A few days ago space shuttle Discovery lifted off for her final ride to space. Earlier in the week I read various retrospectives on Discovery. One in particular was with former astronaut Eileen Collins, who recounted her first journey to space onboard Discovery during shuttle mission STS-63, sixteen years ago this month. In it she recollected about the mission’s objective to conduct the first rendezvous of a shuttle with the Russian space station Mir, and how it almost didn’t happen due to the loss of a critical jet on the shuttle after launch.
See, I was in Mission Control for that mission, and I was working furiously behind the scenes to make the mission happen despite the setbacks in real time. In honor of Discovery’s final trip, I’m going to share my own special retrospective of my most favorite mission flown by Discovery, STS-63.
In late 1993 I was early in my career at NASA and was nearing completion of the training and certification program to become a fully-fledged shuttle flight controller in Mission Control for the rendezvous guidance and procedures position, with call sign “RENDEZVOUS.” In December of that year, US Vice President Al Gore and Russian Prime Minister Viktor Chernomyrdin signed agreements that established Russia as a partner in what was to become the International Space Station Program. Additionally, the agreement called for flying Russian cosmonauts on the shuttle and American astronauts onboard the Russian space station Mir. One of the key shuttle flights in this sequence was a dress rehearsal for a shuttle rendezvous and close approach to Mir, which within a few weeks was assigned to shuttle mission STS-63, slated to fly in February 1995, a little more than a year later.
I happened to be in the right place at the right time. Other shuttle missions already had lead rendezvous officers assigned to them, and to shuffle assignments with mission planning already underway might prove to be troublesome. Knowing that I was on course to complete my certification and training in a few months, I was assigned as the lead rendezvous officer immediately and began work on STS-63.
In the year leading up to the flight, I became acquainted with the fledgling joint US-Russian cooperative efforts that were being rekindled after twenty years of dormancy, dating back to the Apollo-Soyuz mission in 1975. I experienced 6 AM teleconferences, accounting for the nine-hour difference between Houston and Moscow. I experienced how frustrating and slow progress was when nearly everything had to go through interpreters. I also spent a lot of time in the simulator, designing the piloting procedures for flying the shuttle to within 30 feet of the docking port on Mir, backing away, then conducting the constant-range flyaround loop of Mir. I also observed the crew in the simulator with the rendezvous instructors, flying the procedures I designed and getting their comments firsthand.
One other key area of work for me was in creating the set of mission-specific flight rules governing the rendezvous, approach, and departure. It was the work I did in this area that proved to be the area of excitement during the mission. I had no idea that this might be so in the months leading up to the mission.
See, the Russians (and rightfully so) were concerned about possible contamination on their solar arrays due to the plumes from the shuttle’s jets used for maneuvering in space. I quickly wrote a flight rule that said, “The shuttle will not come within 1000 feet of Mir if it is leaking any contaminants.” Frankly (and I’ve never admitted this until now), I took the easy way out; how often does the shuttle leak contaminants – like almost never? I felt that a long, protracted dialogue over a series of 6 AM teleconferences through interpreters wasn’t worth the effort of an almost-zero probability event, so I wrote the rule as black and white with no conditionals. I also affirmed another pre-existing rule and applied it to the mission with Mir: if the shuttle loses redundancy in its LOW Z translation mode, it would not approach within 1000 feet of Mir. (LOW Z is a special translation mode of the shuttle that uses nose and tail jets in concert to avoid using upward-firing jets. This avoids impinging the rendezvous target with jet plumes.)
So much for the best-laid plans…
Shortly after achieving orbit, Discovery got an indication of jet failures. One of the jets failed in the off position, which is OK. However, two of the jets failed in the leak position, meaning that unless the crew closed the manifolds feeding the jets, they would continue to leak. That was exactly the scenario that I thought could not and would not happen. Yet it did.
If we went by the rule I wrote, the crew would have to close the manifold and thus would sacrifice several other functional jets to avoid the leak on the leaking jet. The problem is that the leading jet was on a critical manifold for the rendezvous, and closing the manifold would violate the LOW Z redundancy rule. So, we were in a quandary: to be able to approach within 1000 feet, we would have to close the manifold per the contamination rule; however, by closing the manifold we would lose LOW Z redundancy and thus could not approach within 1000 feet per the LOW Z redundancy rule. Same outcome either way – Kobayashi Maru: the no-win scenario.
Or was it?
At first, I was feeling pretty bad because I took the easy way out before the mission and wrote a rather black-and-white rule that put us in a quandary with respect to mission success. I kept asking myself what if: what if I had thought through the logic and rationale when I had more time before the mission, had the protracted dialogue with my Russian counterparts, and arrived at a different rule that would have avoided the quandary in the first place?
Yet I put that behind me and with the flight director engaged in several days of real-time negotiations with our Russian counterparts, while the clock was counting down to the rendezvous. Both sides wanted a successful outcome of the mission, yet both sides were still unfamiliar with the other regarding deep-set motivations and decision-making frameworks. We were still in the process of working out trust, and there is nothing like the pressure of real time to put trust to the test. The Russians felt they were the ones more at risk and thus were rather cautious and conservative in the dialogue. In the end, both sides agreed upon a plan that modified the LOW Z redundancy rule – basically the revised plan dropped it. We entered into a series of technical conditionals concerning LOW Z and any next failure that got the Russian side comfortable. I breathed a sign of relief and began focusing on the technical aspects of my first rendezvous execute shift in Mission Control.
I remember the excitement of being in Mission Control that day, following along with the crew as they executed the procedures I wrote for the rendezvous while simultaneously monitoring the real-time data from the onboard navigation system on Discovery. I remember the crew call-down of a visual tally-ho on Mir at the unheard of distance (for the time) of 190 nautical miles (about 220 statute miles) – up to that point, visual tally-ho’s were usually only possible within a few miles, because we had never rendezvoused with anything as large as Mir previously. I remember the buzz of excitement in the flight control room when unexpectedly we received live video images from Moscow showing Discovery from the vantage point of Mir – we’ve never seen the shuttle live in orbital free flight previously. I remember watching commander Jim Wetherbee smoothly fly Discovery to within 30 feet of Mir, just like it was in the simulator. The speeches exchanged by the astronauts and cosmonauts went passed me as I continued to watch over Jim’s shoulder (so to speak) and focus on the telemetry. The backaway and subsequent flyaround flown by rookie pilot Eileen Collins was flawless.
In one respect, it went by in a blur. In another, I remember moments with crystal clarity. I remember the depths of deep disappointment with the flight rule quandary. I remember the determination to find a way out of the apparent no-win scenario. I remember the excitement of watching history being made, and being a participant in it. I remember the friendships that were forged, both on the US side as well as Russian side, that carry forward to this day. And lastly, I remember as Discovery sails on its final mission in space, the wonderful achievements of its previous missions. She is a remarkable machine, made all the more so by the remarkable people who flew her, prepared her for her missions, and cheered her successes.
Text © Joe Williams 2011
Image credit: NASA