Affordable Development of a Nuclear Cryogenic Propulsion Stage

Houts, Michael G.; Kim, Tony; Emrich, William; Hickman, Robert; Broadway, Jeramie; Gerrish, Harold P.; Adams, Robert B.; Bechtel, Ryan D.; Borowski, Stanley K.; George, Jeffrey A.

doi:10.2514/6.2012-5143

Cited by 2 publications

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“…Investment in better propulsion systems will raise P acc . High power solar electric propulsion seems to be the currently most straightforward way to increase the acceptable delta--v for NEO missions (Brophy et al 2010), though nuclear propulsion options are promising in principle (Houts et al 2012).…”

Section: Discussionmentioning

confidence: 99%

How many ore-bearing asteroids?

Elvis

2014

Planetary and Space Science

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A simple formalism is presented to assess how many asteroids contain ore, i.e. commercially profitable material, and not merely a high concentration of a resource. I apply this formalism to two resource cases: platinum group metals (PGMs) and water. Assuming for now that only Ni--Fe asteroids are of interest for PGMs, then 1% of NEOs are rich in PGMs. The dearth of ultra--low delta--v (<4.5 km s --1 ) NEOs larger than 100 m diameter reduces the ore--bearing fraction to only 1 in 2000 NEOs. As 100 m diameter NEOs are needed to have a value ≥US$1 B and the population of near--Earth objects (NEOs) larger than 100 m diameter is 20,000 (Mainzer et al. 2011) the total population of PGM ore--bearing NEOs is roughly 10. I stress that this is a conservative and highly uncertain value. For example, an order of magnitude increase in PGM ore--bearing NEOs occurs if delta--v can as large as 5.7 km s --1 . Water ore for utilization in space is likely to be found in 1/1100 NEOs. NEOs as small as 18 m diameter can be water--ore--bodies because of the high richness of water (~20%) expected in 25% of carbonaceous asteroids, bringing the number of water--ore--bearing NEOs to 9000 out of the 10 million NEOs of this size. These small NEOs are, however, hard to find with present surveys. There will be 18 water--ore--bearing NEOs >100 m diameter. These estimates are at present highly imprecise and sensitive to small changes, especially in the maximum delta--v allowed. Nonetheless the low values found here mean that much improved determinations of each of the terms of the formalism are urgently needed. If better estimates still find small numbers of ore--bearing NEOs then thorough surveys for NEA discovery and, especially, characterization are needed. Strategies for the two classes are likely to be different.

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Section: Discussionmentioning

confidence: 99%

How many ore-bearing asteroids?

Elvis

2014

Planetary and Space Science

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“…The large nuclear engine is intended to be used in a clustered configuration for human exploration missions. 2 In support of the NCPS project, the NASA Glenn Research Center (GRC) has been working to model four nuclear thermal rockets in the Numerical Propulsion System Simulation (NPSS) framework. The main intent of this work is to analyze the overall system performance and operation of a nuclear thermal rocket.…”

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confidence: 99%

Nuclear Thermal Rocket Simulation in NPSS

Belair

Sarmiento

Lavelle

2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Four nuclear thermal rocket (NTR) models have been created in the Numerical Propulsion System Simulation (NPSS) framework. The models are divided into two categories. One set is based upon the ZrC-graphite composite fuel element and tie tube-style reactor developed during the Nuclear Engine for Rocket Vehicle Application (NERVA) project in the late 1960s and early 1970s. The other reactor set is based upon a W-UO2 ceramicmetallic (CERMET) fuel element. Within each category, a small and a large thrust engine are modeled. The small engine models utilize RL-10 turbomachinery performance maps and have a thrust of approximately 33.4 kN (7,500 lbf ). The large engine models utilize scaled RL-60 turbomachinery performance maps and have a thrust of approximately 111.2 kN (25,000 lbf ). Power deposition profiles for each reactor were obtained from a detailed Monte Carlo N-Particle (MCNP5) model of the reactor cores. Performance factors such as thermodynamic state points, thrust, specific impulse, reactor power level, and maximum fuel temperature are analyzed for each engine design.

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Affordable Development of a Nuclear Cryogenic Propulsion Stage

Cited by 2 publications

References 1 publication

How many ore-bearing asteroids?

How many ore-bearing asteroids?

Nuclear Thermal Rocket Simulation in NPSS

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