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
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
using a two-stage
light-gas gun
The light-gas gun is an apparatus for physics experiments. It is a highly specialized gun designed to generate extremely high velocities. It is usually used to study high-speed impact phenomena (hypervelocity research), such as the formation of ...
, with the ultimate goal of propelling satellites into
Earth orbit
Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi) in a counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes days (1 sidereal year), during which time Earth ...
. Design work on the prototype
space gun Space Gun may refer to:
*Space gun, a method of launching an object into space
* ''Space Gun'' (album), a 2018 album by Guided by Voices
* ''Space Gun'' (video game), a 1990 arcade game
*Ljutic Space Gun, a 12 gauge single-shot shotgun
See also
* ...
began as early as 1985 at the
Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory (LLNL) is a federal research facility in Livermore, California, United States. The lab was originally established as the University of California Radiation Laboratory, Livermore Branch in 1952 in response ...
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 uses an L-shape design with two separate sections; the long steel combustion section & pump tube section is connected to the long launch tube (or barrel) at a
right angle
In geometry and trigonometry, a right angle is an angle of exactly 90 Degree (angle), degrees or radians corresponding to a quarter turn (geometry), turn. If a Line (mathematics)#Ray, ray is placed so that its endpoint is on a line and the ad ...
. 100-ton rail-mounted sleds sit at both ends of the pump tube to absorb recoil energy from firing and a smaller 10-ton sled is mounted on a perpendicular 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
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...
gas mixture in the combustion section behind the piston at the far end of the pump tube. The resultant explosion rapidly drives the 1-ton
steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...
piston down the pump tube and further compresses the pre-pressurized
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
gas that fills the other end of the pump tube. As the piston accelerates toward the junction point, it rapidly compresses the hydrogen gas in the pump tube to a pressure of . The small projectile, meanwhile, rests in the adjacent depressurized launch tube. As the hydrogen gas reaches maximum pressure, a coupling holding the projectile in place is destroyed and the hydrogen drives 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 Hunter, the SHARP gun fired projectiles using expanding
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
and achieved velocities of or
Mach 8.8 for projectiles. Had the project continued, there were plans to elevate the tube and begin space launch trials potentially reaching speeds of up to , or about Mach 21.
The tests were designed as a precursor to the "''Jules Verne Launcher''," an even larger light-gas gun with a barrel length designed in the early 1990s for first-stage
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
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
A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to compress the incoming air forcefully ...
development.
The concept of ballistic
escape velocity
In celestial mechanics, escape velocity or escape speed is the minimum speed needed for a free, non- propelled object to escape from the gravitational influence of a primary body, thus reaching an infinite distance from it. It is typically ...
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
*
Quicklaunch
Quicklaunch is a currently inactive company attempting to use a type of space gun to launch payloads into low Earth orbit. It is a university spin-off of the SHARP project which ended 2005.
Quicklauncher
The Quicklaunch proposed firing apparatu ...
, proposed by SHARP scientist John Hunter.
*
Non-rocket spacelaunch
Non-rocket spacelaunch refers to theoretical concepts for launch into space where much of the speed and altitude needed to achieve orbit is provided by a propulsion technique that is not subject to the limits of the rocket equation. Although al ...
*
Project HARP
Project HARP, short for High Altitude Research Project, was a joint venture 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 and collecting ...
*
Verneshot
A verneshot (named after French author Jules Verne) is a hypothetical volcanic eruption event caused by the buildup of gas deep underneath a craton. Such an event may be forceful enough to launch an extreme amount of material from the crust and ...
*
Operation Plumbbob
Operation Plumbbob was a series of nuclear tests that were conducted between May 28 and October 7, 1957, at the Nevada Test Site, following ''Project 57'', and preceding '' Project 58/58A''.
Background
The operation consisted of 29 explosions ...
References
External links
* ''
rticle about SHARP.' {{subscription required
Fiscal and feasibility comparison of various Earth-basedsatellite launching systems including the SHARP fro
from the nuclearweaponsarchive.org overview of atmospheric nuclear testing in Nevada.
Space guns
Research projects
Non-rocket spacelaunch
de:High Altitude Research Project#SHARP