Tim Furniss/LONDON
Development of an improved version of Japan's H-2 booster is a reflection of the country's determination to cut the production costs of its satellite launchers, to enable it to compete in the growing commercial launch market. Japan will not know how successful this bid is until 2001, when launches of the improved boosters get under way.
The existing H-2 is just too expensive to compete in the commercial launcher market, despite efforts by Rocket Systems to market the vehicle internationally. The quoted launch price for the original H-2 is about $120 million, and this needs to be reduced to at least $80 million to make the booster competitive.
The high price is a result of Japan's reliance on expensive domestic components, to make the H-2 a truly indigenous vehicle. The country's previous large launcher, the N-2, used McDonnell Douglas Delta first stages.
Japan's National Space Development Agency (NASDA) wants to "-ensure higher reliability for the upgraded version of the H-2 and a drastic reduction in launch costs for the purpose of effective promotion of Japan's space development and international co-operation". A new policy has been introduced, therefore, to import foreign technology and components for the H-2A and the J-1U, an uprated development of Japan's J-1 low earth orbit satellite launcher.
Rocket Systems has already received 10 launch reservations from Hughes for H-2A flights during the 2000-4 period, while Space Systems Loral has signed a 10-launch deal for 2000-5. This reflects less on the H-2A's competitiveness, however, and more on the satellite manufacturers' need to guarantee launcher availability in a busy market.
SUPPLY MISSIONS
The H-2A will also be needed to perform logistic supply missions to the International Space Station, particularly for components of the Japanese Experiment Module. The H-2A will also be offered for launches into low earth orbit of communications satellite constellations. Mitsubishi Heavy Industries - the H-2 prime contractor - is building a five-satellite dispenser for the vehicle.
The H-2 was first launched in 1994 and has flown five successful and one failed mission. At least eight more launches are manifested, but some may be carried out with the uprated vehicle.
The initial version of the uprated H-2A will only replicate the 4,000kg payload capability to geostationary transfer orbit (GTO) of the existing H-2, but further variants are planned to increase this.
The initial H-2A, described as the "Standard Type", has the same configuration as the original H-2 but uses uprated and improved LE7A first stage and LE5B second stage liquid-propellant engines, plus a pair of new four-segment SRB-A solid rocket boosters. Each SRB-A will be supplied by Nissan as a complete component ready for integration with the launcher, rather than as segments to be assembled at the launch site as they are for the H-2. This reflects NASDA's insistence that it must "simplify the system design and automate the launch preparation work" as part of the cost-cutting goal.
The next version of the H-2A, the "Reinforced Type" launcher with a 7,500kg GTO payload, will incorporate a strap-on piggyback first stage which duplicates the Standard Type first stage, but is equipped with two LE-7As rather than one. An extra SRB-A sold rocket booster may be added to some models to increase capability still further.
The Standard and Reinforced boosters are part of the formal upgrade programme, but a final version is already on the drawing board. This incorporates two piggyback first stages and two SRB-As, to produce a 9,500kg-to-GTO capability.
The critical design review of the Standard Type launcher was completed in May, and the first test vehicle is in production. A static firing of the SRB-A and verification of the ground test vehicle (GTV) are planned for later this year. The first test vehicle is scheduled for lift-off in early 2000 and the first operational model a year later. The GTV test of the H-2A Reinforced Type will be conducted in 2000, with the test flight scheduled for 2001. This will likely carry a transfer vehicle to supply the International Space Station.
SIMPLIFYING THE INTERFACE
Plans to enhance the efficiency of launch preparation work are in hand. The H-2A has been designed so that the interface between the vehicle and ground equipment is as simple as possible. The system incorporates a new support function for on-board automated check-up.
The H-2A programme will involve enlargement of the vehicle assembly building (VAB), used for the current H-2 at Tanegashima, to conduct all of the pre-launch inspection work for two H-2A boosters simultaneously. The entire H-2A will be moved from the VAB to the launch pad by the mobile launcher on the day of launching. The resulting pre-launch inspection time is estimated to be less than 20 days, much shorter than for the H-2 which is assembled in the VAB, then moved to the pad for check-up.
NASDA, meanwhile, has awarded a study contract to Ishikawajima Harima Industries and Nissan to develop the new J-1U launcher using Russian and US components. The original J-1 flew once in 1996 and is manifested to launch one more payload. If the J-1U goes into production, it will be powered by Russian NK-33 engines modified by US company Aerojet and will use propellant tanks developed by Lockheed Martin for its Atlas III.
Source: Flight International
