The Falcon 9 v1.0 was the first member of the Falcon 9 launch vehicle family, designed and manufactured by SpaceX in Hawthorne, California. Development of the medium-lift launcher began in 2005, and it first flew on June 4, 2010. The Falcon 9 v1.0 then launched four Dragon cargo spacecraft: one on an orbital test flight, then one demonstration and two operational resupply missions to the International Space Station under a Commercial Resupply Services contract with NASA.
The two stage vehicle was powered by SpaceX's Merlin engines, burning liquid oxygen (LOX) and rocket-grade kerosene (RP-1). Had the F9 V1.0 been used for launching payloads other than the Dragon to orbit, it would have launched to low Earth orbit (LEO) and to geostationary transfer orbit (GTO).
The vehicle was retired in 2013 and replaced by the upgraded Falcon 9 v1.1, which first flew in September 2013. Of its five launches from 2010 to 2013, all successfully delivered their primary payload, though an anomaly led to the loss of one secondary payload.
Design
First stage
The Falcon 9 v1.0 first stage was used on the first five Falcon 9 launches, and powered by nine SpaceX Merlin 1C rocket engines arranged in a 3x3 pattern. Each of these engines had a sea-level thrust of for a total thrust on liftoff of about .
The Falcon 9 tank walls and domes were made from aluminum lithium alloy. SpaceX uses an all-friction stir welded tank, the highest strength and most reliable welding technique available.
The Falcon 9 v1.0 first stage used a pyrophoric mixture of triethylaluminum-triethylborane (TEA-TEB) as a first-stage ignitor.
Second stage
The upper stage was powered by a single Merlin 1C engine modified for vacuum operation, with an expansion ratio of 117:1 and a nominal burn time of 345 seconds. For added reliability of restart, the engine has dual redundant pyrophoric igniters (TEA-TEB). The second stage tank of Falcon 9 is simply a shorter version of the first stage tank and uses most of the same tooling, material and manufacturing techniques. This saves money during vehicle production.
The Falcon 9 v1.0 interstage, which connects the upper and lower stage for Falcon 9, is a carbon fiber aluminum core composite structure. Reusable separation collets and a pneumatic pusher system separate the stages. The stage separation system had twelve attachment points (later reduced to just three in the v1.1 launcher).
Control
SpaceX uses multiple redundant flight computers in a fault-tolerant design. Each Merlin engine is controlled by three voting computers, each of which has two physical processors that constantly check each other. The software runs on Linux and is written in C++. For flexibility, commercial off-the-shelf parts and system-wide "radiation-tolerant" design are used instead of radiation-hardened parts.
Four Draco thrusters were to be used for at least the second revision of the Falcon 9 v1.0 rocket second-stage as a reaction control system. It is unknown whether Falcon 9 ever flew with these thrusters; the second revision of Falcon 9 v1.0 was replaced with the Falcon 9 v1.1, which used nitrogen cold gas thrusters. The thrusters were used to hold a stable attitude for payload separation or, as a non-standard service, were also designed to be used to spin up the stage and payload to a maximum of 5 rotations per minute (RPM), although none of the five flown missions had a payload requirement for this service.
Development history
Funding
While SpaceX spent its own money to develop its first launch vehicle, the Falcon 1, the development of the Falcon 9 was accelerated by the purchase of several demonstration flights by NASA. This started with seed money from the Commercial Orbital Transportation Services (COTS) program in 2006. SpaceX was selected from more than twenty companies that submitted COTS proposals. Without the NASA money, development would have taken longer, Musk said.
The development costs for Falcon 9 v1.0 were approximately , and NASA verified those costs. If some of the Falcon 1 development costs were included, since F1 development did contribute to Falcon 9 to some extent, then the total might be considered as high as .
NASA also evaluated Falcon 9 development costs using the NASA‐Air Force Cost Model (NAFCOM)—a traditional cost-plus contract approach for US civilian and military space procurement—at based on a NASA environment/culture, or using a more commercial approach.
Production
In December 2010, the SpaceX production line was manufacturing one new Falcon 9 (and Dragon spacecraft) every three months, with a plan to double the production rate to one every six weeks in 2012.