The Union Recorder

May 9, 2013

OUR SPACE: Fermi dodges the bullet

Beate Czogalla
The Union-Recorder

MILLEDGEVILLE — A short time ago the popular TV series “Mythbusters” explored whether one can in fact “dodge a bullet.” After the usual hilarity liberally sprinkled with science facts and easy to understand graphics, the show’s heroes concluded that, sadly, you cannot dodge a bullet, no matter how quick your reaction time or ability to move out of the way.

In space travel, it’s a bit of a different issue altogether — thank goodness. Earlier this year we contemplated the vast amount of space junk in orbit around planet Earth — the leftover rocket bits and parts, lost hardware, paint flakes and defunct satellites. The pieces that are big enough can be tracked and thus early warning can be given to spacecraft and astronauts about potential collisions.

Enter Fermi, the x-ray telescope that quietly plods along and rarely makes the headlines like its more famous siblings Hubble or Spitzer.

Fermi (formerly known as GLAST), launched June 11, 2008, is conducting research into objects that emit energy in the form of x-rays: it can “see” things that other space-based telescopes cannot because its optics are specializing in those high-frequency wave lengths.

About a year ago mission managers learned that Fermi and a dead Russian satellite, Cosmos 1805, were on a direct collision course. Of course, the precise wording was more along the lines that “both objects would occupy the same point in space within 30 milliseconds of each other.” To you and me this means: KAPOW!

Since the junk satellite was unable to move Fermi had to get out of the way — and quickly.

Now, space telescopes are not designed for swift maneuvering — they trudge along in their orbits doing their thing, and most are able to make only tiny adjustments for pointing their instruments and fine-tuning their position, but bullet-dodging is not on the menu.

Lucky for Fermi, it has an additional small engine system whose sole purpose in life is to eventually bring the telescope to a re-entry into Earth’s atmosphere at the end of its useful life, so it can burn up harmlessly and not become a piece of space junk itself.

Needless to say, this engine has never been tested, but it sure came in handy as a make-shift bullet-dodger-aid. Tensions ran high when the firing occurred, but it all worked like a charm, nudging the telescope far enough off the collision course to turn the fatal situation into a safe fly-by, passing Cosmos 1805 at a safe distance of about six miles.

While collisions with large objects such as that are rare, they do occur, and they exacerbate the problem because they create lots of more debris. In 2009 another dead Russian satellite, Cosmos 2251, was supposed to zip past the fully functioning Iridium 33 satellite at 1,900 feet distance. Plenty of elbow room, right? And yet, suddenly all contact with Iridium 33 was lost and more debris appeared on the tracking screens. Predictions such as exact distances are notoriously tricky, especially if it involves space junk, which can’t give you exact position updates and which has to be tracked by other means, and it’s just not an exact science.

All of this proves to show that sometimes you actually can dodge the bullet — if you have plenty of warning and can plan for the move well ahead of time.

Fermi is alive and well, doing awesome science while Cosmos 1805 gets to be space junk for a while longer.

Learn more about Fermi at the Fermi website at http://fermi.gsfc.nasa.gov/



Beate Czogalla is the Professor of Theater Design in the Department of Theatre and Dance at Georgia College & State University. She has had a lifelong interest in space exploration and has been a Solar System Ambassador for the Jet Propulsion Laboratory/ NASA for many years. She can be reached at  our_space2@yahoo.com