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Model 3390

Keithley Instruments, Cleveland, OH, has introduced the Model 3390 50- MHz arbitrary waveform/function generator, a programmable signal generator with function, pulse, and arbitrary waveform capabilities. Features include 50-MHz maximum sine wave frequency, 25 MHz pulse frequency with 10-nanosecod minimum width, and 256K, 14-bit resolution arbitrary waveform generation. The built-in function generator includes capabilities such as sine, square, triangle, noise, and DC. The unit incorporates LXI Class C-compliant Ethernet, with USB and standard GPIB interfaces, as well as built-in AM, FM, PM, FSK, and PWM modulation. Pulses and square waves feature less than 10-nanosecond rise/fall times. A 10-MHz external time base is included for multiple-unit synchronization. The unit includes KiWAVE software, a waveform creation utility for creating custom arbitrary waveforms and managing waveform memory. It enables users to view waveforms in real units and perform waveform editing. For Free Info

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Garrett Reisman, Astronaut, NASA Johnson Space Center, Houston, TX

In March 2008, astronaut Garrett Reisman flew aboard the Space Shuttle Endeavour to the International Space Station, where he spent 95 days living and working in space. After performing his first spacewalk to help install the Space Station’s new robotic manipulator, called Dextre, he returned to Earth in June aboard the Space Shuttle Discovery. NASA Tech Briefs: You began your professional career at TRW as a spacecraft guidance navigation and control engineer. How did you go from there to becoming an astronaut? Did you approach NASA, or did they recruit you? Garrett Reisman: No, NASA doesn’t really do any recruiting. We have more people applying than we have spots available, so I definitely applied to them. It was something I always dreamed about doing, since I was a little kid, but I didn’t really get serious about applying or anything like that until I was almost finished with college and I realized that this was something that was within the realm of possibility. When I was in grad school at Cal Tech I put in my application, and there was a requirement for a couple of years of related work experience. So I thought, well, maybe a couple of years of being a graduate student would count for that. I sent in my application then and I didn’t get too far, but I got farther than I thought I would. I thought, NASA’s probably going to laugh at me for not having the field work requirements, but it worked out okay. The second time was when I was with TRW and that time I made it all the way through the application process, and through the interview, and I got selected. NTB: In June 2003 you participated in a two-week training exercise called NEEMO where you lived on the ocean floor 3.5 miles off the coast of Key Largo, Florida in an underwater laboratory called Aquarius. Describe for our readers what that experience was like and some of the challenges you faced. Reisman:That was amazing! That was one of the most remarkable things – probably the most remarkable thing – I got to do, up until I blasted off in the Space Shuttle. We moved down there for two weeks and we were going outside making scuba dives almost every day, and we had these giant windows in our habitat so we could see all the fish outside. It was a really healthy reef where we were, so it was remarkable how much sea life there was outside the window. It was very good preparation for spaceflight because we use the same types of tools and we do a lot of the experiments that we did down there. I ended up doing the same things up on the Space Station. The food was the same. We tried to make it as similar to flying in space as possible. I even had the same commander that I would later fly with as part of our mission, so it was great preparation and also a fantastic experience. NTB: You recently spent 95 days aboard the International Space Station, orbiting the Earth at a speed of 17,400 miles per hour. What is it like living in that environment?Reisman: It’s tremendous fun and probably, on a day-to-day basis, the most fun thing is being able to float. And you do float, but when you push off it’s more like flying. You kind of feel like a superhero. You can just jump off the floor, like Superman, and you keep going up and up and up until you hit something. It’s really a joy. Now, when I watch science-fiction movies and I see everybody walking around on spaceships, I wonder why they would deprive themselves of that joy of flying. NTB: How difficult is it adjusting to weightlessness over an extended period of time? Reisman: Over an extended period of time you get better and better at it. Initially you’re just flying about and you lose things and it can be kind of awkward. But over time you get much better at it. You get much more graceful with your motions and you get more efficient. You’re able to work more effectively and you just learn how to deal with it. Over time it actually gets better. NTB: What would you say are some of the more unique challenges faced by astronauts living aboard the Space Station, aside from broken toilets of course? Reisman: One of the things about working in zero gravity is you can’t put anything down. That’s really an issue. Just think about trying to work on your car, because when we’re doing maintenance work on the Space Station it’s kind of like working on a car. Every time you unscrew a bolt, you can’t just put it down; you have to put it into a zip lock bag, or tape it somewhere, or Velcro it to a wall. If you just let go of it, or you turn your back on it, it may be gone when you turn back around again and good luck finding it because it’s hard to find things up there. So that’s a unique challenge up there. It makes it very easy to lose stuff, and it takes a long time in the beginning until you get good at managing all the parts. NTB: As part of your mission aboard the Space Shuttle Endeavor, I understand you performed your first spacewalk. What was that like? Reisman: Well, it was the most extraordinary experience I had in the whole time I was there. At times I would describe it as a strange mix of the familiar and the outlandish. What I mean by that is, at times it felt just like training. We have this big pool here in Houston that we practice spacewalking in, and they do a great job of making it very realistic. So there were times I actually forgot that we were in space because it felt just like training. I’d be looking right in front of me at what I was doing, and it felt just like I was in the pool during one of our training exercises, and then you look over your shoulder and you see the entire east coast of the United States, and that is very different from training. So it was kind of a rollercoaster ride between things that felt normal and things that felt completely abnormal. NTB: A lot of people don’t realize that astronauts can’t simply don a spacesuit, exit the airlock, and go spacewalking. Preparations begin the night before with something called the “Campout Prebreathe Protocol” to prevent decompression sickness. Describe what that whole procedure entails.Reisman: You’re right in saying that you can’t just go right out the door because, just like in scuba diving, you have to be careful. There are certain maximum times you can spend at certain pressures, and with scuba diving if you come up to the surface too quickly, or after having stayed down for too long, you can get the bends. The same thing can happen to us. When we go outside it’s kind of like surfacing after a scuba dive, because you’re going from high pressure to low pressure, so to prepare for that you have to purge the nitrogen out of your bloodstream to make it safe. We kind of do it in stages. What we do is, we lock ourselves up in the airlock the night before and we reduce the pressure from 14.7 psi to 10.2 psi, and we stay at that overnight. As we do that, the nitrogen is slowly coming out of our blood. Then we get into our suits, and even before we put on the masks we breathe 100-percent oxygen. When we breathe 100-percent oxygen, we’re purging more and more nitrogen out of our blood. When you get in your suit, you’re breathing 100-percent oxygen in the suit, and when you finally get down to around 3 or 4 psi in the suit, you’re ready. At that point you’re not going to get the bends. NTB: One of the projects you worked on in space is a new Canadian-built robot called Dextre. Tell us about Dextre and what it’s designed to do. Reisman: Dextre is a really neat robot that is designed to do basically the same kind of things that we do during a spacewalk. It has two arms, and it has a body, and it can pivot about its waist, and it can grab a box of equipment outside of the Space Station. It can unbolt it; it can put it away; and it can take a new box to replace it and bolt that into place. Those are the kind of things it’s designed to do. It has its limitations as well, and we’re still working on exactly how we’re going to use it. I think in the future it’s going to be a very good helper. It will help make us more efficient during spacewalks and we might be able to to get the workspace set up before we get there. It can help us in that way. NTB: There were some problems assembling Dextre, namely some stuck bolts and a power feed problem that could’ve prevented the robot’s heaters from operating properly. How serious were those problems, and how did the crew overcome them? Reisman: Oh, they were very serious. First off, we had to figure out why it wasn’t getting power when we expected it to. Then we had to figure out how to work around that. The solution for the power problem was all worked out on the ground; we have some very smart people down here that figured out what to do. We just managed to use the other robot’s arm to attach to it and connect cables to it, and through that it was able to get power through the other robot. Of course, once it got power we didn’t know…it might have been dead. We didn’t know if it could’ve stayed healthy in that cold space without any power, but as it turned out it’s a true Canadian and it did just fine with the cold. When we got power to it, it worked just like it was supposed to. When you have problems like that and you find ways to work around them, and you’re ultimately successful, that’s one of the most fulfilling things that can happen to you as an astronaut. NTB: While in space you had the honor of throwing out a ceremonial first pitch for your beloved New York Yankees when they played the Boston Red Sox on April 16. On August 26 you again threw out the first pitch, this time in person at Yankee Stadium when the Bombers faced the Sox. Which pitch was the bigger thrill for you? Reisman: Well, I’ve got to say I was certainly a lot more nervous about being there, because it was easy to throw that pitch in space. I didn’t have to worry about bouncing it. It was pretty easy to throw a strike. But now, coming back down to Earth and dealing with gravity again, I was worried that my arm might not quite be in shape to throw a good strike. But being present at the stadium, in person, with all the fans, that was overwhelming. That was a dream come true for me. For more information, contact Katherine Trinidad, NASA Public Affairs at Katherine.trinidad@nasa.gov.To download this interview as a podcast,  

Posted in: Who's Who

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Converting EOS Data From HDF-EOS to netCDF

A C-language computer program accepts, as input, a set of scientific data and metadata from an Earth Observing System (EOS) satellite and converts the set from (1) the format in which it was created and delivered to (2) another format for processing and exchange of data on Earth. The first-mentioned format can be either HDF-EOS 2 or HDF-EOS 5 (“HDF” signifies “Hierarchical Data Format”). The second-mentioned format is netCDF (“CDF” signifies “Common Data Format”), which is an open-standard, machine-independent, self-describing format for scientific-data files. In the absence of this or a similar program, incompatibilities among the three file formats can cause loss of metadata upon conversion.

Posted in: Briefs, TSP, Software

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HDF-EOS 2 and HDF-EOS 5 Compatibility Library

The HDF-EOS 2 and HDF-EOS 5 Compatibility Library contains C-language functions that provide uniform access to HDF-EOS 2 and HDF-EOS 5 files through one set of application programming interface (API) calls. (“HDF-EOS 2” and “HDF-EOS 5” are defined in the immediately preceding article.) Without this library, differences between the APIs of HDF-EOS 2 and HDF-EOS 5 would necessitate writing of different programs to cover HDF-EOS 2 and HDF-EOS 5. The API associated with this library is denoted “he25.”

Posted in: Briefs, TSP, Software

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Page-Rendering Software for eBooks and Manufacturers

Rapidly evolving eBook technology promises to deliver books, catalogs, newspapers, or magazines anywhere electronically on compact, easy-to-carry readers. eBooks face challenges that physical books do not: file security during transmission, speed of transmission, and the risk of piracy. The ReadAllOver™ system is a proprietary dual solution of compressed file format and rendering software engineered for the next generation of eBooks. ReadAllOver is based on proprietary halftone algorithms, printing to the screen in much the same way as presently is done with ink and paper. The algorithms offer improved edge detail allowing the entire page, images, and typography to be processed at once. The result is a more print-like look and feel.

Posted in: Techs for License

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Anti-Reflective Coating for Films

Able to withstand abrasion even with steel wool, these antireflective coating formulations for display applications offer high durability and reflectivity that ranges from 1.2% down to 0.5%. Reducing ambient light reflectance significantly improves image clarity on LCD and PDP displays and rearprojection televisions, especially in daylight or outdoor conditions. Lenses and other optical equipment may be additional applications. This DuPont technology is a single-pass roll-toroll (microgravure) coating process. Because of its refractive index and thickness, light reflected by the underlying substrate is out of phase with light reflected from the front surface. The two phases cancel each other out, dramatically reducing reflectance and improving image clarity. All the formulations offer exceptional adhesion to the substrate, a neutral color, and exceptional durability. The single applied coating spontaneously forms two layers to improve scratch resistance, adhesion, and improved optical benefits. Get the complete report on this technology at: Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: Techs for License

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HDF-EOS Web Server

A shell script has been written as a means of automatically making HDF-EOS-formatted data sets available via the World Wide Web. (“HDF-EOS” and variants thereof are defined in the first of the two immediately preceding articles.) The shell script chains together some software tools developed by the Data Usability Group at Goddard Space Flight Center to perform the following actions:

Posted in: Briefs, TSP, Software

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