DESIGN OPTIONS FOR ADVANCED MANNED LAUNCH SYSTEMS

Various concepts for advanced manned launch systems are examined for d elivery missions to space station and polar orbit. Included are single - and two-stage winged systems with rocket and/or air-breathing propul sion systems. For near-term technologies, two-stage reusable rocket sy stems are favored over single-stage rocket or two-stage air-breathing/ rocket systems. Advanced technologies enable viable single-stage-to-or bit (SSTO) concepts. Although two-stage rocket systems continue to be lighter in dry weight than SSTO vehicles, advantages in simpler operat ions may make SSTO vehicles more cost-effective over the life cycle. G enerally, rocket systems maintain a dry-weight advantage over air-brea thing systems at the advanced technology levels, but to a lesser degre e than when near-term technologies are used. More detailed understandi ng of vehicle systems and associated ground and night operations requi rements and procedures is essential in determining quantitative discri mination between these latter concepts.