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The stated goals of NASA’s Research Announcement for the Space Launch System (SLS) Advanced Booster Engineering Demonstration and/or Risk Reduction (ABEDRR) are to reduce risks leading to an affordable Advanced Booster that meets the evolved capabilities of SLS and enable competition by mitigating targeted Advanced Booster risks to enhance SLS affordability. Dynetics, Inc. and Pratt & Whitney Rocketdyne—now Aerojet Rocketdyne— formed a team to offer a wide-ranging set of risk reduction activities and full-scale, systemlevel demonstrations that support NASA’s ABEDRR goals. Among several efforts funded by the ABEDRR program, the Dynetics Team is applying state-of-the-art manufacturing and processing techniques to the heritage F-1 rocket engine to reduce the risk to achieving a low recurring cost engine that retains the benefits of Apolloera experience. Dynetics and Aerojet Rocketdyne are using NASA facilities to perform fullscale F-1 gas generator and powerpack hot-fire test campaigns for engine risk reduction. Dynetics will also fabricate and test a tank assembly to verify the structural design. As a result of the reduced risks and demonstrations from ABEDRR, we believe NASA can and should proceed with an SLS Advanced Booster Design, Development, Test, and Evaluation (DDT&E) competition. First, NASA will obtain the best overall booster price through a full and open competition. NASA can constrain the acquisition to its current booster budget. It can incentivize contractors based on long-term flight hardware recurring cost savings. It can evaluate the realism and reasonableness of proposed approaches. Second, a booster competition offers the potential for additional performance beyond the SLS 130 mT requirement. Excess performance above the requirement could afford NASA higher margins on the SLS and/or reduced performance requirements on elements (like an upper stage), leading to lower development risk and lower cost. Increased performance may also enable broader, bolder options for exploration missions within the constrained budgets. We believe there is a strong case for an Advanced Booster DDT&E competition as soon as funding allows. A lower cost, higher performing booster will increase the chance of success of other system and mission elements. Prioritizing the Advanced Booster competition and selection will allow NASA to accurately assess the SLS capabilities and environments and focus future procurement requirements on affordable, achievable missions.

For NASA's Space Launch System (SLS) Advanced Booster Engineering Demonstration and/or Risk Reduction (ABEDRR) procurement, Dynetics, Inc. and Pratt & Whitney Rocketdyne (PWR) formed a team to offer a wide-ranging set of risk reduction activities and full-scale, system-level demonstrations that support NASA's goal of enabling competition on an affordable booster that meets the evolved capabilities of the SLS. During the ABEDRR effort, the Dynetics Team will apply state-of-the-art manufacturing and processing techniques to the heritage F-1, resulting in a low recurring cost engine while retaining the benefits of Apollo-era experience. ABEDRR will use NASA test facilities to perform full-scale F-1 gas generator and powerpack hot-fire test campaigns for engine risk reduction. Dynetics will also fabricate and test a tank assembly to verify the structural design. The Dynetics Team is partnered with NASA through Space Act Agreements (SAAs) to maximize the expertise and capabilities applied to ABEDRR.

Achieving airplane-like safety and reliability on ETO launch systems requires fundamental changes in vehicle propulsion and flight trajectories. Current launch systems all have extended regions where catastrophic engine failure means loss-of-vehicle (LOV) either through loss of control or insufficient thrust to weight (T/W < 1.0). These regions have been euphemistically termed “dead zones” for obvious reasons. The most straightforward solution is to supply extra engines to give “engine-out capability”, but this approach has limited use because of the additional cost and weight penalties, and the fact that uncontained engine failures will often result in “engine fratricide”, which can still reduce T/W < 1. In this paper we examine causes of unreliability, available intact abort options, and a variety of approaches for enhancing the safety of different reusable launch systems. We are focusing on reusable launch systems because reuse has historically resulted in one to two orders of magnitude reduction in vehicle loss rate (after a reasonable flight test program).

Andrews has developed the Peregrine Launch System (PLS), a horizontal takeoff horizontal landing (HTHL) vehicle capable of providing high levels of operational flexibility. The PLS is currently being considered for full-scale demonstration as part of the DARPA / Air Force FALCON program due to its unique capability to meet force projection and responsive spacelift mission needs. The PLS will provide a dramatic leap in the nation’s ability to safely and reliably respond to perceived threat situations while prohibiting other threats via unparalleled force projection capabilities. To accomplish this, the PLS maximizes the use of mature technologies to minimize development risk and overall system complexity effectively reducing maintenance operations and turn around time. Historically, maintenance intense technologies such as thermal protection systems have been minimized by tailoring the flight profile for optimized responsiveness and operability. This focus on responsiveness has resulted in a system uniquely qualified to meet not only the near term needs of the nation but also the emerging commercial market.

U.S. commercial interests, Department of Defense (DoD) global strike and space control desires, and President Bush’s “new plan to explore space and extend a human presence across our solar system” all drive the requirements of American space launch systems, often in disparate directions. The single constant—and major constraint—is a lack of funding. What is needed is a consistent space launch approach that is evolvable, doesn’t necessitate substantial technology advancement, addresses multiple requirement sets, and can be available near-term while still having long-term applicability. Today’s status quo is vertical takeoff, all-rocket, and expendable launch systems. This approach has proven inflexible, risky, and costly. Even the single reusable example (the Space Shuttle) is plagued by the same problems. However, an alternate approach is available which may overcome traditional space lift problems: horizontal takeoff and landing. Andrews Space proposes a responsible spiral development roadmap for horizontal takeoff, horizontal landing (HTHL) launch systems. The key to this roadmap is the operability of HTHL vehicles. Other significant advantages are the synergy across the HTHL family of vehicles, the limited technology development required, and the applicability to both today’s needs and future plans. These advantages all lead to considerable improvements in system life cycle cost. Andrews Space also proposes three vehicles as representative members of the HTHL family: a small launch vehicle for immediate DoD global strike and small satellite launch needs, a midsize vehicle with moderate (10-15klb to LEO) payload capacity to compete with existing expendables, and an advanced system capable of heavy lift for NASA exploration missions. Acronyms

Andrews Space has developed the “Alchemist” Air Collection and Enrichment System (ACES), a dualmode propulsion system that enables safe, economical launch systems that take off and land horizontally. Alchemist generates liquid oxygen through separation of atmospheric air using the refrigeration capacity of liquid hydrogen. The key benefit of Alchemist is that it minimizes vehicle takeoff weight. All internal and NASA-funded activities have shown that ACES, previously proposed for hypersonic combined cycle RLVs, is a higher payoff, lower-risk technology if LOX generation is performed while the vehicle cruises subsonically.