                        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.

                                 2025 May 1

                       MESSENGER's Last Day on Mercury
    Image Credit: NASA, Johns Hopkins Univ. APL, Arizona State Univ., CIW

   Explanation: The first to orbit inner planet Mercury, the MESSENGER
   spacecraft came to rest on this region of Mercury's surface on April
   30, 2015. Constructed from MESSENGER image and laser altimeter data,
   the projected scene looks north over the northeastern rim of the broad,
   lava filled Shakespeare basin. The large, 48 kilometer (30 mile) wide
   crater Janacek is near the upper left edge. Terrain height is color
   coded with red regions about 3 kilometers above blue ones. MESSENGER'S
   final orbit was predicted to end near the center, with the spacecraft
   impacting the surface at nearly 4 kilometers per second (over 8,700
   miles per hour) and creating a new crater about 16 meters (52 feet) in
   diameter. The impact on the far side of Mercury was not observed by
   telescopes, but confirmed when no signal was detected from the
   spacecraft given time to emerge from behind the planet. Launched in
   2004, the MErcury Surface, Space ENvironment, GEochemisty and Ranging
   spacecraft completed over 4,000 orbits after reaching the Solar
   System's innermost planet in 2011.

                    Tomorrow's picture: burning hydrogen
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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