SHARPER FOCUS
Radio telescope array to give high-res images of solar system
Imagine a radio telescope so powerful it can “see” high-resolution details of planets at the farthest reaches of our solar system. After a two-year “proof of concept” test, scientists have demonstrated such an instrument using the powerful Green Bank Telescope in West Virginia as a transmitter, and the continent-wide Very Long Baseline Array, or VLBA, as a receiver.
The initial images from the test were of geologic features on the moon, said Dave Finley, spokesman for the National Radio Astronomy Observatory in Socorro, which operates the VLBA.
“But this paves the way for designing a more powerful transmitter for the Green Bank Telescope, and the ability to do enhanced detection and imaging of small objects passing by the Earth, moons orbiting other planets, and reaching out as far as Uranus and Neptune,” Finley said.
Imaging distant objects in space using radio telescopes and radar is not new. Essentially, it involves transmitting a radio signal and bouncing the signal off an object.
“When the reflected signal comes back, you can use it to create an image of the object the signal was bounced from,” Finley said.
The clarity of the image depends primarily on how far the bounced signal travels, he said.
The antennas in the VLBA are receivers. Spread across eight locations in the continental U.S. and one each in Hawaii and the Virgin Islands, they can be synced together to perform as one giant receiver.
The Very Large Array, or VLA, is the Y-shaped 27-antenna system on the Plains of San Augustin, about 50 miles west of Socorro. It is not part of the
VLBA, but can be synced to it if required, Finley said.
The Green Bank Telescope, the world’s largest fully steerable radio telescope, had been a receiver only until it was outfitted with a transmitter developed by Raytheon Intelligence and Space.
With the detailed images of the moon indicating that the new radio telescope system works, Finley said, the goal now is to outfit Green Bank with an even more powerful transmitter to bounce signals off the most distant celestial bodies in the solar system.
“And by using multiple, widely separated antennas of the VLBA to receive the reflected signals, we’ll likely be able to make 3-D images,” allowing the terrain of those distant bodies to be seen in relief, Finley said.
Astronomers, planetary geologists, engineers and other scientists are still working with the prototype to refine techniques for processing the data after it’s been received and turning that data into images, Finley said.
After that, “We’ll go out and look for the money for the larger system, which is still a few years away,” he said. “We don’t have a price tag for it yet, because we haven’t designed the final system yet.”