Iran's Safir launch vehicle

Abstract

Iran joined a select group of nations having indigenous satellite launch capability, when it orbited its Omid satellite on the night of February 02, 2009 on board its indigenously developed launch vehicle Safir 2. The event was widely covered in the media and images and video footage of the launch have been posted on the internet. According to the media information Safir is a two stage launch vehicle and Omid is a 27 kg ‘store and forward’ communication satellite with a life of 2 to 3 months. The satellite is placed in 248 x 378 km and orbits the earth 15 times a day. The first stage: The launch images confirm the first stage pedigree with the North Korean Nodong missile. The fin shape, the jet vane control system and the exhaust plume signature of the Nodong and Safir first stage are quite similar. North Korea has sold and transferred the technology of this missile to Iran, where it is known as Shahab 3B. (It may be noted that the Pakistani missile Ghauri has a similar linkage to Nodong missile). From the nozzle exhaust signature, it is clear that a single engine (and not a cluster of 2 or 4 engines) is employed for the first stage. The following inferences are drawn on the basis of the North Korean Nodong missile heritage: The stage uses a hypergolic propellant combination comprising AK -271 (27% N2O4 + 73% HNO3) as oxidizer and TM-185 (20% Gasoline + 80% Kerosene) as fuel. The diameter though not directly measurable can be inferred to be about 1.3 m. The stage uses jet vanes for steering. This system originally employed in the Scud missiles was adapted by the North Koreans for their Nodong missiles. From measurements on the Safir images the length of the first stage is about 15 m. This length includes the engine, the oxidizer and fuel tanks. Our earlier measurement of engine length on the Shahab 3 missile was seen to be 2.25 m. Taking this length for the Safir engine and making allowances for the engine-tank interface as well as the space between the oxidizer and fuel tanks, the total tank length is estimated to be 11.8 m— longer than the tank length of 9.3 m in Shahab 3A and 11 m in Shahab 3B, resulting in improved propellant loading. From this, the propellant and the total stage mass have been estimated to be 18.6 tonnes and 21.6 tonnes respectively.