Japan is redesigning its H2 booster to enable it to compete in the launcher market.

Tim Furniss/LONDON

AN UPRATED VERSION of Japan's H2 satellite launcher will have its first flight in 2000, in a late attempt to make a viable entry into the commercial-launcher market and to play a role in projects supporting the International Space Station.

The original $2.3 billion H2 - Japan's first large indigenously built satellite launcher - which had its first flight in 1994 and has since notched up three successful flights, costs a prohibitive $172 million per launch because of high production costs.

"The international environment has changed substantially in the last decade," says Japan's National Space Development Agency (NASDA). To meet today's demands for more communications and Earth-observation satellites and for logistics to be ferried to the Space Station, "-it is imperative that transportation costs be reduced and vehicle capabilities increased", the agency says. The objective will be to reduce production costs by 50% and to have the new rocket ready within four years.

Attempts by Rocket Systems, a Mitsubishi-led consortium of more than 70 Japanese aerospace companies, to market the original launcher commercially were doomed from the start. NASDA hopes that the redesigned rocket, called the H2A, can reduce the launch cost to a competitive $70 million, on a par with the cost of an Ariane 4. A second H2 launch pad at the Tanegashima space centre -and a faster launch turnaround - will help Japan overcome the disadvantage of having only two 45-day launch windows during January-February and August-September each year, imposed by restrictions forced by the powerful fishing-industry lobby. Even this may not be enough to persuade some future customers.

Rocket Systems has already received an extraordinary boost for an unproven vehicle, of a potential $910 million contract for ten launches, starting in 2000, from Hughes Communi-cations. Hughes, the world's leading communications-satellite supplier, has also reserved launches on the new Delta 3 and the Sea Launch, in addition to its traditional bookings on the Ariane, Long March, Proton and Atlas vehicles, ensuring that it has a continuous launch capacity in the event of delays to any launcher programme.

The first version of the streamlined and simpler H2A will replicate the 2,000kg payload to the geostationary-transfer-orbit (GTO) capability of the original H2, but will use a new LE-7 first-stage engine. It will also be equipped with shorter and lighter Nissan solid-rocket boosters, made with US-supplied carbonfibre-reinforced-plastic casings instead of steel, offering a 1,000kg increase in thrust, to 4,600kg, and a 12s longer burn time of 100s.

Another addition is a Mitsubishi LE-5B second-stage engine, with 1,500kg additional thrust to reduce weight. Testing of the 14,000kg-thrust LE-5B has already begun, including 300s firings of the first engine. The engine will equip the current H2 model after its seventh flight in 1999, carrying the Advanced Earth Observation Satellite 2 (ADEOS).

The current H2 has a full manifest of launches, starting in August with the launch of the ADEOS 1. This will be followed in the first 1997 launch window period by the Communications and Broadcasting Engineering Test Satellite (ETS) and, in 1998, by the ETS 7 and the Tropical Rainfall Measuring Mission. The eighth H2, configured with the H2-A second stage upgrade, will be used to launch the Multi-functional Transport Satellite, which will act as a meteorological platform as well as augmenting global-positioning-system signals and air-traffic-control links.

Spacecraft assigned to fly the H-2A are the first payload (the Hope unmanned space plane), two data-relay-technology satellites, a new Earth-observation satellite and another ETS. A Moon-explorer craft, called the Lunar, may join the launch queue later.

NASDA has more-ambitious H2 upgrades planned. The second version of the H2-A will have an unusual configuration; basically the first H2-A with a piggyback duplicate first stage with a two-nozzle LE-7A engine. This will increase GTO capability to 3,000kg, while the third H2-A, which will incorporate two piggyback stages, will launch 4,000kg into GTO.

At the same time, Japan's other space agency, the Institute of Space and Astronautical Science, is developing a new booster to replace its retired M3S2 solid-propellant booster. Called the M5, this uprated vehicle will be capable of despatching to the Moon payloads weighing 520kg. Its first flight is scheduled for early 1997, carrying the Muses B space observatory.

As work proceeds with new H2-A and M5 vehicles, a derivative of older models will still be flying. Called the J-1, this NASDA-ISAS booster, launched earlier this year and which has one more firm payload (the Optical Inter-orbit Communications ETS) is based on an upper stage of old M3S2 and the original solid-rocket booster of the H2.

Source: Flight International