Space Launch Report:  New Launchers - Galaxy Express GX
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In contrast to the SpaceX Falcon private commercial development effort and Europe's all-government Vega program, Japan's Galaxy Express was a government-commericial partnership.

Galaxy Express Corporation was established in March 2001 to develop a new medium commercial launch vehicle, initially named J-2 (or J1-Upgrade), but renamed Galaxy Express (GX) in January 2003.  The program was originally intended to provide a lower-cost replacement for Japan's J1 rocket.  J1 had been cancelled by spiraling costs after performing only one suborbital mission in 1996.   

The company was formed by seven Japanese companies, including Ishikawajima-Harima Heavy Industries Co. (IHI), Mitsubishi Heavy Industries Corp., Kawasaki Heavy Industries Ltd., IHI Aerospace Co. (the former Nissan Aerospace), Japan Aviation Electronics Industry Ltd., Fuji Heavy Industries Ltd. and Kokusai Sohko Co..  Lockheed Martin of the United States later signed on as a shareholder.

Galaxy Express was capitalized at $820,000, with launch vehicle development expected to cost $325-400 million.  Plans called for the Japanese government to pay two-thirds of the development cost.  The new rocket was expected to fly in 2005 and to enter revenue service in 2006.

Initial plans called for the new launch vehicle to use a liquid oxygen/kerosene first stage based on stainless steel balloon-type Atlas tanks provided by Lockheed Martin.  The stage was to be powered by a single NK-33 engine from Aerojet.   The second stage was to be powered by a new liquid natural gas (LNG)/liquid oxygen (LOX) pressure-fed engine developed by IHI.

Several months after Galaxy Express was formed, GX plans shifted toward the use of the already-existing Atlas III first stage powered by an Energomash RD-180 instead of an NK-33.  This change coincided with Lockheed Martin’s investment in the company.   

GX was designed to lift 4.4 metric tons (tonnes) to low earth orbit, or 1.4 tonnes to geosynchronous transfer orbit, giving it roughly the lifting capability of a Delta 2 or Soyuz/Fregat.   GX was expected to perform 3-4 commercial and/or government launches per year.  Payloads could include mobile communications, geodetic survey, navigation, weather, information gathering, land survey, space science, research and experimentation.  GX would lift off from the old "N"/H-1 "Osaki" pad at Tanegashima Space Center located several miles south of the H-IIA "Yoshinobu" launch site.

Initially, few took note of what in hindsight was an obvious schizophrenic element of the GX design.  Galaxy Express said that GX would use existing hardware to minimize development costs.  This was certainly true of the planned first stage, but the second stage, which required the development of an untried LNG propulsion system and of cutting edge high-pressure tank materials, was an entirely different matter.  This aspect, all the more puzzling in the wake of the high-cost J1 program failure, may have been created as a way to justify the substantial government investment.  In order to fund the work, the second stage project had to provide new technology for Japan. 

Unfortunately, the effort gradually shifted from a development program into a costly research project that fell nearly one-half decade behind schedule.  GX development was finally halted by Japan's government in December 2009.

GX Stage 2 (JAXA)GX Development

The National Space Development Agency of Japan (NASDA, since renamed Japan Aerospace Exploration Agency, or JAXA), was tasked with leading the development of the second stage and its new liquefied natural gas (LNG) propulsion system.  The stage would be the world’s first LNG orbital rocket stage.  The program got off to a bad start when approval for the expected three-year-long LNG development effort was delayed until March 2003.  By that time the LNG stage project alone was expected to cost $384 million to $427 million. 

By the end of 2003, a full-scale model of the planned second stage cryogenic composite fuel tanks had been tested in ambient and cryogenic temperatures.  Not all objectives were fulfilled during these tests.  Structural testing was also performed on hardware designed to hold the planned cluster of four composite cryogenic tanks.  The novel tank structure consisted of aluminum liner wrapped in Carbon Fiber Reinforced Plastic (CFRP).    The design called for two LNG tanks and two LOX tanks to be bundled together, along with several sizable helium pressurization tanks. 

A 353 second “Mission Duty Cycle” firing demonstration of the LNG engine was performed during 2003, followed by a “Battleship Firing Test” for the entire LNG propulsion system, using heavy thick-wall tanks.

By the end of 2004, JAXA was still performing structural testing of the composite cryogenic propellant tanks.  The LNG igniter was tested during 2004.  Some unexpected results occurred during the testing, requiring modifications to the design.  Problems also cropped up during firing tests of a one-fifth scale model of the LNG engine when the injector failed at the time of engine cutoff.  The failure, caused by abnormal combustion resulting from the backward flow of combustion gas from the combustion chamber back to the injector, required more design effort.

gx2009s.jpg (8044 bytes)GX Shape Shifter 

By late 2006, JAXA and contractor Ishikawajima-Harima Heavy Industries had encountered enough problems with second stage development to substantially delay the program.  Costs for developing the engine alone had grown to about $300 million, 3.5 times the initial estimate, which meant that the second stage project cost had grown to something like $600 million.  Problems with the CFRP tanks had finally forced a switch to stainless steel tanks.  The planned pressure fed engine design was also reconsidered, with boost pumps added to feed propellant to the engine.

While JAXA and IHI struggled with second stage development, and while the entire GX development effort suffered criticism for its rising costs, Lockheed Martin maintained a completed GX first stage in storage at its ex-General Dynamics factory in San Diego, California.  Lockheed's shift of its space launch business to the United Launch Alliance consortium in December 2006 clouded the picture.  By 2008, it was not at all clear that ULA would be able to produce Atlas III based stages for GX.  By 2007, schedules called for GX first flight in 2011 or 2012, but it was not apparant when or if the rocket would ever fly.

JAXA performed a successful full scale test of the LNG upper stage engine during October 2007, but the overall development budget was cut by 2/3rds for 2008.  According to some reports, consideration was given to cancelling the program in May 2008.

In early 2009, United Launch Alliance released new information about the GX program.  According to the ULA update, Galaxy Express had dropped the Atlas III based first stage in favor of an Atlas V Common Core Booster, powered by an RD-180 engine.  GX would also use Atlas V avionics.  The JAXA LNG stage would  essentially replace the Atlas V 401 Centaur stage to create the GX rocket.  ULA also said that GX would initially fly from Vandenberg AFB, with the first of two test flights expected to occur in 2012.  From Vandenberg, GX was expected to be able to lift about 3 metric tonnes to a 500 km sun sychronous low earth orbit, an improvement on the original Atlas III based design.

GX Program Cancelled

In late 2009, Japan's government cancelled funding for the GX program.  On January 15, 2010, IHI liquidated the Galaxy Express joint venture.  The company said that $778 million had been spent by all participants on the effort, but that an additional $1.04 billion was required to complete development. 

Vehicle Configurations

  LEO Payload
(metric tons)
(1) 200 km x 30 deg
(2) 800 km x 98 deg
GTOx28.5 deg Payload
(metric tons)
Configuration Liftoff
(metric tons)

Price (2005)

(2004 Design)
4.4 t (1)
2.0 t (2)
1.4 t (using solid 3rd stg) Atlas III Stg1 + LNG Stg2 48 m 210 t Unknown

Vehicle Components

  Stage 1
Single Stage Atlas
Stage 2 (2004) Stage 2 (2007) Payload
Diameter (m) 3.1 m 3.3 m 3.3 m 3.3 m
Length (m) 30.6 m 7.8 m 8 m 9.6 m
Empty Mass (tonnes) 14 t 2.1 t 2.6 t 1  t
Propellant Mass (tonnes) 183 t 9.9 t 17 t  
Total Mass (tonnes) 197 t 12 t 19.6 t  
Engine RD-180 LNG LNG  
Mfgr Energomash IHI IHI  
Propellants RP-1/LOX LNG/LOX LNG/LOX  
(SL tons)
390 t      
(Vac tons)
423 t 9.89 t 12 t  
ISP (SL sec) 311 s      
ISP (Vac sec) 338 s 355 s 323 s  
Burn Time (sec) 237 s 342 s 480 s  
No. Engines/Motors 1 1 1  
Turbopump fed throttleable
Full gimbal control
He gas pressure-fed restartable
Gimbal/GN2 jet control
Boost pump-fed restartable
Gimbal/GN2 jet control


"Outline of GX Launch Services", Galaxy Express Corporation, August 2005
"GX Launch Vehicle, Easy Access to Space", Galaxy Express Corporation, December 2004
"LNG Propulsion System", JAXA, 2004

Last Update:  January 24, 2010
by:  Ed Kyle