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S-520 [JAXA]

The S-520 is a powerful Japanese single-stage rocket which is optionally equipped with three-axis attitude control and a recovery system. It has a capability for launching a 100 kg payload far above 300 km and provides more than five minutes of micro-gravity flight environment.

The S-520 was developed to replace the K-9M and K-10 type sounding rockets, and succeeded in doubling the payload capability of the K-9M by applying high-performance propellant, an optimum thrust program and a lightweight structure.

The experience of S-310 was put to good use in the thrust program and stabilization strategy, which delivered stable flight performance since its first flight early in 1980.

The merits of S-520, such as simplification of flight operation without staging, settlement of impact-related maritime safety, and reduction of launch cost, make the application of this sounding rocket more meaningful.

The HTPB composite propellant grain is cast and molded in the case in the same way as the first stage of Mu launch vehicles. The propellant grain is single, and gives a dual-thrust profile similar to the S-310's. The forward portion of the grain has a seven pointed gear configuration and provides an initial period of high thrust, while the aftward portion with a simple tubular design sustains a lower level thrust period. The nozzle with an initial expansion ratio of 8:1 is designed to improve the effective specific impulse. The chamber is made of high tensile steel HT-140. For weight saving and heat resistance, the leading edge of the tail fins is made of titanium alloy and their body is an aluminum honeycomb sandwich plate with GFRP/CFRP laminated surface plates.

Scientific instruments are stored inside the nose fairing made of GFRP, and common instruments are in the parallel section. As an option, an attitude control module or recovery module can be put into the part between common instruments and the rocket motor.

The fourth flight carried out payload retrieval, and the third flight, launched later than the fourth, performed attitude control of the nose by the hydrazine side jet system. The attitude outside the atmosphere is stabilized by succeeding spinning with tail fins. The spin reaches 2.2 Hz at the last stage to be decelerated using a yo-yo despinner system.

Launch Vehicle Stage 1
S-520 S-520
Nr  TypeNr  Vehicle          Serial      Date          LS             Suc    Payload     

 1     1    S-520            S-520-1     18.01.1980    Ka LP-KS (ot)  *      Heat Pipe
 2     2    S-520            S-520-2     29.01.1981    Ka LP-KS       *      TPE 2
 3     3    S-520            S-520-4     05.09.1981    Ka LP-KS       *      Payload Recovery Test
 4     4    S-520            S-520-3     14.02.1982    Ka LP-KS       *      0.3 m telescope test
 5     5    S-520            S-520-5     06.09.1982    Ka LP-KS       *      0.1 m telescope
 6     6    S-520            S-520-6     29.08.1983    Ka LP-KS       *      MINIX
 7     7    S-520            S-520-7     11.02.1985    Ka LP-KS       *      ?
 8     8    S-520            S-520-9     15.01.1987    Ka LP-KS       *      E-field
 9     9    S-520            S-520-8     21.02.1987    Ka LP-KS (it)  *      GUV
10    10    S-520            S-520-10    04.09.1989    Ka LP-KS       *      CIR
11    11    S-520            S-520-11    21.02.1990    Ka LP-KS       *      CIR
12    12    S-520            S-520-12    26.02.1990    And            *      ?
13    13    S-520            S-520-14    12.02.1991    And            *      ?
14    14    S-520            S-520-13    16.02.1991    Ka LP-KS (?t)  *      EUV Telescopes
15    15    S-520            S-520-15    01.02.1992    Ka LP-KS (it)  *      CIR
16    16    S-520            S-520-16    18.02.1993    Ka LP-KS       *      METS
17    17    S-520            S-520-21    01.12.1994    And            *      ?
18    18    S-520            S-520-17    23.01.1995    Ka LP-KS       *      ?
19    19    S-520            S-520-19    28.01.1995    Ka LP-KS       *      EUV Telescopes
20    20    S-520            S-520-20    17.09.1995    Ka LP-KS (it)  * F    Lunar Penetrator Test
21    21    S-520            S-520-18    30.01.1997    Ka LP-KS       *      Lunar Penetrator Test
22    22    S-520            S-520-22    31.01.1998    Ka LP-KS (ot)  *      SOLAR-BXUV Doppler Telescope
25    23    S-520            S-520-23    02.09.2007    Ka LP-KS (ot)  *      WIND
26    24    S-520            S-520-24    02.08.2008    Ka LP-KS (it)  *      Microgravity
27    25    S-520            S-520-25    30.08.2009    Ka LP-KS (ot)  *      T-REX
28    26    S-520            S-520-26    12.01.2012    Ka LP-KS (ot)  *      Li release
29    27    S-520            S-520-28    17.12.2012    Ka LP-KS (it)  *      Microgravity
30    28    S-520            S-520-27    20.07.2013    Ka LP-KS (ot)  *      MSTID
31    29    S-520            S-520-29    17.08.2014    Ka LP-KS (of)  *      Sporadic E study
32    30    S-520            S-520-30    11.09.2015    Ka LP-KS       *      Dust nucleation
35    31    S-520            S-520-31    26.07.2021    Ka LP-KS       *      DES / RATS
37    32    S-520            S-520-RD1   23.07.2022    Ka LP-KS       *      RD-1
38    33    S-520            S-520-32    11.08.2023    Ka LP-KS       *      ?
39    34    S-520            S-520-33    02.12.2023    Ka LP-KS       *      ?


Launch sites:

And = Andøya Space Center (Andøya Rocket Range), Andøya, Nordland, Norway Norway
Ka  = Kagoshima Space Center / Uchinoura Space Center, Kagoshima, Kyushu, Japan Japan


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