Simorgh (rocket)

Simorgh is a two-stage liquid-fueled rocket developed from the Safir rocket. It is able to place a 250 kg (550 lb) payload into a circular 500 km (310 mi) low Earth orbit (LEO). It is also the first Iranian rocket that can place multiple payloads into orbit (e.g., one main payload and several secondary cubesats). In comparison, the Safir was only able to place a 50 kg payload into a 250x375 km elliptic orbit.[8][9]

The Simorgh rocket is 26.5 metres (87 ft) long, and has a launch mass of 87 tonnes (192,000 lb). Its first stage with a diameter of 2.4 meters is powered by a cluster of four synchronized Safir-1B first-stage engines with four separate turbopumps, each of these engines generating up to 37,000 kilograms-force (360 kN; 82,000 lbf) of thrust. The first stage also utilize a set of four vernier engines sharing a single turbopump used for attitude control and providing an additional 14,000 kgf (140 kN; 31,000 lbf). At liftoff, these engines generate a total 162,000 kgf (1,590 kN; 360,000 lbf) of thrust.[10][11] The second stage with a diameter of 1.5 meters utilizes a set of four smaller engines similar to the two engines of Safir's second stage. These produce a total 7,000 kgf (69 kN; 15,000 lbf) of thrust.[11][12]

The Simorgh's total flight time to a 500-530km orbit is between 480 and 495 seconds.[8] The first stage burns for about 102 seconds.[13] Stages separation takes place at an altitude of 90 km and a velocity of 2300 m/s. The fairing shroud is ejected simultaneously to the second stage engines ignition. The satellite is then accelerated to 7400 m/s and injected into its designated orbit.[8]

In contrast to its predecessor Safir, the Simorgh is integrated and assembled vertically on a launch pad located at the Imam Khomeini Space Center. Each stage goes through manufacturing horizontally and is subsequently brought to the launch pad, where final assembly of the stages are completed with the aid of a custom designed service tower.[8]

The Simorgh launch pad at the Imam Khomeini Space Center.

Saman-1 is a solid-fueled orbital transfer system under development that produces 1,300 kgf (13 kN; 2,900 lbf) of thrust and will be used as an additional upper stage in future.[11][12][14]

The development of the Simorgh has been marked with difficulties and unreliability of certain sub-systems due to the overcomplexity of its engines and turbopumps. Out of the system's first four launches (two orbital and two sub-orbital launches) there have been three failures, giving the rocket a reliability rating of twenty five percent. There were however, indications of progressive improvements to the design and reliability of the system with each successive launch; with the 2017 launch operating for 120 seconds before failure, the 2019 launch operating 450 seconds before failure, and the 2020 launch operating correctly for 475 seconds out of the 490 seconds of operation required for a successful mission, giving the missions a 25, 92, and 97 percent success rate respectively, indicating a trend of increasing reliability in the design.[8][15][16]

• 
  Simorgh during the launch of Payam satellite on 15 January 2021
• 
  Simorgh during launch preparations
• 
  Simorgh in its servicing tower

• Comparison of orbital launchers families
• Comparison of orbital launch systems
• Iranian Space Agency
• Saman-1 (rocket stage)

Other Iranian satellite launch vehicles

• Safir (rocket)
• Qased (rocket)
• Qaem-100 (rocket)
• Zuljanah (rocket)