Cast Glance: Gyro-Stabilized Optical Platform
Cast Glance Crew
- Steve Tack
- Brett Bush
P-3 Orion Crew
- Lt. Elliott Porter
- Lt. Conrad Metzler
Blair and Franklin visit the Cape to check out HYTHIRM’s ace in the hole for infrared images of the Shuttle as it reenters the Earth’s atmosphere. That ace is Cast Glance, a specialized, gyro-stabilized optical system housed in a P-3 Orion aircraft – not to be confused with the Orion spacecraft. The auteur film director of the Cast Glance crew, Steve Tack, gives NASA EDGE a behind the scenes look at his highly stylized work with one of his favorite subjects, the Space Shuttle. Franklin and Ron, the Set Therapist, enjoy Blair’s unique new role with the Cast Glance crew.
BLAIR: Welcome to NASA EDGE.
FRANKLIN: An inside and outside look at all things NASA.
BLAIR: Franklin, when I’m here at the Cape I think technology.
FRANKLIN: Whenever I’m in Florida I think technology, especially when you’re at Kennedy in the Cape.
BLAIR: Yeah, we’re here at the Cape to talk to the people that get the images for HYTHIRM, the cast glance group if you will.
FRANKLIN: We’re going to find out how the Cast Glance group tracks the space shuttle on reentry and gets some very good images that you probably won’t see anywhere else in the world.
BLAIR: They use technology to be sure, but it’s not just technology, human factors as well.
FRANKLIN: A little hand-eye coordination.
BLAIR: Let’s check it out.
BLAIR: Amidst the special effects of your aircraft, what exactly do you operate here? How does this big system work?
STEVE: This is a gyro-stabilized, airborne optical platform.
BLAIR: Is that like a steady cam?
STEVE: It’s a steady cam except the only thing moving is a gyro-stabilized mirror. Everything else, the optics, the cameras and the sensors are all fixed. The reason for that is obvious. We can’t have a huge track mount on an airplane. You’re always looking to conserve weight, conserve size on an airplane to keep it small, compact and lightweight, so rather than having a huge pedestal that turns a bunch of optics and cameras, we’re only moving and steering a gimbaled mirror. That gimbaled mirror sits in this cavity. When the aircraft is moving the gyro sends signals to little torque motors that compensate for the aircraft motion. Our standard configuration is with five sensors on it. We’ve modified this particular system with a camera for NASA. This is a high-resolution, standard video camera but we filter it for near IR light, which is at the very edge of the visible spectrum. You may or may not know.
BLAIR: You can assume not.... assume not… assume not.
STEVE: We filter out all the visible light and concentrate on the very edge of that spectral band. We’re trying to thermally map the surface of the shuttle over decent spatial resolution. What we didn’t have was a camera that could give us good spectral response over the spatial resolution, which is why we put this new camera in for NASA.
BLAIR: You need to shuttle balance the camera.
STEVE: That’s right. Shuttle balance is what we call it.
BRETT: I’m in charge of acquiring the data for the NASA-enhanced camera.
FRANKLIN: How much technology is involved in hooking up the computer to the cameras?
BRETT: We bought some normal camera off the shelf, hooked it up to this computer. For the most part, it’s a relatively simple system.
FRANKLIN: Off the shelf at Best Buy or off the government shelf?
BRETT: It’s a little more technical than Best Buy. NASA added a camera. Its maximum use is good for the near infrared imaging. Rather than looking at visible light, we’re more interested in infrared radiation coming off the Shuttle. That heating, depending on what temperature, puts out a different amount of infrared light. While we’re measuring that light through the calibrations we’ve done, we can take that energy that we measure with the camera and go back to calculate what temperatures are coming from the shuttle. I’m looking at it in real time and saying it looks pretty bright. I’m going to dial down the integration time so our data is useful throughout the whole data collection.
FRANKLIN: That’s pretty interesting stuff.
BRETT: It has been fun working with the project.
STEVE: The operator will sit at the system. In this case it will be me. All the tracking is done manually. We have assistance to help us find the shuttle as it comes over the horizon. As you can appreciate, it is a very complex task to find something several hundred miles away from us initially moving in excess of mach 15.
LT PORTER: The “ac site” or acquisition site is a way we can visually track the target we’re trying to put the camera on. When we’re using this, we’ll stand off of this for a little bit then we’ll catch the target with both eyes and bring it in, acquire it visually. It feeds it into the Cast Glance system in the back and allows the Cast Glance operator to slew the camera to the target that’s in the “ac site.”
FRANKLIN: When you say slew, it basically talks to the cameras in the back?
LT PORTER: It provides a position for the cameras. We’re using a pilot’s best instruments, his eyes. They know we have the best eyes on the airplane, that’s where they put the “ac site.”
STEVE: The tracking is done through these tracking monitors here. The operator sits and he can look right out the window or he can look at any one of the views on any of these cameras that we have. If I’m in track mode, I can move this back and forth. You can see the arrow indicators giving us the exact angle that we’re looking out the window. We have to maneuver the aircraft such that the shuttle remains in that cone. Within that cone, we track.
BLAIR: You have to be in close communication with the pilot because he’s helping you.
STEVE: That’s right. As mission director, I’m constantly evaluating these numbers as we’re tracking. As the shuttle gets closer and closer, it will eventually necessitate a turn. What starts off as a benign turn, as it gets very close to us, turns into a dramatic, much more aggressive turn.
FRANKLIN: So you’re in communication with Steve. What is he telling you? Bank left, bank right?
LT METZLER: He’s telling us bank left, bank right, it needs more rudder. Hopefully he’s telling us it’s looking good. The camera has a very small field of view. He’s letting us know where the subject is.
STEVE: Just let it catch up here.
PILOT: Steve, you’re driving the plane at this point, right.
STEVE: Yeah. We’re 20 up. It’s going to start to pass us. Let’s start to bring the turn about. Now start to turn.
PILOT: Starting to turn.
STEVE: We’re good. We’re at 10 forward. Little more wing up if we can. Wing up. There we go. Bring it around harder. That’s good.
STEVE: We fly a racetrack to get our timing down. All the headings and all the angles of the turns are designed such that as the shuttle passes we can maintain that viewing angle.
BLAIR: So again, it’s your communication, your team with the pilot all working in concert in mission to make sure you get success.
STEVE: That’s exactly right. To me that’s the most rewarding part of the whole thing, bringing the team together. There’s a lot of people on board the plane, from the pilots to the navigators to our cast glance team. You’ve got people running data acquisition computers. You’ve got people tracking. It’s a very dynamic thing, particular in that moment of interface where we’re actually tracking. Sometime months of planning, particularly on this mission, that go into those few seconds of time. Every thing has to work just right. Everything we do here is manual, hands-on. It really becomes more of an art form. There is wonderful technology in the original gimbal design here, which is probably 25 years old. It still holds up to this day. You mentioned teamwork. That’s the beauty of this. Our success is built on everybody’s efforts rather than relying solely on technology.
BLAIR: So Steve, if the cast glance crew is a lot like a film crew what kind of position do you think I would have on your team?
STEVE: The operation does have a lot of positions for somebody with your background and expertise. Matter of fact, I think I have a perfect job for you.
BLAIR: Wow! Can’t wait.
STEVE: Yeah, hi Blair. Hey Blair. Yeah. What… Hey Blair, can you stop talking for a second. What I need from you right now is 6 foot-longs, two of them with extra pepperocinis, one of them with Dijon mustard, not American mustard. Okay? Okay. You know maybe you’re not up for this. I think we’ll redirect you.
RON: What position did Steve give Blair?
FRANKLIN: I think he’s working in lighting.
BLAIR: I wonder if they’ll need me during the shuttle landing?
Page Editor: Blair Allen