Stockton Astronomical Society

Valley Skies - March 2006 Issue

Editor's Corner...

Last year it was a limited success. I mean, what's the point of a star party under total overcast?

Who needs a "point" anyway? More than 200 people turned out in spite of the threatening weather on April 30.

Remember, we cancelled the original plan for March 19, 2005 because of a wet forecast, and rescheduled for April 30.

I'm talking, of course, about the community star party at Micke Grove. The first one on April 24, 2004 was a great success. April 30, 2005 was cloudy, but we entertained the folks anyway. And we're going to do it again.

Beginning or end of April, we have to chance the weather. April 1st is five weeks ahead of the official Astronomy Day (May 6). But for a community star party, there are problems with a May 6 event: the bright, familiar winter constellations will be just a dim memory, and Saturn won't rise till well after everyone goes home. And with the sun setting at 8 p.m., it would be a late night out for families with young children.

On April 1st, the last day of standard time, the sun will set about 6:30 p.m. We'll still have Saturn high in the sky, along with the Winter Six, the Orion Nebula, the Pleiades, the Double Cluster, etc. etc. The winter sky is a tough act to beat for a public show. Spring skies pale-literally- by comparison.

April 1, 2006, 7:00 -- 9:30 p.m.

Micke Grove Community Star Party

We'll need the full support and attendance of as many SAS members as possible. At least twenty volunteers with telescopes will be needed to keep viewing lines to a reasonable length. Thirty would be even better!

We also need members without telescopes to staff information tables, to point out constellations, to direct people to various activities, to answer questions, and generally provide a strong SAS presence.

In other words, WE NEED YOU, if you can possibly be there.

This is an opportunity for those members who don't ordinarily participate in star parties to help with the club's public outreach. Try it! You'll be glad you did. You can be part of sharing the wonders of the night sky with hundreds of eager visitors.

We're counting on you...No Foolin'...Please be there.

And keep your fingers crossed for clear skies on April 1.

...Trevor Atkinson

Desert Sunset Star Party

The 4th annual Desert Sunset Star Party will be held April 26-30, 2006. Please check details at our website http://www.chartmarker.com/sunset.htm

Registration is now open. Caballo Loco RV Ranch gives us a special camping rate for this group event. There is no star party fee this year but we will sell door prize tickets. The residents of Caballo Loco will also be serving breakfast ($3) and dinner ($5) on Saturday. We are located between Kitt Peak Observatory and Whipple Observatory, both excellent day trips.

Pat and Arleen Heimann
Chart Markers and More

In 2005, SAS members Monty and Deborah Shindler attended the Desert Sunset Star Party (near Tucson, AZ) and had a "wonderful time." The photo at right shows Monty at the EOS Technologies facility, one of the daytime tours offered as part of the five-day annual event.

Call the Shindlers [see newsletter for phone number] if you'd like more feedback from members who have made the trip.

The Science Directorate at NASA's Marshall Space Flight Center sponsors the Science@NASA web sites. The mission of Science@NASA is to help the public understand how exciting NASA research is and to help NASA scientists fulfill their outreach responsibilities.

Radiation Resistant Computers

Researchers are developing advanced computers that can think clearly even when they're bombarded by space radiation.

November 18, 2005:  When your computer behaves erratically, mauls your data, or just "crashes" completely, it can be frustrating. But for an astronaut trusting a computer to run navigation and life-support systems, computer glitches could be fatal.

Unfortunately, the radiation that pervades space can trigger such glitches. When high-speed particles, such as cosmic rays, collide with the microscopic circuitry of computer chips, they can cause chips to make errors. If those errors send the spacecraft flying off in the wrong direction or disrupt the life-support system, it could be bad news.

The humans inside this spacecraft aren't the only ones who need protection from space radiation; their computers do, too.

To ensure safety, most space missions use radiation hardened computer chips. "Rad-hard" chips are unlike ordinary chips in many ways. For example, they contain extra transistors that take more energy to switch on and off. Cosmic rays can't trigger them so easily. Rad-hard chips continue to do accurate calculations when ordinary chips might "glitch."

NASA relies almost exclusively on these extra-durable chips to make computers space-worthy. But these custom-made chips have some downsides: They're expensive, power hungry, and slow -- as much as 10 times slower than an equivalent CPU in a modern consumer desktop PC.

With NASA sending people back to the moon and on to Mars, mission planners would love to give their spacecraft more computing horsepower.

Having more computing power onboard would help spacecraft conserve one of their most limited resources: bandwidth. The bandwidth available for beaming data back to Earth is often a bottleneck, with transmission speeds even slower than old dial-up modems. If the reams of raw data gathered by the spacecraft's sensors could be "crunched" onboard, scientists could beam back just the results, which would take much less bandwidth.

On the surface of the moon or Mars, explorers could use fast computers to analyze their data right after collecting it, quickly identifying areas of high scientific interest and perhaps gathering more data before a fleeting opportunity passes. Rovers would benefit, too, from the extra intelligence of modern CPUs.

Using the same inexpensive, powerful Pentium and PowerPC chips found in consumer PCs would help tremendously, but to do so, the problem of radiation-induced errors must be solved.

This is where a NASA project called Environmentally Adaptive Fault-Tolerant Computing (EAFTC) comes in. Researchers working on the project are experimenting with ways to use consumer CPUs in space missions. They're particularly interested in "single event upsets," the most common kind of glitches caused by single particles of radiation barreling into chips.

Space radiation hits a computer chip, an artist's concept. Credit: ESA.

Team member Raphael Some of JPL explains: "One way to use faster, consumer CPUs in space is simply to have three times as many CPUs as you need: The three CPUs perform the same calculation and vote on the result. If one of the CPUs makes a radiation-induced error, the other two will still agree, thus winning the vote and giving the correct result."

This works, but often it's overkill, wasting precious electricity and computing power to triple-check calculations that aren't critical.

"To do this smarter and more efficiently, we're developing software that weighs the importance of a calculation," continues Some. "If it's very important, like navigation, all three CPUs must vote. If it's less important, like measuring the chemical makeup of a rock, only one or two CPUs might be involved."

This is just one of dozens of error-correction techniques that EAFTC pulls together into a single package. The result is much better efficiency: Without the EAFTC software, a computer based on consumer CPUs needs 100-200% redundancy to protect against radiation-caused errors. (100% redundancy means 2 CPUs; 200% means 3 CPUs.) With EAFTC, only 15-20% redundancy is needed for the same degree of protection. All of that saved CPU time can be used productively instead.

EAFTC computers in a space-ready flight chassis. Credit: NASA/Honeywell.

"EAFTC is not going to replace rad-hard CPUs," cautions Some. "Some tasks, such as life support, are so important we'll always want radiation hardened chips to run them." But, in due course, EAFTC algorithms might take some of the data-processing load off those chips, making vastly greater computer power available to future missions.

EAFTC's first test will be onboard a satellite called Space Technology 8 (ST-8). Part of NASA's New Millennium Program, ST-8 will flight-test new, experimental space technologies such as EAFTC, making it possible to use them in future missions with greater confidence.

The satellite, scheduled for a 2009 launch, will skim the Van Allen radiation belts during each of its elliptical orbits, testing EAFTC in this high-radiation environment similar to deep space.

If all goes well, space probes venturing across the solar system may soon be using the exact same chips found in your desktop PC - just without the glitches.

Micro-sats with Macro-potential

By Patrick L. Barry

Future space telescopes might not consist of a single satellite such as Hubble, but a constellation of dozens or even hundreds of small satellites, or "micro-sats," operating in unison.

Such a swarm of little satellites could act as one enormous telescope with a mirror as large as the entire constellation, just as arrays of Earth-bound radio telescopes do. It could also last for a long time, because damage to one micro-sat wouldn't ruin the whole space telescope; the rest of the swarm could continue as if nothing had happened.

And that's just one example of the cool things that micro-sats could do. Plus, micro-sats are simply smaller and lighter than normal satellites, so they're much cheaper to launch into space.

The Space Technology 5 mission will test crucial micro-satellite technologies.

In February, NASA plans to launch its first experimental micro-sat mission, called Space Technology 5. As part of the New Millennium Program, ST5 will test out the crucial technologies needed for micro-sats-such as miniature thrust and guidance systems-so that future missions can use those technologies dependably.

Measuring only 53 centimeters (20 inches) across and weighing a mere 25 kilograms (55 pounds), each of the three micro-sats for ST5 resembles a small television in size and weight. Normal satellites can be as large and heavy as a school bus.

"ST5 will also gather scientific data, helping scientists explore Earth's magnetic field and space weather," says James Slavin, Project Scientist for ST5.

Slavin suggests some other potential uses for micro-sats:

A cluster of micro-sats between the Earth and the Sun-spread out in space like little sensor buoys floating in the ocean-could sample incoming waves of high-speed particles from an erupting solar flare, thus giving scientists hours of warning of the threat posed to city power grids and communications satellites.

Or perhaps a string of micro-sats, flying single file in low-Earth orbit, could take a series of snapshots of violent thunderstorms as each micro-sat in the "train" passes over the storm. This technology would combine the continuous large-scale storm monitoring of geosynchronous weather satellites-which orbit far from the Earth at about 36,000 kilometers' altitude-with the up-close, highly detailed view of satellites only 400 kilometers overhead.

If ST5 is successful, these little satellites could end up playing a big role in future exploration.

The ST5 Web site at nmp.jpl.nasa.gov/st5 has the details. Kids can have fun with ST5 at spaceplace.nasa.gov, by just typing ST5 in the site's Find It field.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

AstroWord

OK, this is plagiarism at its worst. There's a great game in the newspaper called Wonderword, and I've made one where the topic is astronomy. Enjoy! - Jeff and Glenda Baldwin.

HOW TO PLAY:  All the words listed below appear in the puzzle, horizontally, vertically, diagonally, even backward. Find them and CIRCLE THEIR LETTERS ONLY -- DO NOT CIRCLE THE WORD. The left over letters will spell the AstroWord, which has 11 letters.

K R A U Q P R S R A R D Y H E

N R U T A S A R S O P L A T A

B A R L O W T A E H L O A R V

S L E W K N S M R T V O N A O

T A A O C O E Y E P I E C E N

A R G C E O L R C F A T G P O

R Y A W K M B S O I L E A A I

P L U T O H U B B L E M L N T

A S T R O N O M Y T R O U I C

R O R I O N D L H E A C B E N

T N A I G D E R E R L U E T U

Y G O L O M S O C E F R N S J

S D I O R E T S A N U S Y N N

S T C A R F E R E L G A N I O

I N O T W E N O R T S E L E C

AANC, ALPO, Asteroids, Astronomy, Barlow, Black Hole, Celestron, Ceres, Color, Comet, Conjunction, Cosmology, Double Star, Earth, Einstein, Eyepiece, Filter, Flare, Hubble, Hydra, ISS, Keck, Lyra, Mars, Moon, Nagler, Nebula, Newton, Novae, Nuclear, Orion, Pluto, Quark, Red Giant, Refract, Saturn, Slew, Soil, Star Party, Sun, Ursa, Vega, Yaw.

Copyright © 2006 by Stockton Astronomical Society
Last Updated: 3/1/2006
http://astro.sci.uop.edu/~sas/Newsletter/VS0603.html