will include continuing research into the advanced propulsion for space exploration
Los Alamos has played an active role in the United States' manned space program -- which reached its zenith with the Apollo 11 moon landing in 1969 -- since its formative years. Future space missions, manned or unmanned, will require new technologies that can propel rockets and their payloads to other planets in the solar system or even other stars.
Research and development for space travel was a major scientific thrust at Los Alamos from the mid 1950s until about 1972. Project Rover -- a joint effort between Los Alamos, the former Atomic Energy Commission and the National Aeronautics and Space Administration's Space Nuclear Propulsion Office -- sought to build a nuclear reactor to power a rocket in space. Between 1959 and 1972, 23 reactors were built and tested by Los Alamos scientists.
The advantage of a nuclear rocket is its high exhaust velocity, which is more than two times greater than that of the engines on Space Shuttle rockets. The higher velocity translates into lower fuel mass of the ship in orbit and to faster trip times to planets.
Today, Los Alamos scientists are engaged in several efforts
to develop new ways to test and build nuclear rockets. SAFE,
or Subsurface Active Filtering of Exhaust, builds on technology
developed in the nuclear weapons program. With SAFE, gases emitted
from nuclear rockets are diffused underground into permeable
subsurface rock. Los Alamos has requested $10 million from NASA
to test the SAFE process using a chemical rocket.
Los Alamos also collaborated with NASA's Marshall Space Flight
Center in Huntsville, Ala., on a three-dimensional fluid dynamics
computer model for a gas core nuclear rocket. If proven feasible,
a gas core nuclear rocket would perform three times better than
the solid core nuclear rocket developed during the Project Rover
era. A gas core nuclear rocket still remains to be built and
tested.
In a gas core nuclear rocket, cold hydrogen is pumped into the
main axis of the rocket's engine. The hydrogen circulates creating
a recirculation vortex in the chamber. Uranium particles are
injected into the center of the vortex until the uranium accumulates
to near-critical mass. After the chamber is stabilized, control
drums in reflector walls rotate, driving the uranium to criticality.
The now-hot uranium gas -- temperatures approach 100,000 degrees
Fahrenheit -- radiates energy to the surrounding hydrogen, which
exits through a nozzle to provide thrust.
Because of the extreme operating conditions in a gas core engine,
design issues in fluid mechanics, materials, thermal load and
radiation transport are at the state of the art or beyond. The
gas core rocket development is a grand challenge commensurate
with the capabilities of a national laboratory.
Scientists now must test and verify that the vortices in the
gas core rocket can be formed and stabilized.
If the technology proves successful, a manned mission to Mars
-- some 200 times farther than the Moon -- could be completed
in nine months, versus an estimated three years using chemical
rockets. Astronauts on such a mission would receive far less
exposure to space radiation.
Development of a high performance nuclear rocket will enable
humankind to finally break the bonds of Earth and gaze at undiscovered
vistas throughout the solar system.
CONTACT: Steve Sandoval at steves@lanl.gov
or (505) 665-9206. For more "Science for the 21st Century,"
go to http://www.lanl.gov/orgs/pa/science21
on the World Wide Web.