Epsilon flight F2 before launch in December 2016
FunctionLaunch vehicle
Country of originJapan
Cost per launchUS$39 million[1]
Height24.4 m (Demonstration Flight)
26 m (Enhanced)
27.2 m (Epsilon S)[2]
Diameter2.5 m
Mass91 t (Demonstration Flight)
95.4 t (Enhanced)
~100 t (Epsilon S)
Payload to 250 x 500 km orbit
Standard 3 stages configuration
Mass1,500 kg (3,300 lb)
Payload to 500 km orbit
Optional 4 stages configuration
Mass700 kg (1,500 lb)
Payload to 500 km orbit
Epsilon S
Mass1,400 kg (3,100 lb)[2]
Payload to 500 km SSO
Optional 4 stages configuration
Mass590 kg (1,300 lb)
Payload to 700 km SSO
Epsilon S
Mass600 kg (1,300 lb)[2]
Launch history
Launch sitesUchinoura
Total launches6
Partial failure(s)0
First flight14 September 2013
Last flight12 October 2022
First stage (Demonstration Flight/Enhanced) – SRB-A3
Powered by1 solid
Maximum thrust2,271 kN (511,000 lbf)[3]
Specific impulse284 s (2.79 km/s)
Burn time116 seconds
First stage (Epsilon S) – SRB-3
Powered by1 solid
Maximum thrust2,158 kN (485,000 lbf)[4]
Specific impulse283.6 s (2.781 km/s)
Burn time105 seconds
Second stage (Demonstration Flight) – M-34c
Powered by1 solid
Maximum thrust371.5 kN (83,500 lbf)[3]
Specific impulse300 s (2.9 km/s)
Burn time105 seconds
Second stage (Enhanced) – M-35
Powered by1 solid
Maximum thrust445 kN (100,000 lbf)[3]
Specific impulse295 s (2.89 km/s)[5]
Burn time129 seconds [5]
Second stage (Epsilon S) – E-21[2]
Powered by1 solid
Maximum thrust610 kN (140,000 lbf)[2]
Specific impulse294.5 s (2.888 km/s)[2]
Burn time120 seconds[2]
Third stage (Demonstration Flight) – KM-V2b
Powered by1 solid
Maximum thrust99.8 kN (22,400 lbf)[3]
Specific impulse301 s (2.95 km/s)
Burn time90 seconds
Third stage (Enhanced) – KM-V2c
Powered by1 solid
Maximum thrust99.6 kN (22,400 lbf)[3]
Specific impulse299 s (2.93 km/s)[5]
Burn time91 seconds[5]
Third stage (Epsilon S) – E-31[6]
Powered by1 solid
Maximum thrust135 kN (30,000 lbf)[6]
Specific impulse~295 s (2.89 km/s)
Burn time108 seconds[6]
Fourth stage (Optional) – CLPS
Maximum thrust40.8 N (9.2 lbf)
Specific impulse215 s (2.11 km/s)[3]
Burn time1100 seconds (maximum)

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 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.[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]

Requirements for the improvement:[18]

Planned characteristics:[18]

Catalog performance according to IHI Aerospace:[19]

Final characteristics:[7][20]

Epsilon S

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]

Major changes of Epsilon S from Epsilon are:[21]

Planned performance of Epsilon S is:[21]

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

  •   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]

Flight No. Date / time (UTC) Rocket,
Launch site Payload Payload mass Orbit Customer Launch
1 14 September 2013
Epsilon 4 Stages [27] Uchinoura Space Center SPRINT-A (HISAKI) 340 kg LEO JAXA Success
Demonstration Flight
2 20 December 2016
11:00:00 [28]
Epsilon 3 Stages Uchinoura Space Center ERG (ARASE) 350 kg [29] Geocentric JAXA Success
3 17 January 2018
21:06:11 [30]
Epsilon 4 Stages [31] Uchinoura Space Center ASNARO-2 570 kg SSO Japan Space Systems Success
4 18 January 2019
00:50:20 [32]
Epsilon 4 Stages Uchinoura Space Center RAPIS-1
200 kg SSO JAXA Success[28]
Innovative Satellite Technology Demonstration-1; component demonstration and technology validation.[33]
5 9 November 2021
00:55:16 [34][35]
Epsilon PBS Uchinoura Space Center RAISE-2
110 kg SSO JAXA Success
Innovative Satellite Technology Demonstration-2.
6 12 October 2022
00:50:00 [36]
Epsilon 4 Stages Uchinoura Space Center RAISE-3
110 kg SSO JAXA, iQPS Failure
RAISE-3 and the six CubeSats were part of Innovative Satellite Technology Demonstration-3. QPS-SAR 3/4 were Epsilon's first commercial satellites launch contracts. Vehicle was destroyed by flight termination system shortly after second stage cutoff due to an attitude control fault.[36][37] A report regarding the cause has been published and is available for viewing, although it is in Japanese.[38]

Planned launches

Date / time (UTC) Rocket,
Launch site Payload Orbit Customer
2024[39] Epsilon S Uchinoura Space Center LOTUSat-1[40] SSO VNSC
2025 Epsilon S Uchinoura Space Center Innovative Satellite Technology Demonstration-4 LEO JAXA
2025[41] Epsilon S Uchinoura Space Center DESTINY+ Heliocentric JAXA
2027 Epsilon S Uchinoura Space Center Innovative Satellite Technology Demonstration-5 LEO JAXA
July 2028[42] Epsilon S Uchinoura Space Center Solar-C EUVST[43][44] SSO JAXA
2028 Epsilon S Uchinoura Space Center JASMINE[45] SSO JAXA
2029 Epsilon S Uchinoura Space Center Innovative Satellite Technology Demonstration-6 LEO JAXA
2030[46] Epsilon S Uchinoura Space Center HiZ-GUNDAM [ja] SSO JAXA
2031 Epsilon S Uchinoura Space Center Innovative Satellite Technology Demonstration-7 LEO JAXA

Sources: Japanese Cabinet[47]

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.[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]

See also


  1. ^ "U.S. GAO - Surplus Missile Motors: Sale Price Drives Potential Effects on DOD and Commercial Launch Providers". U.S. Government Accountability Office. 16 August 2017. Retrieved 18 January 2019.
  2. ^ a b c d e f g "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.
  3. ^ a b c d e f "イプシロンロケットの開発および準備状況" (PDF). JAXA. Retrieved 16 September 2013.
  4. ^ "H3 Launch Vehicle Brochure" (PDF). Archived (PDF) from the original on 11 February 2017. Retrieved 20 September 2016.
  5. ^ a b c d Koki KITAGAWA; Shinichiro TOKUDOME; Keiichi HORI; Haruhito TANNO; Nobuyuki NAKANO2 (2019). "Development and Flight Results of Solid Propulsion System for Enhanced Epsilon Launch Vehicle". Trans. JSASS Aerospace Tech. Japan. 17 (3): 289–294. Bibcode:2019JSAST..17..289K. doi:10.2322/tastj.17.289. Retrieved 9 March 2023.((cite journal)): CS1 maint: numeric names: authors list (link)
  6. ^ a b c "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.
  7. ^ a b "Epsilon Launch Vehicle" (PDF). JAXA. Retrieved 25 January 2018.
  8. ^ "Asteroid probe, rocket get nod from Japanese panel". Spaceflight Now. 11 August 2010. Retrieved 29 October 2012.
  9. ^ a b c Clark, Stephen (14 September 2013). "Japan's 'affordable' Epsilon rocket triumphs on first flight". Spaceflight Now. Retrieved 16 September 2013.
  10. ^ "J-I Launch Vehicle". Japan Aerospace Exploration Agency. 2007. Archived from the original on 18 August 2012. Retrieved 11 July 2015.
  11. ^ "Epsilon launch vehicle". JAXA. Archived from the original on 21 January 2013. Retrieved 29 October 2012.
  12. ^ 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.
  13. ^ Kazuyuki Miho; Toshiaki Hara; Satoshi Arakawa; Yasuo Kitai; Masao Yamanishi (10 July 2009). "A minimized facility concept of the Advanced Solid Rocket launch operation" (PDF). 27th International Symposium on Space Technology and Science.
  14. ^ Zhao, Long; Xin, Chao-Jun; Shi, Mei-Ling; Yang, Chen; Wang, Huai-Peng (1 March 2020). "Current Status of Research on Space Emergency Launch". Journal of Physics: Conference Series. 1510 (1): 012023. Bibcode:2020JPhCS1510a2023Z. doi:10.1088/1742-6596/1510/1/012023. ISSN 1742-6588. See figure 6
  15. ^ Keating, Fiona (14 September 2013). "Japan's Laptop-Controlled Space Rocket Blasts Off (video)". International Business Times. Archived from the original on 23 September 2013.
  16. ^ "JAXA readies small rocket to break cost, use barriers". Japan Times. 9 November 2012. Retrieved 2 December 2012.
  17. ^ Epsilon Launch Vehicle Information
  18. ^ a b c "強化型イプシロンロケット プロジェクト移行審査の結果について" (PDF). 30 October 2014. Retrieved 9 July 2015.
  19. ^ "EPSILON a solid propellant launch vehicle for new age" (PDF). IHI Aerospace. Archived from the original (PDF) on 25 January 2018. Retrieved 25 January 2018.
  20. ^ イプシロンロケットについて (PDF) (in Japanese). JAXA. 24 November 2016. Retrieved 25 January 2018.
  21. ^ a b c d 「イプシロンSロケットの開発及び打上げ輸送サービス事業の実施に関する基本協定」の締結について (in Japanese). JAXA. 12 June 2020. Retrieved 13 June 2020.
  22. ^ "Cosmic Penguin".
  23. ^ "eepsilon rocket all aces this time". Asahi Shimbun. Archived from the original on 23 September 2013. Retrieved 14 September 2013.
  24. ^ "Launch rehearsed for new rocket". Japan Times. 9 September 2013. Retrieved 14 September 2013.
  25. ^ "Interview: Yasuhiro Morita, Project Manager, Epsilon Launch Vehicle". JAXA. Archived from the original on 23 November 2012. Retrieved 29 October 2012.
  26. ^ Stephen Clark (5 November 2012). "Japan schedules launch of innovative Epsilon rocket". Spaceflight Now. Retrieved 8 November 2012.
  27. ^ "Launch Result of Epsilon-1 with SPRINT-A aboard". JAXA. 14 September 2013. Archived from the original on 7 April 2014. Retrieved 18 September 2013.
  28. ^ a b "Success of Epsilon-2 Launch with ERG Aboard". JAXA. 20 December 2016. Retrieved 20 December 2016.
  29. ^ "Exploration of energization and Radiation in Geospace (ERG)". JAXA. Retrieved 20 December 2016.
  30. ^ "JAXA launches Epsilon-3 rocket". No. 17 January 2018. NHK World. Archived from the original on 18 January 2018. Retrieved 17 January 2018.
  31. ^ "Pre-Dawn Epsilon Liftoff Sends Japanese Radar-Imaging Satellite into Orbit". Spaceflight101. Retrieved 17 January 2018.
  32. ^ "Epsilon 4 launched by JAXA". 18 January 2019. Retrieved 18 January 2019.
  33. ^ "革新的衛星技術実証1号機に搭載する実証テーマ候補" (in Japanese). JAXA. Retrieved 19 January 2018.
  34. ^ "Launch Schedule". Spaceflight Now. 30 October 2021. Retrieved 31 October 2021.
  35. ^ "革新的衛星技術実証2号機" [Innovative Satellite Technology Demonstration No. 2] (in Japanese). JAXA. June 2021. Retrieved 20 August 2021.
  36. ^ a b "Epsilon launched by JAXA". 12 October 2022. Retrieved 12 October 2022.
  37. ^ Clark, Stephen (18 October 2022). "Failure of Japan's Epsilon rocket blamed on attitude control system". Spaceflight Now. Retrieved 23 October 2022.
  38. ^ 宇宙航空研究開発機構, 国立研究開発法人 (19 May 2023). "Report on the investigation into the cause of the launch failure of Epsilon Rocket 6" (PDF). Retrieved 13 March 2024.
  39. ^ "The 'LOTUSat-1' Project—NEC's Interdepartmental Team's First Satellite System Export to Elevate Vietnam's Space Capabilities". NEC. 28 September 2023. Retrieved 18 December 2023.
  40. ^ ベトナム向け地球観測衛星「LOTUSat-1」のイプシロンロケットによる打上げ受託について (in Japanese). JAXA. 12 June 2020. Retrieved 13 June 2020.
  41. ^ Jones, Andrew (6 November 2023). "Japan's mission to bizarre asteroid Phaethon delayed to 2025". Space.com. Retrieved 18 December 2023.
  42. ^ Shimizu, Toshifumi (15 December 2023). SH54A-03 The SOLAR-C EUVST mission: Coronal physics advanced by novel EUV spectroscopy. AGU23. Retrieved 26 December 2023.
  43. ^ "NASA Approves Heliophysics Missions to Explore Sun, Earth's Aurora" (Press release). NASA. 29 December 2020. Retrieved 30 December 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  44. ^ "Instruments | Next-generation solar-observing satellite Solar-C_EUVST". NAOJ. Retrieved 30 December 2020.
  45. ^ "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. ISSN 0915-8863. Retrieved 29 April 2021.
  46. ^ 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.
  47. ^ "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.
  48. ^ a b Iain Thomson (30 November 2012). "Malware slurps rocket data from Japanese space agency". The Register. Retrieved 2 December 2012.
  49. ^ "Japan's New Military Buildup Seen as Response to North Korea, China". National Journal. 23 August 2013. Retrieved 24 September 2013.
  50. ^ "Virus hits Japan space programme". 3 News NZ. 3 December 2012. Archived from the original on 22 September 2013. Retrieved 2 December 2012.