The distance between Orlando, FL and Miami, FL is 377 km (234 mi.). This is the approximate orbital altitude of the Russian Salyut and MIR space stations; Skylab and the existing International Space Station (ISS). With the exception of the Apollo missions, virtually all human space flight has occurred within the distance between Orlando and Miami. In other words, very close to the Earth. This is significant because NASA's goal is to explore Beyond low-Earth Orbit (BEO) and is building the Space Launch System (SLS) capable of sending humans to cis-lunar space, the surface of the Moon, asteroids and Mars. Unlike operations in low-earth orbit, astronauts on BEO missions do not have rapid emergency return or frequent resupply opportunities and are exposed to potentially lethal radiation. Apollo missions were by comparison short. The longest was 12.5 days compared to cis-lunar missions currently being sized for 60 and 180 days. For radiation, one of the largest solar particle events (SPE) on record (August 4-9, 1972) occurred between the Apollo 16 and 17 flights. This was fortunate because the magnitude of this SPE would likely have been fatal to astronauts in space suits or the thin-walled Lunar Excursion Module. A cislunar habitat located at one of the Earth-Moon Lagranian points (EM L2) is being studied. This paper presents an overview of the factors influencing the design and includes layout options for the habitat. Configurations include ISS-derived systems but there is an emphasis on SLS-derived versions using a propellant tank for the habitat pressure vessel.
Most view the Apollo Program as expensive. It was. But, a human mission to Mars will be orders of magnitude more difficult and costly. Recently, NASA's Evolvable Mars Campaign (EMC) mapped out a step-wise approach for exploring Mars and the Mars-moon system. It is early in the planning process but because approximately 80% of the total life cycle cost is committed during preliminary design, there is an effort to emphasize cost reduction methods up front. Amongst the options, commonality across small habitat elements shows promise for consolidating the high bow-wave costs of Design, Development, Test and Evaluation (DDT&E) while still accommodating each end-item's functionality. In addition to DDT&E, there are other cost and operations benefits to commonality such as reduced logistics, simplified infrastructure integration and with inter-operability, improved safety and simplified training. These benefits are not without a cost. Some habitats are sub-optimized giving up unique attributes for the benefit of the overall architecture and because the first item sets the course for those to follow, rapidly developing technology may be excluded. The small habitats within the EMC include the pressurized crew cabins for the ascent vehicle, rover, Mars-moon taxi and exploration vehicle. In addition, the scope of commonality is broadened to include a precursor cis-lunar Exploration Augmentation Module (EAM) and the logistic elements supporting both the EAM and Mars surface operations. Together, these amount to over 20 flight vehicles. The approach to maximizing commonality combines not only the physical and functional characteristics of the habitats, but also methods of acquisition and management spanning the multi-decade exploration campaign. The paper presents a method of quantifying the cost benefits of developing common habitats. First, based on the campaign schedule, the time for developing individual habitat is identified. Then this is compared to strategy that combines all habitat requirements into a core for a single DDT&E with follow-on delta development for each end item. The savings as a result of overall program schedule compression is measured using analogous DDT&E and recurring costs escalated to a common year dollar. In order to demonstrate a workable common solution, three design/analysis products are shown. These include a commonality analysis tool derived from the master equipment list for each habitat, a cost analysis tool and representative configurations that validate the initial common core tailored to each vehicle.
NomenclatureCBM = Common Berthing Mechanism CDR = Critical Design Review CSM = Command Service Module DDT&E = Design Development Test and Evaluation EAM = Exploration Augmentation Module EMC = Evolvable Mars Campaign EMU = Extravehicular Mobility Unit HAT = Human Spaceflight Architecture Team ISS = International Space Station LEM = Lunar Excursion Module LCC = Life Cycle Cost LEO = Low Earth Orbit MACES = Mars Advanced Crew Escape Suit MAV = Mars Ascent Vehicle MEL = Master Equipment List M...
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