Falcon 1 Overview
The Falcon Launch Vehicle Family is designed to provide breakthrough advances in reliability, cost, flight environment and time to launch. The primary design driver is and will remain reliability, as described in more detail below. We recognize that nothing is more important than getting our customer’s spacecraft safely to its intended destination.
Falcon 1 is a two stage, liquid oxygen and rocket grade kerosene (RP-1) powered launch vehicle. It is designed from the ground up for cost efficient and reliable transport of satellites to low Earth orbit.
| Length: | 27.4 m (90 ft) |
| Width: | 1.7 m (5.5 ft) |
| Mass: | 46,760 kg (103 klbs) |
| Thrust on liftoff: | 556 kN (125 klbf) |
| All performance data reflects the updated Falcon 1e vehicle available starting in 2010. | |
Falcon 1 DemoFlight 2 prior to liftoff. The March 20, 2007 test flight reached an altitude
of approximately 290 km.
First Stage
The primary structure is made of a space grade aluminum alloy in a patent pending, graduated monocoque, common bulkhead, flight pressure stabilized architecture developed by SpaceX. The design is a blend between a fully pressure stabilized design, such as Atlas II, and a heavier isogrid design, such as Delta II. As a result, we have been able to capture the mass efficiency of pressure stabilization, but avoid the ground handling difficulties of a structure unable to support its own weight.
A single SpaceX Merlin engine (described below) powers the Falcon 1 first stage. After engine start, Falcon is held down until all vehicle systems are verified to be functioning normally before release for liftoff.
Helium tank pressurization is provided by composite over-wrapped inconel tanks from Arde Corporation, the same model used in Boeing’s Delta IV rocket.
Stage separation occurs via dual initiated separation bolts and a pneumatic pusher system. All components are space qualified and have flown before on other launch vehicles.
The first stage returns by parachute to a water landing, where it is picked up by ship in a procedure similar to that of the Space Shuttle solid rocket boosters. The parachute recovery system is built for SpaceX by Irvin Aerospace, who also builds the Shuttle booster recovery system.
Second Stage
The tank structure is made of aluminum-lithium, an alloy possessing the highest strength to weight ratio of any aluminum and currently used by the Space Shuttle External Tank. Although we intend to continue researching alternatives in the long term, for this particular application it has the lowest total system mass for any material we have examined, including liquid oxygen compatible super-alloys and composites.
The tanks are precision machined from thick plate with integral flanges and ports, minimizing the number of welds necessary. The major circumferential welds are all done by an automated welding machine, reducing the potential for error and ensuring consistent quality.
A single SpaceX Kestrel engine powers the Falcon 1 upper stage. A highly reliable and proven TEA-TEB pyrophoric system is used to provide multiple restart capability on the upper stage.
Helium pressurization is again provided by composite over wrapped inconel tanks from Arde. However, in this case the helium is also used in cold gas thrusters for attitude control and propellant settling when a restart is needed.
Typical Falcon 1 flight profile for direct insertion from launch through deployment and recovery of 1st stage
SpaceX Merlin Engine
The main engine, called Merlin, was developed internally at SpaceX, but draws upon a long heritage of space proven engines. The pintle style injector at the heart of Merlin was first used in the Apollo Moon program for the lunar module landing engine, one of the most critical phases of the mission.
Propellant is fed via a single shaft, dual impeller turbo-pump operating on a gas generator cycle. The turbo-pump also provides the high pressure kerosene for the hydraulic actuators, which then recycles into the low pressure inlet. This eliminates the need for a separate hydraulic power system and means that thrust vector control failure by running out of hydraulic fluid is not possible. A third use of the turbo-pump is to provide roll control by actuating the turbine exhaust nozzle.
Combining the above three functions into one device that we know is functioning before the vehicle is allowed to lift off means a significant improvement in system level reliability.
| Sea Level Thrust : | 125,000 lb |
| Vacuum Thrust: | 138,400 lb |
| Sea Level Isp: | 275s |
| Vacuum Isp: | 304s |
With a vacuum specific impulse of 304s, Merlin is the highest performance gas generator cycle kerosene engine ever built, exceeding the Boeing Delta II main engine, the Lockheed Atlas II main engine and the Saturn V F-1.
SpaceX Kestrel Engine
Kestrel, also built around the pintle architecture, is designed to be a high efficiency, low pressure vacuum engine. It does not have a turbo-pump and is fed only by tank pressure.
Kestrel is ablatively cooled in the chamber and throat and radiatively cooled in the nozzle, which is fabricated from a high strength niobium alloy. As a metal, niobium is highly resistant to cracking compared to carbon-carbon. An impact from orbital debris or during stage separation would simply dent the metal, but have no meaningful effect on engine performance. Helium pressurant efficiency is substantially increased via a titanium heat exchanger on the ablative/niobium boundary.
Thrust vector control is provided by electro-mechanical actuators on the engine dome for pitch and yaw. Roll control (and attitude control during coast phases) is provided by helium cold gas thrusters.
A highly reliable and proven TEA-TEB pyrophoric system is used to provide multiple restart capability on the upper stage. In a multi-manifested mission, this allows for drop off at different altitudes and inclinations.
| Vacuum Thrust: | 6,900 lb |
| Vacuum Isp: | 320s |
Designed for Maximum Reliability
The vast majority of launch vehicle failures in the past two decades can be attributed to three causes: engine, stage separation and, to a much lesser degree, avionics failures. An analysis of launch failure history between 1980 and 1999 by Aerospace Corporation showed that 91% of known failures can be attributed to those subsystems.
Engine Reliability
It was with this in mind that we designed Falcon 1 to have the minimum number of engines. As a result, there is only one engine per stage and only one stage separation event – the minimum pragmatically possible number.
Another notable point is the SpaceX hold-before-release system – a capability required by commercial airplanes, but not implemented on many launch vehicles. After first stage engine start, the Falcon is held down and not released for flight until all propulsion and vehicle systems are confirmed to be operating normally. An automatic safe shut-down and unloading of propellant occurs if any off nominal conditions are detected.
Fairing Volume
Below are the standard fairing dimensions for Falcon 1 Launch Vehicles. Dimensions are in meters and in inches inside the parentheses. Custom fairings in larger lengths and diameters are available at incremental cost.
Falcon 1 fairing (L) and the Falcon 1e fairing (R)
The upgraded Falcon 1e vehicle will be available starting in 2010.
Pricing and Performance
SpaceX offers open and fixed pricing that is the same for all customers, including a best price guarantee. Modest discounts are available for contractually committed, multi-launch purchases. The Falcon 1 Launch Vehicle Family includes the Falcon 1 and an enhanced version, Falcon 1e. Beginning in 2010, Falcon 1e will offer enhanced performance capabilities and payload capacities due to weight saving and propulsion improvements.
Falcon 1 is the world’s lowest cost per flight to orbit of a production rocket.
| Falcon 1 | Falcon 1e | |
| Price: | $7.9M | $9.1M |
| LEO Mass to Orbit (185 km circular): | 420 kg | 1010 kg |
| Performance is based on a 185km circular orbit launched due east (9.1 deg) from SpaceX's Kwajalein Launch Facility. Pricing reflects US dollars Paid-In-Full at Authority-to-Proceed, January 1, 2008. SpaceX offers milestone-based financing at 5% APR. |
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The Falcon 1 Data Sheet (2MB) and Falcon Lunar Capability Guide (1.2MB) provide further information on Falcon 1 performance. The Falcon 1 User's Guide (2 MB) provides detailed information on performance, environments, and launch facilities. To inquire further about SpaceX Launch Services, email us at FalconGuide@spacex.com.