Space Launch Report:  SS-520 Data Sheet
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ss520-4rs.jpg (12805 bytes)SS-520

Vehicle Configurations

Vehicle Components

Launch Log

SS-520-4 On Launch Rail

SS-520 is a two-stage sounding rocket developed by Japan's ISAS that was combined with a small solid third stage motor in an unsuccessful 2017 orbital launch attempt.   

The sounding rocket was designed to lift up to 140 kg to a suborbital apogee of about 800 km.  The rocket is rail-launched like most sounding rockets and uses spin stabilization effected by canted tail fins. 

SS-520 debuted in January, 1998 from Kagoshima (as SS-520-1).  ISAS launched a subsequent SS-520 (SS-520-2) from Spitsbergen, Norway in 2000.  SS-520-3 is planned to fly from Norway in the future.  SS-520-4 performed a failed inaugural 2017 orbital attempt.  SS-520-5 successfully orbited Tricom 1R on February 3, 2018.

ss520-4.jpg (6258 bytes)Sounding Rocket Orbit Try Fails

Japan's SS-520-4, a small experimental three-stage orbital launcher based on an existing two-stage sounding rocket, failed during its inaugural attempt from Uchinoura Space Center at Kagoshima on January 14, 2017. The solid-fueled rocket zipped skyward from its rail launcher at the KS sounding rocket pad at 23:33 UTC, aiming to place Tricom 1, a 3kg Cubesat, into a 180 x 1,500 km x 31 deg orbit after a rapid ascent lasting just over four minutes.

The first stage burn appeared to be good, ending after about 31 seconds, but the second stage never ignited as planned after a 140 second coast. Reports indicated that telemetry was lost even before first stage cutoff. Second stage ignition needed to be enabled from the ground, which was impossible without an established downlink. The vehicle apparently fell into the expected first stage drop zone, indicating that the first stage propulsion phase had more or less succeeded.

SS-520-4 (SS-520 serial number 4) weighed about 2.6 tonnes at launch, which would have made it the lightest-ever orbital rocket had it succeeded. The rocket was 9.54 meters long and 0.52 meters diameter.  It's first stage HTPB solid fuel motor produced about 18 tonnes of liftoff thrust.

The launch was expected to be a one-off experiment, but after the failure program officials decided to make a second attempt.

SS-520-5 (JAXA)Modified Sounding Rocket Orbits Cubesat

 Japan's SS-520, serial number 5 (SS-520-5), a small experimental three-stage orbital launcher based on an existing two-stage sounding rocket, succeeded during its second orbital attempt from Uchinoura Space Center at Kagoshima on February 3, 2018. The success made SS-520-5 the smallest rocket ever used to orbit a satellite.

SS-520 is a two-stage sounding rocket developed by Japan's ISAS that first flew in 1998. A small solid third stage motor was added for orbital launch attempts. Its first orbital attempt, on January 14, 2017, ended in failure when telemetry was lost during the first stage burn, preventing ignition of the second stage. An investigation determined that a power supply failed, likely due to a short circuit that appeared during the high-g ascent.

The 2.6 tonne, 9.65 meter tall solid-fueled rocket zipped skyward from its rail launcher at the KS sounding rocket pad at 05:03 UTC, aiming to place a tiny, 3kg cubesat named Tricom 1R into a 180 x 1,500 km x 31 deg orbit after a rapid ascent lasting only 4 minutes 23 seconds. The finned, spin-stabilized first stage fired for 31.7 seconds, producing a maximum of about 18 tonnes of thrust, and seperated after one minute, sending the vehicle on a suborbital trajectory with a 179 km apogee. A nitrogen gas attitude control system controlled the upper stages during the latter part of the coast.

Near apogee at T+3 minutes the 325 kg second stage ignited to burn for 24.4 seconds. SS-520-5's 78 kg third stage seperated and ignited at T+3 minutes 58 seconds and burned out at T+4 minutes 23.6 seconds. Tricom 1R was jettisonned 7.5 minutes after liftoff.

U.S. tracking data subsequently showed two objects in a 191 x 2,010 km x 30.9 deg orbit. The mission was a validation test of the "nano-launcher" concept. Japan currently has no plans to fly more SS-520 rockets to orbit.


 

Vehicle Configurations

  LEO
Payload
(metric tons)
[1] 180 x 1,500km x 31 deg
  Configuration LIftoff
Height
(meters)
Liftoff
Mass
(metric tons)
SS-520 (3-stg) ~4kg   2stg SS-520 + stg3 9.65 m 2.6 t
           


Vehicle Components

  Stg 1 Stg 2 Stg 3 Payload
Fairing
Diameter (m) 0.52 m 0.52 m -  m - m
Length (m) - - - -
Propellant Mass (tonnes) - - - -
Empty Mass (tonnes) - - - -
Total Mass (tonnes) 1.587 t 0.325 t 0.078 t ~0.00162 t
Engine - - - -
Engine Mfgr - - - -
Fuel Solid
HTPB
Solid
HTPB
Solid
HTPB
-
Oxidizer - - - -
Thrust
(SL tons)
~18 t - - -
Thrust
(Vac tons)
- - - -
ISP (SL sec) - - - -
ISP (Vac sec) - - - -
Burn Time (sec) 31.7 s ~24 s ~30s -
No. Engines 1 1 1 -

SS-520 Orbital Launch Log


                        SS-520 ORBITAL SPACE LAUNCH LOG

DATE     VEHICLE           ID        PAYLOAD               MASS(t) SITE*      ORBIT*
------------------------------------------------------------------------------------
01/14/17 SS-520            SS-520-4  Tricom 1              0.003   KA KS     [FTO][1]
02/03/18 SS-520            SS-520-5  Tricom 1R             0.003   KA KS      LEO
------------------------------------------------------------------------------------
[1] Telemetry lost during Stg 1 burn, power supply failure.  Stg 2 not enabled.   

 Site Code:

KA = Kagoshima, Japan
KS = KS Sounding Rocket 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:  February 03, 2018

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