Space Launch Report:  Epsilon Data Sheet
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epsilonxs.jpg (5773 bytes)Epsilon

Vehicle Configurations

Vehicle Components

Launch Log

Original Prototype Epsilon Design

After phasing out the M-5 (or M-V) launch vehicle in 2006, the Japan Aerospace Exploration Agency (JAXA) began development of a smaller solid propellant launch vehicle named "Epsilon" that it hoped would cost less to fly than M-5 had cost.  Epsilon would continue the long-running tradition of smaller, lower cost "Mu" series orbital launchers that the Institute of Space and Astronautical Sciences (ISAS) had managed.  Formerly independant ISAS became the Space Science Research Disvision of JAXA on October 1,2003. 

Epsilon will use three solid motors and an optional "Compact Liquid Propulsion System" (CLPS) fourth stage.  The first stage will be a modified SRB-A motor, weighing 74.4 tonnes and similar to the 230 tonne thrust monolithic boosters used by JAXA's H-2A and H-2B launch vehicles.  The second stage will be an 11.6 tonne M-34c motor, a modified version of the M-5 rocket's third stage that uses an extendible nozzle.  A small KM-V-2b solid motor, derived from the M-5 fourth stage motor and weighing 3 tonnes will serve as the third stage.    The three motors will burn for 120, 104.7 and 91.1 seconds, respectfully.

A 2.5 meter diameter payload fairing will enclose the payload and the third and fourth (CLPS) stages (when used).  CLPS will provide orbit trimming and raising manuevers on some missions.  With CLPS, Epsilon will be able to lift 700 kg to a 500 km x 30 deg orbit, or 450 km to a 500 km sun synchronous orbit.  Without CLPS, Epsilon will be able to boost 1.2 tonnes into a 250 x 500 km x 30 deg orbit.

Epsilon is designed to simplify launch check out procedures.  The rocket will perform its own self-tests using its on-board computer, which will be able to be monitored and controlled via. standard network connections from anywhere, making the launch control system independant of launch site.

Use of the monolithic SRB-A first stage motor eliminates the need to stack motor segments, as was required for the M-5 first stage.  Epsilon will weigh only 91 tonnes at liftoff, compared to 140 tonnes for M-5.   It will also be less capable, but smaller payloads should mean smaller budgets.

Epsilon was meant to cost one-third as much as M-5.   The 2006 goal was to cut costs from $60 million to $20 million per flight.   

epsilon1.jpg (16280 bytes)Epsilon Inaugural Success

First Epsilon Launch

Japan's new Epsilon launch vehicle scored an inaugural success on September 14, 2013 when it boosted Sprint-A (Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere) into orbit from the Uchinoura Space Center, Kagoshima on the island of Kyushu.  The 348 kg orbiting telescope was aimed toward a 950 x 1,150 km x 31 deg. orbit.  Sprint-A will study ineractions of the solar wind with the atmospheres and magnetoshpheres of Mars, Venus, and Jupiter at extreme ultraviolet wavelengths. 

On this flight, the first stage burned for 112 seconds, the second stage for 102 seconds, and the third stage for 89 seconds.   The vehicle coasted for 53 seconds between the first and second stage burn and for 361 seconds between the second and third stage burn.  Epsilon coasted for another 140 seconds after third stage burnout before the hydrazine fueled "Post Boost Stage" (PBS) separated and ignited.  On this flight, the PBS performed a nearly 11 minute long initial burn and a 6.5 minute long second burn that were separated by a 23 minute long coast.  Sprint-A separated 61 minutes 39 seconds after liftoff. 

Once on orbit, Sprint-A was given the nickname "Hisaki", which means "beyond the sun" in Japanese.       

The success followed an August 27 last second aborted attempt that was found to have been caused by latent sensor signal delays that spoofed the ground launch launch control program.

Epsilon was designed to reduce the cost of scientific satellite launches compared to its M-V predecessor.  Japan Aerospace Exploration Agency (JAXA) began development of "Epsilon" in 2006 to continue the long-running tradition of smaller, lower cost "Mu" series orbital launchers that the Institute of Space and Astronautical Sciences (ISAS) had managed.  Formerly independant ISAS became the Space Science Research Disvision of JAXA on October 1,2003.  

Epsilon uses three solid motors and an optional "Post Boost Stage" (PBS), or "Compact Liquid Propulsion System" (CLPS) fourth stage.  The first stage is a modified SRB-A motor, weighing 74.4 tonnes and similar to the 230 tonne thrust monolithic boosters used by JAXA's H-2A and H-2B launch vehicles.  The second stage is an 11.6 tonne M-34c motor, a modified version of the M-5 rocket's third stage that uses an extendible nozzle.  A small KM-V-2b solid motor, derived from the M-5 fourth stage motor and weighing 3 tonnes serves as the third stage.     Epsilon weighs 91 tonnes at liftoff. 

A 2.5 meter diameter payload fairing enclosed Sprint-A and the third and fourth stages.  The PBS provides orbit trimming and raising manuevers on some missions.  With CLPS, Epsilon can lift 700 kg to a 500 km x 30 deg orbit, or 450 km to a 500 km sun synchronous orbit.  Without CLPS, Epsilon can boost 1.2 tonnes into a 250 x 500 km x 30 deg orbit.

enhanced2s.jpg (9479 bytes)Enhanced Epsilon

Enhanced Epsilon, on Right, Stands Taller than the Original Epsilon Launch Vehicle

Enhanced Epsilon, set to fly in December 2016, uses improved second and third stages and a stretched payload fairing.  Enhanced Epsilon is designed to haul about 30% more payload mass to low earth orbit.  The rocket's second stage carries more propellant and is no longer enclosed within the fairing.   The third stage also carries more propellant. 

Both solid upper stages use fixed, rather than extendible, nozzles, with appropriately stretched interstage sections.  The changes make Enhanced Epsilon stand two meters taller and weigh 4.4 tonnes more than the original prototype Epsilon Launch Vehicle.

 

Vehicle Configurations

  LEO
Payload
(metric tons)
[1] 250 x 500km x 30 deg
[2] 500 km x 30 deg
[3] 500 km x 98.6 deg
[4] 200 x 33,100 km x 31 deg
Ellipitical Earth
Orbit Payload
(metric tons)
Configuration LIftoff
Height
(meters)
Liftoff
Mass
(metric tons)
Epsilon (3-stg) 1.20 t [1]   SRB-A + M-34c + KM-V2b + PLF 24 m 91 t
Epsilon (4-stg) 0.70 t [2]
0.45 t [3]
  SRB-A + M-34c + KM-V2b + CLPS + PLF 24 m 91 t
Enhanced Epsilon (3-stg) 1.50 t [1] 0.365 t [4] SRB-A + M-35 + KM-V2c + PLF 26 m 95.4 t
Enhanced Epsion (4-stg) 0.59 t [3]   SRB-A + M-35 + KM-V2c + CLPS + PLF 26 m 95.4 t

* GEO:  Geosynchronous Earth Orbit

Vehicle Components

  Stg 1
(SRB-A)
Stg 2
(M-34c)
Stg 2
(M-35)
Stg 3
(KM-V2b)
Stg 3
(KM-V2c)
Stg 4
Compact Liquid
Propulsion System
(CLPS)
Payload
Fairing
Enhanced
Payload
Fairing
Diameter (m) 2.5 m 2.2 m 2.5 m 1.45 m 1.45 m 1.2 m 2.5 m 2.5 m
Length (m) 13.27 m (Original)
13.97 m (Enhanced)
Incl I/S
3.6 m 5.17 m
Incl I/S
1.75 m 2.25 m 1.2 m 9.19 m
(Enclosed
Stg 2)
9.19 m
Propellant Mass (tonnes) 66 t 10.8 t 15.0 t 2.5 t 2.5 t 0.120 t
0.145 t (Enhanced)
   
Empty Mass (tonnes) 9.3 t 0.8 t 2.2 t 0.5 t 0.8 t 0.180 t
0.155 t (Enhanced)
   
Total Mass (tonnes) 75.5 t
75.3 t (Enhanced)
11.6 t 17.2 t 3.0 t 3.3 t 0.3 t ~0.80 t ~0.80 t
Engine SRB-A M-34c M-35 KM-V2b KM-V2c      
Engine Mfgr Nissan              
Fuel Solid
HTPB
Solid
HTPB
Solid
HTPB
Solid
HTPB
Solid
HTPB
Hydrazine    
Oxidizer                
Thrust
(SL tons)
219.24 t              
Thrust
(Vac tons)
161.12 t avg 38.46 t 45.38 t 8.29 t 10.16 t 0.0408 t    
ISP (SL sec) - - - - -      
ISP (Vac sec) 283.6 s 299.9 s 295 s 301.7 s 299 s 215 s    
Burn Time (sec) 109 s 104.7 s 129 s 91.1 s 89 s -    
No. Engines 1 1 1 1 1 1    

Epsilon Launch Log


                        EPSILON ORBITAL SPACE LAUNCH LOG

DATE     VEHICLE           ID      PAYLOAD                 MASS(t) SITE*      ORBIT*
------------------------------------------------------------------------------------
09/14/13 Epsilon           E-01    Sprint A                 0.35   KA M5      LEO
12/20/16 Enh. Epsilon      E-02    ERG                     0.365   KA M5      EEO [1]
------------------------------------------------------------------------------------
[1] First Enhanced Epsilon.  To 219 x 33,200 km x 31.4 deg orbit. 

 Site Code:

KA = Kagoshima, Japan 
TA = Tanageshima, Japan
YO = Yoshinobu Launch Pad
M5 = M5 Launch Pad

 Orbit Code:

EEO/M = Molynia (12-hr) Elliptical Earth Orbit
FTO = Failed to Orbit
FSO = Failed Suborbital
GTO = Geosynchronous Transfer Orbit
GTO+ = Supersynchronous or High Perigee Transfer Orbit
GTO- = Subsynchronous Transfer Orbit
GTOi = Inclined GTO
GEO = Geosynchronous Orbit
HCO = Heliocentric (solar) Orbit
HTO = High Earth Transfer Orbit
LEO = Low Earth Orbit
LEO/S = Sun Synchronous Low Earth Orbit
LEO/P = Polar Low Earth Orbit
MEO = Medium Earth Orbit
MTO = Medium Earth Transfer Orbit 
SUB = Suborbital
xxx

References

Epsilon Launch Vehicle brochure, JAXA, 2012
"System Design of Enhanced Epsilon Launch Vehicle", Takayuki IMOTO, Sengen

 Last Update:  December 20, 2016

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