                        Astronomy Picture of the Day

    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
    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: NASA, STS-41B

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

                   Tomorrow's picture: unexplained shocks
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
                  NASA Web Privacy, Accessibility, Notices;
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

