If a massive asteroid someday threatens Earth, we may owe the thanks for whatever advance warning we have to a team of scientists that includes a Seneca Falls woman.
Dr. Judith Pipher, a town resident since 1971 and an emeritus professor in physics and astronomy at the University of Rochester, is working on a sensor that uses infrared light to detect asteroids. She is the senior researcher on a team that includes representatives from the university, NASA’s Jet Propulsion Laboratory and Teledyne Imaging Systems.
The team’s Near Earth Object Camera (NEOCam) sensor recently passed a key test and, if all goes well, it could fly into space by 2016 or 2018. The large, earth-bound asteroids it will scan for are a remote but real threat.
“There probably was one at about the time of the dinosaurs, so that tells you how often it happens,” Pipher said. “So it’s a small probability, but it’s not zero.”
But big asteroids — the so-called planet killers — are only part of the story. The sensor could also help detect small threats, such as the asteroid that recently exploded over Russia, injuring hundreds.
“That was only 20 meters in size,” Pipher said. “With these smaller asteroids, you wouldn’t be trying to deflect those. What you would do is have knowledge of them, and it’s sort of like a hurricane. You get people out of the way.”
Pipher has been working on sensors for decades, initially with a variety of space applications in mind. The sensors, which contain the elements mercury, cadmium and tellurium, detect infrared light at specific wavelengths.
“It was a very hard project to develop these detector arrays,” Pipher said. “We started small, and we proposed the idea to NASA and also to Teledyne. ... There had been various improvements, and we got to a certain point in about 2003 that was very promising, but at that point funding was very difficult. So what happened was that we aligned with Amy Mainzer at Jet Propulsion Laboratory, who started this NEOCam project, and she was interested in the technology because it fit with her mission to search for near-earth asteroids.”
The technology fit because asteroids reflect visible light — making them hard to observe with optical telescopes — but emit infrared radiation.
“We can learn more about asteroids when we look at them with infrared light,” Mainzer said in a University of Rochester press release. “When you observe a space rock with infrared, you are seeing its thermal emissions, which can better define the asteroid’s size as well as tell you something about it’s composition.”
Pipher and the Rochester team previously worked on a sensor for the Spitzer Space Telescope, which detects a different wavelength of infrared radiation. Work on the new sensor began about a year ago. It marks an improvement, “but it’s really just a different window on the universe,” Pipher said.
If further tests show that the sensor can withstand cosmic rays and meet NASA’s other requirements, it will become part of a space-based telescope.
Putting it in space will allow it to observe near-earth objects without interference from cloud cover and daylight that earth-based telescopes face. Scientists hope that will help them survey at least 90 percent of the near-earth objects.
The sensor will also help NASA find the best destinations for future exploration by humans or robots.
“This sensor works at higher temperatures than any other similar ones we have at the moment,” said Pipher, a 2007 inductee into the National Women’s Hall of Fame. “This means they can be passively cooled, making the instrument less heavy and less expensive to put into space.”