Super High Altitude Research Project
Encyclopedia
The Super High Altitude Research Project (Super HARP, SHARP) was a U.S. government project conducting research into the firing of high-velocity projectiles high into the atmosphere
using a two stage light gas gun
, with the ultimate goal of propelling satellites into Earth orbit. Design work on the prototype space gun
began as early as 1985 at the Lawrence Livermore National Laboratory
in California and became operational in December 1992. It is the largest gas gun in the world.
. At each end of the pump tube, there sits a 100-ton rail-mounted sled to absorb recoil energy from firing. A smaller 10-ton sled is also mounted on a set of tracks at the aft-end of the launch-tube near the junction point.
The firing sequence begins with the ignition of a methane gas mixture in the combustion section at the far end of the pump tube, which has been filled with pressurized hydrogen gas. The resultant explosion drives a 1-ton steel piston down the pump tube towards the junction point, rapidly compressing the hydrogen gas in the pump tube to a pressure of 60000 psi (4,082.8 atm). Meanwhile, a small projectile rests in the adjacent depressurized launch tube. As the hydrogen gas reaches maximum pressure, a coupling holding the projectile in place is destroyed, driving the projectile down a 4-in diameter barrel at extremely high velocities until it bursts through a thin plastic sheet covering the end of the gun. All recoil forces are absorbed by the rail-mounted sleds as they are propelled outwards along their tracks.
, the SHARP gun fired projectiles using expanding hydrogen
and achieved velocities of 3 km/s or Mach
8.8 for 5 kg (11 lb) projectiles. Had the project continued, there were plans to elevate the tube and begin space launch trials potentially reaching speeds of up to 7 km/s, or about Mach 21.
The tests were designed as a precursor to the "Jules Verne Launcher," an even larger light gas gun with a 3500 m (11,482.9 ft) barrel length designed in the early 1990s for first-stage satellite
launch. This was to cost $1 billion, but funding was not forthcoming and the project was eventually canceled in 1995. However, the SHARP gun continued to be used for high-speed tests in other areas of research, such as scramjet
development.
The concept of ballistic escape velocity
is well proven. The largest challenge is maintaining such high velocities, because air resistance and aerothermal heating will significantly slow down any such object.
Earth's atmosphere
The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
using a two stage light gas gun
Light gas gun
The light-gas gun is an apparatus for physics experiments, a highly specialized gun designed to generate very high velocities. It is usually used to study high speed impact phenomena , such as the formation of impact craters by meteorites or the erosion of materials by micrometeoroids...
, with the ultimate goal of propelling satellites into Earth orbit. Design work on the prototype space gun
Space gun
A space gun is a method of launching an object into outer space using a large gun, or cannon. It provides a method of non-rocket spacelaunch.In the HARP Project a U.S...
began as early as 1985 at the Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...
in California and became operational in December 1992. It is the largest gas gun in the world.
Design and operation
Rather than a single straight barrel, the SHARP gun is actually of an L-shape design comprising 2 separate sections—a 270 ft (82.3 m) long steel combustion section & pump tube, and a 155 ft (47.2 m) long launch tube (or barrel)—joined together at a right angleRight angle
In geometry and trigonometry, a right angle is an angle that bisects the angle formed by two halves of a straight line. More precisely, if a ray is placed so that its endpoint is on a line and the adjacent angles are equal, then they are right angles...
. At each end of the pump tube, there sits a 100-ton rail-mounted sled to absorb recoil energy from firing. A smaller 10-ton sled is also mounted on a set of tracks at the aft-end of the launch-tube near the junction point.
The firing sequence begins with the ignition of a methane gas mixture in the combustion section at the far end of the pump tube, which has been filled with pressurized hydrogen gas. The resultant explosion drives a 1-ton steel piston down the pump tube towards the junction point, rapidly compressing the hydrogen gas in the pump tube to a pressure of 60000 psi (4,082.8 atm). Meanwhile, a small projectile rests in the adjacent depressurized launch tube. As the hydrogen gas reaches maximum pressure, a coupling holding the projectile in place is destroyed, driving the projectile down a 4-in diameter barrel at extremely high velocities until it bursts through a thin plastic sheet covering the end of the gun. All recoil forces are absorbed by the rail-mounted sleds as they are propelled outwards along their tracks.
Tests and cancellation
Headed by John HunterJohn Hunter (scientist)
John Hunter is a projectile researcher, who developed the 1994 "supergun" Super High Altitude Research Project at the Lawrence Livermore National Laboratory...
, the SHARP gun fired projectiles using expanding hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
and achieved velocities of 3 km/s or Mach
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...
8.8 for 5 kg (11 lb) projectiles. Had the project continued, there were plans to elevate the tube and begin space launch trials potentially reaching speeds of up to 7 km/s, or about Mach 21.
The tests were designed as a precursor to the "Jules Verne Launcher," an even larger light gas gun with a 3500 m (11,482.9 ft) barrel length designed in the early 1990s for first-stage satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
launch. This was to cost $1 billion, but funding was not forthcoming and the project was eventually canceled in 1995. However, the SHARP gun continued to be used for high-speed tests in other areas of research, such as scramjet
Scramjet
A scramjet is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow...
development.
The concept of ballistic escape velocity
Escape velocity
In physics, escape velocity is the speed at which the kinetic energy plus the gravitational potential energy of an object is zero gravitational potential energy is negative since gravity is an attractive force and the potential is defined to be zero at infinity...
is well proven. The largest challenge is maintaining such high velocities, because air resistance and aerothermal heating will significantly slow down any such object.
See also
- Non-rocket spacelaunchNon-rocket spacelaunchNon-rocket space launch is a launch into space where some or all needed speed and altitude is provided by non-rocket means, rather than simply using conventional chemical rockets from the ground. A number of alternatives to rockets have been proposed...
- Project HARPProject HARPProject HARP, short for High Altitude Research Project, was a joint project of the United States Department of Defense and Canada's Department of National Defence created with the goal of studying ballistics of re-entry vehicles at low cost; whereas most such projects used expensive rockets, HARP...
- VerneshotVerneshotA verneshot is a hypothetical volcanic eruption event caused by the buildup of gas deep underneath a craton...
- Operation Plumbbob
External links
- 1994 Charlene Crabb New ScientistNew ScientistNew Scientist is a weekly non-peer-reviewed English-language international science magazine, which since 1996 has also run a website, covering recent developments in science and technology for a general audience. Founded in 1956, it is published by Reed Business Information Ltd, a subsidiary of...
article about SHARP: Shooting at the moon. - Fiscal and feasibility comparison of various Earth-based satellite launching systems including the SHARP from JOBS for the 21st Century.
- The flying mineshaft cover is discussed under the section Pascal-B from the nuclearweaponsarchive.org overview of atmospheric nuclear testing in Nevada.