NASA just solved its exposure problem – and the result is spectacular.
If you try to snap a picture of a rocket launch, the flames shooting out of the end of the craft will be so bright that they will look like just a whitish blob in the resulting image.
That image is fine for memories and to demonstrate just how fiery a rocket launch can be, but for researchers who want to see if everything went smoothly during a test, the bright blotch obscures much of the scene.
So researchers began designing a new video camera that could account for that overexposure without darkening the rest of the image. And it works, the space agency announced Saturday.
The plume of fire that shoots out of a rocket motor is so bright that any camera attempting to film a launch or a test will have to dramatically reduce its exposure settings to avoid capturing a washed-out image. But that makes the whole image darker, not just the bright flames, and scientists can't see much of the motor to see if its components worked as they were supposed to.
One reason it has been difficult to capture an image that is neither overexposed nor underexposed is that video cameras typically use just one exposure at a time. But engineers found a way around that challenge.
The High Dynamic Range Stereo X (HiDyRS-X) project designed a video camera that can record multiple, slow motion images at the same time. Then these images are combined to create an evenly exposed video.
When NASA did a full-scale test of its Space Launch System (SLS)'s booster, the engineers had an opportunity to test their new camera.
Before the big day, the researchers had practiced and reviewed the start procedures for using the HiDyRS-X camera, but nonetheless the team hit a couple of snags on the day of the test.
The researchers had set up an automatic timer to go off when the booster test began. The booster fired up its engines, but inside the HiDyRS-X camera, nothing happened.
But the engineers moved quickly and manually overrode the timer to start the camera, just missing the beginning of the rocket booster test.
Then, partway through the test, the powerful rocket booster caused such shakes and quakes that the camera's power source disconnected.
"I was bummed," Howard Conyers, a structural dynamist at NASA's Stennis Space Center, said in a NASA press release. "Especially because we did not experience any failures during the dry runs."
But that frustration quickly faded when Dr. Conyers and his team saw the footage their camera had captured.
"I was able to clearly see the exhaust plume, nozzle, and the nozzle fabric go through its gimbaling patterns, which is an expected condition, but usually unobservable in slow motion or normal playback rates," Conyers said.
Despite the start and power problems, the test had proved that the camera itself accomplished its goals: It offered a never-before-seen view of rocket motor tests. The researchers saw the rocket in a completely new light.
"Failure during testing of the camera is the opportunity to get smarter," Conyers said. "Without failure, technology and innovation is not possible."