picture of the encyclopedia
previous next
Version 0.81 comes with a new web design! Please allow popups for navigation.

ISAS launchers

by Jean-Jacques Serra
The first japanese sounding rockets were designed in the mid-50ies bu the TOkyo Department of Applied Industries (TODAI) to contribute to the International Geophysical Year of 1957-58.

In the early sixties, university of Tokyo decided to design 3-stage rockets named Lambda while going on developping new 2-stage sounding rockets of the Kappa series. The most powerful Kappa rockets (9 & 10) weighed 1.5 to 1.7 tons and had 42 cm base stages; despite the Lambda-3 had a 73 cm diameter first stage and weighed over 7 tons. For the International Quiet Sun Year (IQSY) of 1964-65 those launchers performed 1000 km altitude orbit with 100 kg payload. The rocket workgroup at University of Tokyo then became the ISAS.


In 1965 the TODAI started developping a satellite launcher derived from the Lambda-3 sounding rocket which in its most powerful configuration (Lambda-3H) was able to orbit 100 kg at 2000+ km. This launcher was achieved by adding a fourth stage and solid fuel boosters to Lambda-3.

Four orbit injection attempts were made in Sep & Dec 1966, Apr 1967 and Sep 1969. Those launches occured from Uchinoura (31.2° North, 130.6° East) near Kagoshima on the Kyushu island. Finaly success occured in 1970.

This first Japanese launcher named Lambda-4S was 16.5 m high, weighed 9.5 tons and burned only solid fuel. The first stage was 73 cm in diameter and provided 363 kN during 28 seconds. It was assisted during the first 7 seconds by 2 solid fuel boosters of 255 kN thrust. The second stage (same diameter) provided 118 kN during 28 seconds. The third stage was 50 cm in diameter; it was capable of 64 kN during 27 seconds. The top stage was made of a 113 kg powder bloc providing 7.8 kN during 27 seconds which spherical shield made up the satellite's structure. The latter was only a technological capsule which mass at burn shutdown didn't exceed 23 kg. The vehicle was launched from an inclined ramp. It wasn't piloted; a gyroscopic system only controled the fourth stage's altitude before ignition after the ballistic phase (which follows the third stage shutdown).

On 11 Feb 1970 the Lambda-4S number 5 orbited the first capsule named Ohsumi at 351 km x 5142 km x 31.2°. This is the only object launched by a Lambda rocket... because it was abandonned as a space launcher.

Mu series rockets

Seven months after the successful Lambda-4S orbiting the Japanese fired the first model of a new launcher. The Mu-4S kept the same technology but had much greater performances. It was 23.6 m high, 43.6 tons in weight and could put a 100 kg payload in a 31°, 500 km circular orbit.

It's first stage was 1.41 m in diameter and thrusted 834 kN during 61 seconds. It was assisted by eight 127 kN boosters during the first 5.5 seconds of the flight. The second stage had the same diameter whereas the third was 86 cm and while the 77 cm fourth stage supported a 79 cm diameter cap. The respective thrusts were: 285, 127 and 26.5 kN. The guidance system remained simplistic: only the fourth stage was piloted by jet deviation.

After a failure in September 1970 for the first flight, Mu-4S succeeded the 3 next attempts between Feb 1971 and Aug 1972.

In 1974 a new version of Mu with only 3 stages was introduced. This launcher named Mu-3C was equipped with the old first stage and boosters. The second stage was modified and equipped with a radio-inertial guidance which controlled a jet deviation piloting device (freon injection) and a roll control using lateral propellers. This stage provided 343 kN thrust during 55 seconds. The third stage was inherited from Mu-4S fourth stage; it had 65 kN thrust capability during 45 seconds. It was also under the 1.41 m diameter fuse cap.

This 41.6 t launcher with its 20.2 m height had similar performances to Mu-4S although lowerer at high altitude. It was used 4 times between Feb 1974 and Feb 1979; 3 launches were successful.

A more powerful launcher appeared in 1977: Mu-3H. The first stage was longer than the former one: its solid fuel engine (27 tons) provided 1080 kN during 56 seconds. The cap had been lengthened and could host a fourth stage to reach very elliptical orbits.

Mu-3H was 23.8 m high for 48.7 tons at takeoff. It could orbit 100 kg at 700 km in the 3-stage version and more twice as much in the 4-stage version. It was used 3 times with success between Feb 1977 and Feb 1979 including a launch with 30500 km apogee orbit.

The fourth version of the launcher, Mu-3S, only differed from the former vehicle by the addition of a piloting system to the first stage. It was based on a nozzle freon injection device and on a roll control system provided by 4 gas generators fixed at the end of the 4 empannages. The vehicle had the same performances as Mu-3H performances. It was used to launch 4 satellites between Feb 1980 and Feb 1984.

The next version was Mu-3S2; it was complety modified, only the first stage remained the same. The number of boosters was brought back to two but they mesured 74 cm in height and 285 kN (31 seconds duration). The second stage was lenghtened; it provided 490 kN during 52 seconds. The third stage's diameter was increased to 1.41 m; it provided 108 kN during 82 seconds. The launchers reached 61.2 tons in mass and 27.2 m in height. The orbitable payload which took place in an enlarged cap of 1.65 m diameter was almost twice as heavy as for Mu-3S1: 680 kg at 31°, 250 km altitude.

Mu-3S2 was used 8 times (1 failure) between Jan 1985 and Jan 1995. It launched 2 interplanetary probes to the Moon and to the Halley comet.

Mu-5 series

While the Mu-5 series were based on a 1.41 m diameter first stage Mu-5 uses a new first stage. It is 2.51 m in diameter and much more powerful. It enable the doublement of the payload mass in LEO.

This M-14 stage is 13.7 m long and weighs 80.8 tons with over 70 tons propellant (PBHT) in 2 segments. It provides 3870 kN thrust during 49 seconds. The second stage, M-24, has the same diameter. It is 6.7 m in length and 33.2 tons in mass, including 30 tons solid fuel. It makes use of the FIH (Fire In the Hole) technology, i.e. it is linked to the first stage by a mesh structure and ignited at separation between first and second stage. It provides 1370 kN during 63 seconds.

The third stage M-34 is 4.1 m long and 2.2 m diameter. It used advanced technologies such as a CFRP (Carbon Fiber Reinforced Plastic) envelope and a deployable nozzle which enables to shorten the 3rd stage by 1 meter and to leighten it from 300 kg. Thus is weighs 11 tons including 10 tons propellant and provides 300 kN thrust during 101 seconds.

Mu-5 is 30.5 m high with the cap. It weighs 135 tons. It can place 1.8 tons in low orbit at 240 km. For its first flight on 12 Feb 1997 from Kagoshima it delivered Haruka in correct orbit (220/21000 km).

Configuration summary

Designation First launch 1st stage 2nd stage 3rd stage 4th stage
Mu-4S 1970 M-10 M-20 M-30 M-40
Mu-3C 1974 M-10 M-22 M-3A  
Mu-3H 1977 M-13 M-22 M-3A  
Mu-3S 1980 M-13* M-22 M-3A  
Mu-3S2 1985 M-13* M-23 M-3A  
(*) M-13 stage with thrust vector control

Mu launches

# Launch id Payload Launch date Type Status/Comment (orbit in perigee x apogee x inc. x period)
1 n/a MS-F1 25 Sep 1970 Mu-4S Failure (61 kg)
2 71011 Tansei 1 (MS-T1) 16 Feb 1971 Mu-4S  
3 71080 Shinsei (MS-F2) 28 Sep 1971 Mu-4S  
4 72064 Denpa (REXS) 19 Aug 1972 Mu-4S  
5 74008 Tansei 2 (MS-T2) 16 Feb 1974 Mu-3C  
6 75014 Taiyo (SRATS) 24 Feb 1975 Mu-3C  
7 n/a Corsa A 04 Feb 1976 Mu-3C Failure (86 kg)
8 77012 Tansei 3 (MS-T3) 19 Feb 1977 Mu-3H 824 x 3932 x 65.8 x 134.3
9 78014 Kyokko (Exos A) 04 Feb 1978 Mu-3H  
10 78087 Jikiken (Exos B) 16 Sep 1978 Mu-3H  
11 79014 Hakucho (Corsa B) 21 Feb 1979 Mu-3C  
12 80015 Tansei 4 (MS-T4) 17 Feb 1980 Mu-3S1  
13 81017 Hinotori (Astro A) 21 Feb 1981 Mu-3S1  
14 83011 Tenma (Astro B) 20 Feb 1983 Mu-3S1  
15 84015 Ohzora (Exos C) 14 Feb 1984 Mu-3S1  
16 85001 Sakigake/MS-T5 07 Jan 1985 Mu-3S2 probe to Halley comet (138 kg)
17 85073 Suisei/PLANET-A 18 Aug 1985 Mu-3S2 probe to Halley comet (140 kg)
18 87012 Ginga (Astro C) 05 Feb 1987 Mu-3S2  
19 89016 Akebono (Exos D) 21 Feb 1989 Mu-3S2  
20 90007 Hiten (Muses A)
24 Jan 1990 Mu-3S2 Probe to the Moon (193 kg)
21 91062 Yohkoh (Solar A) 30 Aug 1991 Mu-3S2  
22 93011 Asuka (Astro D) 20 Feb 1993 Mu-3S2  
23 n/a EXPRESS 15 Jan 1995 Mu-3S2 Partial failure
24 97005 Haruka (Muses B) 12 Feb 1997 Mu-5  
25 98041 Nozomi (Planet B) 3 Jul 1998 Mu-5 space probe
26 n/a Astro E 10 Feb 2000 at 01:30 UT Mu-5 Failure: first stage motor problem with a nozzle led to suborbital trajectory
27 03019 Muses C 9 May 2003 Mu-5-2  
28 05025 Astro E2 10 Jul 2005 at 03:30 UT Mu-5-2 248 x 540 km x 31.4°
29 06005 A: Astro F
B: Solar Sail
C: Cute 1.7
21 Feb 2006 at 21:28 UT Mu-5-8 302 x 728 km x 98°
30 06041 A: Solar B
B: Hit-Sat
F: Solar Sail 2
22 Sep 2006 at 21:36 UT Mu-5  

Note: All launches from Kagoshima (Uchinoura)

© TBS Internet, all rights reserved. All reproduction, copy or mirroring prohibited. Legal notice
francais anglais contact