A lot has been written about the recovery from the Columbia accident in terms of changes we needed to make to get back to flying the Shuttle again. In general, the changes fell into two categories. One bucket contained changes to hardware, the other were changes to management practices.
In the early summer of 2003, we didn’t know how much time we’d eventually have to make these changes—just that we’d take whatever time was necessary to get them done, and with the confidence we did them right. But based on the recovery from the Challenger accident of 1986, we figured we wouldn’t be flying again for a couple of years. Could be longer; could be a little quicker. But the charge to all of us was to get the work done correctly, first and foremost. Sort of like resolving a problem in the final throes of launch countdown – solve the problem first, then look up at the clock and see if you have any time left in which to launch.
That’s not to say we were lackadaisical about it. Hardly. We were well aware of the need to get flying again to the ISS. But once again, it was ‘schedule awareness’ vs ‘schedule pressure’. There was a difference from the time critical launch environment of course where technical problems were solved based solely on data, and bad decisions couldn’t be recalled. In the recovery period, lengthy, philosophical debates were fairly common. But decisions needed to be made and progress in the improvements needed to be real.
The foam loss problem on the external tank needed to be fixed. Adding the capabilities to inspect the Orbiter’s tiles and effect some level of repair prior to re-entry was also necessary. These were obviously the top two flight hardware upgrades undertaken. But each Project (Orbiter, ET, SRB, Ground Processing, etc.) was asked to essentially recertify their existing system as flight-worthy, or suggest upgrades aimed at improving safety margins. These suggestions would be debated at the Program-level change boards and either accepted for implementation (and funded) or not.
Changes weren’t too widespread for us at KSC and the Ground Processing directorate. For the most part, our work practices on the flight hardware were mature and adequate. Extra care was to be taken when working on the External Tank’s foam to avoid damage, but nothing too onerous.
One significant finding in the accident review that we were responsible for correcting was the inadequate ascent imagery. As you may recall, on Columbia‘s final launch one ground tracking camera was inoperable, another was out of focus, and the just sheer number of assets documenting the critical portion of ascent couldn’t guarantee the full suite of images necessary to help resolve issues. As a result, we undertook a complete review of the ‘imagery system’ composed of tracking video cameras, still photography, high-speed engineering film assets, and the Operational Television System (pad cameras). We needed to be sure we had enough visual documentation to address issues, and have confidence on launch day the assets were working and could ‘see’ the vehicle. The Columbia Accident Investigation Board (CAIB) even recommended we have Launch Commit Criteria (LCC) for the system. More on that in a moment.
In addition to improving the visible launch documentation we needed some sort of long-range tracking system that could detect issues long after ground-based cameras effectively lost sight of the vehicle. Later – the C-band radar system. Likewise, on-orbit imagery needed to be understood and policies firmed up to enlist help from the intelligence community if needed.
For the sake of brevity, the final ground-based system we installed was one of guaranteeing adequate views at least through SRB separation, from three independent positions, and from both north of the pad and south of the pad. We needed close-in views, mid-length (2-5 miles), and longer-range views from 10 miles or beyond. No distance requirement was set, just that we had these three ‘zones’ covered. Obviously, siting the individual assets would be case-dependent. At least two cameras at each location added to the certainty of coverage. The status of each would be reported to the responsible system engineer on the launch team and relayed to us. They would be committed for launch during the hold at T-9 minutes.
What about the CAIB launch commit criteria requirement? What about clouds obstructing one or more views? What about night launches? Good questions.
The CAIB did not specify what type LCC they wanted, although in informal talks they were going after specific camera views and operability. Given the uncertainty of guaranteeing views, I opted to enact an LCC based solely on the system operating properly. The issue of adequate views (cloud coverage, one or more specific cameras being down, etc.) was left to judgment on launch day. That decision would be made jointly by me (as Launch Director) and the Mission Management Team chairperson. The CAIB accepted the idea, so we pressed on with buying and installing an elaborate collection of video and still cameras located north and south of the pad. And we installed a control system for the cameras close to or at the pad. It was that control system that had the LCC. On launch day, the pre-launch MMT chair and I would get information on the views we would get during ascent and would decide if we’d launch with anything less than the full complement.
We had a requirement to launch during the light of day for the Return to Flight mission. That mandate remained in place until we had confidence the foam loss issue was resolved, AND that the radar system could detect debris issues regardless of daylight. We relaxed the lighted-launch requirement starting with STS-116 in December 2006, the first night launch of a Shuttle since the Columbia accident.
The system proved to be a great addition to the safety for the astronauts and the vehicle. Never again would the vehicle be hidden from view during ascent. We had enough cameras to make up for one or two not working as designed and had all angles covered. Ground-based imagery never caused a scrub and always provided clear views of the vehicle – and plenty of them.