ADVANCED MANNED LAUNCH SYSTEM STUDY STATUS

Various concepts for advanced manned launch systems (AMLS) are examine d for delivery missions to space station and polar orbit. Included are single- and two-stage winged systems with rocket and/or airbreathing propulsion systems. For near-term technologies, two-stage, reusable ro cket systems are favored over single-stage rocket or airbreathing/rock et systems. Advanced technologies enable viable single-stage-to-orbit (SSTO) concepts. Although two-stage rocket systems continue to be ligh ter in dry weight than SSTOs, advantages in simpler operations may mak e SSTOs more cost effective over the life cycle. Generally, rocket sys tems maintain a dry weight advantage over airbreathing systems at adva nced technology levels, but to a lesser degree than when near-term tec hnologies are used. More detailed understanding of vehicle systems and associated ground and flight operations requirements and procedures i s essential in determining quantitative discrimination between these l atter concepts.