February: Spotting Solar Sails and Satellites

February 2011

Spotting Solar Sails and Satellites

By Calvin L. Chrisman

If you enjoy satellite watching, for the next few months, there is a new target in the sky. NASA has launched NanoSail-D into low earth orbit. NanoSail-D is an experimental solar sail that uses sunlight much like a conventional sail uses wind. There is a constant flow of charged particles blowing out from our Sun and scientists have recognized its potential as a driver for spacecraft of the future. It could save tremendously on fuel (heavy, expensive) and could eventually propel a spacecraft to higher speeds than any chemical reaction could achieve. Many consider this the only practical way to make interstellar travel a reality. The purpose of NanoSail-D is mainly to prove feasibility of launching and deploying such a craft from its parent satellite (in NSAS-speak, to demonstrate that it can avoid “re-contact with the primary satellite” – i.e. crashing together).

The satellite was launched in a package approximately 4 inches square and 15 inches long and has now been deployed into a solar sail that is approximately 100 feet square. From our perspective, the interesting thing will be to see it pass by in the night sky as it is made of highly reflective polymer and can be quite bright if viewed at the right angle. At the moment, there are no bright passes projected for our area, but variability of the orbit due to atmospheric conditions makes it difficult to predict for more than a few weeks out. Initial expectations are for NanoSail-D to remain in orbit perhaps as late as May, so you can visit www.heavens-above.com for predictions. Sometime later in the year the satellite will “de-orbit” (also NASA-speak for crashing) and will no longer be visible. It is interesting to note that this solar sail technology may also be used in the future to “de-orbit” (yes, crash) old satellites into the atmosphere rather than letting them become dangerous space junk.

In the meantime, our area is a good one for bright visible passes of the International Space Station and its passengers. Starting the evening of February 18th and continuing through the 21st at least, there will be a number of visible passes in the evening. Currently, NASA plans to launch the Space Shuttle Discovery to the ISS on February 24th. Again, check www.heavens-above.com for ISS/Space Shuttle Discovery passes at this time. We may get to see Discovery on its next-to-last trip to space as it is piloted by the husband of Congresswoman Gabriel Gifford.

Finally, if you are a morning person, on February 28th and March 1st look to the Southeast an hour before sunrise. There you will see the waning crescent moon first on the right and the next morning on the left of beautiful bright Venus. If you have a telescope, you will notice Venus is waxing during the month and will be approximately 70% illuminated by month’s end.

Clear Skies!

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