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 February 15
   [2]An astronaut is seen hovering over the Earth. In the top part of the
     image, the astronaut is seen against the darkness of space. In the
    lower part of the image, the Earth is bright blue with white clouds.
          Please see the explanation for more detailed information.

                            To Fly Free in Space
                      Image Credit: [3]NASA, [4]STS-41B

   Explanation: What would it be like to fly free in space? About 100
   meters from the cargo bay of a [5]space shuttle, Bruce McCandless II
   was living the dream -- floating farther out than anyone had ever been
   before. Guided by a [6]Manned Maneuvering Unit (MMU), astronaut
   McCandless, [7]pictured, was [8]floating free in space. During [9]Space
   Shuttle mission [10]41-B in 1984, [11]McCandless and fellow [12]NASA
   astronaut [13]Robert Stewart were the first to [14]experience such an
   "un[15]tethered [16]space walk". The [17]MMU worked by shooting jets of
   [18]nitrogen and was used to help deploy and [19]retrieve satellites.
   With a mass over 140 kilograms, an [20]MMU is heavy on [21]Earth, but,
   like everything, is weightless when drifting in orbit. The MMU was
   later replaced with the [22]SAFER backpack propulsion unit.

                   Tomorrow's picture: unexplained shocks
     __________________________________________________________________

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    Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell
                                 ([37]UMCP)
          NASA Official: Amber Straughn [38]Specific rights apply.
            [39]NASA Web Privacy, [40]Accessibility, [41]Notices;
                A service of: [42]ASD at [43]NASA / [44]GSFC,
                         [45]NASA Science Activation
                           & [46]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2602/freeflyer_nasa_3000.jpg
   3. https://www.nasa.gov/
   4. https://www.nasa.gov/mission/sts-41b/
   5. https://www.nasa.gov/space-shuttle/
   6. https://en.wikipedia.org/wiki/Manned_Maneuvering_Unit
   7. https://www.nasa.gov/image-feature/nasa-celebrates-50-years-of-spacewalking
   8. https://youtu.be/RvnC--JjDBw
   9. https://apod.nasa.gov/apod/ap990411.html
  10. https://www.nasa.gov/mission/sts-41b/
  11. https://www.nasa.gov/press-release/astronaut-bruce-mccandless-ii-dies-at-80
  12. https://www.nasa.gov/humans-in-space/astronauts/
  13. https://www.nasa.gov/wp-content/uploads/2023/03/stewart-robert.pdf
  14. https://youtu.be/7K5DiKsZhTk
  15. http://www-istp.gsfc.nasa.gov/Education/wtether.html
  16. https://apod.nasa.gov/apod/ap990801.html
  17. https://youtu.be/92ZRVlKuc0U
  18. https://periodic.lanl.gov/7.shtml
  19. https://apod.nasa.gov/apod/ap121209.html
  20. http://en.wikipedia.org/wiki/Manned_Maneuvering_Unit
  21. https://science.nasa.gov/earth/facts/
  22. https://apod.nasa.gov/apod/ap011002.html
  23. https://apod.nasa.gov/apod/ap260214.html
  24. https://apod.nasa.gov/apod/archivepix.html
  25. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  26. https://apod.nasa.gov/apod/lib/aptree.html
  27. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  28. https://apod.nasa.gov/apod/calendar/allyears.html
  29. https://apod.com/feed.rss
  30. https://apod.nasa.gov/apod/lib/edlinks.html
  31. https://apod.nasa.gov/apod/lib/about_apod.html
  32. https://asterisk.apod.com/discuss_apod.php?date=260215
  33. https://apod.nasa.gov/apod/ap260216.html
  34. http://www.phy.mtu.edu/faculty/Nemiroff.html
  35. http://www.phy.mtu.edu/
  36. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  37. http://www.astro.umd.edu/
  38. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  39. https://www.nasa.gov/about/highlights/HP_Privacy.html
  40. https://www.nasa.gov/general/accessibility/
  41. https://www.nasa.gov/privacy/
  42. https://astrophysics.gsfc.nasa.gov/
  43. https://www.nasa.gov/
  44. https://www.nasa.gov/centers/goddard/
  45. https://science.nasa.gov/learners
  46. http://www.mtu.edu/