Feature: New Heights for Photogrammetry
Professional Surveyor Magazine - May 2011
Software development was Mike Kitaif’s ticket to being part of NASA’s space shuttle program, fulfilling a childhood passion for space exploration.
by Nancy Luse
Mike Kitaif’s childhood fascination with space travel has grown from the days of standing on the beach near his home in Florida and watching nearly every launch to actually working for NASA in a role that has saved the program time and money as well as improving safety. Kitaif, co-owner of Cardinal Systems, LLC
, a Flagler Beach, Florida, company that provides software modules for use by engineers, surveyors, and mapping companies, described his association with NASA as “the story of a redneck from Florida who wrote a little software and ended up hanging around with some of the smartest people in the world.”
itaif and software expert/co-author Tom Blankenship had been designing and developing mapping software the past 20 years. NASA first approached Cardinal Systems in 2004, interested in Kitaif and Blankenship’s mapping software that included a 3D stereo component, ideal for taking detailed photos of the craft’s exterior. The Columbia disaster the previous year, in which a piece of foam insulation broke off the external fuel tank during launch causing the shuttle to then break up during re-entry, had NASA looking for a backup inspection system to prevent another tragedy.
“I had always been fascinated by close-range photogrammetry, the ability to take photos of things close up and map from that,” Kitaif said. “One thing that they always have on the shuttle are cameras, plus they have cameras on the International Space Station
, so that part was already there. What they proposed to do was take pictures of those areas [needing closer inspections] and send them back to Houston, at which time the overlapping photographs could be set up and measurements could be made of the damaged area. NASA asked me to do a technical test for them, we did, and we got the contract [in 2005], even though we were up against some big players.”
As Kitaif explains it, the shuttle is arranged in what is called “the stack.” There’s the orbiter where the astronauts are seated, the huge orange tank that carries liquid oxygen and liquid hydrogen, and then the two solid rocket boosters. Those rockets come off after 128 seconds while the orange tank stays attached to the shuttle until it goes into low orbit and then it’s jettisoned. As the tank falls away, it’s traveling at the same speed as the shuttle, or 17,500 mph.
On Cardinal’s first job for NASA, Shuttle Training Flight (STS) 114, “they lost a 39-inch piece of foam on that orange tank, a huge piece of foam. Had it hit the leading edge again, it may have been a problem. It didn’t hit anything, but it certainly concerned NASA,” Kitaif said.
“This was the first mission where they put a digital camera (a Kodak Nikon DCS 760) in the bottom of the shuttle. As that tank fell away, about 20 usable pictures were taken that they were able to send back to the Johnson Space Center
in Houston the day they launched. I got two of those photos and was able to see 3D on that tank and make measurements. We were able to measure the length, width, depth, and the amount of material that was missing,” he said.
“They needed some answers because this could have been another problem.”
As a result, NASA changed some of its procedures, including the way the foam was laid in. “They’ve made improvements to the tanks, they’ve made improvements to the thermal protection system—it’s better than it’s ever been,” Kitaif said, considering that the shuttle program is close to 30 years old and is winding down. A flight took place in April, and at press time the final mission for Atlantis was planned for this summer provided there is funding.
Just as NASA adapted with making changes to what it had been doing, Kitaif said his end of the project also went through some growth. “Because the photography is not restrained as it is in aerial mapping, they don’t have the control over the photography, and we’ve had to be more innovative, we’ve had to develop the software better …. And that’s been very good for us, not just for the publicity of working for NASA, but from a technical standpoint” of improving what they do.
“I’ve been in the business 30 years and with NASA since 2005, and I’ve learned 10 times more about my profession in the short time I’ve worked for NASA than I did the whole time I’ve been in the business,” he said. “NASA has several very qualified photogrammetrists, namely Donn Liddle, Orrin Thomas, and Ed Oshel. They are on the cutting edge and use the technology in real-time situations to provide the data needed by the mission managers for important decision making during the missions.”
The principles and methods of photogrammetry are widely understood in surveying and mapping applications. Although this article relates a unique and drastically different application, those principles still apply. Basic 2D measurements can be made from many types of photos, but, as Kitaif mentions, overlapping photos are needed to create the 3D effect that allows measurement of relief. Luckily in the case of the foam falling from the shuttle’s tank, enough photos were taken to provide the necessary overlap.
In typical survey/mapping situations, it is the surveyor who provides horizontal and vertical control for the photography, in the form of panel or picture points. In this situation, that control did not exist; as Kitaif notes, the photos were “unrestrained,” which required an innovative approach. But this was not the only tricky part.
The photos overlapped, but they were taken during separation of the tank and shuttle, as they moved away from—and rotated in relation to—one another. This caused the images to be at different scales and to have different camera angles. As Kitaif noted in his analysis, “The rotation angles and scale changes made orientation of stereo models challenging.”
The control used in the initial analysis was a known dimension between two features on the tank and several “elevation” points on a known, consistent portion of the surface. Interestingly, from those controlling features, Kitaif proceeded to grid the surface, identify hard breaklines, create a DTM, and contour the surface: the same process used in any typical mapping job! This time the area of interest was much smaller (216 square inches), and the stakes were much higher.
Saving Time, Being Safe
On STS 114 another issue to be addressed was when a heat blanket came up next to the window of commander Eileen Collins’ cabin. “Again, they were concerned that if it tore off, it could hit the vertical stabilizer or something like that during re-entry,” Kitaif said. “On the mission’s first space walk, astronaut Soichi Noguchi worked his way over and took some pictures of the heat blanket area.”
Using traditional photogrammetric techniques, Kitaif was able to set up Noguchi’s imagery in stereo and derive a 3D model of the heat blanket.
“The thermal engineers looked at this damaged area, and they were able to make some decisions from this stereo imagery …. They decided not to fix the blanket based on what they saw from the photogrammetry, backed up with a wind tunnel test.”
Kitaif said that out of the last seven missions when there were questions or concerns, five had the matters cleared based on photogrammetry. “So they didn’t have to bring out the robotic arm; they relied on photographs. They looked at the areas and said they were fine,” he said. “The arm is not something that they can just bring out and move around, and they certainly don’t want to run that thing into the shuttle and cause more damage.” Plus, “anytime they put on a suit and go outside” there’s the potential for problems.
In addition to safety, there’s also a time factor, he said, with the mission losing a day each time the robotic arm has to be deployed.
Beyond the Last Shuttle
Kitaif and his partner at Cardinal, Jane Smith, are grateful for their role in the space program and see a future with NASA even after the last shuttle mission. “It certainly has been a great honor to have been involved,” Smith said. “We have enjoyed every moment working in such an exciting environment and have met some wonderful, brilliant people along the way. It is sad to know that we are approaching the end of an era, but we are proud to have made a contribution. Let’s hope that all involved in the shuttle program have an opportunity to transition into another worthy cause and photogrammetry gets to show its value again.”
Kitaif said, ”Once the shuttle stops flying, they can still use the information [from his software] on the International Space Station …. They have to have a way to inspect it, “ for example if there is a micro-meteor hit. “We very well may be included in that process as well.”
Saying that he would have done the shuttle work for free, Kitaif is still as excited as he was as a kid watching the Apollo launches. “With all the criticism of the shuttle program, you have to keep in mind that we put that thing up 133 times; we’ve lost two of them.”
He said he continues to be amazed at the shear size of the spacecraft that measures 184 feet at launch. “Each time I go out to the pad and take pictures of it,” he is overwhelmed. Added to its size is its power. “The thing goes from 0 to 17,500 mph in less than eight minutes. It’s the fastest vehicle ever made. When it re-enters the atmosphere, it’s traveling 17,500 mph, and we have successfully thrown it back into the atmosphere 131 times,” grateful for that “huge heat shield. It’s a technical marvel.”
Kitaif can get unabashedly
emotional about the space program, recalling a time he choked up when an astronaut doing a walk and from the vastness of space recited the procedure Kitaif helped write for taking photogrammetry photos.
But the feeling started even further back when Cardinal received the contract. “I was at home, and when I found out about it I was in tears. My wife said, ‘I can’t believe it, you’re in your 50s and you’ve had a childhood dream come true.’”
Nancy Luse is the assistant editor at Professional Surveyor Magazine.
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