Archive

Archive for March, 2011

Goddard's First Homegrown Satellite, Explorer 10, Was Launched 50 Years Ago Today: We Talk to the Father of Explorer 10, James Heppner, About the 'Opportunity Years' at the Dawn of NASA


photo of Earl Angulo (at left) and Ron Browning examining an Explorer-10 model attached to a test fixture
This photo from the early 1960s shows Goddard employees Earl Angulo (at left) and Ron Browning examining an Explorer 10 model attached to a test fixture. They were responsible for the mechanical engineering and testing of the satellite.


Fifty years ago today, Goddard’s first homegrown scientific satellite roared off the pad at Cape Canaveral on a Thor-Delta rocket. Although key components came from outside the gates, Explorer 10 was the first satellite to be designed, assembled, tested, and flown from Goddard Space Flight Center.

James Heppner, a young space physicist (barely 30 then) and one of NASA’s early employees, conceived of the mission that came to be called Explorer 10. Heppner functioned as a sort of one-man band — Project Manager, Project Scientist, and Principal Investigator for the magnetometer instruments on the satellite.

Before NASA was founded, Heppner worked for the Naval Research Laboratory (NRL) on the Potomac River in Washington, D.C. It was there he developed methods to measure Earth’s magnetic field. At NRL he used sounding rockets to study charged particles and magnetic fields high in Earth’s atmosphere. His earlier research in Alaska focused on the aurora and its effects on radio wave propagation, and was the basis for his Caltech PhD thesis.

Heppner calls these times the “opportunity years,” a period when methods and technology for measuring magnetic fields and space plasma — the bread and butter of space physics — were being invented. He was at the right place at precisely the right time.

In late 1958, as Heppner and many of his colleagues were being “handed over” to the nation’s new aerospace agency, he had already helped create a magnetometer for the Vanguard program. Vanguard, an NRL project, was created to loft the first civilian scientific payloads into space for the International Geophysical year of 1957-58. Heppner’s proton magnetometer went into space aboard Vanguard 3 on September 18, 1959.

NASA satellite P-14 was renamed Explorer 10

NASA satellite P-14 was renamed Explorer 10

At the time of the transition to NASA, Heppner today recalls, he conceived of a satellite to measure the magnetic field of the moon. The mission, then called P-14, would accomplish its goal by extreme measures:

“I originally proposed Explorer 10 when NASA was formed,” explains Heppner, 83, who spoke with me recently from his home in New Market, Maryland. “And the intent was to try to hit the moon and measure the moon’s magnetic field on the way in.”

The original plan was deferred. The truth is, hitting the moon — even intentionally — was no simple trick in those days. It wasn’t clear the Thor-Delta launch system would accomplish the task, and even tracking a spacecraft to the moon was straining the technical capabilities of the time.

“With time we realized that the odds of hitting the moon would be extremely low, from the vehicle performance and ability to track, things like that,” Heppner explains. “I was told that with the odds of hitting the moon being so low, it would be embarrassing to even try. So I was essentially directed by NASA headquarters to make sure that the trajectory was such that it couldn’t be interpreted as an attempt to hit the moon.”

The new mission goal was to measure magnetism and plasma particles in space from outside of Earth’s protective magnetic bubble, or magnetosphere. This had been attempted previously, but not with great success. To do it required launching P-14/Explorer 10 into a highly elliptical orbit that would take it a great distance from Earth, dozens of time the planet’s radius.

The satellite weighed approximately the same as a space physicist: 79 kilograms, or 178 pounds. “It was very light,” Heppner says. “We were trying to get distance.” An engineering model hangs in the Smithsonian if you care to look at the real thing..

For the records, here is the complete entry in the NASA/National Space Science Data Center mission database:

“Explorer 10 was a cylindrical, battery-powered spacecraft instrumented with two fluxgate magnetometers and one rubidium vapor magnetometer extending from the main spacecraft body, and a Faraday cup plasma probe. The mission objective was to investigate the magnetic fields and plasma as the spacecraft passed through the earth’s magnetosphere and into cislunar space. The satellite was launched into a highly elliptical orbit. It was spin stabilized with a spin period of 0.548 s. The direction of its spin vector was 71 deg right ascension and minus 15 deg declination. Because of the limited lifetime of the spacecraft batteries, the only useful data were transmitted in real time for 52 h on the ascending portion of the first orbit. The distance from the earth when the last bit of useful information was transmitted was 42.3 earth radii, and the local time at this point was 2200 h. All transmission ceased several hours later. “


On March 25, 1961, a rocket similar to this one launched Explorer 10 into space. This historic Delta rocket stands in the Goddard Visitor Center's "rocket garden." (Image: Wikipedia RadioFan)

On March 25, 1961, a rocket similar to this one launched Explorer 10 into space. This historic Delta rocket stands in the Goddard Visitor Center's "rocket garden." (Image: RadioFan)

Rubidium vapor magnetometers could measure extremely weak magnetic fields, and were a totally new technology, Heppner says. They were invented at a company called Varian Associates in Palo Alto, California. The Faraday cup plasma instrument, which measured particles streaming off the sun’s “solar wind,” came courtesy of a team of scientists at MIT led by the pioneering X-ray astronomer and plasma physicist Bruno Rossi.

Finally the big day came on March 25, 1961. The launch managers for the Thor-Delta rocket worked in “the block house” at the Cape, while Heppner and his colleagues were encamped in a machine shop, peering at oscilloscopes to assess the health of their satellite and staying in contact with the blockhouse, and the other scientists and engineers, by telephone.

Explorer 10, as was typical in those days, was powered by a expendable battery. The craft radioed back data for 52 hours as it swooped through and outside of the magnetosphere, travelling for 42.3 Earth radii — about 167,466 miles — before the battery dimmed and the craft shut down. (For comparison, consider that the average distance form Earth to the moon is 238,857 miles.)

After launch, tracking stations record data on tapes and send them to the scientists. Heppner published a number of scientific papers from the data. He headed the Goddard Magnetic Fields Group, and worked on many major missions over the succeeding years.

The next big missions for Heppner after Explorer 10 were the Orbiting Geophysical Observatories, which grew substantially in mass and capability. He retired from the civil service in 1989, but continued to work as a contractor until 1996.

How were those days different from the later, larger, more complex place NASA has become? What was it like in the opportunity years?

“It was a very busy period in the sense that the technology was developing,” Heppner explains. “The early satellites weren’t very sophisticated because everything was new.”

But things moved fast. Heppner summed it up best in a chapter he wrote for a 1997 book, Discovery of the Magnetosphere.

“Opportunities for new endeavors were plentiful and the time between conception and results was unbelievably short when viewed in the light of today’s space programs.”

_____________________________________________________________________________________________________
OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.

//
</p> <div><a href=”http://www.w3counter.com” mce_href=”http://www.w3counter.com”><img src=”http://www.w3counter.com/tracker.php?id=39986″ mce_src=”http://www.w3counter.com/tracker.php?id=39986″ style=”border: 0″ mce_style=”border: 0″ alt=”W3Counter” /></a></div> <p>

Magnetic Loops A'Crackling on the Sun


image of magnetic loops on sun

The latest amazing close-up shot of solar activity is available courtesy of Steele Hill and NASA’s Solar Dynamics Observatory. Steele is a Goddard media specialist who sends out packages of sun images and videos that get displayed in hundreds of museums and science centers. In Steele’s own words. . .

“When a substantial active region rotated into view, it was a hot-bed of dynamic motion and loops (Mar. 21-22, 2011). As observed by Solar Dynamics Observatory (SDO) in extreme ultraviolet light, the region’s powerful magnetic forces tangled, broke apart and reconnected with a vengeance, even popping off a few flares. Very tight close-ups such as this one had not been possible until the SDO began operations just a year ago.”



Here is an extreme close-up view of the active region and its loopy magnetic fields:





. . . and a larger view of the magnetic loopiness and the sun’s boiling surface.



_____________________________________________________________________________________________________
OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.

w3counter(39986);

W3Counter

That Was the Week that Was, March 14-18, 2011. . . Best of Goddard People, Science, & Media and the blogpodcastotwittersphere


Tsunami Damage, Rikuzentakata, Japan

Tsunami Damage, Rikuzentakata, Japan


Japan Earthquake
After the March 12 earthquake and tsunami in Japan, it’s as if the world collectively gasped — and then what followed was almost a feeling of disbelief as the harsh facts begin to register. Entire seaside communities erased from existence. . . tens of thousands of lives feared lost. . . giant ocean swells flooding the coastline. . . cars and houses looking like toys bobbing in the water. And then there are the satellite images, which provide a critical wide-angle perspective.

NASA’s Earth-observing fleet has helped to reveal the full scope and power of the catastrophe. As Mark Imhoff, the Terra satellite project scientist at Goddard, said in a report by West Virginia Public Broadcasting:

“It’s been heart wrenching seeing some of these images because the first set images that we got in on the day after the earthquake on March 12, even though the resolution from of the satellite wasn’t very good, the data from the Miser instrument at Jet Propulsion’s Laboratory showed that there were a large area of coastline that really weren’t there anymore and so you could really get an impression that a lot of villages and agricultural areas had really been severely impacted by the ocean.”


NASA released a web feature on March 17, five days after the quake, showing tsunami after-effects documented by Landsat 7.

NASA Earth Observatory has compiled a gallery of earthquake-related images from various NASA spacecraft, including EO-1, Terra, Aqua, and astronaut photos from the International Space Station.

As usual, EO’s in-depth captions provide context and explanations for the various destructive effects of the earthquake on coastal Japan. An even larger selection of imagery is available in this NASA web feature about the disaster.


lola_trio_600

New LRO Data
On March 15, the Lunar Reconnaissance Orbiter mission released the final set of data from the mission’s exploration phase, along with the first measurements from its new life as a science satellite. The press release explains the details. The slideshow below takes a look back at some of the coolest imagery from the mission so far. All the images in the slideshow, and many more, are archived here on the NASA LRO website, which includes detailed captions.




Messenger Makes It
The third major story out of Goddard this week was the arrival in Mercury orbit of the Messenger spacecraft. After three spectacular fly-bys earlier (see slideshow below), Messenger is now in position to really dig into its science mission to reveal the nature and history of the first rock from the sun. An earlier post discusses some of the research being conducted on Mercury’s thin “exosphere” of atoms and ions wispily clinging within the planet’s gravity.


_____________________________________________________________________________________________________
OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.


//
</p> <div><a href=”http://www.w3counter.com” mce_href=”http://www.w3counter.com”><img src=”http://www.w3counter.com/tracker.php?id=39986″ mce_src=”http://www.w3counter.com/tracker.php?id=39986″ style=”border: 0″ mce_style=”border: 0″ alt=”W3Counter” /></a></div> <p>

How sweet it is! The first spacecraft goes into orbit around Mercury

March 18, 2011 3 comments


A visualization of the sodium "exosphere" around Mercury courtesy of Matthew Burger at NASA's Goddard Space Flight Center.

A visualization of the sodium "exosphere" around Mercury courtesy of Matthew Burger at NASA's Goddard Space Flight Center.



In the space exploration racket, there is no sweeter word than “first.” And so it was last night that a NASA spacecraft made an important First in planetary exploration:

“NASA’s MESSENGER spacecraft successfully achieved orbit around Mercury at approximately 9 p.m. EDT Thursday. This marks the first time a spacecraft has accomplished this engineering and scientific milestone at our solar system’s innermost planet.”


We flung the Mariner 10 spacecraft past Mercury in fly-by missions in 1974-75. And Messenger itself did three fly-bys as it got into position for the final “orbital insertion.” Now it is the first space probe to park in orbit around the first rock from the sun.





Rosemary Killen, a researcher at Goddard, is one of the many scientists who will reap rewards from this so-far spectacularly successful mission. Her target is the thin “exosphere” of sodium, potassium, and calcium knocked off Mercury’s barren rocky surface by the “solar wind” streaming from the sun.

If you want all the scientific details, read a short explanation below by Rosemary Killen about her work And also read about some of the instruments that Goddard scientists and engineers helped to put on the spacecraft.

Otherwise, enjoy the slide show of Messenger images, 2004-2011, and an informative video by Tom Watters (below), a geologist in the Center for Earth and Planetary Studies at the Smithsonian Institution. He explains the goals of Messenger.





Rosemary Killen:

“I am a Participating Scientist on the MESSENGER mission and a member of the MASCS (Mercury Atmospheric and Surface Composition Spectrometer) team. MASCS is a spectrometer covering ultraviolet, visible, and near-infrared wavelengths. The MASCS ultraviolet and visible channel is designed primarily to observe the exosphere, or the very tenuous atmosphere about Mercury, by scanning over selected, diagnostic wavelength ranges.

“Our goals are to determine the composition of the exosphere (which is only partially known at present), and, over the mission lifetime, to determine its spatial and temporal variability. We do this by observing emission lines from atoms (and a few ions) in the exosphere above Mercury’s surface. In so doing we hope to determine the processes that eject atoms from the surface into the exosphere and that lead to the loss of material from the Mercury system.

“Important factors include the relationships among the exosphere and the solar ultraviolet flux, the solar wind and interplanetary magnetic field, and the planet’s intrinsic magnetic field. We hope to be able to determine the effects (if any) of meteor streams that may intersect Mercury’s orbit.

“One intriguing question is the nature of the deposits seen by Earth-based radar (specifically that at the Arecibo Observatory) in polar craters on Mercury, and what that tells us about the sequestration of volatiles. The visible and near-infrared channel of MASCS is primarily designed to measure the reflectance spectrum of the surface in order to determine the mineralogy of surface materials. Ultimately the goal is to unravel the history of the planet: its origin and evolution to the state it occupies today.”

_____________________________________________________________________________________________________
OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.


//
</p> <div><a href=”http://www.w3counter.com” mce_href=”http://www.w3counter.com”><img src=”http://www.w3counter.com/tracker.php?id=39986″ mce_src=”http://www.w3counter.com/tracker.php?id=39986″ style=”border: 0″ mce_style=”border: 0″ alt=”W3Counter” /></a></div> <p>

That Was the Week that Was, March 7-11, 2011. . . Coolest Goddard People, Science, & Media PLUS Best of the Blogpodcastotwittersphere

March 11, 2011 2 comments


photo of isim on goddard centrifuge

A big chunk of the Webb Telescope goes out for a spin: This week a web feature story came out about ongoing testing of the metal cage that will hold the various scientific instrument on the Webb Telescope – the heir to the Hubble Space Telescope now under construction here at Goddard and elsewhere in NASA.

Webb will undergo significant shaking when it is launched on the large Ariane V rocket. To be sure the telescope’s “chassis” is ready for this “bumpy road,” the ISIM is subjected to some extreme testing.  During the testing process, the ISIM is spun and shaken while many measurements are taken. Afterwards, engineers compare the measurements with their models of the ISIM. If there are discrepancies, then the engineers track down why, and make corrections.


That centrifuge is a pretty impressive piece of hardware, let me tell you. Months ago, I got a chance to film a preliminary spin-up test of the giant centrifuge. This thing, at full throttle, can spin about once every two seconds. The test I saw was a lot tamer than that, spinning at roughly 2 rpm. Check it out:




The centrifuge room is pretty noisy, and the equipment is massive — on the order of a half-million pounds. And so it starts out slow. But gradually it picks up speed. At very high speed, it’s way too dangerous to be in the room. (The engineers work in a separate control room during actual tests.) If even a small bit of hardware were to fly off the centrifuge, it could cause a serious injury. My friend Jay Friedlander (the cameraman) and I were very grateful to the engineers for letting us witness an actual spin-up of the centrifuge — an uncommon site at Goddard.

Here comes the sun on the Goddard Flickr channel: The Goddard Flickr channel was all aglow this week with images of the sun, courtesy of NASA’s solar observing fleet. A web feature by one of Goddard’s newest solar scribes, Karen Fox, announced the 400-year anniversary of the first scientific publication about sunspots. Goddard’s Flickr photomistress, Rebecca Roth, obliged with an entire set of spectacular sun imagery. Here is my favorite, a super-high-resolution image of a sunspot by the Hinode spacecraft. Go to the Flickr set to see the rest.

hinode spacecraft image of sunspot

_____________________________________________________________________________________________________
OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.

w3counter(39986);

W3Counter

"Space Math" project at Goddard hits 3 million downloads!

screen shot of space math home page

Astronomer Sten Odenwald has a LOT of problems — math problems.

This month he deserves three cheers for his education project, “Space Math,” one of the most successful educational efforts based at Goddard Space Flight Center. Space Math@NASA provides a steady stream of space- and astronomy-related math problems to middle and high school instructors and students. And in late February, some anonymous student or teacher out there clicked a mouse and received the 3 millionth PDF download from the site.

Screen shot 2011-03-08 at 2.56.13 PM

Space mathematician Sten Odenwald

Odenwald founded the program in 2004, and it has grown steadily in scope and audience. At the time, he had been doing education and public outreach for the IMAGE spacecraft project, centered mostly on scientific findings

“That led me to get a better sense of students’ needs and teacher interests. I had a real sense there was a need for more quantitative content — math-oriented content for the upper grade students and teachers.”

That led to the Space Math website and issuing a weekly math problem every Friday, “which then rapidly spiraled out of control,” Odenwald says.

To keep things fresh and interesting, Odenwald often ties the math problems he creates — sometimes approaching 20 new problems per month — to current events and recent scientific discoveries. This provided a “second inroad” to the schools, via mathematics education, in addition to all the content NASA pipes into science classrooms.

For example, recently the twin STEREO spacecraft reached positions 180 degrees apart with respect to the sun. This allowed the pair to simultaneously observe both solar hemispheres. Odenwald issued this problem, the 404th he has written:

“Problem 404: STEREO Spacecraft Give 360 Degree Solar View Students use two images from the STEREO satellites to explore the geometry of the satellite orbits and their change in time. They also identify from the pair of images which features can be seen from Earth, and which cannot.”

The Space Math site is a gold mine of problems that run students through their mathematical paces on questions of unit conversion and other basic skills. The problems are all issued as PDFs, allowing Odenwald to crank out a steady stream of material without overhead costs for printing.

The site sees 15,000 to 18,000 visitors per month, and continues to grow at 5 percent a month. But after 6 years and more than 404 problems issued, Odenwald’s enthusiasm for Space Math is undiminished.

Odenwald has also written a PDF book of 240 problems for Algebra II students, and has additional problem collections in the works for pre-algebra, Algebra I, calculus, the NASA Astrobiology Institute, remote sensing in Earth science, and a book for the 2012 transit of Venus on June 6 (when Venus will cross in front of the sun).

Whew! Sten Odenwald sure has a lot of problems!

Fortunately for him, Odenwald has the kind of problems that math teachers and their students want. Although he began as an infrared astronomer with a Harvard PhD, Odenwald’s slide into mathematics education is in keeping with a solid track record for public education. He has written many articles for the public about astronomy, and is an active participant in the ongoing Sun-Earth Day team at Goddard. It is a somewhat unconventional career path for an astronomer, but ultimately a happy one, Odenwald explains.

“Here I am, doing it full time, getting paid for it, and having the real time of my life doing things that I know a lot of formal educators are really appreciating. It’s very satisfying.”

_____________________________________________________________________________________________________
OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.


//
</p> <div><a href=”http://www.w3counter.com” mce_href=”http://www.w3counter.com”><img src=”http://w3counter.com/tracker.php?id=39986″ mce_src=”http://w3counter.com/tracker.php?id=39986″ style=”border: 0″ mce_style=”border: 0″ alt=”W3Counter” /></a></div> <p>

What does a Shuttle launch really look from the public viewing area?

March 3, 2011 3 comments






My friend Jarrett Cohen, a science writer at Goddard, was one of the lucky NASA employees to receive a chance to see the final liftoff of space shuttle Discovery on Thursday, February 24. While he was there, he shot this footage. After seeing so many videos of past launches using telephoto lenses, it was sort of interesting to see what it REALLY looks like. And even from a distance, it’s still a glorious sight.

And to compliment the glory, here is the launch set to a performance by the U.S. Air Force Band of “Mars, Bringer of War,” from Gustav Holst’s The Planets. Enjoy.

Here is Jarrett recalling the launch:

I have wanted to attend a space shuttle launch for some time. With STS-133 being the last launch of Discovery–a shuttle with such a great history–I put in for a car pass despite the tough odds of getting one. Out of several hundred Goddard employees who applied, I was fortunate to be randomly chosen for one of fewer than 60 passes available.

Many of us flew down to Florida for what turned out to be three unsuccessful launch attempts in early November. Although the timing was challenging, I decided to return for the February 24 launch attempt. A group of us who know each other from the NASA Center for Climate Simulation (NCCS), along with family and friends, drove together in two vans and arrived about 4 hours before launch time.

It was beautiful weather for a launch, and we had a clear view of the launch pad from the Kennedy Space Center Causeway seven miles way. A computer problem with the range safety system almost led to another postponement. Cheers went up when we heard the announcer say that launch was a go, and Discovery made the launch window with a few seconds to spare. As captured on my digital camera (using no zoom), the shuttle slowly emerges from a cloud of smoke and accelerates through the sky to reach several thousand miles per hour within seconds. It was a remarkable combination of speed and grace.

_____________________________________________________________________________________________________
OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.


//
</p> <div><a href=”http://www.w3counter.com” mce_href=”http://www.w3counter.com”><img src=”http://w3counter.com/tracker.php?id=39986″ mce_src=”http://w3counter.com/tracker.php?id=39986″ style=”border: 0″ mce_style=”border: 0″ alt=”W3Counter” /></a></div> <p>

Categories: space shuttle Tags:

What exploded on the sun last Thursday morning?

March 2, 2011 10 comments



feb24_prom+earth

The eruption that occurred on the sun last week, February 24, was many times larger than Earth in scale and represented a tremendous release of energy. But what exactly happened? Here is a wide view of the event:





This type of event is called a prominence eruption. It occurs in the extended, hot outer atmosphere of the sun, called the corona. The material that appears to glow red is plasma, a mix of electrically charged hydrogen and helium.


OK, now let’s take a closer look. Here is a close-up view of the prominence:




The plasma is flowing along a tangled and twisted structure of magnetic fields generated by the sun’s internal dynamo. Prominences occur when such a structure becomes unstable and bursts outward, releasing plasma.

At Goddard, Holly Gilbert is one of the physicists trying to understand what triggers such explosive events. We have a pretty good idea of what prominence eruptions are, but less of a clear idea of what causes them.

“Here you have a magnetic structure that holds prominence plasma and somehow become unstable and erupts,” Gilbert says, “and by doing so you get this beautiful structure not only flying outward and escaping the gravitational field, but only also draining back because the magnetic topology allows it to do so. What we’re not sure of is what is initiating the eruption.”

In the video, the event appears to stop and start playing backward. But this is not so. Actually, plasma is falling back toward the sun and flowing along the complex surfaces formed by magnetism around the sun.

“It is not uncommon for prominence material to drain back to the surface as well as escape during an eruption,” Gilbert says. “In fact, it’s a little strange when ALL of the mass escapes. Prominences are large structures, so once the magnetic fields supporting the mass are stretched out so that they are more vertical, it allows an easy path for some of the mass to drain back down.”

This particular eruption was not directed toward Earth. If it were, the material released and its imprinted magnetic field might have triggered a geomagnetic storm, with bright auroras and the potential for disturbance in communications and electrical power networks. Scientists at NASA study such “space weather” events intensely in hopes of predicting them better someday.

_____________________________________________________________________________________________________
OH AND DID I MENTION? All opinions and opinionlike objects in this blog are mine alone and NOT those of NASA or Goddard Space Flight Center. And while we’re at it, links to websites posted on this blog do not imply endorsement of those websites by NASA.


//
</p> <div><a href=”http://www.w3counter.com” mce_href=”http://www.w3counter.com”><img src=”http://w3counter.com/tracker.php?id=39986″ mce_src=”http://w3counter.com/tracker.php?id=39986″ style=”border: 0″ mce_style=”border: 0″ alt=”W3Counter” /></a></div> <p>