NASA’s new cooling pump doesn’t need moving parts, set to sit back out in space next month

The more advanced the electronics, the more power they use. The more power they use, the warmer they get. The warmer they get, the much more likely they’ll overheat. It doesn’t take a rocket scientist to know what typically happens next: The electronics fry.

On earth of electronics, thermal control is often one of several limiting factors — particularly in space where there is not any air to aid settle down electronic components.

However, Jeffrey Didion, a thermal engineer on the NASA Goddard Space Flight Center in Greenbelt, Md., and Dr. Jamal Seyed-Yagoobi, a professor on the Illinois Institute of Technology in Chicago, Ill., have collaborated to develop a technology that can overcome current limitations. They’ve formed technical partnerships with the U.S. Air Force and National Renewable Energy Laboratory to deal with the thermal-control concerns.

Called electrohydrodynamic (EHD)-based thermal control, the technology promises to make it easier and more efficient to take away heat from small spaces — a specific challenge for engineers building advanced space instruments and microprocessors which could fail if the warmth they generate is just not removed.

“Today, higher-power computer chips can be found, but they generate an excessive amount of heat,” said Didion, who’s leading the technology-development effort also involving Matthew Showalter, associate branch chief of Goddard’s Advanced Manufacturing Branch, and Mario Martins of Edge Space Systems, an engineering company that specialize in thermal systems in Glenelg, Md. “If i will carry away more heat, engineers should be ready to use higher-power components. In other words, they are going to be ready to do more things.”

The project, a joint activity between NASA Goddard and its partners, received support from the Goddard Internal Research and Development (IRAD) program, which funds the construction of promising new technologies which could advance NASA’s scientific and exploration goals. It’s being demonstrated in June on a Terrier-Improved Orion sounding rocket mission, which is also flying the Small Rocket/Spacecraft Technology (SMART) platform, a microsatellite also developed at Goddard. This new microsatellite measures about 16 inches in diameter and was specifically designed to present scientific users low-cost access to space.

The primary objective of the EHD demonstration is showing that a prototype pump can withstand the extraordinary launch loads because the rocket lifts off and hurtles toward space. Should it survive the vibration, the technology can have achieved a significant milestone in its development, Didion said. It would mean that it’s at or near operational status, making it a viable technology to be used on spaceflight instruments.

“Any electronic device that generates a number of heat goes to profit from this technology,” said Ted Swanson, assistant chief for technology for Goddard’s Mechanical Systems Division. This might include everything from sensors flown in space to these utilized in automobiles and aircraft.

No Moving Parts

The technology promises significant advantages over more traditional cooling techniques. Unlike current technologies used today by instrument and component developers, EHD doesn’t depend on mechanical pumps and other moving parts. Instead, it uses electric fields to pump coolant through tiny ducts inside a thermal cold plate. From there, the waste heat is dumped onto a radiator and dispersed faraway from heat-sensitive circuitry that must operate within certain temperature ranges. “Its architecture, therefore, is comparatively straightforward,” Didion said. Electrodes apply the voltage that pushes the coolant in the course of the ducts.

“The benefits are many,” he added. “Without mechanical parts, the system is lighter and consumes less power, roughly half a watt. But perhaps more importantly, the system could be scaled to different sizes, from larger cold plates to microscale electronic components and lab-on-a-chip devices.”

Besides flying the technology at the sounding rocket mission, the EHD development team will fly a prototype EHD cold plate as an experiment at the International Space Station in 2013. “This effort will demonstrate the long-term operation of an EHD thermal-control system,” Didion said.

Lab-on-a-Chip Devices

Meanwhile, the team is constant its work to further advance EHD, Didion said. The team is operating with Goddard detector engineer Timothy Miller to develop EHD pumps in microchannels which are etched onto silicon wafers. They plan to further experiment with other substrate and composite materials in addition to special micro-fabrication techniques and coatings to create smaller, more robust EHD pumps.

These multifunctional devices may be used as stand-alone, off-the-shelf components ideal for speedy-turnaround spacecraft — an ability that particularly interests the Air Force — or as units embedded throughout the walls of the electronic device.

Your next step is placing the technology on circuit cards, with the final goal of scaling it to the chip level where the ducts will be no larger than 100 microns (0.0039 inch), or in regards to the width of a human hair. “The purpose is that you really want to position the thermal-control unit toward the source of warmth,” Didion said. “This will be much more efficient at eliminating waste heat.”