Subscribe to our free daily newsletters
  Energy News  




Subscribe to our free daily newsletters



ENERGY TECH
Spacecraft 'Nuclear Batteries' Could Get a Boost from New Materials
by Staff Writers
Pasadena CA (JPL) Oct 14, 2016


Sabah Bux, a technologist at JPL, is shown using a furnace in her work to develop thermoelectric materials, which convert heat into electricity. Image courtesy NASA/JPL-Caltech. For a larger version of this image please go here.

No extension cord is long enough to reach another planet, and there's no spacecraft charging station along the way. That's why researchers are hard at work on ways to make spacecraft power systems more efficient, resilient and long-lasting.

"NASA needs reliable long-term power systems to advance exploration of the solar system," said Jean-Pierre Fleurial, supervisor for the thermal energy conversion research and advancement group at NASA's Jet Propulsion Laboratory, Pasadena, California. "This is particularly important for the outer planets, where the intensity of sunlight is only a few percent as strong as it is in Earth orbit."

A cutting-edge development in spacecraft power systems is a class of materials with an unfamiliar name: skutterudites (skut-ta-RU-dites). Researchers are studying the use of these advanced materials in a proposed next-generation power system called an eMMRTG, which stands for Enhanced Multi-Mission Radioisotope Thermoelectric Generator. What is an RTG?

Radioactive substances naturally generate heat as they spontaneously transform into other elements. Radioisotope power systems make use of this heat as fuel to produce useful electricity for use in a spacecraft. The radioisotope power systems on NASA spacecraft today harness heat from the natural radioactive decay of plutonium-238 oxide.

The United States first launched a radioisotope thermoelectric generator (RTG) into space on a satellite in 1961. RTGs have powered NASA's twin Voyager probes since their launch in 1977; more than 10 billion miles (16 billion kilometers) away, the Voyagers are the most distant spacecraft from Earth and are still going. RTGs have enabled many other missions that have sent back a wealth of science results, including NASA's Mars Curiosity rover and the New Horizons mission, which flew by Pluto in 2015.

The new eMMRTG would provide 25 percent more power than Curiosity's generator at the start of a mission, according to current analyses. Additionally, since skutterudites naturally degrade more slowly that the current materials in the MMRTG, a spacecraft outfitted with an eMMRTG would have at least 50 percent more power at the end of a 17-year design life than it does today.

"Having a more efficient thermoelectric system means we'd need to use less plutonium. We could go farther, for longer and do more," Bux said.

What are skutterudites?
The defining new ingredients in the proposed eMMRTG are materials called skutterudites, which have unique properties that make them especially useful for power systems. These materials conduct electricity like metal, but heat up like glass, and can generate sizable electrical voltages.

Materials with all of these characteristics are hard to come by. A copper pot, for example, is an excellent conductor of electricity, but gets very hot quickly. Glass, on the other hand, insulates against heat well, but it can't conduct electricity. Neither of these properties are appropriate in a thermoelectric material, which converts heat into electricity.

"We needed to design high temperature compounds with the best mix of electrical and heat transfer properties," said Sabah Bux, a technologist at JPL who works on thermoelectric materials. "Skutterudites, with their complex structures composed of heavy atoms like antimony, allow us to do that."

RTGs in space
A team at JPL is working on turning skutterudites into thermocouples. A thermocouple is a device that generates an electrical voltage from the temperature difference in its components. Compared to other materials, thermocouples made of skutterudites need a smaller temperature difference to produce the same amount of useful power, making them more efficient.

In Curiosity's power system, the Multi Mission RTG (MMRTG), 768 thermocouples encircle a central can-like structure, all facing the same direction towards the heat source, at the center of the generator. The enhanced MMRTG (eMMRTG) would have the same number of thermocouples, but all would be made from skutterudite material instead of the alloys of telluride currently used.

"Only minimal changes to the existing MMRTG design are needed to get these results," Fleurial said. A group of about two dozen people at JPL is dedicated to working on these advanced materials and testing the resulting thermocouple prototypes.

The new skutterudite-based thermocouples passed their first major NASA review in late 2015. If they pass further reviews in 2017 and 2018, the first eMMRTG using them could fly aboard NASA's next New Frontiers-class mission.

Earth-based applications of skutterudite
There are many potential applications for these advanced thermoelectric materials here on Earth.

"In situations where waste heat is emitted, skutterudite materials could be used to improve efficiency and convert that heat into useful electricity," said Thierry Caillat, project leader for the technology maturation project at JPL.

For example, exhaust heat from a car could be converted into electricity and fed back into the vehicle, which could be used to charge batteries and reduce fuel use. Industrial processes that require high temperatures, such as ceramic and glass processing, could also use skutterudite materials to make use of waste heat. In 2015, JPL licensed patents on these high-temperature thermoelectric materials to a company called Evident Technologies, Troy, New York.

"Over the last 20 years, the field of thermoelectrics has come into being and blossomed, especially at JPL," said Fleurial. "There's a lot of great science happening in this area. We're excited to explore the idea of taking these materials to space, and benefitting U.S. industry along the way."

JPL's work to develop higher-efficiency thermoelectric materials is carried out in partnership with the U.S. Department of Energy (DOE), Teledyne Energy Systems and Aerojet Rocketdyne, and is funded by NASA's Radioisotope Power System program, which is managed by NASA Glenn Research Center in Cleveland. The spaceflight hardware is produced by Teledyne Energy Systems and Aerojet Rocketdyne under a contract held by the DOE, which fuels, completes final assembly and owns the end item. Caltech manages JPL for NASA.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
JPL
Powering The World in the 21st Century at Energy-Daily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
ENERGY TECH
New 3D design for mobile microbatteries
Paris, France (SPX) Oct 14, 2016
In the race towards miniaturization, a French-US team-mostly involving researchers from the CNRS, Universite de Lille, Universite de Nantes and Argonne National Laboratory (US) as part of the Research Network on Electrochemical Energy Storage (RS2E)-has succeeded in improving the energy density of a rechargeable battery without increasing its size (limited to a few square millimeters in mobile s ... read more


ENERGY TECH
UNESCO urges Bangladesh to scrap Sundarbans plant

NREL releases new cost and performance data for electricity generation

Strong at the coast, weak in the cities - the German energy-transition patchwork

Europe ups energy security ante

ENERGY TECH
Spacecraft 'Nuclear Batteries' Could Get a Boost from New Materials

Inspiration from the ocean

New 3D design for mobile microbatteries

Scientists find static 'stripes' of electrical charge in copper-oxide superconductor

ENERGY TECH
Prysmian Secures Contract for Offshore Wind Farm Inter-Array Submarine Cables Supply in Belgium

California eyes wind, wave potential

Wind turbines killing more than just local birds

Wind turbines a risk to birds living as far as 100 miles away

ENERGY TECH
NREL model offers insights of higher wind and solar generation in US east

juwi Group announces expansion for Solar Power Plant in Fukushima Province

Energy hijacking pathway found within photosynthesis

UMASS Amherst taps Con Edison solutions for large-scale solar power initiative

ENERGY TECH
Germany approves controversial nuclear waste deal

Anti-nuclear politician's win hurts Japan atomic push

Japan nuclear reactor shuttered for safety work

South Africa's nuclear programme kicked into touch, again

ENERGY TECH
'Super yeast' has the power to improve economics of biofuels

Unraveling the science behind biomass breakdown

With designer lignin, biofuels researchers reproduced evolutionary path

Engineers transform brewery wastewater into energy storage

ENERGY TECH
China closer to establishing permanent space station

Ambitious space satellite projects set for liftoff

China's permanent station plans ride on mission

China to enhance space capabilities with launch of Shenzhou-11

ENERGY TECH
Indonesia ratifies Paris climate accord

EU meets on climate with countries in former Soviet sphere

Rich countries 'confident' of meeting climate finance pledge

Stanford researchers capture Central Asia's 'de-greening' over millions of years




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement