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Epsilon flight F2 before launch in December 2016
Epsilon flight F2 before launch in December 2016

The Epsilon rocket (イプシロンロケット, Ipushiron roketto) (formerly Advanced Solid Rocket) is a Japanese solid-fuel rocket designed to launch scientific satellites. It is a follow-on project to the larger and more expensive M-V rocket which was retired in 2006. The Japan Aerospace Exploration Agency (JAXA) began developing the Epsilon in 2007. It is capable of placing a 590 kg payload into Sun-synchronous orbit.[3]

Vehicle description


The development aim is to reduce costs compared to the US$70 million launch cost of an M-V.[4] The Epsilon costs US$38 million (£23m) per launch, which is half the cost of its predecessor.[5] Development expenditures by JAXA exceeded US$200 million.[5]

To reduce the cost per launch the Epsilon uses the existing SRB-A3, a solid rocket booster on the H-IIA rocket, as its first stage. Existing M-V upper stages will be used for the second and third stages, with an optional fourth stage available for launches to higher orbits. The J-1 rocket, which was developed during the 1990s, but abandoned after just one launch, used a similar design concept, with an H-II booster and Mu-3S-II upper stages.[6]

The Epsilon is expected to have a shorter launch preparation time than its predecessors.[7][8][9] Due to a function called "mobile launch control",[10] the rocket needs only eight people at the launch site, compared with 150 people for earlier systems.[11]

The rocket has a mass of 91 tonnes (90 long tons; 100 short tons) and is 24.4 metres (80 ft) tall and 2.5 metres (8.2 ft) in diameter.[12][13]

After the successful launch of the Epsilon first flight (demonstration flight), the improvement plan was decided to handle the planned payloads (ERG and ASNARO-2).[14]

Requirements for the improvement:[14]

  • Apogee ≧ 28700 km (summer launch), ≧ 31100 km (winter launch) of a 365 kg payload
  • Sun-synchronous orbit (500 km) of a ≧ 590 kg payload
  • Larger fairing

Planned characteristics:[14]

  • Height: 26.0 m
  • Diameter: 2.5 m
  • Mass: 95.1 t (Standard) / 95.4 t (Optional 4th stage (post-boost stage))

Catalog performance according to IHI Aerospace:[15]

  • Low-earth orbit (250 km × 500 km): 1.5 t
  • Sun-synchronous orbit (500 km × 500 km): 0.6 t

Final characteristics:[3][16]

  • Height: 26.0 m
  • Diameter: 2.6 m (max), 2.5 m (fairing)
  • Mass: 95.4 t (Standard) / 95.7 t (Optional)

Launch statistics


Launch history


Epsilon rockets are launched from a pad at the Uchinoura Space Center previously used by Mu rockets. The maiden flight, carrying the SPRINT-A scientific satellite, lifted off at 05:00 UTC (14:00 JST) on September 14, 2013. The launch was conducted at a cost of $38 million.[17]

On August 27, 2013, the first planned launch of the rocket had to be aborted 19 seconds before liftoff because of a botched data transmission. A ground-based computer had tried to receive data from the rocket 0.07 seconds before the information was actually transmitted.[18]

The initial version of Epsilon has a payload capacity to low Earth orbit of up to 500 kilograms,[19][20] with the operational version expected to be able to place 1,200 kilograms (2,600 lb) into a 250 by 500 kilometres (160 by 310 mi) orbit, or 700 kilograms (1,500 lb) to a circular orbit at 500 kilometres (310 mi) with the aid of a hydrazine fueled stage.[5]

Planned launches


Sources: Japanese Cabinet[28]

Internet data leak


In November 2012, JAXA reported that there had been a possible leak of rocket data due to a computer virus. JAXA had previously been a victim of cyber-attacks, possibly for espionage purposes.[29] Solid-fuel rocket data potentially has military value,[29] and Epsilon is considered as potentially adaptable to an intercontinental ballistic missile.[30] The Japan Aerospace Exploration Agency removed the infected computer from its network, and said its M-V rocket and H-IIA and H-IIB rockets may have been compromised.[31]

See also


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