SOHEIL
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Al-Abid LV
As declared by Iraq, Al Abid, was a project to design and manufacture a space launcher capable of putting a satellite into orbit and was an entirely civilian project. The project commenced in 1988. The programmes declared name was Al Abid. The project was carried out under the auspices of MIMI and involved scientists from Iraqs Space Research Centre, who had built a 50 kg test satellite and engineers from Project 144, primarily Project 144/2, to develop a launch vehicle.
Their task was to prepare independent studies for a space launcher capable of delivering a 100-300 kg payload to a low earth orbit (about 200-500 km altitude). The delivery system had to be produced using assets already existing in Iraq, mainly Scud, versions of indigenously modified Scud and SA-2 liquid propellant missiles.
A number of design configurations were studied by SRC. Among the initial design options studied were configurations based on 4, 5 or 6 extended burn-time Scud rockets as a first stage clustered around another extended burn-time Scud as second stage, with a specially designed solid propellant rocket as the third stage.
Another study focused on various configurations using 5 or 7 Scud-based rockets as a first stage, separated from a second stage modified Scud rocket by an inter-stage mechanism, and a specially designed rocket for the third stage. By early 1989, the SRC proposals had apparently converged on a design comprising 5 clustered modified Scud's for the first stage; another modified Scud for the second stage and a double-base propellant rocket for third stage.
The other team of two foreign specialists provided the results of their studies in two reports in February 1989. Their studies were based on design configurations comprising a modified Scud rocket with strap-on rockets of either four or eight SA-2 liquid propellant rockets or four or eight Scud rockets. Both a liquid propellant and a solid propellant second stage were considered and a representative apogee motor was used for their parametric calculations.
The basic vehicle design configuration chosen by the Iraqis by mid-1989 consisted of five clustered, extended burn Scud engines for the first stage and a 1250mm diameter liquid propellant rocket for the second stage. It is unclear if details of the third stage rocket had been determined at that time, although some evidence points to use of another modified Scud. The major effort at the time was on the first and second stages.
The first test launch of the Al Abid occurred in December 1989 at the fixed launch site that had been constructed at Al Anbar. However, only the first stage of the vehicle tested was operational, while stages two and three were steel mockups. A videotape of the test showed that the first stage of five clustered Scud missiles was working successfully until the vehicle exploded at 45 seconds. Iraq suspected that the explosive bolts that were being used to effect stage separation functioned prematurely.
While primary concentration in the initial flight test was on validating the first stage, work for the second and third stages had also commenced. In the initial design studies undertaken by SRC, the second stage was to be a Scud with an extended burn-time but with the standard airframe diameter of 880mm. However, by the beginning of 1989 the diameter of the second stage had been increased to 1250mm.
Al-Abid LV on base of Al-Abbas missiles
The main problem that Iraq had with the second stage was that a standard Scud liquid propellant engine produced only sufficient impulse to achieve their minimum requirements. SRC had highlighted through its early parametric studies that orbital capability, that is, heavier payload or higher orbit, was markedly more sensitive to changes in second stage performance than to changes in the first stage performance.
They proposed that the performance of the second stage rocket engine could be improved, firstly, by increasing the expansion ratio of the engine nozzle from 10 to 30 by addition of a nozzle skirt and, secondly, by changing the fuel to diethylenetriamine (DETA) or a mixture of DETA and unsymmetrical dimethyl hydrazine (UDMH).
Iraq focused on improving the Scud engine. Project 1728 was conducting work in parallel with the work done by Project 144/2, looking to improve the performance of Al Abid second stage engine. A test was carried out on 1 Dec 1990 by Project 1728 that used a nozzle extension for increased expansion ratio and UDMH as fuel for higher energy. However, without any cooling to emulate a high altitude condition the skirt melted and the test failed after 14 seconds.
Iraq declared that they came up with the idea to use a new engine with four Scud combustion chambers and a single turbo-pump for the Al Abid first stage. The new engine would fit the 1250mm airframe, and using a mixture of DETA and UDMH fuel would provide an alternative to the cluster of five Scud missiles.
Further informations: http://www.thespacereview.com/archive/1498.pdf
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