| Function | Launch vehicle |
|---|---|
| Manufacturer | OTRAG |
| Country of origin | Germany |
| Launch history | |
| Status | Retired |
| Launch sites | Shaba North,Congo Sabha, Libya Esrange,Sweden |
| Total launches | 18 |
| First flight | 18 May 1977 |
| Last flight | 19 September 1983 |
| Common Rocket Propulsion Unit | |
| Height | 16 m (52 ft) |
| Diameter | 0.27 m (11 in) |
| Empty mass | 150 kg (330 lb) |
| Gross mass | 1,500 kg (3,300 lb) |
| Powered by | 1 × OTRAG |
| Maximum thrust | 26.960 kN (6,061 lbf) |
| Specific impulse | 297 s (2.91 km/s) |
| Burn time | 140 seconds |
| Propellant | N2O4 |
TheOTRAG rocket was a modular satellite-deliveryrocket developed by theOTRAG company (German:Orbital Transport- und Raketen-Aktiengesellschaft,[1][2] orOrbital Transport and Rockets, Inc.) in the 1970s and 80s.[3][4][5] The OTRAG rocket was to become a rocket built up from several mass-produced units, intended to carry satellites with a weight of 1-10 tons or more into orbit. Mass production meant that the vehicle was projected to have been 10x cheaper than conventional vehicles of similar capability.
The West German company was based inStuttgart, and in the late 1970s and early 1980s planned to develop an alternativepropulsion system forrockets. OTRAG was the first commercial developer and producer of spacelaunch vehicles. The rocket was claimed to be an inexpensive alternative to existing launch systems through mass-production ofCommon Rocket Propulsion Units (CRPU).
OTRAG was a design quite different from conventionalmultistage rockets. The OTRAG design used parallel stages assembled from parallel tank tubes with flat bulkheads. The rockets were designed to carry loads up to two tons, the then usual weight of acommunications satellite, into ageostationary orbit. It was planned to later increase the capacity to ten tons or more using multiple identical modules.[6]
The rocket was to consist of individual pipes, each 27 cm in diameter and six meters long. Four of these pipes would be installed one above the other resulting in a 24 meter long fuel and oxidizer tank with a rocket engine at the lower end making up a CRPU. The fuel was intended to bekerosene with a 50/50 mixture ofnitric acid anddinitrogen tetroxide as an oxidiser. Ignition was provided by a small quantity offurfuryl alcohol injected before the fuel, which igniteshypergolically (immediately and energetically) upon contact with the nitric acid. To simplify the design, pumps were not used to move the fuel to the engines, instead the fuel tanks were only 66% filled, with compressed air in the remaining space to press propellants into theablatively cooled combustion chamber. Thrust control is by partially closing the electromechanical propellant valves. Pitch and yaw control can thus be achieved by differential throttling. In principle this is extremely reliable and cheap in mass production.
The modular design was intended to result in a large cost reduction due toeconomies of scale. The CRPU-based satellite launching rocket was estimated to cost approximately one tenth of conventional designs. Automated production processes for all components would reduce labor cost from 80% to 20% and remove the justification for reusability of spent stages.
One large 4 stage configurationOTRAG 10K[6] was supposed to launch a payload of 10,000 kg to a 185 km Orbit. The planned liftoff thrust was around 26 MN with a total mass of 2,300 tonnes:
The engines were tested extensively on ground rigs, on both German and African test sites. Experiments were run with varying fuel and oxidiser formulations, as the general design was quite robust.
Small, 4-unit vehicles were built and tested several sites:Shaba North in modernDemocratic Republic of the Congo andSeba Oasis,Libya. The rockets used were 6 and 12 meters long, and obtained heights of 20 to 50 kilometres. The basic CRPU concept was shown to be workable, though some rockets experienced guidance or component failures. The last launch of an OTRAG rocket took place on September 19, 1983, atEsrange. Following this launch, the OTRAG rocket was to be used in high altitude research.
Political pressure then shut down the project, as discussed in theOTRAG article.
After the company had left Libya in 1987, some remaining equipment was confiscated by the government. However, enough parts and knowledge were missing to prevent Libya from continuing the project.[citation needed]
| Date | OTRAG variant | Apogee (km) | Launch site | Details |
|---|---|---|---|---|
| 1977 May 18 | 4x9m | 15 | Shaba North | Four-module test vehicle, 6 m long; propulsion test |
| 1978 May 19 | 4x9m | 30 | Shaba North | Four-module test vehicle, 6 m long; high altitude night test |
| 1978 Jun 5 | 4x15m | 0 | Shaba North | Lost control and crashed after seconds |
| 1981 Mar 1 | 4x15m | 150? | Sabha, Libya | 300 km apogee according to astronautix; failure according to Leitenberger |
| 1981 Jun 7 | 4x15m | 50? | Sabha, Libya | High acceleration test, 20 % propellant load |
| 1981 Sep 17 | 1x15m | 50? | Sabha, Libya | Engine induced roll test |
| 1981 Oct 1 | 1x15m | 50? | Sabha, Libya | Burn to depletion test |
| 1981 Oct 24 | 1x15m | 50? | Sabha, Libya | Oxidizer depletion test |
| 1981 Nov 19 | 1x15m | 50? | Sabha, Libya | Fuel depletion test |
| 1981 Dec 12 | 1x15m | 50? | Sabha, Libya | Onboard TV camera test |
| 1982 Jun 2 | 1x15m | 50? | Sabha, Libya | Deep throttling test |
| 1982 Jun 24 | 1x15m | 10? | Sabha, Libya | Early cut-off and destruct test |
| 1982 Sep 2 | 1x15m | 50? | Sabha, Libya | Roll control test |
| 1982 Sep 11 | 1x15m | 50? | Sabha, Libya | Stage separation simulation |
| 1982 Nov 10 | 1x15m | 50? | Sabha, Libya | 60 degree elevation launch |
| 1982 Nov 16 | 1x15m | 50? | Sabha, Libya | RFNA oxidizer test |
| 1982 Dec 9 | 1x15m | 50? | Sabha, Libya | JP-4 fuel test |
| 1983 Sep 19 | 4x9m | 4 | ESRANGE |
 | |
| Industry | Alternative propulsion system for rockets |
|---|---|
| Founded | 1974 (1974) inNeu-Isenburg,West Germany |
| Founder | Lutz Kayser |
| Defunct | 1987 |
| Fate | Nationalized byLibya |
| Headquarters | Stuttgart ,West Germany |
Area served | West Germany,Zaire, Libya |
Key people | Lutz Kayser Kurt H. Debus Frank Wukasch Wolfgang Pilz Wernher von Braun |
OTRAG was founded on October 17, 1974[10] by German aerospace engineerLutz Kayser. OTRAG's goal was to develop, produce, and operate a low-cost satellite launch vehicle. It was the first private company to attempt to launch a private spacecraft.[11] TheOTRAG rocket was intended to be an inexpensive alternative to the European rocketAriane and the NASASpace Shuttle.[12] Kayser and a private consortium of six hundred European investors financed the development and production of the OTRAG satellite launch vehicle. Dr.Kurt H. Debus served as Chairman of the Board of OTRAG (1974–1980) after his retirement as director of NASA'sKennedy Space Center,[13][14] and Dr.Wernher von Braun served as scientific adviser to Kayser.
In the face of doubts by Debus and von Braun, Kayser chose in 1975 to set up testing and launch facilities in Shaba,Zaire (nowKatanga Province,Democratic Republic of the Congo). Debus and von Braun were concerned about the possibility of Zairian acquisition ofmissile technology from the facilities. Kayser decided to proceed despite their opposition.
Otrag's first test was on May 17, 1977, with the second successful launch on May 20, 1978. The third test, 16 days later, failed on June 5, 1978, withZairian PresidentMobutu Sese Seko watching the launch.[15]
Political pressure to halt the company's operations mounted quickly. France and the Soviet Union were historically opposed to German long-distance rocket development and pressured the Zairian government into closing down the development facility in 1979. Immediately afterwards, PresidentsGiscard d'Estaing of France andLeonid Brezhnev of the Soviet Union convinced theWest German government to cancel the OTRAG project and close down its German operations. In 1980, OTRAG moved its production and testing facilities to a desert site in Libya. A series of successful tests was conducted at this site beginning in 1981.[16]
OTRAG shut down in 1987.[15] As the company left Libya,Muammar Gaddafi confiscated all equipment and installations, hoping to later use the technology, and German investors lost their money.[17]
Only a few political controversies are known concerning OTRAG, which involve the concerns of neighbors in Zaire and Libya about thedual use potential of rockets. A full orbital launch vehicle was never assembled. Modules were flight tested inZaire andLibya. 6,000static rocket engine tests and 16 single-stage qualification tests were made to prove the concept as feasible[citation needed].
Hans Dietrich Genscher, the then-minister of German foreign affairs, is said to have finally stopped the project under pressure from France and the Soviet Union,[citation needed] and West Germany joined the co-financed "European rocket"Ariane project, which made the OTRAG project unnecessary and eliminated political entanglements of a still divided Germany in the early 1980s.
Around 2009, Lutz Kayser had been advisingInterorbital Systems, resulting in a similar modular rocket design for their Neptune series.[18]
John Carmack, CEO ofArmadillo Aerospace met withLutz Kayser, the founding engineer of OTRAG, in May, 2006 who loaned Carmack some of their original research hardware.
"I have been corresponding with Lutz for a few months now, and I have learned quite a few things. I seriously considered an OTRAG style massive-cluster-of-cheap-modules orbital design back when we had 98% peroxide (assumed to be a biprop with kerosene), and I have always considered it one of the viable routes to significant reduction in orbital launch costs. After really going over the trades and details with Lutz, I am quite convinced that this is the lowest development cost route to significant orbital capability. Eventually, reusable stages will take over, but I actually think that we can make it all the way to orbit on our current budget by following this path. The individual modules are less complicated than our current vehicles, and I am becoming more and more fond of high production methods over hand crafter prototypes." -- June 2006 Armadillo Aerospace Update[19]
ARCA Space Corporation have also been inspired by the OTRAG rocket for the design of the EcoRocket Heavy.[20][unreliable source?]Interorbital Systems also uses a similar configuration in some variants of their NEPTUNE rocket.
