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Fusion Science and Technology
Trump leaves space nuclear policy executive order for Biden team
A hot fire test of the core stage for NASA’s Space Launch System rocket at Stennis Space Center in Mississippi was not completed as planned. The SLS is the vehicle meant to propel a crewed mission to the moon in 2024. Source: NASA Television
Among the executive orders President Trump issued during his last weeks in office was “Promoting Small Modular Reactors for National Defense and Space Exploration,” which builds on the Space Policy Directives published during his term. The order, issued on January 12, calls for actions within the next six months by NASA and the Department of Defense (DOD), together with the Department of Energy and other federal entities. Whether the Biden administration will retain some, all, or none of the specific goals of the Trump administration’s space nuclear policy remains to be seen, but one thing is very clear: If deep space exploration remains a priority, nuclear-powered and -propelled spacecraft will be needed.
The prospects for near-term deployment of nuclear propulsion and power systems in space improved during Trump’s presidency. However, Trump left office days after a hot fire test of NASA’s Space Launch System (SLS) rocket did not go as planned. The SLS rocket is meant to propel crewed missions to the moon in 2024 and to enable a series of long-duration lunar missions that could be powered by small lunar reactor installations. The test on January 16 of four engines that were supposed to fire for over eight minutes was automatically aborted after one minute, casting some doubt that a planned November 2021 Artemis I mission can go ahead on schedule.
D. Testa, H. Carfantan, R. Chavan, J. B. Lister, J-M. Moret, M. Toussaint
Fusion Science and Technology | Volume 57 | Number 3 | April 2010 | Pages 208-237
Technical Paper | dx.doi.org/10.13182/FST10-A9468
Articles are hosted by Taylor and Francis Online.
The measurement performance of the baseline system design for the ITER high-frequency magnetic diagnostic has been analyzed using an algorithm based on the sparse representation of signals. This algorithm, derived from the SparSpec code [S. Bourguignon et al., Astron. Astrophys., 462, 379 (2007)] has previously been extensively benchmarked on real and simulated JET data. To optimize the system design of the ITER high-frequency magnetic diagnostic, we attempt to reduce false detection of the modes and to minimize the sensitivity of the measurement with respect to noise in the data, loss of faulty sensors, and the displacement of the sensors. Using this approach, the original layout design for the ITER high-frequency magnetic diagnostic system, which uses 168 sensors, is found to be inadequate to meet the ITER measurement requirements.Based on this analysis, and taking into account the guidelines for the risk mitigation strategies that are given in the ITER management plan, various attempts at optimization of this diagnostic system have been performed. A revised proposal for its implementation has been developed, which now meets the ITER requirements for measurement performance and risk management. For toroidal mode number detection, this implementation includes two arrays of 50 to 55 sensors and two arrays of 25 to 35 unevenly spaced sensors each on the low-field side and two arrays of 25 to 35 unevenly spaced sensors each on the high-field side. For poloidal mode number detection, we propose six arrays of 25 to 40 sensors each located in nonequidistant machine sectors, not covering the divertor region and, possibly, poloidal angles in the range 75 < [vertical bar][vertical bar](deg) < 105, as this region is the most sensitive to the details of the magnetic equilibrium. In this paper we present the general summary results of this work, for which more details and an overview of our test calculations are reported in the companion paper.