Date: March 28, 2011
Title: Space Junk
Podcaster: Kate Becker
Links: SpaceCraft science writing: www.spacecrafty.com
Inside NOVA: http://www.pbs.org/wgbh/nova/insidenova/author/kathryn-becker/
The Daily Camera: www.dailycamera.com
Social media: http://www.facebook.com/katembecker, www.twitter.com/kmbecker
Description: With so much orbital debris circling the Earth, we just might become trapped by our own space trash.
Bio: Kate Becker is a story researcher for NOVA, the public television science documentary series, and an astronomy columnist for the Daily Camera in Boulder, Colorado. Kate studied physics at Oberlin College and astronomy at Cornell University, and she’s had the good fortune to observe with the Arecibo Observatory in Puerto Rico and the Very Large Array in New Mexico—two of the very best places on this pale blue dot of a planet, if you ask her. Kate lives in Brookline, Massachusetts.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2011, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at signup@365daysofastronomy.org.
Transcript:
You know that television show about hoarders—people who collect so much junk that they have to buy extra houses to keep it in? People who end up literally trapped by their own trash?
I confess, I’ve never actually watched the show. The 30-second commercials are enough to make me want donate the bulk of my possessions to Good Will.
Okay, so maybe the yoga mats and ball jars taking up space in my office don’t qualify me to be the subject of a 60-minute special on A&E. But we the people of planet Earth have a hoarding problem of our own: we are hoarders of space junk. And just like those unfortunate souls on the show, we are running the risk of becoming trapped by our own junk.
You might think that space is so big that we couldn’t fill it up with excess stuff. Yet because most of the stuff we send into space occupies a relatively small region less than 2,000 kilometers from the surface of Earth, this region, called low-Earth orbit, is just as vulnerable to hoarding as any three-bedroom ranch. Space is littered with defunct satellites, spent rockets, and even astronaut trash. NASA’s Orbital Debris Program estimates that there are almost 20,000 pieces of large debris (“large” being a technical term for “bigger than a grapefruit”), half a million particles measuring between 1 and 10 cm in diameter, and tens of millions of pieces of even tinier detritus, like paint flakes, circling the Earth today.
All of that trash endangers active satellites and can even pose a threat to astronauts on the space shuttle and aboard the International Space Station. In fact, much of what we know about the smallest impactors, which can’t be tracked with radar like larger debris, comes from looking at tiny pocks and dents in space shuttles after they’ve returned to Earth. Though these vessels are shielded against the hail of fine-grained debris they encounter, they occasionally have to fire their engines to maneuver out of the path of larger debris chunks. In two instances in 2008 and 2009, astronauts on the International Space Station took shelter in their Soyuz “lifeboat” when NASA tracked debris on a near-collision-course. Luckily, the debris passed without hitting the space station.
That’s the bad news. The worse news is that debris breeds debris: When two pieces of space junk hit each other, they create a cascade of wreckage that increases the risk of future collisions. Each new fragment is smaller than the original debris pieces, but because they’re traveling at seven or eight kilometers per second, they still carry enough energy to do serious damage. Some scientists have predicted a worst-case scenario in which space debris multiplies so quickly that we become trapped on Earth; it will no longer be worth the risk to send new satellites and spacecraft into orbit.
How do we avoid being trapped by our own junk? It’s a two-part solution: First, we have to figure out what to do with all the stuff that’s already up there. Then, we need to make sure that we don’t end up in this situation again. The second part of this equation is the easier and cheaper nut to crack. It starts with choosing lower orbits for things like discarded rockets; the lower the orbit, the more quickly the object will fall back to Earth, (hopefully) burning up in Earth’s atmosphere on the way down. Just a few hundred miles of altitude can mean the difference between a rocket stage staying in space for a few years, and hanging out up there for more than a century. In the future, satellites might also come equipped with sails or tethers that would be unfurled when the spacecraft’s mission was complete, creating a kind of electrical drag which would tug the satellite into a lower orbit from which is would descend back to Earth.
It would also help if countries could agree not to intentionally blow up their satellites; China’s infamous test of an antisatellite device in 2007 strew hundreds of shards of debris across space.
Even if governments and private companies agreed to seriously reduce their new contributions to our space junk load, we would still be left with the problem of the debris that’s already up there. And this is where things get a little wilder. On paper, at least, there are plenty of ways to solve this problem. You could use lasers vaporize the debris. The problem? Your vaporizing space laser might also accidentally start World War III. Less disturbing to international policymakers would be a kinder, gentler laser that could nudge dangerous debris off course using the faint pressure of light itself. Other have suggested dispatching orbiting garbage trucks to scoop up trash, or attaching propulsion systems to debris on the fly so that the junk can power itself out of orbit—and crash down to Earth.
So what’s stopping us from cleaning up space? A little bit of technology, a little bit of diplomacy, and a lot of money. So far, there isn’t enough of an economic incentive to keep space clean. But we’d better get motivated—before our entire planet needs a hoarders intervention.
This is Kate Becker with the 365 Days of Astronomy Podcast. Want to get in touch? Email me at kate at spacecrafty dot com, or find me on Twitter—I’m @kmbecker—or Facebook, where I’m katembecker. Wishing you clear skies.
End of podcast:
365 Days of Astronomy
=====================
The 365 Days of Astronomy Podcast is produced by the Astrosphere New Media Association. Audio post-production by Preston Gibson. Bandwidth donated by libsyn.com and wizzard media. Web design by Clockwork Active Media Systems. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. Until tomorrow…goodbye.