NASA Debuts 'Sentinels of the Heliosphere' Film in New Orleans
visualization of Earth with paths of orbiting satellites created with actual data › Watch "Sentinels of the Heliosphere"
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Members of Goddard's SVS Members of the "Sentinels of the Heliosphere" team, with an image from the video projected behind them. From left to right: Greg Shirah, Horace Mitchell, Tom Bridgman, Ernie Wright. Credit: NASA/Bill Hrybyk
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Greg Shirah isn’t holding his breath, but a new 7-minute visualization that he and his team created called "Sentinels of the Heliopshere" to show the dance of NASA’s heliophysics satellites could be considered for an Academy Award nomination. Greg is a visualizer at the Scientific Visualization Studio (SVS) at NASA Goddard Space Flight Center, Greenbelt, Md.

SIGGRAPH 2009, an international conference and exhibition on computer graphics and interactive techniques, will present the visualization as one of the world’s 135 most innovative and stimulating computer-generated animated films at its Computer Animation Festival in New Orleans Aug. 3-7.

The festival’s "best in show award" qualifies the winner to be considered for nomination in the Academy of Motion Picture Arts and Sciences "Best Animated Short Film" category.

Tough Competition

Though winning the best in show award would be nice, and an Oscar even better, Shirah is pragmatic. He’s pleased that Sentinels made the cut in the first place, especially considering the caliber of films submitted for inclusion in the festival. "Most of the movers and shakers in the computer-graphics industry are there," Shirah said, referring to the bevy of animators, including Hollywood types, who attend the confab each year.

Making the recognition even sweeter, at the show, Shirah will be presenting the techniques that Goddard’s SVS used to create Sentinels. The movie tours the regions of near-Earth orbit, the Earth’s magnetosphere, the expanse between Earth and the sun, and finally out beyond Pluto where Voyager 1 and 2 are exploring the boundary between the sun and the rest of the Milky Way.

In short, Sentinels shows a veritable fleet of spacecraft whose looping orbits are as different as the missions the spacecraft were designed to perform.

The Studio

This isn’t the first time SVS has presented a film at SIGGRAPH. The studio, which works closely with scientists to create products that promote a greater understanding of Earth and space science, also will present a stereoscopic version of its "Safe Landing Sites" animation at this year’s event. In addition, Helen-Nicole Kostis, another SVS staff member, plans to give a talk on stereoscopic visualization.

The Dance of a Fleet of Satellites

Referring to his own creation, Shirah concedes that "there’s a lot of data in the film," including the orbits of 25 spacecraft, eight planets, Pluto, and the moon. "What we wanted to show was how many satellites we have out there, how big the sun’s influence really is, and how NASA’s trying to study these gigantic structures."

Shirah believes the film achieves those objectives, and does this without compromising scientific accuracy. Most everything -- including the position of the background stars as Earth makes its journey around the sun and the relative size of its protective magnetic shield -- is accurate. As the camera zooms in for a close-up of Earth, viewers even can see moving clouds and the line that separates day and night as the planet rotates on its axis. "What isn’t accurate, of course, is the size of the Moon, the planets, and the spacecraft," Shirah said. "We had to scale them so that they could be seen."

Orbital Precision

Also accurate is how the team depicted the satellites’ varying orbits, including the paths of two spacecraft that make up NASA’s Solar Terrestrial Relations Observatory (STEREO). When the Agency launched the spacecraft in 2006, they initially flew in a tight, highly elliptical orbit around Earth. As the film shows, the two started pulling away from one another after performing a "bank shot" off the Moon. While one continued traveling away from the Earth-Moon system towards its final orbit, the other intercepted the Moon’s orbit a second time to execute a rollercoaster-like maneuver that then propelled it farther out into space.

As the film points out, sometimes travel isn’t the goal. To achieve a certain scientific objective, the satellite needs to "park" near one of the so-called Lagrange points -- where the gravitational pull of two objects balances one another. NASA’s Solar and Heliospheric Observatory (SOHO) is one such spacecraft. Parked in a halo orbit along Lagrange Point 1, the animation shows the observatory’s location between the sun and Earth and its unobstructed that allows it to study solar activity in unprecedented detail.

The film even shows the far-flung orbits of Voyager 1 and 2, which are now investigating a vast region at the edge of our solar system where solar wind runs up against the thin gas between stars.

Next Steps

"We’re really pleased with the results," Shirah said. "We’ve never shown the dance of heliophysics spacecraft like this before. What we hope is that people will look at this and appreciate" the sheer number of satellites patrolling the heliopshere and the amazingly complex paths they take to carry out their jobs.

But he concedes he isn’t quite finished with the project. He wants to add an animated overlay showing a coronal mass ejection, a balloon-shaped burst of solar wind that sweeps over Earth a few days after it explodes from the sun’s corona, frequently resulting in strong geomagnetic storms, auroras and electrical power blackouts. "Sentinels is a great first step," he said.

The film is now available online. NASA employees can get a peek at the movie here or by going to SVS also has developed more than 2,900 other products, which are available at the organization’s Web site,

"Sentinels" Contributors

Director and Visualization Lead: Greg Shirah
Science Advisors: Jeffrey Hayes, Jennifer Rumburg
Visualizers: Ernie Wright, Tom Bridgman, Horace Mitchell, Trent Schindler and Cindy Starr
Script and Narration: Michael Starobin
Editor: Stuart Snodgrass
IT System Support: James Williams
Audio Design and Mixing: Michael Starobin, Mike Velle
Database Management: Joycelyn Jones
Lori Keesey
NASA's Goddard Space Flight Center