Opportunity Rover Delta II Launch

The second Mars Exploration Rover, Opportunity, was the first NASA mission lifted on what is referred to as a Delta II "heavy" rocket. It is a more powerful vehicle that uses larger strap-on solid rocket motors developed for the Delta III launch vehicle. The launch of the MER-B spacecraft was the second use of a core Delta II "Heavy" launch vehicle and the first use of a Delta II "Heavy" launch vehicle with an upper stage.

The use of this rocket for the Mars Exploration Rover mission helped pave the way for many future space missions that will need a bit more energy to send them on their way beyond Earth. The MESSENGER mission to Mercury, the seventh mission selected for NASA's Discovery Program, was launched August 3rd, 2004, on a Delta II heavy. [More on the Mars Exploration Rover launch vehicle.]

The traditional Delta II rocket (used to lift Spirit) has been used to propel many NASA missions into space and has a history of more than 40 successful launches, but some spacecraft need more energy to propel them on their way to Mars and other planets.