The Haas rocket series was named after Austrian-Romanian medieval rocket pioneer Conrad Haas (1509-1579),. The series ranges from a small orbital launcher able to launch 10kg of payload to LEO, up to a heavy launcher able to put 60 tons of payload to LEO.

This program debuted in 2012 but it was impacted in terms of development schedule by various factors as ARCA's involvement in the ESA's ExoMars program or the opening of an ARCA branch in the US in 2014..

However, the Haas rocket program is the foundation on which we are building the EcoRocket's upper stages.



The Haas 2CA Single Stage to Orbit (SSTO) rocket, was designed to launch 100 kg of payload into low earth orbit at $1million/launch. The rocket has an exceptional mass ratio and it has one stage that is fuelled by hydrogen peroxyde and kerosene. The SSTO configuration is made possible by the use of:


- dense propellants;

- advanced fabrication techniques for the composite propellant tanks;

- the Executor linear aerospike engine that promises optimum performance at virtually all flight levels, allowing the use of up to 30% less fuel than any other rocket engine;

- the thrust vectoring control achieved by throttling 8 out of 16 combustion chambers, eliminating the heavy and complex gimbaling system for the engine.

This rocket is extremely simple and, therefore, affordable to construct and operate. After the full qualification, the vehicle could be operated from inland spaceports as there are no stages that fall to the ground at burnout. It's intended to be the most responsive orbital launcher ever created, being able to reach orbit in less than 24 hours from the moment of launch decision.

The Haas rocket can be used as a stand alone SSTO rocket or in combination with the Launch Assist System that significantly increases the rocket's payload capability up to six times.



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. The Executor aerospike engine aims to keep construction costs low, without sacrificing the high performance. The thrust vectoring control is achieved by throttling the 16 combustion chambers, changing the individual chamber mixture ratio. This eliminates the heavy and complex gimbaling system for the engine.

In the photos below: XRS-2200 linear aerospike engine (left), the Executor linear aerospike engine for the Haas 2CA (right).



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. The Haas 2CA rocket has an exceptional mass ratio of 29. 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.



Length (m):


Diameter (m):


Empty weight (kg):


Take-off weight (kg):


Engine type:


Number of stages:


Engine feed:

pressure fed


heated LHe


HTP + RP-1

Cooling type:

ablative + film

Engine run time (s):


Thrust SL (kgf):


Thrust VAC (kgf):


Specific impulse SL (s):


Specific impulse VAC (s):


Peroxide flow rate (kg/s):


RP-1 flow rate (kg/s):


Mixture ratio including film: 


Tank pressure (barg):


Chamber pressure (barg):


Payload to LEO (kg):





Since the successful development of the ecological, exceptionally cost effective Launch Assist System, ARCA is committed to build an orbital launcher as clean and cost effective as possible and the Haas rocket design and technology will be included in the EcoRocket program. The Haas rocket technology will be the base on which we will develop the EcoRocket upper stage, incorporating the aerospike engine, the fully composites construction with exceptional mass ratio.

Below: three configurations of Haas and LAS vehicles connected for enhanced performance of the Haas design.