Our current national, government-funded human spaceflight effort lacks clarity of purpose. Despite NASA's obsession with human missions to Mars, a return to the Moon offers more benefits, a larger number of near-term milestones, and prepares us for future missions to the planets. We offer a logical, justifiable alternative to the existing program that identifies a compelling purpose for human spaceflight - to learn how to use the material and energy resources of space to create new spaceflight capabilities. As in our previous plan, robotic surface elements begin harvesting lunar water for use prior to human arrival on the Moon, resulting in the creation of a permanent, space-based cislunar transportation system. However, we continue this effort with two significant updates. We use the SLS Block-1 and Block 1B configuration launch vehicle for outpost buildup, which allows much more mass and volume in a single launch, and craft an architecture that minimizes cost (almost 50% reduction in crew cycle cost compared to our previous architecture) for a crew lunar mission cycle by relying upon Commercial Crew launch services. Employing a reusable in-space cislunar crew stage and a reusable human lunar lander, a crew can be launched commercially by any of several providers and returned 6-months later using the Commercial Crew service. To improve safety, we station an Orion at a Low Lunar Orbit (LLO) fuel depot that can be used as an assured crew return vehicle at any time in case of emergency. As a consequence of this strategy, we develop more capability to harvest lunar water for propellant compared to the previous architecture; at the end of the 16-year first phase of the architecture, we produce more than 300 metric tons of lunar water per year, with a production capacity of 500 metric tons per year. We use aerobraking during Earth return to recover the reusable cislunar crew stage; this non-propulsive maneuver removes excess energy for an insertion to Low Earth Orbit to transfer crew to the Commercial Crew vehicle before returning home. We take advantage of a LEO fuel depot, loaded by commercial or government water deliveries to the depot from Earth, to fuel the cislunar crew stage on its way to the Moon. The use of both commercial crew and commercial water transferred to the LEO fuel depot allows the campaign to better use and stimulate commercial space industry, transferring technology and experience from NASA to the commercial sector regarding the ability of humans to use local (off-planet) resources in an effective way to explore and grow off-planet. The total estimated cost for this new architecture is $ 87.7 billion, about $ 550 million more than our previous plan. In addition, we have examined possible international contributions to the architecture, with specific suggestions for bartered and in-kind contributions. With these possible contributions, we can reduce the peak NASA funding to $ 5.5 billion per year while reducing the total program cost to $ 69 billion, a reduction of roughly one-quarter (25%). At the end of the first phase of the lunar campaign, we will have demonstrated and determined the degree to which humans can effectively use local resources to live and thrive off-planet. At that point, future missions to other deep-space destinations (like Mars) can be undertaken, leveraging the technology gained and lessons learned from the lunar experience as well as utilize the consumables and propellant produced from lunar resources. These new products can be used and exploited by government, commercial, or international entities as we continue to expand our reach in cislunar space and beyond.
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