Delta 2 lifts off successfully for 75th time to launch Earth-imaging satellite

A Delta 2 rocket lifted off successfully for the 75th consecutive time from the Vandenberg Air Force Base in Santa Barbara, California at 4.30 am (IST) on Wednesday 19 September (4.00 pm on Tuesday 18 September, local time). This makes it the most reliable expendable launch vehicle (rocket) currently in operation around the world.

The Delta 2 series of rockets has been launched 130 times, with only two failures. Its current string of 75 straight successful missions started in May 1997. Originally designed and built by McDonnell Douglas, it was first launched on 14 February 1989. The rocket was later built by Boeing's Integrated Defence Systems, and is now owned by United Launch Alliance, a joint venture between Lockheed Martin and Boeing.

Among its successful launches have been the Mars Phoenix lander in 2007, the Mars Exploration Rover (MER), which included the rovers Spirit and Opportunity, in 2003, and the Mars Odyssey in 2001. The NASA Dawn mission, a robotic probe to explore asteroids, is scheduled to lift off on 26 September onboard a Delta 2 rocket.

The rocket was carrying WorldView 1, a hi-tech 2.5-tonne Earth-imaging satellite that can see objects on the Earth's surface as small as 20 inches (51 cm) across. The satellite was placed in a polar orbit about 308 miles (496 km) above the Earth. It has the ability to produce images with a 1.6-foot (0.5-m) resolution of about 290,000 sq miles (750,000 sq km) of the Earth's surface each day.

WorldView1 will play an important role in the US government's military intelligence surveillance programme. It will also have commercial applications in various fields of interest. One of its customers is Google Earth.

DigitalGlobe Corporation, which owns the WorldView 1 satellite, is based in Longmont, Colorado. It also operates the QuickBird satellite, the only commercial spacecraft before WorldView 1 that is able to produce sub-metre resolution imagery of the Earth's surface from space.