Single Stage to Orbit (SSTO)

A Single Stage to Orbit (SSTO) vertical launch vehicle is the simplest launch system and promises to be the most reliable craft ever considered. Staged rockets, even though they provide more payload performance for the same takeoff mass, are less reliable because of the increased number of parts due to flight events requested by staging and ignition of the upper stage engine. Also, staged rockets are more expensive because they are literally made up of more than one rocket. Manufacturing and assembling more rockets into one launcher requires more personnel, time, and money. The SSTO technology, once implemented, will increase the space flight responsiveness and will lower the cost to the value expected by the industry for decades.



Linear Aerospike Rocket Engine

The Executor linear aerospike rocket engine is based on a technology tested extensively by NASA beginning in the 1960's. The aerospike engine was a candidate for the Space Shuttle and then the Venture Star Single Stage to Orbit craft. Due to various reasons, related to other factors than to the aerospike engine itself, no vehicle equipped with an aerospike engine ever reached space to this day. An aerospike engine exhaust jet ideally expands from sea level up to space, ensuring superior efficiency at all flight levels. A "classic" bell-shaped nozzle works efficiently at only one flight level, usually at sea level, or a little bit above sea level. After that point, the engine isn't properly taking advantage of the atmospheric pressure decrease as the gases are contained by the nozzle. An aerospike nozzle allows virtually unlimited expansion ratios, thus significantly increasing the specific impulse of the engine at high altitude. For instance, the Executor aerospike rocket engine gains 33% more thrust at altitude compared with at sea level for the same fuel consumption. Another interesting comparison between one of the most advanced rocket engines available to date, the Merlin 1D that offers 311s of specific impulse in vacuum at almost 100 bars of chamber pressure using LOX and RP-1, and the Executor Aerospike that offers 314s of specific impulse in vacuum at 16 bars, emphasizes the advantages of the aerospike configuration. In the photos above: XRS-2200 linear aerospike engine (left), the Executor linear aerospike engine for the Haas 2CA (right).



Fully Composites

A SSTO vehicle needs to be as light as possible as any mass that is used by its structure can become payload since the whole vehicle reaches orbit at the end of the flight. Therefore, the logical answer for the Haas 2CA airframe is the composite materials. Even though the Haas 2CA tanks are used in the pressure fed configuration, they are the lightest ever integrated on a space vehicle, twice as efficient as the ones of the Atlas rocket, a vehicle that was the closest configuration to a SSTO vehicle ever to reach orbit. The composite tanks for hydrogen peroxide and RP-1 were extensively tested at ARCA since the beginning of 2002. Not a single vehicle built by ARCA with this technology ever failed.





Due to unprecedented simplicity, the Haas 2CA is designed to perform an orbital flight in 24 hours from the moment of the launch decision. The capability to launch in 24 hours could solve emergency situations that may occur in orbit for crewed vehicles by delivering neccessary supplies, or for launching fast a reconnaissance satellite needed on a particular orbit.




Extreme Simplicity

The extreme simplicity of the SSTO rockets offers the possibility to drop the cost per launch around four times compared to launchers with similar payload performance. The Haas 2CA has a cost of $1,400,000/launch. The simplicity also comes with high reliability as the Haas 2CA is arguably the simplest orbital vehicle ever built. Staging is one of the most common causes of orbital rockets' failures. The SSTO technology eliminates the risk associated with staging.











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