Chapter 3: 'If I Can Just Get My ARM Around This …'
Hello from Star City, Russia; about one week removed from Montreal, Canada! I am back in Russia for my second four-week International Space Station training session, but this Chapter relates my experiences during a two-week stint with the Canadian Space Agency (CSA) experts and their attempt to make me an MRO ... Mission Robotics Operator!
The two-week session was intense! Five days each week, some days lasting 10-12 hours ... and my brain was hurting! Sometimes I heard little noises near my ears ... I think it was brain cells falling out as the robotic arm experts in Canada tried to shove a few more bits of knowledge in.
Image at left: Astronaut Clayton Anderson participates in a Canadarm2, or Space Station Remote Manipulator System training session in an International Space Station simulator at the Canadian Space Agency. Credit: NASA
I was fortunate to be training with fellow astronaut John Herrington. A Space Shuttle veteran (STS-113; the flight preceding Columbia), John is a Navy test pilot, veteran space walker and good friend. In addition, he is the first registered American Indian to have flown in space ... from the Chickasaw Nation. He and I have already shared some interesting adventures as we both participated in eight days of winter survival training in Cold Lake (Edmonton, Alberta), Canada and also as part of the NEEMO 5 crew ... John was our back-up crewmember. He will get to make his “plunge” to Aquarius this summer as the commander of the NEEMO 6 mission.
The Station’s robotic arm is similar to the arm we have used many times on the Space Shuttle (also provided by CSA). However, the station version has additional capability and is incredibly more complex. In technical terms, the Shuttle’s arm flies using “6 Degrees of Freedom (DOF)” while the station’s arm can fly using 6 or 7. What does that mean, you say? Let’s try a demonstration.
Imagine you are flying the arm ... but it’s your arm (we’ll choose our right arms for illustrative purposes). It is attached at the shoulder, much the same way the real thing attaches to a point on the station (more on that later). Your joints, providing your DOF’s, are very similar to the real thing. Your shoulder and wrist move in ways not unlike our engineering marvel. They may pitch (up/down), roll (twist right or left) or yaw (slide back and forth). The elbows may only pitch (up or down). Your hand is what we call the LEE or Latching End Effector. Confused? Don’t be. Using your “robotic” arm, at a comfortable distance away (about 1-2 feet), extend your arm out and pick up a ketchup bottle from your kitchen counter by grasping it with your “LEE.” Successful grapple?! If so, move the bottle of ketchup directly over your head while rotating it so that the pouring spout faces to your left. Note how your “joints” move in order to place it there. Next, if you dare, holding the bottle in the exact same position, try and move it behind your left ear. Do any of your joints start to reach their “joint limits?!?” From there try to move it behind your right shoulder blade ... etc. If you can do these last two moves, you have a future in the circus! Hopefully this exercise shows just how complex the arm must be to allow computer software to “drive” it as we did in our demo.
There are several key differences between the shuttle and station arms; we already talked about their DOF’s. Some are more interesting. Consider the fact that on the shuttle, we can view the arm and its motion from the windows, and its shoulder is permanently attached to its sill (side). On the station, we don’t have that luxury and we must use sophisticated video TV cameras and lights to see what we’re doing. I also mentioned how the arm may be “anchored” to our “shoulder” points. Well, the station arm can grab with one end, release with the other, move to a new position, reach out and grab the station there, release its other end again and repeat the process. Over and over it can inchworm across the station! It also has a cool set of “train” tracks on the front of the station complete with its own “engine.” This gives us the ability to park the arm on the “engine” and “drive” along the “tracks” until we reach the point where we want to stop and work. Is that cool, or what?
As a result of my completing the Robotic Arm Training, I am now designated (officially) as a Mission Robotics Operator, MRO. Hopefully, with additional training back in Houston, I will one day be classified as an MRO Specialist. This means that I may actually perform robotic operations in space onboard the International Space Station! If that happens, I will be one excited MRO; or maybe I should just say that I will be "... heavily armed!”