7V space chamber upgrade project provides cutting-edge capabilities to test customer

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  Imagine driving down the interstate, trying to navigate heavy traffic and find an exit in an unfamiliar part of the country, while wearing slightly outdated prescription glasses. That gives someone a sense of the limitation AEDC engineers overcame recently with an upgrade to Arnold's 7V Space Chamber.

The 7V Space Chamber, a cutting-edge deep space test facility, was designed to evaluate and assess high performance interceptors and surveillance sensors at the conditions of space.

The U.S. wants to deploy a new generation of space-based staring array sensors in geo-stationary satellites. These sensors are cameras that detect and locate infrared heat signatures, often from rocket motors but also from other intense heat sources, some of which are natural phenomena. This could include charged particles, solar radiation, out-gassing (release of gas from materials used to build satel¬lite components) and con-tamination from thrusters.

A specialized camera, the "TMS" or Target Monitoring System, calibrated to meet National Institute of Standards and Technology (NIST) specifications, is newly installed in 7V to allow test engineers to compare the view of simulated sources in space with a sensor under test.

Elijah Minter, the 650th Test Systems Squadron's investment program manager, said this system upgrade has already paid off for both AEDC and the command's test customers and their sponsors.

"The previous camera system capability in the 7V Chamber involved the Alignment Monitor System (AMS)," he said. "The AMS needed to be replaced - it was more than 16 years old and very antiquated. It suffered from limited spectral range, field-of-view coverage and spatial resolution. The AMS could not be integrated into the 7V Chamber facility control systems, and AMS data collection operations were highly inefficient.

"The TMS is an extremely versatile instrument that significantly expands the 7V Chamber target characterization capability," he added. "It provides the ability to characterize the 7V Chamber target systems in spectral bands that were not attainable previously and will greatly improve the efficiency of test operations, thereby reducing the cost for a complete 7V Chamber test entry.

"The TMS has already been used to support a customer test during which its unique capabilities have been extremely useful for understanding performance of one of the 7V Chamber target systems that was used in a different manner during the test event. During sensor testing in general, the better the test facility performance is understood, the better the quality of the data provided and the greater the confidence in the test results obtained."

Jim Burns, the 718th Test Squadron's lead for space chambers testing, said it is important to keep upgrades in perspective.

"7V was, and is a state-of-the-art test facility," Burns said. "For example, the AMS was state-of-the-art when built. In the last few years, the state-of-the-art moved, so we replaced the AMS with the TMS to maintain 7V as a cutting-edge facility. It is part of the constant upgrade we do to keep all the capabilities in 7V current or ahead of the state-of-the-art."

The recent test Minter mentioned was conducted on a ground demonstration developmental model of a Ball Aerospace wide-field-view staring sensor.

"It [was] to be used nominally in a geo-stationary satellite," said Peter Thomas an Aerospace Corp., test engineer with the project. "[It was a] wide-field-of-view missile detection staring [sensor] for observing a large portion of the Earth."

Thomas said the advantage of the Target Monitoring System is that it allows the customer to make a more rapid assessment between 7V's "ground truth" sources and the sensor under test.

"The advantage of the TMS is that you can make a near real time comparison," he said. "It's a lot quicker response and the TMS is AEDC's and our ground truth camera.

"So, we see something with the Ball ASIRT [Advanced Staring Infrared Testbed] sensor and then we can, a minute later, look at that same source or series of sources with the TMS and now we have a comparison. That allows Ball ASIRT or any other customer's sensor should it see artifacts or ghosts or other image anomalies, to then look at the TMS and say, is that real or is it an artifact of the sensor under test?"

Thomas explained that even with the TMS camera, the field of view is limited and the test team had to move the test sensor two additional times to capture the sources in space being viewed at three field positions.

"We did get a good mix of high quality data, field of view coverage and [it took] less time to conduct testing," he said. "AEDC's TMS is a very wide spectral range camera.

"That means that over a very deep range of infrared energies, wavelengths, that [7V's] camera can see all the way into the long wavelengths. So, although the Ball ASIRT is not a long wave camera, the TMS will allow better calibration of other, LWIR sensors requiring the ability to detect warm things against other warm things."

For more information about the 7V Space Chamber, go to www.arnold.af.mil and click on Factsheets under the Library tab.