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OSTP memo guides space nuclear plan
A White House Office of Science and Technology Policy (OSTP) memorandum released on Tuesday guides NASA, the Department of Energy, and the Department of Defense on their roles in deploying near-term space nuclear power.
This follows a series of NASA announcements last month—driven by the executive order “Ensuring American Space Superiority,” issued by Trump in December—including an ambitious timeline for establishing a moon base, which would rely on fission surface power (FSP) to survive the long lunar night at the moon’s south pole, and plans for a nuclear electric propulsion (NEP) rocket to be launched in 2028.
Yoshiko Harima, Yukio Sakamoto, Naohiro Kurosawa, Akinao Shimizu
Nuclear Technology | Volume 168 | Number 3 | December 2009 | Pages 861-866
Shielding | Special Issue on the 11th International Conference on Radiation Shielding and the 15th Topical Meeting of the Radiation Protection and Shielding Division (PART 3) / Radiation Protection | doi.org/10.13182/NT09-A9319
Articles are hosted by Taylor and Francis Online.
The geometric-progression (G-P) formula can accurately reproduce buildup factor data up to depths of 40 mean free paths (mfp) within a few percent. This formula was improved to apply to depths up to 100 mfp, using the buildup factor data of Shimizu et al. (2004) calculated with the Invariant Embedding method.The behavior of the K parameter as a function of distance was examined, and a new formula was introduced from the depth of Xm ([approximately]40 mfp). The fitting parameters were determined using a minimizing procedure of the maximum fractional deviation (MMD). Within some sets of parameters determined by the MMD fit, one set of parameters was selected that realized the interpolation of the buildup factor with regard to energy, using interpolated G-P parameters. Consequently, discrete buildup factor data were converted to continuous data with regard to both energy and distance.
