美国未来航天计划顾问委员会去年11月提出应以现有技术迅速研制新型运载工具,供空间布署大型有效载荷使用,从而减轻对航天飞机的压力。据此,美政府和航天局希望研制国有发射系统,以提高国防部和NASA的发射效率和成本效益。这一希望的实现,将极大程度地取决于先进发射发展计划(ALDP) In November last year, the Advisory Committee of the Future Space Program of the United States proposed that the state-of-the-art technology should be used to quickly develop new types of vehicles for the deployment of large-scale space payloads, thereby alleviating the pressure on the space shuttle. Accordingly, the U.S. government and NASA hope to develop a state-owned launch system to improve the launch efficiency and cost-effectiveness of the Department of Defense and NASA. The realization of this hope will depend very much on the Advanced Launch Development Plan (ALDP)