Nav: Home

Next-generation photodetector camera to deploy during demo mission

July 31, 2018

Testing tools and technologies for refueling and repairing satellites in orbit won't be the only demonstration taking place aboard the International Space Station during NASA's next Robotic Refueling Mission 3, or RRM3.

An advanced, highly compact thermal camera that traces its heritage to one now flying on NASA's Landsat 8 has been mounted in a corner of the RRM3 payload and from that position will image and videotape Earth's surface below once the SpaceX Dragon resupply vehicle delivers the payload to the orbiting outpost in November.

While RRM3 demonstrates its specially developed satellite-servicing tools developed by NASA's Satellite Servicing Projects Division, its hitchhiker companion, the Compact Thermal Imager, or CTI, will image and measure fires, ice sheets, glaciers, and snow surface temperatures.

CTI will also measure the transfer of water from soil and plants into the atmosphere -- important measurements for understanding plant growth. Many of the conditions that Earth scientists study, including these, are easily detected in the infrared or thermal wavelength bands.

Strained-Layer Superlattice Technology Enables CTI

CTI's enabling technology is a relatively new photodetector technology known as Strained-Layer Superlattice, or SLS.

In addition to being very small, measuring nearly 16 inches long and six inches tall, SLS consumes little power, operates at liquid-nitrogen temperatures, is easily fabricated in a high-technology environment, and is inexpensive "almost to the point of being disposable," said Murzy Jhabvala, a detector engineer at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Jhabvala collaborated with his industry partner, the New Hampshire-based QmagiQ, to develop the SLS detector assembly.

The detector technology is also quickly and easily customized for different applications, he added. The Goddard Detector Development Laboratory, for example, recently fabricated a 1,024 x 1,024-pixel SLS array and plans to increase its size to 2,048 x 2,048 pixels in the very near future.

Another enabling technology that CTI and its SLS detectors will employ is the Goddard-developed SpaceCube 2.0, a powerful hybrid computing system that will control the instrument and process the images and video that it takes while in orbit.

The demonstration's goal, Jhabvala said, is to raise SLS's technology-readiness level to nine -- or TRL-9 -- meaning that it has flown in space and has demonstrated that it operates well under the extreme environmental conditions found in space. "This is a very important technology milestone," Jhabvala said. "We needed this mission. When we demonstrate our detector array, multiple copies can be made, assembled, and aligned into focal plane arrays that would allow us to image large swaths of Earth's surface from space in the future."

QWIP Based

SLS is based on the Quantum Well Infrared Photodetector, or QWIP, technology that Jhabvala and his government and industry collaborators spent more than two decades refining. The QWIP detectors are now operating on Landsat 8 and will be flying on the upcoming Landsat 9 Thermal Infrared Sensor Instrument, which Goddard scientists built to monitor the ebb and flow of land-surface levels and the health of vegetation -- data that western states use to monitor water consumption.

Like its QWIP predecessor, SLS is a large-format detector. The arrays are fabricated on a semiconductor wafer. The wafer's surface consists of hundreds of alternating, very thin layers of differing materials that are epitaxially grown and tuned to absorb infrared photons and convert them into electrons -- the fundamental particles that carry an electric current. Only light with a specific energy, or wavelength, can release the electrons. A read-out chip directly mated to the array then converts the electrons to a voltage that a computer uses to recreate an image of the infrared source. The CTI can also capture video from its orbit nearly 249 miles above Earth's surface.

Ten Times More Sensitive

Compared with its QWIP predecessor, SLS detectors are 10 times more sensitive and operate over a broader infrared spectral range and at substantially warmer temperatures -- 70K (about -334 degrees Fahrenheit) for the SLS array compared with 42K (about -384 degrees Fahrenheit) for the QWIP array.

The increase in operating temperature will have multiple positive effects on future missions, Jhabvala said.

Infrared radiation is sensed as heat. Therefore, detectors designed to measure infrared wavelengths must be cooled to prevent heat generated inside an instrument or spacecraft from contaminating the measurements of the object being observed. That's why engineers use cryocoolers and other devices to keep the detector arrays and other critical instrument components as cold as necessary.

Because Jhabvala and his team have created an array that can operate at warmer temperatures, its cooling system is smaller and consumes less power. In the future, these attributes will lead to smaller satellites, increased longevity, shorter build cycles, and a lower cost, Jhabvala said.

Just a few months before the RRM3 launch, Jhabvala reflected on the evolution of his photodetector technology and collaboration with QmagiQ, which has received NASA Small Business Innovation Research grants to create the technology that the CTI team then ruggedized for use in space. "Together, with this company, we have made some outstanding achievements over the years," Jhabvala said. "Our on-going collaboration has yielded some truly extraordinary returns for NASA and the U.S. government. I give QmagiQ and NASA a lot of credit."
-end-


NASA/Goddard Space Flight Center

Related International Space Station Articles:

Experiment aboard space station studies 'space weather'
To study conditions in the ionosphere, Cornell University research engineer Steven Powell and others in the College of Engineering have developed the FOTON (Fast Orbital TEC for Orbit and Navigation) GPS receiver.
Earth science on the Space Station continues to grow
Two new Earth science instruments are scheduled to make their way to the station Feb.
For space station astronauts, spinal muscles shrink after months in space
While astronauts on long space missions do not experience a change in spinal disc height, the muscles supporting the spine weaken, find researchers at University of California San Diego School of Medicine.
Swarm of satellites to explore Earth's shield from International Space Station
A swarm of 50 small satellites -- known as cubesats and weighing an average of 2 kg each -- will be launched from the International Space Station in the European-led as QB50 mission to explore the little-understood region above Earth known as the thermosphere.
Pitt researcher's work headed to International Space Station
Rocky S. Tuan, Ph.D., has received a research grant from the Center for the Advancement of Science in Space to continue his work on a 3-D microphysiological system to be conducted on board the International Space Station to evaluate the accelerated aging and degeneration process of bones that occurs in space.
Antarctic fungi survive Martian conditions on the International Space Station
European scientists have gathered tiny fungi that take shelter in Antarctic rocks and sent them to the International Space Station.
How mold on space station flowers is helping get us to Mars
When Scott Kelly tweeted a picture of moldy leaves on the current crop of zinnia flowers aboard the International Space Station, it could have looked like the science was doomed.
Getting into the flow on the International Space Station
The Packed Bed Reactor Experiment (PBRE) is a basic science investigation designed to fill in the missing information as to how two-phase mixtures flow through porous media in microgravity.
Waterloo to lead new experiment aboard International Space Station
A spacecraft carrying supplies for a new physiology experiment led by a University of Waterloo researcher will launch to the International Space Station on Thursday, the Canadian Space Agency announced.
Space station investigation goes with the flow
The investigation's success could help scientists develop countermeasures that will influence the future of human spaceflight on long-duration missions.

Related International Space Station Reading:

International Space Station: Architecture beyond Earth
by David Nixon (Author)

You Are Here: Around the World in 92 Minutes: Photographs from the International Space Station
by Chris Hadfield (Author)

International Space Station: An insight into the history, development, collaboration, production and role of the permanently manned earth-orbiting complex (Owners' Workshop Manual)
by David Baker (Author)

Hello, Is This Planet Earth?: My View from the International Space Station
by Tim Peake (Author)

International Space Station (Let's-Read-and-Find-Out Science 2)
by Dr. Franklyn M. Branley (Author), True Kelley (Illustrator)

Endurance: A Year in Space, A Lifetime of Discovery
by Scott Kelly (Author)

If You Were a Kid Docking at the International Space Station
by Josh Gregory (Author), Jason Raish (Contributor)

International Space Station: The Science Lab in Space (Xtreme Spacecraft)
by Professor John Hamilton (Author)

The International Space Station: 52 Fascinating Facts For Kids (Volume 30)
by Karen Wright (Author)

View From Above: An Astronaut Photographs the World
by Terry Virts (Author), Buzz Aldrin (Foreword)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Circular
We're told if the economy is growing, and if we keep producing, that's a good thing. But at what cost? This hour, TED speakers explore circular systems that regenerate and re-use what we already have. Guests include economist Kate Raworth, environmental activist Tristram Stuart, landscape architect Kate Orff, entrepreneur David Katz, and graphic designer Jessi Arrington.
Now Playing: Science for the People

#504 The Art of Logic
How can mathematics help us have better arguments? This week we spend the hour with "The Art of Logic in an Illogical World" author, mathematician Eugenia Cheng, as she makes her case that the logic of mathematics can combine with emotional resonance to allow us to have better debates and arguments. Along the way we learn a lot about rigorous logic using arguments you're probably having every day, while also learning a lot about our own underlying beliefs and assumptions.