NASA is pinning its hopes for a Shuttle replacement on the Space Launch Initiative
Graham Warwick/WASHINGTON DC
Barely is the ink dry on the first contracts awarded under the USA's $4.5 billion Space Launch Initiative (SLI) and already industry is casting doubts on NASA's hopes the programme will lead to commercial development of a second-generation reusable launch vehicle (RLV) to replace the Space Shuttle.
The problem is cost, with estimates for development of a second-generation RLV ranging from $7 billion to $17 billion. In the eyes of most US industry leaders, this rules out the possibility of the commercial sector financing development of a Shuttle replacement - certainly one which could become operational in the timeframe envisaged by NASA.
This calls into question SLI's stated goal, which is to develop the technology needed "to enable full-scale development by 2005 and operations by 2010 of a commercially competitive, privately owned and operated launch vehicle". Instead, industry would like to see the US Government fund further upgrades to the Shuttle to keep it in service longer, while investing in "breakthrough" technologies to produce a viable second- generation RLV.
NASA's hopes ride on the SLI after the failure of the $1.27 billion Lockheed Martin X-33 programme to produce a viable commercial successor to the Shuttle. Thomas Young, chairman of the NASA Advisory Council's spaceflight committee, has said the agency's plan to phase out the Shuttle by 2012 is "no longer realistic", following cancellation of the X-33, and has predicted the Shuttle will continue to fly to at least 2022. Space executives at Boeing and Lockheed Martin, which operate the Shuttle under the United Space Alliance joint venture, also predict the 20-year-old vehicle will keep flying for longer than currently planned.
NASA's original plan was to decide in 2000 on development of a replacement for the Shuttle, to be operational by 2005. This was predicated on successful flight testing of theX-33, to demonstrate technology for Lockheed Martin's VentureStar RLV, which the company planned to develop commercially. Failure of the X-33's composite liquid-hydrogen tank during ground testing delayed the first flight to 2003, and earlier this year NASA decided not to fund the programme further under the SLI.
This effectively killed the X-33, although the US Department of Defense (DoD) has expressed interest in picking up the programme. Talks are under way between Lockheed Martin, NASA and the DoD, which is interested in using the X-33 to provide a rapid-reaction launch capability for the Space Manoeuvre Vehicle, a small unmanned reusable spaceplane to be developed out of Boeing's X-37 and X-40 technology demonstrators.
The X-33 was always considered to be high risk because it was intended to demonstrate technology for a single-stage-to-orbit (SSTO) RLV. For the SLI, NASA has selected only multi-stage designs, with SSTO now considered a third-generation RLV concept and, therefore, unlikely to be viable before 2025 at the earliest. Boeing, Lockheed Martin and Orbital Sciences/Northrop Grumman have proposed two-stage-to-orbit designs, while Kelly Space &Technology and Vought Aircraft Industries, have proposed a towed-launch RLV.
NASA has also elected not to fund work on a Shuttle-derived vehicle under the SLI. This raises questions about how the Shuttle will be evolved if it is to remain in service, as industry increasingly expects, for another 30 years.
Source: Flight International
