Nuclear Energy May be a Practical Option for Mission to Marsby Jeremy Whitlock
This topic is the speciality of the University of Florida's "Innovative Nuclear Space Power and Propulsion Institute" (INSPI), of which Dr. Anghaie is the Director, as well as being a professor of nuclear engineering at the University. Dr. Anghaie has been the lead U.S. investigator in a joint Russian-American space nuclear power project for the development of high-temperature nuclear fuels and materials.
Dr. Anghaie explained how conventional chemical energy sources are pushed to their limits in current space missions, leaving no "energy margin" for extra manoeuvrability once the target planet has been reached. He suggested that the recent spectacular failures of unmanned Mars probes were partly due to this lack of flexibility. Manned missions would require even more energy margin in order to guarantee the safe return of astronauts at any point in their mission.
Even more compelling is the reduction in travel time, which is directly related to the subsequent health of the astronauts. Nuclear propulsion can reduce the time for a manned Mars mission to 200 days from 600 days. Cosmic radiation exposure to astronauts is a significant concern once they leave the protective shielding of Earth's atmosphere, and reducing the time spent in this harsh environment becomes very important. So important, Dr. Anghaie points out, that the longer missions with chemical rockets may well be impossible.
Dr. Anghaie outlined some of the unprecedented engineering challenges presented by high-impulse nuclear rockets. Specifically, there is a need for extremely high temperatures of the hydrogen propellant (5000 deg.C), which requires nuclear fuel that can operate reliably in this range.
High-temperature graphite-core nuclear rockets were tested at Los Alamos Laboratories in the U.S. during the 1960s, and since then many proposals have been made for gaseous-fuel designs promising higher performance. Dr. Anghaie started his presentation with a 10-minute video of an ambitious project, now on the backburner in the U.S., to create a rocket with uranium plasma. The plasma is heated to many thousands of degrees, at which point the problems of confinement and stability become reminiscent of the challenges facing practical fusion technology.
Dr. Anghaie's INSPI institute entered the field in 1993 and has advanced the knowledge of both solid- and gaseous-core space reactors.
During questioning, Dr. Anghaie emphasized that the goal of a manned mission to Mars is simply the "holy grail" driving international political support of space reactor development. More realistically, the technology will be applied in satellite and probe technology long before humans are carried to Mars with nuclear rockets.
On the subject of public support, with reference to the uproar over unmanned probes carrying plutonium sources, Dr. Anghaie feels that the scientific establishment is a more important target. Public discontent can be settled in the courts on the basis of the facts, he says, but a project can die if influential scientific advisory groups are not supportive.
Those seeking more information about Dr. Anghaie's institute, and nuclear space propulsion in general, can go to the INSPI website: www.inspi.ufl.edu.