Epsilon (rocket)

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Epsilon rocket F2.jpg
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)
Diameter2.5 m
Mass91 t (Demonstration Flight) / 95.4 t (Enhanced)
Payload to 250x500 km orbit
Standard 3 stages configuration
Mass1,500 kilograms (3,300 lb)
Payload to 500 km orbit
Optional 4 stages configuration
Mass700 kilograms (1,500 lb)
Payload to 500 km SSO
Optional 4 stages configuration
Mass590 kilograms (1,300 lb)
Launch history
Launch sitesUchinoura
Total launches4
First flightSeptember 14, 2013
Last flightJanuary 18, 2019
First stage – SRB-A3
Engines1 solid
Thrust2,271 kN[2]
Specific impulse284 seconds[2]
Burn time116 seconds[2]
Second stage (Demonstration Flight) – M-34c
Engines1 solid
Thrust371.5 kN[2]
Specific impulse300 seconds[2]
Burn time105 seconds[2]
Second stage (Enhanced) – M-35
Engines1 solid
Thrust445 kN[2]
Specific impulse295 seconds[2][failed verification]
Burn time129 seconds[2][failed verification]
Third stage (Demonstration Flight) – KM-V2b
Engines1 solid
Thrust99.8 kN[2]
Specific impulse301 seconds[2]
Burn time90 seconds[2]
Third stage (Enhanced) – KM-V2c
Engines1 solid
Thrust99.6 kN[2]
Specific impulse299 seconds[2][failed verification]
Burn time88 seconds[2][failed verification]
Fourth stage (Optional) – CLPS
Thrust40.8 N
Specific impulse215 seconds[2]
Burn time1100 sec. (max.)

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.[3]

Vehicle description[edit]

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]

Enhanced version[edit]

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)

Epsilon S[edit]

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.[17]

Major changes of Epsilon S from Epsilon are:[17]

  • 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 Post-Boost Stage is mandatory, whereas Epsilon's PBS was optional.

Planned performance of Epsilon S is:[17]

  • Sun-synchronous orbit (350 - 700km): ≧ 600 kg
  • Low-earth orbit (500 km): ≧ 1400 kg

The first launch of Epsilon S is planned in 2023.[17]

Launch statistics[edit]

Launch outcomes[edit]

  •   Failure
  •   Partial failure
  •   Success
  •   Planned

Launch history[edit]

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.[18]

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.[19]

The initial version of Epsilon has a payload capacity to low Earth orbit of up to 500 kilograms,[20][21] 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]

Flight No. Date / time (UTC) Rocket,
Launch site Payload Payload mass Orbit Customer Launch
1 September 14, 2013
Epsilon 4 Stages[22] Uchinoura Space Center SPRINT-A (HISAKI) 340 kg LEO JAXA Success[5]
Demonstration Flight
2 December 20, 2016
Epsilon 3 Stages Uchinoura Space Center ERG (ARASE) 350 kg[24] Geocentric JAXA Success[23]
3 January 17, 2018
Epsilon 4 Stages[26] Uchinoura Space Center ASNARO-2[26] 570 kg[26] SSO Japan Space Systems Success[23]
4 January 18, 2019
Epsilon 4 Stages Uchinoura Space Center RAPIS-1
200 kg SSO JAXA Success[23]
Innovative Satellite Technology Demonstration-1; Component demonstration and technology validation.[28]

Planned launches[edit]

Date / time (UTC) Rocket,
Launch site Payload Orbit Customer
October 1, 2021[29][30] Epsilon Uchinoura Space Center RAISE-2
2022 Epsilon Uchinoura Space Center RAISE-3
2023 Epsilon S Uchinoura Space Center LOTUSAT-1[31] SSO VNSC
2024 Epsilon Uchinoura Space Center Innovative Satellite Technology Demonstration-4 LEO JAXA
2024 Epsilon S Uchinoura Space Center DESTINY+ Heliocentric JAXA
2026 Epsilon Uchinoura Space Center Innovative Satellite Technology Demonstration-5 LEO JAXA
2026–2027 Epsilon S Uchinoura Space Center Solar-C_EUVST[32][33] SSO JAXA
2028 Epsilon Uchinoura Space Center JASMINE[34] SSO JAXA
2028 Epsilon Uchinoura Space Center Innovative Satellite Technology Demonstration-6 LEO JAXA
(TBD) Epsilon Uchinoura Space Center Innovative Satellite Technology Demonstration-7 LEO JAXA

Sources: Japanese Cabinet[35]

Internet data leak[edit]

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.[36] Solid-fuel rocket data potentially has military value,[36] and Epsilon is considered as potentially adaptable to an intercontinental ballistic missile.[37] 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.[38]

See also[edit]


  1. ^ "U.S. GAO - Surplus Missile Motors: Sale Price Drives Potential Effects on DOD and Commercial Launch Providers". GAO.gov. U.S. Government Accountability Office. August 16, 2017. Retrieved January 18, 2019.
  2. ^ a b c d e f g h i j k l m n o p "イプシロンロケットの開発および準備状況" (PDF). JAXA. Retrieved September 16, 2013.
  3. ^ a b "Epsilon Launch Vehicle" (PDF). JAXA. Retrieved January 25, 2018.
  4. ^ "Asteroid probe, rocket get nod from Japanese panel". Spaceflight Now. August 11, 2010. Retrieved October 29, 2012.
  5. ^ a b c d Clark, Stephen (September 14, 2013). "Japan's 'affordable' Epsilon rocket triumphs on first flight". Spaceflight Now. Retrieved September 16, 2013.
  6. ^ "J-I Launch Vehicle". Japan Aerospace Exploration Agency. 2007.
  7. ^ "Epsilon launch vehicle". JAXA. Retrieved October 29, 2012.
  8. ^ Yasuhiro Morita; Takayuki Imoto; Hiroto Habu; Hirohito Ohtsuka; Keiichi Hori; Takemasa Koreki; Apollo Fukuchi; Yasuyuki Uekusa; Ryojiro Akiba (July 10, 2009). "Advanced Solid Rocket Launcher and its Evolution" (PDF). 27th International Symposium on Space Technology and Science. Retrieved September 20, 2009.
  9. ^ Kazuyuki Miho, Toshiaki Hara, Satoshi.Arakawa, Yasuo Kitai, Masao Yamanishi (July 10, 2009). "A minimized facility concept of the Advanced Solid Rocket launch operation" (PDF). 27th International Symposium on Space Technology and Science. Retrieved September 20, 2009.CS1 maint: multiple names: authors list (link)
  10. ^ "New Epsilon rocket chalks up first launch". Japan Times. Retrieved September 15, 2013.
  11. ^ "Japan's Laptop-Controlled Space Rocket Blasts Off". International Business Times. Retrieved September 14, 2013.
  12. ^ "JAXA readies small rocket to break cost, use barriers". Japan Times. November 9, 2012. Retrieved December 2, 2012.
  13. ^ Epsilon Launch Vehicle Information
  14. ^ 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). October 30, 2014. Retrieved July 9, 2015.
  15. ^ "EPSILON a solid propellant launch vehicle for new age" (PDF). IHI Aerospace. Retrieved January 25, 2018.
  16. ^ イプシロンロケットについて (PDF) (in Japanese). JAXA. November 24, 2016. Retrieved January 25, 2018.
  17. ^ 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. June 12, 2020. Retrieved June 13, 2020.
  18. ^ "Epsilon rocket all aces this time". Asahi Shimbun. Archived from the original on September 23, 2013. Retrieved September 14, 2013.
  19. ^ "Launch rehearsed for new rocket". Japan Times. Retrieved September 14, 2013.
  20. ^ "Interview: Yasuhiro Morita, Project Manager, Epsilon Launch Vehicle". JAXA. Retrieved October 29, 2012.
  21. ^ Stephen Clark (November 5, 2012). "Japan schedules launch of innovative Epsilon rocket". Spaceflight Now. Retrieved November 8, 2012.
  22. ^ "Launch Result of Epsilon-1 with SPRINT-A aboard". JAXA. September 14, 2013. Retrieved September 18, 2013.
  23. ^ a b c d "Success of Epsilon-2 Launch with ERG Aboard". JAXA. December 20, 2016. Retrieved December 20, 2016.
  24. ^ "JAXA | Exploration of energization and Radiation in Geospace (ERG)". JAXA | Japan Aerospace Exploration Agency. Retrieved December 20, 2016.
  25. ^ "JAXA launches Epsilon-3 rocket" (17 January 2018). NHK World. Archived from the original on January 18, 2018. Retrieved January 17, 2018.
  26. ^ a b c "Pre-Dawn Epsilon Liftoff Sends Japanese Radar-Imaging Satellite into Orbit". Spaceflight101. Retrieved January 17, 2018.
  27. ^ "Epsilon 4 launched by JAXA". January 18, 2019. Retrieved January 18, 2019.
  28. ^ "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 January 19, 2018.
  29. ^ イプシロンロケット5号機による革新的衛星技術実証2号機の打上げについて [About the launch of Innovative Satellite Technology Demonstration No. 2 by Epsilon rocket No. 5]. JAXA (Press release) (in Japanese). August 20, 2021. Retrieved August 20, 2021.
  30. ^ "革新的衛星技術実証2号機" [Innovative Satellite Technology Demonstration No. 2]. JAXA (in Japanese). June 2021. Retrieved August 20, 2021.
  31. ^ 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. June 12, 2020. Retrieved June 13, 2020.
  32. ^ "NASA Approves Heliophysics Missions to Explore Sun, Earth's Aurora". NASA (Press release). December 29, 2020. Retrieved December 30, 2020.
  33. ^ "Instruments | Next-generation solar-observing satellite Solar-C_EUVST". NAOJ. Retrieved December 30, 2020.
  34. ^ "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. March 1, 2021. p. 6. ISSN 0915-8863. Retrieved April 29, 2021.
  35. ^ "宇宙基本計画工程表 (令和2年度改訂)" (PDF) (in Japanese). Cabinet Office. December 15, 2020. Retrieved April 29, 2021.
  36. ^ a b Iain Thomson (November 30, 2012). "Malware slurps rocket data from Japanese space agency". The Register. Retrieved December 2, 2012.
  37. ^ "Japan's New Military Buildup Seen as Response to North Korea, China". National Journal. August 23, 2013. Retrieved September 24, 2013.
  38. ^ "Virus hits Japan space programme". 3 News NZ. December 3, 2012. Archived from the original on September 22, 2013. Retrieved December 2, 2012.

External links[edit]