Drilling the Red Planet

Within the next two years, robotic moles will begin drilling into the red terrain of Mars, searching for geological clues into the planet’s history. And two new devices that researchers hope will yield a wealth of information in the Mars Express project (run by a consortium consisting of NASA, the European Space Agency and the Italian Space Agency) are intertwined with advances in medical technology.

The first of these planetary samplers is a small jackhammer called the ultrasonic/sonic driller/corer, or USDC, developed at NASA’s Jet Propulsion Laboratory. With just three moving parts, it weighs 0.7 kilograms and requires no more power than a flashlight. Yet a prototype can drill 12-millimeter-deep holes into solid granite and bring out core samples five millimeters in diameter.

Rock Pounding

Because the tiny jackhammer uses a rapid pounding motion- rather than the carving action of a traditional drill-the bit doesn’t need to be sharpened. It also requires 20 to 30 times less pressure than a traditional drill to bore into rock, which makes the device ideal for asteroids and comets, small, light objects that must be penetrated in zero gravity, says Yoseph Bar-Cohen, leader of the Jet Propulsion Lab team developing the device.

The drill’s rock-breaking force comes from a stack of wafers that expand and contract as an electric voltage is applied. The bit, tipped with a piece of silica carbide, is harder than most rock and has been able to punch through all samples the JPL team could find.

While Mars duty may be a few years away, the drill already shows promise as surgical tool. By hammering instead of spinning, the device cuts through tissue and bone without grabbing and “spinning them up,” says Tom Peterson, president of Cybersonics, the Erie, PA, company developing commercial applications.

The USDC isn’t limited to just making round holes. Any shape bit can be used, Peterson says. Cybersonics is planning to develop a smaller, orthoscopic version for detaching pacemaker leads during replacement operations without opening a patient’s chest. The miniaturized drill would be attached to the tip of a probe that could be inserted into a small incision and guided to the pacemaker leads, with a fiber-optic camera riding along with the drill. There are also plans to develop a unit that can drill into bone, either to sample marrow or to attach orthopedic devices such as rods or prosthetic hips, says Peterson.

Like Pulling Teeth

A second drill, already slated for use on Martian soil, contains a component inspired by dental technology. The Mars Express mission will contain a highly miniaturized drill/corer developed by Russian scientists. Inside the corer, a specially adapted set of dental forceps will grab the rock cores and bring them back inside the lander for return to Earth.

The forceps were originally designed to grip dental inlays. Hong Kong-based dentist Ng Tze-chuen miniaturized them to fit inside the Russian corer-keeping its total mass below the 0.3-kilogram limit for the Mars Express’s Beagle 2 lander.

Regardless of how deep either drill bores into Mars, it’s clear, says Cybersonics’s Peterson, that we are just scratching the surface of what could come from the cross-pollination of technologies.