Astronomy Picture of the Day

   [1]Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                               2026 January 2
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                                 NanoSail-D2
               Image Credit & [3]Copyright: [4]Ralf Vandebergh

   Explanation: In 2011, on January 20, [5]NASA's NanoSail-D2 unfurled a
   very thin and very reflective 10 square meter sail becoming the first
   solar sail spacecraft in low Earth orbit. Often considered the [6]stuff
   of science fiction, sailing through space [7]was suggested 400 years
   ago by astronomer Johannes Kepler, who had observed comet tails blown
   by the solar wind. But [8]modern solar sail spacecraft designs, like
   NanoSail-D2, Japan's interplanetary spacecraft [9]IKAROS, or the
   Planetary Society's [10]Lightsail A, rely on the small but
   [11]continuous pressure from sunlight itself for thrust. Glinting in
   the sunlight as it circled planet Earth, NanoSail-D2's solar sail was
   periodically bright and visible to the eye. These remarkably detailed
   images were captured by manually tracking the orbiting solar sail
   spacecraft with a small telescope.

                      Tomorrow's picture: moon lighting
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    Authors & editors: [23]Robert Nemiroff ([24]MTU) & [25]Jerry Bonnell
                                 ([26]UMCP)
          NASA Official: Amber Straughn [27]Specific rights apply.
            [28]NASA Web Privacy, [29]Accessibility, [30]Notices;
                A service of: [31]ASD at [32]NASA / [33]GSFC,
                         [34]NASA Science Activation
                           & [35]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2601/NanosailD2_reprocessed1a.png
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://satellite-imaging.jouwweb.nl/selected-project-samples-best-works
   5. https://en.wikipedia.org/wiki/NanoSail-D2
   6. https://en.wikipedia.org/wiki/Sunjammer
   7. https://apod.nasa.gov/apod/ap040821.html
   8. http://en.wikipedia.org/wiki/Solar_sail
   9. https://global.jaxa.jp/countdown/f17/overview/ikaros_e.html
  10. https://apod.nasa.gov/apod/ap150619.html
  11. http://www.phy6.org/stargaze/Solsail.htm
  12. https://apod.nasa.gov/apod/ap260101.html
  13. https://apod.nasa.gov/apod/archivepix.html
  14. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  15. https://apod.nasa.gov/apod/lib/aptree.html
  16. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  17. https://apod.nasa.gov/apod/calendar/allyears.html
  18. https://apod.com/feed.rss
  19. https://apod.nasa.gov/apod/lib/edlinks.html
  20. https://apod.nasa.gov/apod/lib/about_apod.html
  21. https://asterisk.apod.com/discuss_apod.php?date=260102
  22. https://apod.nasa.gov/apod/ap260103.html
  23. http://www.phy.mtu.edu/faculty/Nemiroff.html
  24. http://www.phy.mtu.edu/
  25. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  26. http://www.astro.umd.edu/
  27. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  28. https://www.nasa.gov/about/highlights/HP_Privacy.html
  29. https://www.nasa.gov/general/accessibility/
  30. https://www.nasa.gov/privacy/
  31. https://astrophysics.gsfc.nasa.gov/
  32. https://www.nasa.gov/
  33. https://www.nasa.gov/centers/goddard/
  34. https://science.nasa.gov/learners
  35. http://www.mtu.edu/