The Epsilon Launch Vehicle, or 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 scientificsatellites. 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.[7]
Vehicle description
The development aim is to reduce the US$70 million launch cost of an M-V;[8] the Epsilon costs US$38 million per launch.[9] Development expenditures by JAXA exceeded US$200 million.[9]
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-I 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.[10]
The Epsilon is expected to have a shorter launch preparation time than its predecessors;[11][12][13] a function called "mobile launch control" greatly shortens the launch preparation time, and needs only eight people at the launch site,[14] compared with 150 people for earlier systems.[15]
The rocket has a mass of 91 t (90 long tons; 100 short tons) and is 24.4 m (80 ft) tall and 2.5 m (8 ft 2 in) in diameter.[16][17]
Enhanced version
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).[18]
Epsilon's first stage has been the modified SRB-A3 which is the solid-rocket booster of H-IIA. As the H-IIA is to be decommissioned and to be replaced by H3, Epsilon is to be replaced by new version, named Epsilon S.[21]
The first stage is based on SRB-3, the strap-on solid-rocket booster of H3.
The third stage is a new design, whereas Epsilon's third stage was based on the M-V's third stage. New third stage is three-axis stabilized using Post-Boost Stage (PBS), whereas Epsilon's third stage was spin-stabilized. Also the third stage is outside the fairing, whereas Epsilon's fairing covered the third stage.
The Epsilon S Post-Boost Stage is mandatory, whereas Epsilon's PBS was optional.
The first launch of Epsilon S is planned in 2023.[21]
On July 14, 2023, the second stage of Epsilon S failed during a test firing.[22]
Launch statistics
Launch outcomes
1
2013
'14
'15
'16
'17
'18
'19
2020
'21
'22
Failure
Partial failure
Success
Planned
Launch history
Epsilon launch vehicles are launched from a pad at the Uchinoura Space Center previously used by Mu launch vehicles. The maiden flight, carrying the SPRINT-A scientific satellite, lifted off at 05:00 UTC (14:00 JST) on 14 September 2013. The launch was conducted at a cost of US$38 million.[23]
On 27 August 2013, the first planned launch of the launch vehicle 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 launch vehicle 0.07 seconds before the information was actually transmitted.[24]
The initial version of Epsilon has a payload capacity to low Earth orbit of up to 500 kilograms,[25][26] with the operational version expected to be able to place 1,200 kg (2,600 lb) into a 250 by 500 km (160 by 310 mi) orbit, or 700 kg (1,500 lb) to a circular orbit at 500 km (310 mi) with the aid of a hydrazine fueled stage.[9]
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.[48] Solid-fuel rocket data potentially has military value,[48] and Epsilon is considered as potentially adaptable to an intercontinental ballistic missile.[49] 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.[50]
^ abcdefg"イプシロンSロケット開発状況に関する説明会" [Press Briefing on the development status of the Epsilon S rocket] (PDF) (in Japanese). JAXA. 7 July 2023. Retrieved 16 March 2024.
^ abc"イプシロンSロケット第3段モータ（E-31）地上燃焼試験結果" [Results of ground test firing of 3rd stage of the Epsilon S rocket (E-31)]. 9 June 2023. Retrieved 16 March 2024.
^Yasuhiro Morita; Takayuki Imoto; Hiroto Habu; Hirohito Ohtsuka; Keiichi Hori; Takemasa Koreki; Apollo Fukuchi; Yasuyuki Uekusa; Ryojiro Akiba (10 July 2009). "Advanced Solid Rocket Launcher and its Evolution"(PDF). 27th International Symposium on Space Technology and Science.
^"JASMINE（赤外線位置天文観測衛星）で拓く天の川中心核と地球型惑星の探査" [JASMINE (Infrared Astrometry Satellite) will pioneer the exploration of the Milky Way's core and terrestrial planets] (PDF). NAOJ News (in Japanese). No. 332. National Astronomical Observatory of Japan. 1 March 2021. p. 6. ISSN0915-8863. Retrieved 29 April 2021.
^Yonetoku, Daisuke (8 September 2021). "ガンマ線バーストを用いた初期宇宙・極限時空探査計画HiZ-GUNDAM"(PDF) (in Japanese). Group of Optical and Infrared Astronomers. Retrieved 16 November 2021.
^"宇宙基本計画⼯程表 (令和５年度改訂)" [Basic Plan on Space Policy (2023 Revision)] (PDF) (in Japanese). Cabinet Office. 22 December 2023. p. 45. Archived(PDF) from the original on 25 December 2023. Retrieved 26 December 2023.
This Template lists historical, current, and future space rockets that at least once attempted (but not necessarily succeeded in) an orbital launch or that are planned to attempt such a launch in the future
Symbol † indicates past or current rockets that attempted orbital launches but never succeeded (never did or has yet to perform a successful orbital launch)
