Epsilon (rocket) explained

Epsilon
Function:	Launch vehicle
Country-Origin:	Japan
Cpl:	US$39 million^[1]
Height:	24.4 m (Demonstration Flight) 26 m (Enhanced) 27.2 m (Epsilon S)^[2]
Diameter:	2.5 m
Mass:	91 t (Demonstration Flight) 95.4 t (Enhanced) ~100 t (Epsilon S)
Stages:	3–4
Capacities:	Location: 250 x 500 km orbit Standard 3 stages configuration Location: 500 km orbit Optional 4 stages configuration Location: 500 km orbit Epsilon S Location: 500 km SSO Optional 4 stages configuration Location: 700 km SSO Epsilon S
Status:	Active
Sites:	Uchinoura
Launches:	6
Success:	5
Fail:	1
Partial:	0
First:	14 September 2013
Last:	12 October 2022
Stagedata:	Type: stage Stageno: First Diff: Demonstration Flight/Enhanced Engines: 1 solid Thrust: ^[3] Si: 284isp Burntime: 116 seconds Type: stage Stageno: First Diff: Epsilon S Engines: 1 solid Thrust: ^[4] Si: 283.6isp Burntime: 105 seconds Type: stage Stageno: Second Diff: Demonstration Flight M-34c Engines: 1 solid Si: 300isp Burntime: 105 seconds Type: stage Stageno: Second Diff: Enhanced M-35 Engines: 1 solid Si: 295isp^[5] Burntime: 129 seconds Type: stage Stageno: Second Diff: Epsilon S E-21 Engines: 1 solid Si: 294.5isp Burntime: 120 seconds Type: stage Stageno: Third Diff: Demonstration Flight KM-V2b Engines: 1 solid Si: 301isp Burntime: 90 seconds Type: stage Stageno: Third Diff: Enhanced KM-V2c Engines: 1 solid Si: 299isp Burntime: 91 seconds Type: stage Stageno: Third Diff: Epsilon S E-31^[6] Engines: 1 solid Si: ~295isp Burntime: 108 seconds Type: stage Stageno: Fourth Diff: Optional Si: 215isp Burntime: 1100 seconds (maximum) Fuel: Hydrazine

The Epsilon Launch Vehicle, or (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 and is tall and 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]

• 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:^[18]

• 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:^[19]

• Low Earth orbit 250 km × 500 km for 1.5 t
• Sun-synchronous orbit 500 km × 500 km for 0.6 t

Final characteristics:^{[7] [20]}

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

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.

Major changes of Epsilon S from Epsilon are:

• 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.

Planned performance of Epsilon S is:

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

The first launch of Epsilon S is planned in 2023.

On July 14, 2023, the second stage of Epsilon S failed during a test firing.^[21]

Launch statistics

Launch outcomes

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.^[22]

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.^[23]

The initial version of Epsilon has a payload capacity to low Earth orbit of up to 500 kilograms,^{[24] [25]} with the operational version expected to be able to place into a orbit, or to a circular orbit at with the aid of a hydrazine fueled stage.^[9]

Flight No.	Date / time (UTC)	Rocket, Configuration	Launch site	Payload	Payload mass	Orbit	Customer	Launch outcome
1	14 September 2013 05:00:00	Epsilon 4 Stages ^[26]	Uchinoura Space Center	SPRINT-A (HISAKI)	340 kg	LEO	JAXA
Demonstration Flight
2	20 December 2016 11:00:00 ^[27]	Epsilon 3 Stages	Uchinoura Space Center	ERG (ARASE)	350 kg ^[28]	Geocentric	JAXA
3	17 January 2018 21:06:11 ^[29]	Epsilon 4 Stages ^[30]	Uchinoura Space Center	ASNARO-2	570 kg	SSO	Japan Space Systems
4	18 January 2019 00:50:20 ^[31]	Epsilon 4 Stages	Uchinoura Space Center	RAPIS-1 MicroDragon RISESAT ALE-1 OrigamiSat-1 AOBA-VELOX-IV NEXUS	200 kg	SSO	JAXA
Innovative Satellite Technology Demonstration-1 component demonstration and technology validation.^[32]
5	9 November 2021 00:55:16 ^[33] ^[34]	Epsilon PBS	Uchinoura Space Center	RAISE-2 HIBARI Z-Sat DRUMS TeikyoSat-4 ASTERISC ARICA NanoDragon KOSEN-1	110 kg	SSO	JAXA
Innovative Satellite Technology Demonstration-2.
6	12 October 2022 00:50:00 ^[35]	Epsilon 4 Stages	Uchinoura Space Center	RAISE-3 QPS-SAR 3 QPS-SAR 4 MAGNARO MITSUBA KOSEN-2 WASEDA-SAT-ZERO FSI-SAT	110 kg	SSO	JAXA, iQPS
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] A report regarding the cause has been published and is available for viewing, although it is in Japanese.^[37]

Planned launches

Date / time (UTC)	Rocket, Configuration	Launch site	Payload	Orbit	Customer
2024^[38]	Epsilon S	Uchinoura Space Center	LOTUSat-1^[39]	SSO	VNSC
2025	Epsilon S	Uchinoura Space Center	Innovative Satellite Technology Demonstration-4	LEO	JAXA
2025^[40]	Epsilon S	Uchinoura Space Center	DESTINY^+	Heliocentric	JAXA
2027	Epsilon S	Uchinoura Space Center	Innovative Satellite Technology Demonstration-5	LEO	JAXA
July 2028^[41]	Epsilon S	Uchinoura Space Center	Solar-C EUVST^[42] ^[43]	SSO	JAXA
2028	Epsilon S	Uchinoura Space Center	JASMINE^[44]	SSO	JAXA
2029	Epsilon S	Uchinoura Space Center	Innovative Satellite Technology Demonstration-6	LEO	JAXA
2030^[45]	Epsilon S	Uchinoura Space Center		SSO	JAXA
2031	Epsilon S	Uchinoura Space Center	Innovative Satellite Technology Demonstration-7	LEO	JAXA

Sources: Japanese Cabinet^[46]

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.^[47] Solid-fuel rocket data potentially has military value,^[47] and Epsilon is considered as potentially adaptable to an intercontinental ballistic missile.^[48] 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.^[49]

See also

• Comparison of orbital launchers families
• Comparison of orbital launch systems

External links

• Epsilon launch vehicle, JAXA
• Epsilon Photobook "EPSILON THE ROCKET"
  • Epsilon Launch Vehicle, IHI Aerospace

Notes and References

1. Web site: U.S. GAO - Surplus Missile Motors: Sale Price Drives Potential Effects on DOD and Commercial Launch Providers. U.S. Government Accountability Office. 18 January 2019. 16 August 2017.
2. Web site: 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 . . 16 March 2024 . Japanese . 7 July 2023.
3. Web site: イプシロンロケットの開発および準備状況. JAXA . September 16, 2013.
4. Web site: H3 Launch Vehicle Brochure. 20 September 2016. 11 February 2017. https://web.archive.org/web/20170211023251/http://global.jaxa.jp/activity/pr/brochure/files/rocket09.pdf. live.
5. Development and Flight Results of Solid Propulsion System for Enhanced Epsilon Launch Vehicle. Koki KITAGAWA. Shinichiro TOKUDOME. Keiichi HORI. Haruhito TANNO. Nobuyuki NAKANO2. Trans. JSASS Aerospace Tech. Japan. 17. 3. 289–294. 2019. 10.2322/tastj.17.289 . 2019JSAST..17..289K . March 9, 2023.
6. Web site: 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. 16 March 2024.
7. Web site: Epsilon Launch Vehicle. JAXA. 25 January 2018.
8. News: Asteroid probe, rocket get nod from Japanese panel. Spaceflight Now. August 11, 2010. October 29, 2012.
9. Web site: Clark. Stephen. Japan's 'affordable' Epsilon rocket triumphs on first flight . Spaceflight Now. September 14, 2013. September 16, 2013.
10. Web site: J-I Launch Vehicle. 2007. Japan Aerospace Exploration Agency. 11 July 2015. 18 August 2012. https://web.archive.org/web/20120818072733/http://www.jaxa.jp/projects/rockets/j1/index_e.html. dead.
11. Web site: Epsilon launch vehicle. JAXA. October 29, 2012. 21 January 2013. https://web.archive.org/web/20130121050940/http://www.jaxa.jp/projects/rockets/epsilon/index_e.html. dead.
12. Advanced Solid Rocket Launcher and its Evolution . Yasuhiro Morita. Takayuki Imoto. Hiroto Habu. Hirohito Ohtsuka. Keiichi Hori. Takemasa Koreki. Apollo Fukuchi. Yasuyuki Uekusa. Ryojiro Akiba . July 10, 2009. 27th International Symposium on Space Technology and Science.
13. A minimized facility concept of the Advanced Solid Rocket launch operation. Kazuyuki Miho. Toshiaki Hara. Satoshi Arakawa. Yasuo Kitai. Masao Yamanishi. July 10, 2009. 27th International Symposium on Space Technology and Science.
14. Zhao . Long . Xin . Chao-Jun . Shi . Mei-Ling . Yang . Chen . Wang . Huai-Peng . Current Status of Research on Space Emergency Launch . Journal of Physics: Conference Series. 1510 . 1 . 1 March 2020 . 1742-6588 . 10.1088/1742-6596/1510/1/012023. free. 012023. 2020JPhCS1510a2023Z . See figure 6
15. Web site: Japan's Laptop-Controlled Space Rocket Blasts Off (video). live. https://web.archive.org/web/20130923001416/http://www.ibtimes.co.uk/articles/506050/20130914/japan-rocket-blast-computer-controlled-epsilon.htm. 23 September 2013. Keating. Fiona. International Business Times. 14 September 2013 .
16. News: JAXA readies small rocket to break cost, use barriers. Japan Times. November 9, 2012. December 2, 2012.
17. http://www.spaceflight101.com/epsilon-launch-vehicle-information.html Epsilon Launch Vehicle Information
18. Web site: 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 . October 30, 2014. July 9, 2015.
19. Web site: EPSILON a solid propellant launch vehicle for new age . IHI Aerospace. 25 January 2018. https://web.archive.org/web/20180125193622/https://www.ihi.co.jp/ia/en/download/i/IHI_Epsilon.pdf. 25 January 2018.
20. Web site: http://fanfun.jaxa.jp/jaxatv/files/20161124_epsilon.pdf. ja:イプシロンロケットについて. JAXA . ja. 24 November 2016. 25 January 2018.
21. Web site: Cosmic Penguin .
22. Web site: eepsilon rocket all aces this time. Asahi Shimbun. September 14, 2013. dead. https://web.archive.org/web/20130923012212/http://ajw.asahi.com/article/behind_news/social_affairs/AJ201309140070. September 23, 2013.
23. Web site: Launch rehearsed for new rocket. Japan Times. 9 September 2013 . September 14, 2013.
24. Web site: Interview: Yasuhiro Morita, Project Manager, Epsilon Launch Vehicle. JAXA. October 29, 2012. 23 November 2012. https://web.archive.org/web/20121123052200/http://www.jaxa.jp/article/interview/vol58/index_e.html. dead.
25. News: Japan schedules launch of innovative Epsilon rocket. Stephen Clark. Spaceflight Now. November 5, 2012. November 8, 2012.
26. Web site: Launch Result of Epsilon-1 with SPRINT-A aboard. JAXA. 14 September 2013. 18 September 2013. 7 April 2014. https://web.archive.org/web/20140407064419/http://www.jaxa.jp/press/2013/09/20130914_epsilon_e.html. dead.
27. Web site: Success of Epsilon-2 Launch with ERG Aboard. JAXA. December 20, 2016. December 20, 2016.
28. News: Exploration of energization and Radiation in Geospace (ERG). JAXA. 2016-12-20.
29. News: JAXA launches Epsilon-3 rocket. 17 January 2018. NHK World . 17 January 2018. https://web.archive.org/web/20180118064647/https://www3.nhk.or.jp/nhkworld/en/news/20180118_08/. January 18, 2018. dead.
30. News: Pre-Dawn Epsilon Liftoff Sends Japanese Radar-Imaging Satellite into Orbit. Spaceflight101. 17 January 2018.
31. Web site: Epsilon 4 launched by JAXA. 18 January 2019. 18 January 2019.
32. Web site: 革新的衛星技術実証1号機に搭載する実証テーマ候補. JAXA. 2018-01-19. ja.
33. Web site: Launch Schedule. Spaceflight Now. 30 October 2021. 31 October 2021.
34. Web site: 革新的衛星技術実証２号機. Innovative Satellite Technology Demonstration No. 2. JAXA. June 2021. August 20, 2021. ja.
35. Web site: Epsilon launched by JAXA. 12 October 2022. 12 October 2022.
36. News: Failure of Japan's Epsilon rocket blamed on attitude control system . Clark . Stephen . Spaceflight Now . 18 October 2022 . 23 October 2022.
37. Web site: 宇宙航空研究開発機構 . 国立研究開発法人 . 2023-05-19 . Report on the investigation into the cause of the launch failure of Epsilon Rocket 6. . 2024-03-13.
38. Web site: The 'LOTUSat-1' Project—NEC's Interdepartmental Team's First Satellite System Export to Elevate Vietnam's Space Capabilities . . 28 September 2023 . 18 December 2023.
39. Web site: https://www.jaxa.jp/press/2020/06/20200612-1-1_j.html. ja. ja: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. JAXA . 12 June 2020. 13 June 2020.
40. Web site: Jones . Andrew . Japan's mission to bizarre asteroid Phaethon delayed to 2025 . . 6 November 2023 . 18 December 2023.
41. Shimizu . Toshifumi . SH54A-03 The SOLAR-C EUVST mission: Coronal physics advanced by novel EUV spectroscopy . . 15 December 2023 . 26 December 2023.
42. NASA Approves Heliophysics Missions to Explore Sun, Earth's Aurora. NASA. December 29, 2020. December 30, 2020.
43. Web site: Instruments Next-generation solar-observing satellite Solar-C_EUVST. NAOJ. December 30, 2020.
44. 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. 6. NAOJ News. 332. National Astronomical Observatory of Japan. March 1, 2021. April 29, 2021. ja. 0915-8863.
45. Web site: 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. Yonetoku. Daisuke. PDF. Group of Optical and Infrared Astronomers. 8 September 2021. 2021-11-16 . ja.
46. Web site: 宇宙基本計画⼯程表 (令和５年度改訂) . Basic Plan on Space Policy (2023 Revision) . 45 . . 22 December 2023 . 26 December 2023 . ja . 25 December 2023 . https://web.archive.org/web/20231225105156/https://www8.cao.go.jp/space/plan/plan2/kaitei_fy05/kaitei_fy0512.pdf . live.
47. News: Malware slurps rocket data from Japanese space agency. Iain Thomson. The Register. November 30, 2012 . December 2, 2012.
48. News: Japan's New Military Buildup Seen as Response to North Korea, China. National Journal. 23 August 2013. 24 September 2013.
49. News: Virus hits Japan space programme. 3 News NZ. December 3, 2012. December 2, 2012. https://web.archive.org/web/20130922235440/http://www.3news.co.nz/Japans-space-agency-probes-possible-data-leak/tabid/1160/articleID/278923/Default.aspx. September 22, 2013. dead.