Author Topic: Japan rocket plans lack direction  (Read 3811 times)

Offline Stowbridge

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Veteran space reporter.

Offline sammie

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Re: Japan rocket plans lack direction
« Reply #1 on: 08/05/2006 09:41 AM »
Interesting, makes me wonder what will happen with the payload scheduled for the 8th M-V launch.
"The dreams ain't broken downhere, they're just walking with a limp"

Offline Space Lizard

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Re: Japan rocket plans lack direction
« Reply #2 on: 08/05/2006 11:14 AM »
There are some mistakes in the story.

The J-1 was not based on M-5 and H-2A elements but on a H-2 multisegment solid booster and upper stages from the old M-3S2 rocket (predecessor to M-5). The launch cost of the J-1 was about 45 M US$. The H-2 solid booster was fairly expensive and had to be replaced by a new, less complex and larger monolithic design for the more cost-effective H-2A.

Designs for a new J vehicle based on H-2A boosters, known as J-1A or J-2 have been circulating around for years.

The GX is not an upgrade to the J-1, although some connections between the two designs were proposed at an early phase. Actually, the GX is a Lockheed Martin Atlas 3 booster stage with a Japanses-built liquid methane upper stage. There are commercial expectations behind it although it is not clear whether it can have any viable operational future beyond technological demo.

As Lunar A is in limbo, the last remaining M-5 payload, the Planet C Venus Climate Orbiter will go on H-2A.
I watch rockets

Offline sammie

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Re: Japan rocket plans lack direction
« Reply #3 on: 08/05/2006 12:41 PM »
Ah I see. I was confused for a second because I knew that a number of Cubesats had to fly on M-5 flight 8. However they flew mission 8  before mission 7, in early 2006.

I guess the G-X is geared for the middle weight class to GTO, so payloads of up to 3000kg to GTO orbit. However they will face competition from launch vehicles such as Soyuz, Delta 2, Zenit 3SLB and the GSLV, not an easy market.
"The dreams ain't broken downhere, they're just walking with a limp"

Offline Skyrocket

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Re: Japan rocket plans lack direction
« Reply #4 on: 08/05/2006 03:15 PM »
The payload of the GX is less than you would expect from a rocket using the Atlas-3 first stage:

LEO: 4.4 t
SSO: 2.0 t
GTO (with additional kick stage): 1.4 t

Source: http://www.galaxy-express.co.jp/english/aboutGXrocket_e_final.pdf

Offline Space Lizard

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Re: Japan rocket plans lack direction
« Reply #5 on: 08/05/2006 04:14 PM »
It lacks the Centaur cryo upper stage. The Japanese LNH stage is much more like an Agena regarding lift performance.
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