MESSENGER was a NASA robotic space probe that orbited the planet Mercury between 2011 and 2015, studying Mercury's chemical composition, geology, and magnetic field. The name is a backronym for "MErcury Surface, Space ENvironment, GEochemistry, and Ranging", and a reference to the messenger god Mercury from Roman mythology.

Delta II is an American space launch system developed by McDonnell Douglas, now part of the Delta rocket family operated by United Launch Alliance. With more than 150 missions and a nearly perfect track record, Delta II has established itself as one of the most successful orbital launch systems.

The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal Corps, the USAF was established as a separate branch of the United States Armed Forces in 1947 with the enactment of the National Security Act of 1947.

• Discovery Program

  Exploration
  The Discovery Program is a series of Solar System exploration missions funded by the U.S. National Aeronautics and Space Administration (NASA) through its Planetary Missions Program Office. The cost of each mission is capped at a lower level than missions from NASA's New Frontiers or Flagship Programs. As a result, Discovery missions tend to be more focused on a specific scientific goal rather than serving a general purpose.
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