Linking back to the original press release, and thence to :-
http://www.isas.jaxa.jp/missions/sounding_rockets/ss-520.html
I find this.
'SS-520 is a two-stage observation rocket combining the first stage rocket of S-520 and the newly developed second stage rocket. The second stage motor / case is made of CFRP, realizing performance improvement by weight reduction and high pressure combustion. It has a diameter of 520 mm, a weight of about 2,600 kg at launch, and has the ability to launch a payload of 140 kg to an altitude of about 800 km. Furthermore, it is also possible to launch a mini satellite on Earth orbit by adding a small third stage rocket. During the first stage flight, like the S - 520 rocket, we maintain a stable aerodynamically posture using the tail wing. In the flight after the second stage, the whole rocket is rotated and the posture is stabilized by the spin stabilization method. If posture change is required while maintaining spin state, ramline attitude control device is installed. ' (my bold)
And from here,
http://www.jaxa.jp/projects/rockets/s_rockets/index_j.html
'The S - 310 type rocket has a single stage type and has the capacity to reach 310 mm in diameter and 150 km in altitude.
S-310 is a policy to positively spin the aircraft from the atmosphere to pass the resonance state at an early stage, to avoid sustaining the resonance state, and to stabilize the disorder of the posture generated at resonance by subsequent aerodynamic damping Has been adopted.
The spin is given by tilting the entire tail blade about 0.8 degrees to the plane containing the axis, and the design final spin at the end of combustion (29 seconds after ignition) is 2.8 Hz. The thrust curve is designed to have the maximum thrust in the initial stage according to the optimum thrust plan and the low thrust is sustained in the latter period when the aerodynamic force predominates, thereby increasing the reaching altitude, suppressing the dynamic pressure, It is devised to relieve heating.
Chamber is chrome molybdenum steel, and grain using butadiene base is composed of a combination of two kinds of wagon wheels, and the above thrust curve is obtained by burning the rear part first.
The tail wing is a single piece of titanium, the opening part of the o-jave shape is made of FRP. For the purpose of reducing the spin to about 1 Hz at the time of scientific observation, the instrument section is equipped with a yo-yo despina which operates 50 seconds after launch.
Since the S-310-1 in January 1975, as of the end of March 2008, 35 aircraft at Uchinoura, 3 aircraft at Andya rocket base in Norway and 7 aircraft at Antarctica were launched, all succeeded today I have reached.'
'The S - 520 - type rocket is a single stage rocket developed by the Institute of Space and Astronautical Science (now JAXA Institute of Space and Astronautical Science) as a substitute for the K - 9M, K - 10 type rocket, high performance propellant and optimum thrust With the adoption of the program and the weight saving of the structure, it has a payload ability to double K-9M, although it is single stage.
The thrust programming and flight stabilization method utilized the experience of the S - 310, and since the first flight in early 1980, four machines have been launched and stable performance has been reached. From the advantages such as simplification of operation by single stage, resolution of security problems accompanying the first paragraph, reduction of launch expenses, etc., it is expected to be useful in the future. The propellant is directly filled with the same butadiene composite propellant as in the first stage of M rocket. Like the S-310, the thrust curve is a two-step thrust type, the front clover-shaped cross section with a large perimeter is designed to guarantee the initial high thrust level and the rear cylindrical section is designed to guarantee the low thrust level in the second half I will. The nozzle opening ratio is relatively large (8), and the effective specific thrust is improved.
The chamber is made of ultra-high tensile steel HT-140. The tail wing has a sandwich structure with the front edge as a titanium alloy, the parallel portion as a core with an aluminum honeycomb as a core and GFRP / CFRP laminate as a top plate, and it has light weight and heat resistance. Scientific observation instruments are housed in the GFRP nose fairing, basic meters are housed in the bottom parallel section, but as an option posture control module or recovery module can be installed between the basic instrument and the motor.
In Unit 4 (the reverse order of Unit 3), collection experiments were performed, and in Unit 3, the attitude of the head was controlled by hydrazine side jet. Posture stabilization outside the atmosphere departs depending on the spin given by the tail, the final spin rate is 2.2 Hz, which is then slowed down appropriately by yo yo despina. In the future as well as the S-310, launch at Antarctic base is planned.'
'The SS - 520 is a two - stage observation rocket, the first stage is the main engine of S - 520 and has the ability to launch a payload of 140 kg to an altitude of about 800 km.
The aim is to reach an altitude of 800 km and at the same time add engineering experiments to develop a rocket to launch a mini satellite by adding a third stage. Like the S - 520 rocket, the first stage is kept aerodynamically stable by the tail wing.
The second stage is heavier than the body of the S - 520 rocket, so we have an extra aerodynamic margin. The second stage motor case is made of CFRP.
The spin induced in the first stage is taken over to the second stage and used for ram line control and spin stabilization. SS-520 rocket debuted in January 1998. Unit 2 was launched from the Subaru Bird rocket experiment site in Norway on December 4, 2000, and made direct observations in the cusp region of the magnetosphere.'
S-310 S-520 SS-520
full length 7.1 m 8 m 9.65 m
diameter 0.31 m 0.52 m 0.52 m
Overall Weight 0.7 t 2.1 t 2.6 t
Arrival height 150 km 300 km 800 km
payload 50 kg 95/150 kg 140 kg
HTH . . .
cheers,
Robin.
