SpaceX launches Falcon 9, With A Customer
DID has covered SpaceX’s role in DARPA’s Responsive Small Spacelift Launch Vehicles program with its Falcon I design, and noted the Low-Earth Orbit launch contracts it had secured for various customers. RSSLV is designed to create a less expensive, quick launch capability. Yet SpaceX is developing a whole family of launch rockets, and recently announced a much larger Evolved Expendable Launch Vehicle (EELV) class rocket called the Falcon 9.
It’s a long way from the venture’s beginnings, when PayPal founder (and SpaceX CEO) Elon Musk noted that “The computer and Internet revolutions have given a great deal of capital to the ‘Star Wars’ fans.” SpaceX stuck to its original plan – giving private firms and government agencies that want to launch satellites a $6 million alternative to the cheapest existing rockets, which now cost $30 million per flight. Now, it’s branching out.
The Falcon 9
SpaceX initially intended to follow its first vehicle development, Falcon 1, with the intermediate class Falcon 5 launch vehicle. However, in response to customer requirements for low cost enhanced launch capability, SpaceX accelerated development of an EELV-class vehicle, upgrading Falcon 5 to Falcon 9. SpaceX has sold a Falcon 9 launch to a US government customer, and still plans to make Falcon 5 available in late 2007. Their efforts are worth watching, and could affect the military satellite launch market.
With up to a 17 ft (5.2 m) diameter fairing, Falcon 9 is capable of launching approximately 21,000 lbs (9,500 kg) to Low Earth Orbit (LEO) in its medium configuration and 55,000 lbs (25,000 kg) to LEO in its heavy configuration, a lift capacity greater than any other launch vehicle. In the medium configuration, Falcon 9 is priced at $27 million per flight with a 12 ft (3.6 m) fairing and $35 million with a 17 ft fairing. Prices include all launch range and third party insurance costs, and SpaceX claims that this makes Falcon 9 the most cost efficient vehicle in its class worldwide.
Nine SpaceX Merlin engines power the Falcon 9 first stage with 85,000 lbs of sea level thrust per engine, for a total thrust on liftoff of 765,000 pounds. After engine start, Falcon is held down until all vehicle systems are verified to be functioning normally before release for liftoff.
Although in-flight failures are very rarely explosive, a Kevlar shield protects each engine from debris in the event of its neighbor failing. 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 results in significant cost savings in vehicle production. A single Merlin engine powers the Falcon 9 upper stage, with dual redundant hypergolic igniters (TEA-TEB) with four injection ports for added reliability of restart.
SpaceX: Rocket Science With A Difference
SpaceX’s approach to vehicle design is interesting, and may make them a strong lower-budget alternative to Boeing and Lockheed – and a potentially strong competitor to Ariane or Russian launch options.
An overview of SpaceX’s Falcon family of rockets and launch schedules can be found here. Their designs incorporate a number of well thought-out approaches to balancing low cost and reliability.
SpaceX’s analysis noted that 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.
In response, they designed Falcon 1 to have only one engine per stage and only one stage separation event – the minimum pragmatically possible number. Falcon 9 uses similar engines, electronics, guidance & control and separation systems to Falcon 1, but is built on a different scale and uses multiple engines.
In the case of Falcon 5 and Falcon 9, the multiple engines are set up so that the vehicles will be capable of sustaining an engine failure at any point in flight and successfully completing their mission. These architectures are improved versions of those employed by the Saturn V and Saturn I rockets of the Apollo Program, which had flawless flight records despite losing engines on a number of missions.
SpaceX hold-before-release system is required by commercial airplanes, but rarely seen on 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. It is, after all, cheaper to reset a launch than to replace a cargo that is often worth hundreds of millions of dollars.
Keeping the design to only one stage separation event, and adding triple redundant flight computers and inertial navigation, with a GPS overlay for additional orbit insertion accuracy, take advantage of design and lowering costs for electronics to address the remaining reliability issues while keeping the cost of launch economical.
Falcon 5 and Falcon 9 will also be the world’s first launch vehicles where all stages are designed for reuse.
Reuse is not currently factored into their launch prices, but SpaceX has publicly stated that it will make further reductions in launch prices when the economics of stage recovery and checkout are fully understood.
SpaceX: The Future
SpaceX founder Elon Musk has stated that eventually, he wants to pave the way for safe and reliable airplane-like trips to space. “If anyone can do it, says Mike Griffin, a former NASA exec (at the time – he’s now NASA Administrator) and president of the venture-capital firm In-Q-Tel
- , “Elon can. He has an incredible track record.”
- = So, Mike Griffin used to be a former executive of NASA and a current head honcho at In-Q-Tel. Now he’s a former In-Q-Tel executive and a current head honcho at NASA. Thanks to the readers who wrote in to point this out. Does this make him a “re-former” NASA executive? I guess we’ll see.