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|
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 Planned: Launch sites: And = Andøya Space Center (Andøya Rocket Range), Andøya, Nordland, Norway Ka = Kagoshima Space Center / Uchinoura Space Center, Kagoshima, Kyushu, Japan