The photographer walked in towards the end of Atlantis’s rendezvous with the International Space Station on Wednesday morning, and I was working hard and looking serious. Because rendezvous is serious! And I’m supposed to be steely-eyed! And serious! And then, while talking to my back room, I made the comment “looking good,” implying that the crew was flying really well on the final approach to the ISS. And my backroom responded “thanks, I know,” implying something about his physical appearance. I couldn’t help it. I smiled. The photographer’s camera clicked. And now I have a picture of me grinning on console. Which is fitting, in the end, since I was pretty darn excited to be working my first rendezvous as the lead Rendezvous Officer.
My big day began at 2:30 a.m. when I woke up, walked into the living room, and found these notes hanging from the monster on our ceiling fan. (There is a little metal gremlin with a cape that hangs on the cord. It’s cute. Really.) In case you can’t tell, it’s the shuttle on the left and the ISS on the right, with an arrow pointing between the two and the exclamation “today!” It made me laugh.
Speaking of creative things, when I arrived on console, I was greeted by this piece of “art” from my coworker, who obviously has mad Photoshop skillz. The commander of the mission’s nickname is Scorch, and he’s notorious for his questions. (In fact, he reminds me of a professor I once had.) He’s one of the sharpest astronauts I’ve encountered, and because he has such a good understanding of what he’s doing, he often pushes back on the way things are done and the way procedures are written. His questions are always good, but they often require you to go off and do more in-depth research to get a proper answer.
Anyway, the training team made up a bunch of “I heart Scorch” stickers, and I stuck one of them in the front of my mission notebook. This apparently amused my coworkers quite a bit, and that’s how I ended up with a stick figure drawing with Scorch’s head pasted on, exclaiming about how much he loves me and rendezvous.
And so the day began! At the beginning of Flight Day 3, the shuttle is more than 1000 miles behind the ISS, but that gap is quickly closed. The station is so big these days, and reflects sunlight so well, that the shuttle astronauts can see their target when they’re still more than 50 miles out. It looks like a very bright star at first, but it starts to take shape as time passes. After a while, the station can see the smaller shuttle as well. I don’t know at what range the above photo was taken, but I would guess it’s in the 5-8 mile range after the final large rendezvous burn takes place.
My main role in the rendezvous begins about 6 hours before docking as the crew begins to configure the shuttle for rendezvous operations. With 4.5 hours to go until docking, the shuttle has closed to 40 miles behind ISS and my job begins in earnest. They perform a large burn and then immediately begin to use the shuttle’s onboard sensors to measure the shuttle’s position relative to the ISS. Most of the work done to keep track of the shuttle’s position is done on the ground, but rendezvous requires such precise control that ground tracking can’t keep up with the rapidly changing distance between the two vehicles. So we need onboard sensors, like star trackers (remember how I said ISS looks like a star?), radar, and ranging lasers to keep track of where we are in the sky. It’s my job to make sure those sensors are giving us good data. If they’re not, it’s my job to make sure we’re still on a good flight path towards the ISS!
What looked like a bright star earlier in the day now looks like this — a real, live space station! The final discrete burn is performed when the shuttle is 2000-3000 feet away from the station.
After that, the commander takes control and flies the shuttle manually using a combination of the view out the window, the view through a camera in the docking mechanism, and a pair of lasers. One of the laser systems is mounted outside and tracks reflectors on the station, and the other laser is a handheld device operated by one of the shuttle astronauts. You can see the handheld laser — the white box with an eyescope on top — in use on the left. You can see Scorch at the controls on the right. This mission has a low solar beta angle, so he’s wearing sunglasses. The beta angle is a measurement of where the sun crosses the sky, and when it’s low, it often shines straight into the cockpit. If it’s bright enough, the astronauts have welder’s glasses they can wear to dim the light and avoid damaging their eyes.
When the shuttle reaches a point about 600 feet directly below the ISS, it’s time for the Rbar Pitch Maneuver. You’ve probably heard this referred to on TV as the “backflip” and they always talk about how the mission commander flies this backflip. This is funny, since the RPM is the only part of the final approach to ISS that the commander does NOT fly. Instead, we use the shuttle’s onboard pointing system to begin rotating at a set rate. The maneuver requires a lot of precision to ensure that the ISS crew can get good photos of the shuttle’s heat shield. After one rotation, the commander resumes manual control.
While the shuttle is flipping beneath the ISS, two astronauts on the station are perched in these two windows, which face the shuttle and the earth below. They’ve got cameras with gigantic zoom lenses and take several dozen photos of the belly of the shuttle to assess the heat shield for any damage to the tiles. This has been done on every flight since the Columbia accident — except for the Hubble mission, since there’s no one on Hubble to take any pictures!
With the “backflip” complete, the shuttle flies a quarter-circle path to a position 300-400 feet in front of the station. (Picture the ISS in the middle of a clock; the shuttle is at the 6:00 position for the RPM maneuver, then the commander flies to the 9:00 position for the final approach.) From there, the shuttle creeps towards the docking port ever so slowly — and I do mean slooooooowly. The closing rate between the two vehicles starts out at around 0.2 feet per second and slows to 0.1 feet per second at docking. To put it in perspective, consider that 0.1 feet per second is less than 0.07 miles per hour. It’s hard to even WALK that slow, but when you’re bringing two vehicles together that combined weight more than a million pounds, you’ve got to be careful!
In the end, the docking went just as we’d planned and practiced dozens of times on the ground. And just like that, I am no longer a “rookie.”
I threw these screen captures from NASA TV in here so that those of you who are interested can figure out where I sit. I’m just about as “front and center” as you can get in the Mission Control Center; my console is on the front row and extends into the middle of the room. It’s dim up at the front of the room (I don’t fully understand why the lights are kept so low in there), so I’m in shadow. Plus, most shots of the control center show the back of my head. Anyway, in the first picture you can see me sitting there below the left side of the world map display. And in the second picture you can see me standing up in the front wearing a green sweater. That was during handover after docking, so I was getting ready to leave.
Everything about the rest of the day was great. I hadn’t seen Jose in two days since he had class on Monday and Tuesday nights, so I knew I’d see him for at least an hour or so before bed last night. When the doorbell rang at 5:00, I was a little confused — especially when I saw the top of Jose’s head through the glass. Did he forget his key or something? But no, he just wanted me to answer the door so he could give me some beautiful flowers as congratulations on my big day. And because he is the best husband in the world.
It was a good day.