Cygnus vs. Dragon: How two private spaceships compare.
If all goes well with Wednesday's launch, the Orbital Sciences' Cygnus spacecraft will be the second private American spacecraft to dock with the International Space Station. How does the Cygnus stack up against its rival, SpaceX's Dragon capsule?
In Pictures Space photos of the day: Visions of the future
Subscribe Today to the Monitor
If successful, Orbital Sciences' Cygnus spacecraft will become the second private robotic American cargo ship to dock with the orbiting laboratory. The first was the Dragon capsule, built by billionaire Elon Musk's California-based spaceflight firm SpaceX. Orbtial Sciences' first Cygnus spacecraft is scheduled to launch toward the space station Wednesday at 10:50 a.m. EDT (1450 GMT). You can watch the Cygnus spacecraft launch live on SPACE.com Wednesday, courtesy of NASA TV.
Both SpaceX and Virginia-based Orbital Sciences have deals with NASA to haul cargo to the International Space Station for astronauts living and working aboard the orbiting outpost. SPACE.com compiled this handy cheat sheet to help you keep Dragon and Cygnus straight. [Photos: Robotic Cygnus Spacecraft's 1st Space Station Test Flight]
RECOMMENDED: Are you a space whiz? Take our quiz!
How does it get into space?
Cygnus: Orbital Sciences' vehicle will fly into space atop the company's Antares rocket, which is expected to launch from Pad 0A at the Mid-Atlantic Regional Spaceport at NASA's Wallops Flight Facility in Virginia on Wednesday at 10:50 a.m. EDT (1450 GMT). The spaceflight firm launched the first Antares test flight in April, but Wednesday's liftoff marks the debut of the fully functional Cygnus.
Antares is about the size of a 13-story building, standing 131.5 feet (40 meters) tall. The two AJ26 engines used in the rocket's first stage are based on the NK-33 engine, which was originally developed to launch Russia's giant N-1 moon rocket — the Soviet answer to America's famous Saturn V — in the 1960s. However, the Soviet heavy-lifter was never launched successfully.
Orbital Sciences is contracted for eight cargo missions with Cygnus and Antares under a $1.9 billion agreement with NASA. Wednesday's launch kicks off a demonstration flight designed to see if the company is ready to begin these contracted supply runs.
Dragon: The Dragon capsule — named for the fictional "Puff the Magic Dragon" in the song by the folk trio Peter, Paul and Mary — is launched to space using SpaceX's Falcon 9 rocket. While Antares' design is modeled after a Russian rocket, the Falcon 9's Merlin engines are new. The two-stage rocket stands taller than Antares at 224.4 feet (68.4 m), and it can lift 28,991 pounds (13,150 kg) into low-Earth orbit.
The Falcon 9 first stage has nine Merlin engines. The rocket can lose up to two of these engines and still finish a mission, SpaceX officials have said. SpaceX designers were inspired by the Saturn V, "which had flawless flight records in spite of engine losses," officials said.