H-IIA

 
 

JAXA * Mitsubishi Heavy Industries, Ltd. * Rocket System Corporation

Die H-II soll ab dem Jahr 2000 von einem Nachfolgemuster, der H-IIA abgelöst werden. Eine der wichtigsten geplanten Veränderungen der Trägerrakete ist eine neue Verbindung der ersten Stufe mit den Starthilfen. Während die H-II auf dem hinteren Ende der SRB’s steht, wird die neue H-IIA auf dem Heck der ersten Stufe stehen. Als Starthilfen sind verschiedene Booster vorgesehen, die in variierter Zusammenstellung zu insgesamt 4 Versionen mit folgenden Nutzlasten führt:

H-IIA 202 0 GTO 4,15 t LEO   9,94 t SSO 4,35 t LTO 2,90 t
H-IIA 2022 GTO 4,50 t LEO 10,74 t SSO 4,94 t  
H-IIA 2024 GTO 5,00 t LEO 11,73 t SSO 5,27 t  
H-IIA 2040 GTO 5,80 t LEO SSO  

In der Nomenklatur dieser 4 Varianten stehen die Zahlen für die Anzahl der Stufen bzw. Starthilfen der Trägerrakete wie folgt:

                                            1. Position: Anzahl der Stufen der Trägerrakete
                                            2. Position: Anzahl von LRB (Liquid Rocket Booster)
                                            3. Position: Anzahl der SRB-A (Solid Rocket Booster)
                                            4. Position: Anzahl der SSB (Solid Strap-on Booster)

Die Verwendung von LRB's ist erst bei der Heavy-Version der H-IIA vorgesehen.

Für die zweite Stufe wird das modifizierte Triebwerk LE-5B verwendet, das gegenüber dem LE-5A einen um 13% höheren Schub erreicht.
Beim Einsatz von SRB-A (graphite-epoxy) werden jeweils zwei in freier Aufhängung montiert. Zusätzlich können einzeln oder als Paar SSB eingesetzt werden. Ein SRB-A entwickelt 10% mehr Schub als ein SRB EM der H-II.
Der Abbrand-Modus der Booster könnte wie folgt aussehen. Bei der H-IIA2020, 2022, 2024 werden die SRB’s gleichzeitig mit der 1. Stufe gezündet, die SSB werden paarweise nacheinander gezündet.


The H-II is the first large launch vehicle designed entirely domestic Japanese technology. The H-II consists of two cryogenic core stages plus two solid strap-on boosters SRB-EM. The new upgraded H-IIA family includes a various strap-on solid fuel (SRB-A, SSB) and liquid fuel (LRB) strap-on boosters.
The major elements of the H-II first stage are the aluminium isogrid propellant tanks and the engine section with an LE-7 LH2/LOX main engine. The hydrogen tank is 18 m long, and the oxygen tank is 8 m long. Avionics are contained in the center body section between the tanks. The first stage of the H-IIA is closely based on the H-II first stage, but includes a number of modifications. The side-mounted turbopumps of the LE-7 are moved to the top on the new main engine LE-7A, making the engine longer.
The liftoff thrust of the H-II is provided by a pair of solid rocket boosters (SRBs). The SRB-EM is a long four-segment solid motor with casings made from steel. The H-IIA booster, designated SRB-A, incorporates several improvements. It is a shorter, monolithic motor. The motor casing is a filament wound composite structure, using technologies from Thiokol. The nozzle is gimbaled using an electromechanical system. The SRB-A can be supplemented by two or four smaller solid strap-on boosters (SSBs), which are Thiokol Castor IVAXL motors. The H-IIA  can also use a large liquid booster LRB for higher performance. The strap-on LRB is similar to the first stage, but includes two engines for higher liftoff thrust. It is capped by an aluminium/composite nose cone.
The second stage of the H-II is closely based on the H-I second stage, with larger propellant tanks and an upgraded LE-5A engine. The 4-m diameter hydrogen tank and the 2.4-m diameter oxygen tank share a common bulkhead. Changes for the H-IIA include larger, separated propellant tanks for higher performance and a more robust LE-5B engine. The new stage fly on the seventh flight of the H-II.

Payload fairings:

  4S                   5S                4/4D-LS        4/4D-LC             5/4D   

H-II/IIA fairings are designated by the diameter (4 or 5 m) and the number of payload compartments (S for single or D for dual).

  Length Diameter Mass Material
Model 4S 12.0 m 4.07 m 1.397 tons Aluminium
Model 5S 12.0 m 5.10 m 1.716 tons Aluminium
Model 4/4D 14.5 m 4.07 m 1.090 + 0.762 tons Aluminium +Graphite-epoxy
Model 4/4D-LC 16.0 m 4.07 m 1.226 + 1.101 tons Aluminium +Graphite-epoxy
Model 5/4D 14.0 m 5.10 + 4.07 m 1.470 + 0.817 tons Aluminium +Graphite-epoxy

Rocket System Corporation is the primary contractor for the H-II series. Mitsubishi Heavy Industries are manufactured the engines and vehicle stages. In 1985 was begun construction the Yoshinobu Launch Complex for launching H-II rockets at the Osaki Range (Tanegashima Space Center).


There are a variety of improvements planned for the basic H-IIA configuration, including an enhanced main engine turbopump, the longer first stage engine nozzle, and modified SRB's with longer burn times.
The first launch with a long  first stage engine nozzle occurred on flight 8 of H-IIA.

The H-IIA Launch Vehicle F11, whose payload is the ETS 8  is the 2040 type. The H-IIA 2040 is equipped with four solid rocket boosters (SRB-A), two additional ones to the conventional H-IIA, to increase the launch capability of a satellite into geostationary transfer orbit to 5.8 tons. The modified SRB's with longer burn times was not yet ready for action.