S-520 is the designation of a Japanese
Japanese people
The are an ethnic group originating in the Japanese archipelago and are the predominant ethnic group of Japan. Worldwide, approximately 130 million people are of Japanese descent; of these, approximately 127 million are residents of Japan. People of Japanese ancestry who live in other countries...

 sounding rocket
Sounding rocket
A sounding rocket, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The origin of the term comes from nautical vocabulary, where to sound is to throw a weighted line from a ship into...

The S-520 is a powerful 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 5 minutes for micro-gravity
Microgravity environment
The term micro-g environment is more or less a synonym of weightlessness and zero-G, but indicates that g-forces are not quite zero, just very small...

 flight environments.

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

The experience of S-310
S-310 is the designation of a Japanese sounding rocket.The S-310 is a middle-size rocket for carrying various payloads. It is a single-stage sounding rocket, 310 mm in diameter, and can reach an altitude of 200 km...

 was put to good use in the thrust programming and stabilization strategy of S-520, enabling quite 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.


Provided by the Japan Aerospace Exploration Agency (JAXA)

Source: Website of the Japan Aerospace Exploration Agency (JAXA)


External links

  • http://www.isas.jaxa.jp/e/enterp/rockets/sounding/s520.shtml
  • http://www.astronautix.com/lvs/s520.htm
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