to experience it for myself.”

Like Eledui, Gasser also cites the hands-on opportunities afforded by the project as especially valuable. “A large portion of the process, most engineers would never do,” he says. “We’re actually doing the manufacturing. We’re not shipping it out.”

But for Johnson, it goes beyond the classroom – all the way to the moon. “It’s possible that some components of our design may wind up involved in the Lunar X PRIZE,” says Johnson, referring to the Google-sponsored $30-million competition to send a robot to the moon in the next few years. And the way he looks at it, there’s still plenty more to discover beyond what we already know.

“There’s a lot known about the moon from lunar orbiters, but when they sent the Apollo missions there, all the samples brought back never came from more than 3 meters below the lunar surface. And I don’t think they went more than a football field away from their lander,” he says. “So out of the entire moon, there’s a lot left to be explored. It’s like when Columbus landed in Cuba, he only saw that, not the entire landscape.”


 

For more information,

contact Ray Garner

256.824.6397

(256.UAH.NEWS)

ray.garner@uah.edu