Back to the Moon with Nuclear Rockets

Figure 7NUCLEAR POWER TO OPEN THE SOLAR SYSTEMThe basic small Nuclear Thermal Rocket engine will provide a versatile capability for avariety of missions. It will enable the exploration, settlement, and commercia developmentof the Moon, and clusters of small nuclear engines can carry men and r laterial toMars. In addition, unmanned robotic exploration missions to the outer planets, vill benefitfrom the stand-alone capabilities of nuclear propulsion.for crew life support and other requirements aboard the spaceship.Some of the advantages in this mission design are thatfewer different transportation system elements are required,the initial mass in low-Earth orbit is reduced, and space operationsare simplified.Currently, NASA's Mars Exploration Study Team is assessinga variety of mission architectures and transportation optionsfor conducting a manned mission to Mars in the timeframeof year 2014. In general outline, the proposal iscentered on split cargo-piloted missions, and in situ productionof propellant on Mars's surface. Two cargo missionswould launch in November 2011, preceding the mannedlaunch in 2014.Borowski's team at NASA Lewis has developed an "allNTR" Mars mission option, based on using standardized engineand other components (Figure 7). Safety and flexibilityare enhanced with this modular approach, vehicle design andassembly are simplified, and costs are reduced.The first step in the manned mission is to deliver the common-corestage of the Nuclear Thermal Rocket to low-Earthorbiton an 80-ton payload launch vehicle, dubbed "Magnum,"which has been proposed by NASA for its studies.Approximately 30 days later, a second Magnum launch willdeliver a structural truss, propellant tank, habitat module, andconsumables to low-Earth-orbit, where rendezvous and dockingwith the core stage takes place. A reusable Shuttle or similarvehicle will then deliver the crew.Because the nuclear-core stage has a higher performancecapability than comparable chemical propulsion systems, itwill be possible to decrease the risk of the mission to thecrew, by carrying along a second,back-up Earth-returncapsule. The first one wouldhave been delivered in a precedingunmanned cargo mission.If the crew, for any reason,cannot land on Mars toretrieve the first return capsule,in this plan, they wouldhave the spare return capsuleavailable.The bimodal nuclear engine,which will stay in Marsorbit after the lander takes thecrew or the cargo to the surface,can produce electricityfor orbital functions, includingcommunications withEarth. It will also provide thestage that will return the crewto Earth at the completion ofits stay on Mars.The manned Mars missionsthat are being developed noware limited by the budgetaryconstraints that the spaceagency leadership believeswill persist into the future. It ispossible, with additional fueltaken to low-Earth-orbit, totrade off some )f the cargo on the manned mission in orderto decrease the trip time to Mars. For the health and well-beingof the crew, this would be the most desirable option." bmorrow's Technology TodayNuclear propulsion is next in the progression of technologiesthat vill enhance the capabilities of mankind inspace, and provide the most efficient method for colonizingthe Moon. \t the same time, moving from chemical tonuclear system will lay the basis for the quantum jumps inenergy technology to follow, most notably thermonuclearfusion.When discussing the great future city that mankind willbuild on the Mcon, space visionary Krafft Ehricke insisted that"Selenopolis w II not be built with yesterday's technology."Thirty years ag >, President Kennedy fully expected that thechallenges of < xploration to follow Apollo would also bebased on tomo row's technology, including nuclear propulsionin space. Txiay, tomorrow's technologies are well withinour grasp.Marsha Freer lan is an associate editor of 2'\st Century Science& Technc logy and the author of How We Got to theMoon: The Stor i of the German Space Pioneers, published by21st Century Sc ence Associates.1. See Marsha Fre iman, "Krafft Ehricke's Moon: A Lush Oasis of Life," 21stCentury, Summe ' 1998, p. 24.2. NASA Technical Memorandum 1998-208834. "Vehicle and Mission DesignOptions for the \ iuman Exploration of Mars/Phobos Using 'Bimodal' NTRand LANTR Prop ulsion."21st CENTURYSummer 1999 63