Steve Howe of Los Alamos chaired the Advanced Development Plans Panel of the Nuclear Propulsion Steering Committee, which delivered its report in November 1990.(1) The Panel observed that the NERVA technology base is significantly more advanced than that of other concepts, and that no other concept appeared to have lower development costs.
Ground test facilities were estimated to require a significant fraction of program resources. The Panel concluded that since all reactor concepts require fuel material development, a Nuclear Furnace type facility would be required for fuel development and testing, and that this facility should have a flexible design to accommodate various reactor concepts. In addition, the Panel concluded that a major System Test Facility will be required, that multiple test stands may be needed at this Facility to accommodate testing of improved and innovative reactor concepts over a period of decades. The Panel concluded that the viability of effluent cleanup for the System Test Facility has been demonstrated at the Nuclear Furnace, and that this approach could be appropriately scaled up.
The Panel urged near-term engineering assessment of the impact of specific reactor design concepts on System Test Facility design, including requirements for:
- Clustered engine tests (notably for the Low Pressure reactor, but potentially for other concepts as well);
- Altitude simulation (particularly for the Low Pressure reactor);
- Temperature simulation;
- Containment of Fission products (for Foil Core, Liquid Core and Gas Core concepts);
- Containment of Uranium releases (for Liquid Core and Gas Core concepts);
The Panel concluded that "a Mars mission can be performed with NERVA technology" and that "incremental component improvements resulting in an Isp > 900 are straight forward development tasks." Rather, the panel contended that "Nuclear Furnace and System Test Facilities are the challenge - an early start is required," (emphasis added) on work on these facilities. The Panel suggested that the Environmental Impact Study for these Facilities should be initiated soon, and would require at least six years to complete. Nuclear Furnace operations could commence eight years following authority to proceed, with System Test Facility operations beginning two years later.
Near term recommendations by the Panel include definition of systems engineering and requirements, as well as Nuclear Furnace and System Test Facility definition. Other near term activities include development of fuel technology and high temperature instrumentation, as well as studies of innovative technology.
For the longer term, the Panel examined two alternatives to the current program for development of nuclear thermal and nuclear electric propulsion.
Current Program - calls for parallel development of NEP and NTP to equivalent Technology Readiness Level 6 by 2005, at which time one or the other would be selected for further development leading to a 2016 Mars mission. This would require expenditures of between $4 to $8 billion in the 1995-2005 period for technology development. This funding level was considered to exceed likely available resources, leading to interest in alternative options.
Option One - Late (2016) Mars Focus - would place early emphasis on establishing NEP feasibility, with work on thruster and power conversion technology, and development of a fuel test facility. NTP work would concentrate on Nuclear Furnace fuel technology testing in the near term, with construction of the System Test Facility delayed until 10 years prior to the first Mars Mission. Total cost of this option would be $2.6 billion from 1995 to 2005.
Option Two - Early (2005) Mars Focus - would immediately start NTP advanced development, with funding of fuel and facility development, and would initiate work on NTP flight development as soon as possible, to support a 2005 Mars mission. This option supports determination of NEP feasibility for the 2016 mission, but proceeds from the recognition that 2-3 year lifetime testing requirements for NEP preclude its use in 2005. Total cost of this option is $4.8 billion from 1995 to 2005.
However, in the absence of funding for SEI generally, these plans came to naught.
1. Howe, Steve, (DOE Los Alamos National Laboratory), "Report to the Steering Committee by the Advanced Development Plans," 18 September 1990, delivered at the NEP/NTP Workshop Feedback Meeting, (Hilton Nassau Bay Hilton, Houston, TX, 15 November 1990).