Atop this ULA Atlas V rocket will be Perseverance, a car-sized rover which will explore an ancient river delta on Mars. Armed with a suite of six scientific instruments, Perseverance will primarily hunt for clues to the planet's distant past, and hopefully uncover signs of ancient life and habitability. The rover also carries an experiment that'll convert carbon dioxide into oxygen, a box-sized helicopter named Ingenuity that'll demonstrate powered flight on Mars, and a system that enables the rover to leave behind samples for later retrieval and return to Earth during NASA and ESA's ambitious sample return mission later this decade.

Atlas V with 5m Fairing, 4 SRB, 1 Centaur upper stage engine.

United Launch Alliance (ULA) is a joint venture of Lockheed Martin Space Systems and Boeing Defense, Space & Security. ULA was formed in December 2006 by combining the teams at these companies which provide spacecraft launch services to the government of the United States. ULA launches from both coasts of the US. They launch their Atlas V vehicle from LC-41 in Cape Canaveral and LC-3E at Vandeberg. Their Delta IV launches from LC-37 at Cape Canaveral and LC-6 at Vandenberg.

• NASA Large Strategic Science Missions

  Exploration
  NASA's large strategic science missions or large strategic missions, formerly known as Flagship missions or Flagship-class missions, are the costliest and most capable NASA science spacecraft. Flagship missions exist within all four divisions of NASA's Science Mission Directorate (SMD): the astrophysics, Earth science, heliophysics and planetary science divisions.
  Program wiki