SpaceX rocket reaches orbit after fourth attempt

Physics Today: After three dramatic failures, the first privately developed liquid fuel rocket has reached low Earth orbit. The fourth flight of the Falcon 1 rocket, which is built by Space Exploration Technologies Corp. (SpaceX) lifted off at 4:15 p.m. (PDT) yesterday from the Reagan Test Site (RTS) on Omelek Island at the US Army Kwajalein Atoll (USAKA) in the Central Pacific, about 2,500 miles southwest of Hawaii. "This is a great day for SpaceX and the culmination of an enormous amount of work by a great team," said Elon Musk, CEO and CTO of SpaceX. "The data shows we achieved a super precise orbit insertion—middle of the bull's-eye — and then went on to coast and restart the second stage, which was icing on the cake." The rocket is currently in an elliptical orbit of 500 km by 700 km, 9.2 degrees inclination.

Falcon 1 carried into orbit a payload mass simulator of approximately 165 kg (364 lbs), designed and built by SpaceX, specifically for this mission. Consisting of a hexagonal aluminum alloy chamber 1.5 meters (5 feet) tall, the payload remains attached to the second stage as it orbits Earth.

This was the fourth launch of the Falcon 1 launch vehicle and second flight for the new SpaceX-developed Merlin 1C regeneratively-cooled engine. A "hold before liftoff" system was used to enhance reliability by permitting all launch systems to be verified as functioning nominally before launch was initiated. A single SpaceX-developed Kestrel engine powered the Falcon 1 second stage.

Space X, which was founded in 2002 (see Physics Today March 2005, page 30) is planning a family of launch vehicles intended to increase the reliability and reduce the cost of both manned and unmanned space transportation. The company is the only remaining winner of NASA's Commercial Orbital Transportation Services competition (COTS), that aims to develop a cargo delivery vehicle called Dragon to the international space station when the shuttle retires in 2010. Under the existing Agreement, SpaceX will conduct three flights of its Falcon 9 launch vehicle and Dragon spacecraft for NASA, culminating in Dragon berthing with the ISS. NASA also has an option to demonstrate crew services to the ISS using the Falcon 9 / Dragon system. The first Falcon 9 will arrive at the SpaceX launch site (complex 40) at Cape Canaveral by the end of 2008 in
preparation for its maiden flight in 2009.