Simorgh (rocket)

Simorgh (Persian: ماهواره‌بر سیمرغ, Simurgh), also called Safir-2, is an Iranian expendable launch vehicle under development.^[4][5] It is the successor of the Safir, Iran's first space launch vehicle.^[6] Its mission is to carry heavier satellites into higher orbit than Safir.^[7]

Simorgh

The Simorgh satellite launch vehicle launching on its first orbital test flight on 27 July 2017.
Function	Small-lift space launch vehicle
Country of origin	Iran
Size
Height	25.9 m (85 ft)
Diameter	2.4 m (7 ft 10 in) first stage, 1.5 m (4 ft 11 in) second stage
Mass	87 t (192,000 lb)
Stages	2 (optional 3rd stage)
Capacity
Payload to LEO 200 km
Mass	800 kg (1,800 lb)[1]
Payload to LEO 500 km
Mass	250 kg (550 lb)[2]
Payload to LEO 500 km (with Saman-1)
Mass	400 kg (880 lb)
Associated rockets
Family	Derived from Safir
Launch history
Status	Active
Launch sites	Imam Khomeini Space Launch Terminal
Total launches	7 or 8 (1 suborbital)
Success(es)	3 (1 suborbital)
Failure(s)	3 or 4
First flight	19 April 2016 (suborbital) 27 July 2017 (orbital)
Last flight	6 December 2024 (orbital)
First stage
Height	17.8 m
Diameter	2.4 m
Powered by	4 × modified Shahab-3 engines[3] + 4 verniers
Maximum thrust	1,590 kN (360,000 lbf)
Burn time	120 seconds
Propellant	N2O4 / UDMH
Second stage
Diameter	1.5 m
Powered by	4 × LRE-4 (R-27 Zyb vernier engines)
Maximum thrust	71.6 kN (16,100 lbf)
Burn time	320 seconds
Propellant	N2O4 / UDMH
Third stage (Optional)
Powered by	Saman-1
Maximum thrust	13 kN (2,900 lbf)
Burn time	40 seconds
Propellant	Solid

The project was unveiled by Iranian President Mahmoud Ahmadinejad on 3 February 2010, as part of celebrations of the first anniversary of the launch of Omid, the first indigenously launched Iranian satellite,^[8] and was launched for the first time on 19 April 2016.^[9]

Design

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.^[10][11]

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.^[12][13] 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.^[13][14]

The Simorgh's total flight time to a 500-530km orbit is between 480 and 495 seconds.^[10] The first stage burns for about 102 seconds.^[15] 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.^[10]

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.^[10]

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.^[13][14][16]

Reliability

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, 97, percent success rate respectively, indicating a trend of increasing reliability in the design.^[10][17][18]

Launch history

Satellite(s)	Date & Time (UTC)	Launch Site	Satellite Mass	Outcome	Remarks
No payload	19 April 2016	Semnan LP-2	N/A	Success	Sub-orbital test flight.[9]
No payload	27 July 2017	Semnan LP-2	100 kg[19]	Failure	Orbital test flight.[15] Simorgh operated for 136 seconds.[15] Second stage failed.[20]
Payam (named "AUT-SAT" previously)[20]	15 January 2019	Semnan LP-2	90 kg[21]	Failure	Orbital test flight.[15] Simorgh operated for 455 seconds.[15] Third stage failed.[22]
Zafar-1[23]	9 February 2020, 15:45	Semnan LP-2	113 kg[24]	Failure	Orbital test flight.[25] Simorgh operated for 475 seconds. Satellite reached speed of 6,500 m/s out of the 7,400 m/s required to orbit. First stage operated fully correctly.[15][26] Second stage failed.[25]
Unknown	12 June 2021	Semnan LP-2		Disputed launch existence	U.S. official stated "is aware of an Iranian rocket launch failure". Satellite imagery "looked like a launch" occurred. Iran's Telecommunications Minister denied any launch.[27]
Three research devices[28]	30 December 2021	Semnan LP-2	TBA	Failure	Orbital test flight.[7]First time Iran launched multiple payloads in the same launch.[7] Simorgh operated for about 600 seconds (500 seconds for the second stage). Devices didn't enter orbit; reached an altitude of 470 km and a speed of 7,350 m/s, out of the 7,600 m/s required.[29][30]
Mahda, Keyhan-2 and Hatef-1	28 January 2024	Semnan LP-2	TBA	Success	First successful orbital launch of Simorgh, placed three satellites into a 1100 x 450 km orbit. The launch occurred just 8 days after the first successful orbital launch of Qaem 100.
Saman-1, Fakhr-1 and one other research satellite	6 December 2024	Semnan LP-2	300 kg	Success	The launch of the Saman-1 orbital transfer block to an altitude of 400 kilometers, along with two other payloads (including the Fakhr-1 satellite), with a total weight of 300 kilograms, breaking weight record.
Navak-1	February 18, 2025.	Semnan LP-2	40 kg	Unknown	Reports initially stated that Iran planned to launch the 40 kg "Navak" satellite into GTO orbit (200 to 31,000 km altitude) on February 18, 2024. However, updates on the mission stopped, suggesting the launch may have failed — though officials likely withheld the news to avoid harming the country’s image. [31]

Gallery

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

See also

• 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)