As reported on Wired.
BY JOE HANSON
Some scientists might pride themselves on their finesse with a pipette or their mathematical expertise. But for others, part of the appeal of scientific research is getting to play with very powerful toys. And naturally, some of those toys are guns.
Only these aren’t your grampa’s shotgun. From physics to astronomy to biology, researchers have come up with some pretty awesome ways to propel something from point A to point B using as much energy as they can muster. And most of the time, the science that the gun is used for is even more interesting than the blunderbuss itself.
Outside of science, guns are too often used to subtract from life. None of the guns on this list are designed to destroy, only to create new knowledge. Here’s a look at some of the most amazing guns of science.
NASA Ames Vertical Gun Range
On March 17, a 40 kilogram meteorite impacted the moon, resulting in a flash of light brighter than most stars and the largest meteorite explosion ever recorded on the lunar surface. Meteorite impacts with the moon are not uncommon, but measuring their power and their effect on the lunar surface requires being able study them up close and personal.
The Ames Vertical Gun Range. Photo credit:NASA
To study these powerful collisions from here on Earth, NASA calls on the Vertical Gun Range at Ames Research Center. Originally intended to support the Apollo missions, it is now used whenever NASA scientists need to fire something very fast at something else. This light gas gun, much smaller than the similarly-powered SHARP gun, uses bursts of hydrogen to shoot a variety of glass, metal, or mineral marbles toward simulated lunar targets at speeds up to 7 kilometers per second. This is still ten times slower than many of the hugely powerful collisions that occur in space, but by witnessing these explosions in the lab, scientists can calibrate their measurements of the blasts they see in space. Analyzing these impacts helps researchers understand the explosive risks future astronauts might encounter in space, and could one day help us return astronauts to the moon, or perhaps even Mars.
Top: Photo of a pyrex marble exploding on impact at the NASA Ames Vertical Gun Range. Photo credit: Peter Schultz, Brown University, and NASA
AEDC Ballistic Range S-3, AKA “The Chicken Gun”
If a “Chicken Gun” sounds like something from an episode of MythBusters, that’s because it was featured on an episode of the show. An Air Force ballistics device that blasts poultry at aircraft has all the trappings of an urban legend, but the “chicken gun” is entirely real.
Testing an aircraft canopy in Ballistic Range S-3 Credit: Arnold Air Force Base
At Arnold Air Force Base in Tennessee, amid wind tunnels and jet engine test ranges, sits the otherwise innocuously labeled Ballistic Range S-3. Inside is a 90-foot-long cannon powered by compressed helium used for impact testing of aircraft canopies and body components. At low altitude, especially during take-off and landing, aircraft are at high risk for bird strikes. Chicken guns at Arnold and elsewhere are used in testing to help ensure that a $300 million aircraft isn’t brought down by a seagull.
The 8-inch-wide barrel is just wide enough to hold a 4-pound chicken carcass (thawed), purchased from a local farm, and a powerful blast of gas propels the poultry projectile towards its target at up to 1,400 feet per second. A suite of high-speed cameras, pressure sensors and microphones observe every scientific angle of the impact.
Range S-3 isn’t just for blasting birds. It was instrumental in helping the Space Shuttle program return to flight following the Columbia disaster. Shortly after Columbia’s launch, a chunk of insulating foam fell from the shuttle’s external fuel tank, struck the thermal insulating tiles and led to the spacecraft’s tragic disintegration upon re-entry. AEDC engineers replaced their chickens with blocks of foam and fired them at various shuttle components in order to better protect astronauts on future missions.
Space Shuttle foam impact testing in Ballistic Range S-3, Credit: Arnold Air Force Base
Space Gun (Project HARP)
In the 1902 silent film Le Voyage Dans la Lune by Georges Méliès, a band of astronomers are shot to space aboard a bullet-shaped capsule, famously lodging themselves squarely in the right eye of the moon. In 1961, the U.S. and Canadian militaries embarked on a similar endeavor. Project HARP, for High-Altitude Research Project, was the brainchild of controversial ballistics engineer Gerald Bull.
Bull and other military scientists originally dreamed up Project HARP as a way to cheaply test ballistic missiles and collect information about the upper atmosphere. But the dawn of the Space Age quickly inspired Bull to use HARP as a way to put satellites into orbit without costly rocket launches. At testing sites from Arizona to the Caribbean, Bull and his team erected enormous artillery pieces pointing toward the sky. At lengths of over 120 feet and barrel diameters as wide as 16 inches, they launched hundreds of test payloads in an effort to achieve the velocity necessary to overcome Earth’s gravity.
Growing political and financial pressure surrounding the Vietnam war and NASA’s focus on large-scale traditional rockets like the Saturn V led to the cancellation of Project HARP in 1966. But that same year, a HARP gun fired a Martlet-2 projectile to an altitude of 180 kilometers (112 miles), a world record for a cannon which lasts to this day.
Bull never gave up on his quest to develop a space gun. After being jailed for designing artillery weapons for the South African army, then under a U.N. weapons embargo because of its apartheid policies, Bull found himself working for an unlikely sponsor. He was contracted by Saddam Hussein to head Project Babylon, a series of space-capable superguns that Bull managed to convince Hussein would make Iraq a true world power. But Bull was assassinated under suspicious circumstances in 1990, and Project Babylon was never completed. His quest to reach space by the power of steel and gunpowder was chronicled in the 1994 HBO film Doomsday Gun.
Top: Project HARP 16-inch gun, Credit: Department of Defense
Decades after HARP, Lawrence Livermore scientist John Hunter came across a plan for an electromagnetic rail gun designed to shoot ballistic missiles out of the sky. While this “star wars” project never came to be, Hunter realized that, with a little tweaking, he could finally fulfill HARP’s dream to shoot things into space with a cannon.
Going active in 1992, Lawrence Livermore’s Super High Altitude Research Project (SHARP) set out again to harness enough power to achieve orbital velocity using a gun. Instead of a traditional gunpowder-driven cannon like HARP, Hunter built what is known as a “light gas gun”. Because a projectile in a gun can not go faster than the gases in the barrel can push it, there is a physical speed limit for a gun when using the relatively heavy gases found normal air. Instead, guns like SHARP rely on hydrogen gas, the lightest gas possible, to drive their projectiles.
Inside the SHARP light gas gun, an explosion-driven piston compresses hydrogen gas within a long tube. When it reaches 4,000 times normal atmospheric pressure, it is released into the near-vacuum gun chamber, and the projectile does as projectiles do. Using small payloads, SHARP was only able to achieve the relatively glacial speed of 3 kilometers per second, less than a third of what’s needed to achieve orbit.
In 1996, SHARP lost funding and was relegated to testing models of supersonic military equipment. Undaunted, Hunter founded a private space-cannon company called Quicklaunch as an alternative to rocket-focused firms like SpaceX. Quicklaunch has yet to fire a prototype.
Top: Project SHARP light gas gun, Credit: Lawrence Livermore National Laboratory
Whale Biopsy Crossbow
Crossbows aren’t typically associated with modern scientific research. They are usually reserved for stories of besieged castles and zombie-hunting Southerners. But whale researchers consider them an indispensable tool for collecting vital data on the genetics, eating habits, and population biology of large marine mammals.
Scientists studying whale populations have long used distinctive tail markings as a sort of fingerprint to identify individual whales. However, these photographic archives only provide limited information about the daily lives of cetaceans, and they require that the whale provides a clear view of its posterior. A bit of blubber can tell a much more detailed story.
Ari Friedlaender studies how whales and dolphins hunt their prey. Tissue biopsies, he explains, can provide a wealth of information about a species that spends up to 90 percent of its life out of sight beneath the ocean. To obtain those biopsies he has to be handy with a crossbow. After a whale is sighted, his research vessel approaches within a few dozen yards to provide a clear shot. The bow is loaded with a special bolt, equipped with a hollow tip surrounded by a foam collar. Friedlander leans his body out over the waves, takes aim near the whale’s dorsal fin and pulls the trigger. On contact, three barbs in the tip extract a plug of skin and blubber about the size of a ballpoint pen cap, and the springy foam immediately ejects the bolt so it can be plucked from the water.
Business end of a biopsy crossbow bolt, held by Ari Friedlander Credit: A. Stimpert (NMFS Permit 808-1735)
Back in the lab, that chunk of tissue reveals all kinds of information. DNA can identify individual whales and even match parents with their offspring. Hormone levels can indicate if a whale is pregnant, or even signal environmental stresses. And by comparing the ratio of certain forms of carbon and nitrogen in the blubber, scientists can determine what sort of prey a particular whale is eating.
Friedlaender also uses other, more high-tech methods for studying the biology of Earth’s largest living creatures. His newest research finds him stickingiPhone-sized, suction-cup mounted sensors to the backs of whales, digitally animating their every move as they communicate, hunt, and migrate across the world’s oceans.
Top: Ari Friedlander takes aim with a biopsy crossbow Credit: A. Stimpert (NMFS Permit 808-1735)
APEX Electron Gun Beam
When Thomas Edison invented the modern movie camera, for the first time stories could be captured on film and replayed for audiences worldwide exactly as they happened. Berkeley’s Advanced Photon Injector Experiment (APEX) is set to invent a movie camera for particle physics, one scientists hope will do for the exploration of matter what Hollywood did for the love story.
A tangle of wires surrounding the APEX electron gun Credit: Lawrence Berkeley National Laboratory
Fernando Sannibale, the physicist in charge of the APEX project, says their device will make the most powerful, high-resolution X-rays on Earth. X-ray light sources are crucial to a wide variety of scientific endeavors, from deciphering the structure of proteins to mapping minute electron waves in semiconductors. The sort of microscopes scientists use to observe things like cells are illuminated primarily by light around the visible range. These optical tools give scientists plenty of valuable information, but when they try to zoom in on individual proteins or molecules, it’s like trying to read a license plate using Google Earth. For closer close- ups, they need to use a light source with a much smaller wavelength. That’s where X-rays come in handy.
To make high-quality X-rays you have to start with high-quality electrons. The electron gun within APEX is unique in sending out pulses of charged particles millions of times every second. This rate is thousands of times higher than electron beams used in today’s most advanced X-ray light sources. Electromagnets then accelerate the electrons to near the speed of light, where special relativity takes over for Newtonian physics. Another set of magnets bends these electron beams, causing them to emit high-energy X-ray pulses, each only a trillionth of a second long.
While X-ray imaging is not new, APEX hopes their high-frequency pulses will take the technology to the next level. Firing millions of X-ray pulses per second could allow scientists to observe chemistry in action. Sannibale imagines that researchers studying photosynthesis could shoot photons at a light-capturing protein, and create a sort of high-speed movie of how the enzyme changes shape, each frame only trillionths of a second long.
So far, APEX has successfully completed its first rounds of testing. Sannibale hopes they will be making femtosecond films within the next few years.
Top: Beamline of the APEX electron gun (false colored), Credit: Lawrence Berkeley National Laboratory
Genetic engineering is the process of rearranging the letters of life’s chemical code to create new lifeforms not found in nature. But no matter the delicate touch with which a scientist creates a customized strand of DNA, getting it to actually do something can require a little brute force. Enter the gene gun.
Considering that all living organisms are packed with DNA, it’s surprisingly hard for scientists to get the stuff into many of the cells they’d like to manipulate. Common laboratory species like bacteria and yeast can be made to slurp up DNA from their environment with relatively simple techniques, but more complex organisms require a bit more force.
The business end of a gene gun uses a puff of helium to deliver DNA-coated gold nanoparticles directly into animal and plant tissues. The microscopic beads act much like traditional bullets, piercing cell membranes like genetic buckshot, but with decidedly less destructive results. Models actually shaped like pistols do exist, but gene guns are more often disguised in innocuous desktop cabinets.
The evolution of synthetic and molecular biology has spawned catalogues full of DNA delivery methods, but few of them sound like as much fun as the gene gun.
Top: PDS 1000-He Biolistic Particle Delivery System (“Gene Gun”), Credit: Steve Jurvetson (Flickr)
Tranquilizer guns come in a variety of shapes and sizes, and for the most part look like normal rifles or handguns. It’s what they shoot that makes them special. Zoologists and wildlife veterinarians regularly tranquilize animals in order to take blood samples, tend to injuries, and apply radio or GPS tracking collars. But putting a collar on a 2,000-kilogram bull elephant is considerably more difficult than collaring the family dog.
Steven Maerder, a South African wildlife vet now living in Michigan, says the drugs used to safely subdue these colossal creatures are some of the most potent morphine derivatives on the market. An injection dart the size of a dry-erase marker is fired from a rifle, often while the shooter is hanging out the door of a helicopter, powered by a blank gunpowder cartridge. When it strikes the animal, the self-activating dart injects a few milligrams of the tranquilizer in just seconds, putting the giants gently to sleep.
Then, the researchers quickly go to work. Due to its massive weight, a grounded elephant can be in danger of respiratory failure and at risk from predators. After collecting samples and tagging the animal, a second drug is injected to reverse the effects of the tranquilizer and get the animal on its way. But things in the field don’t always go as planned.
“They tend to wake up very quickly,” Maerder says. “I was standing next to this elephant and reversed [the tranquilizer], injected it and was packing stuff into a box. The elephant had stood straight up, I hear people shouting at me to run! I looked up and I was standing underneath it almost. I turned and ran. I went one way and he went the other. Luckily, he was just as scared as I was.”
Top: Vladimir Putin uses a tranquilizer gun, much like those used by scientists, to sedate an Amur Tiger during his visit to the Ussurri Nature Reserve Credit: Wikipedia/Premier.gov.ru