Falcon 1

Falcon I was a two stage, reusable, liquid oxygen and kerosene powered launch vehicle. A single engine powered the first stage. It was designed for cost-efficient and reliable transport of satellites to low Earth orbit. First launch of the Falcon I was scheduled for mid-2004 from Vandenberg, carrying a US Defense Department communications satellite. Development delays and problems with USAF clearances for launch from Vandenberg resulted in the first launch attempt being made in 2006 from a private facility at Omelek near Kwajalein atoll in the Pacific.

The first stage primary structure was made of a space grade aluminium alloy in a patent pending, graduated monocoque, common bulkhead, flight pressure stabilized architecture developed by SpaceX. The design was a blend between a fully pressure stabilized design, such as Atlas II, and a heavier isogrid design, such as Delta II. As a result, SpaceX claimed to have captured the mass efficiency of pressure stabilization, but avoided the ground handling difficulties of a structure unable to support its own weight. A single SpaceX Merlin engine powered the Falcon I first stage. After engine start, Falcon would be held down until all vehicle systems were verified to be functioning normally before release for lift-off. Helium tank pressurization was provided by composite over-wrapped inconel tanks from Arde Corporation, the same model used in Boeing's Delta IV rocket. Stage separation occurred via dual initiated separation bolts and a pneumatic pusher system. All components were space qualified and had flown before on other launch vehicles.

The first stage returned by parachute to a water landing, where it was picked up by ship in a procedure similar to that of the Space Shuttle solid rocket boosters. The parachute recovery system was built for SpaceX by Irvin Parachute Corporation, who also builds the Shuttle booster recovery system.

The second stage tank structure was made of aluminium-lithium alloy. SpaceX found this to be the lowest total system mass in this application of any material examined, including liquid oxygen compatible super-alloys and composites. A single SpaceX Kestrel pressure-fed engine powered the Falcon I upper stage. For added reliability of restart, the engine had dual redundant torch igniters. Helium pressurization was again provided by composite over wrapped inconel tanks from Arde. The helium was also used in cold gas thrusters for attitude control and propellant settling when a restart was needed.

Manufacturer: SpaceX. LEO Payload: 670 kg (1,470 lb). to: 200 km Orbit. at: 28.00 degrees. Payload: 430 kg (940 lb). to a: 700 km sun synchronous orbital trajectory. Liftoff Thrust: 318.000 kN (71,489 lbf). Total Mass: 27,200 kg (59,900 lb). Core Diameter: 1.70 m (5.50 ft). Total Length: 21.30 m (69.80 ft). Span: 1.70 m (5.50 ft). Boost Propulsion: Lox/Kerosene. Boost engine: Merlin. Cruise Propulsion: Lox/Kerosene. Cruise engine: Kestrel. Cruise Thrust: 33.300 kN (7,486 lbf). Launch Price $: 6.000 million. in: 2004 price dollars. Cost comments: Initial offering price for contracts signed in 2004.

2006 March 24 - Launch Site: Kwajalein. Launch Complex: Omelek. Launch Vehicle: Falcon I. FAILURE: Fuel leak at T+25 seconds caused a fire in the first stage engine area.

• Falconsat-2 Nation: USA. Mass: 20 kg (44 lb). Class: Technology. Agency: USAFA. Manufacturer: USAFA. COSPAR: F20060324. The satellite fell through the roof of SpaceX's machine shop on the atoll.

• DemoFlight 2 Nation: USA. Class: Technology. Agency: DARPA. COSPAR: F20070321. An oscillation appeared in the upper stage control system 90 seconds into the burn. This instability grew and after 30 seconds induced a roll torque that exceeded the control capability of the second stage roll control thrusters. The propellants were centrifuged away from the outlets, causing flame-out of the Kestrel engine. LOX slosh was believed to be the primary contributor to this instability. Second stage slosh baffles would be included in future boosters to prevent reoccurence of the problem.