The programmes may be complementary, but the X-33 and X-34 launchers meet different needs.
Graham Warwick/ATLANTA
When NASA awarded contracts for the X-33 and X-34 re-usable launch vehicles (RLVs) on the same day in March, it inadvertently created confusion which Rockwell International and Orbital Sciences, particularly, are keen to clear up in the minds of potential customers. Rockwell and Orbital are the only companies involved in both programmes, and they are keen to stress that the differences between the projects are significant.
The X-34 is a small, air-launched, re-usable launcher which Orbital and Rockwell will develop with assistance from NASA. The vehicle developed will be offered for commercial launches by Orbital/Rockwell joint venture American Space Lines, beginning in 1998.
The X-33 is a technology demonstrator being studied by three teams, including Rockwell/Orbital, which will be the forerunner of a large, unmanned, fully re-usable, single-stage-to-orbit launcher which could replace the Space Shuttle after 2005. The first flight of the X-33 is scheduled for 1999.
The two programmes are complementary, explains Dr Antonio Elias, senior vice-president of Orbital's advanced-programmes group and X-34 programme manager. The X-34 will be used to demonstrate technology applicable to the larger X-33 and, if successful, the programme will act as a pathfinder for the industry-led/government-assisted partnership planned for the Shuttle replacement.
Industry will be required to fund a significant proportion of each programme, Elias says. Orbital and Rockwell will contribute $100 million towards X-34 development, with NASA providing $70 million.
For the three-phase X-33 programme, the industry contribution will be even higher. NASA has awarded $24 million in contracts, for the initial design phase and has budgeted $650-800 million, for construction and test of the X-33 but the estimated $5-15 billion cost of developing and operating the Shuttle-replacement RLV, will be borne entirely by industry, says Ira Victer, Rockwell's X-33 deputy programme director.
EQUAL SHARES
NASA divided the initial $24 million equally between the three X-33 teams, led by Lockheed Martin, McDonnell Douglas and Rockwell. Victer says that the two companies will add $29 million of their own money to the $8 million received from NASA for the 15-month effort to define concepts, develop designs and formulate a business plan for the X-33.
By the end of the 15 months, each team is required to have an X-33 design, an RLV concept and a business plan which proves or disproves the commercial viability of a privately developed and operated RLV, Victer indicates. An important part of the business plan, he says, is what guarantee the US Government, as the largest potential user of the RLV, is prepared to give industry concerning its future launch requirements.
This is called "assured tenancy", Victer explains, and is essential if industry is to invest heavily in construction of the X-33 and subsequent development and operation of the RLV. "Industry will need a significant commitment in 1996 that will have to be adhered to in the future. That will have to be understood during Phase 1 before there is private interest in Phase 3," he warns.
Tying the Government to long term commitments, is not the US way of doing things and Victer admits, that a major effort will have to be made during the initial phase, to educate and convince the US Congress, that such guarantees must be legislated, if the concept of a privately operated Shuttle replacement is to be realised.
The X-34 programme will have a major role to play in proving that the X-33 will be technically and commercially feasible, says Orbital's Elias. He sees three major roles for the X-34: as a testbed for RLV technologies; as a pathfinder for the proposed RLV business partnership; and as a classical experimental vehicle, providing a Shuttle-like aero-thermodynamic re-entry environment for piggyback experiments.
The X-34 represents less of a business risk than does the X-33 - not only because it is a smaller vehicle. Orbital is already well established in the small-commercial-launcher market with its Pegasus and Taurus boosters and is projecting a launch rate of between nine and 12 a year by 2000. This could double, Elias believes, as a result of the X-34's lower launch costs.
The major market is seen as the replenishment of low-Earth-orbit communications-satellite constellations with single launches, rather than the clustered launches by larger boosters, which will be used to establish these systems, he says.
Victer believes that the majority of RLV flights, at least initially, will be on Space Station replenishment missions, underlining the importance of securing Government guarantees of launch requirements. The Shuttle would be phased out after the RLV enters service, but Victer expects the USA to maintain an expendable-launch-vehicle capability as a backup.
Source: Flight International
