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September 12, 2012: The Undocking and Release of the Japanese H-II Transfer Vehicle-3


via NASA TV

I might have jinxed it.

On Tuesday, September 11th, I was explaining my role as a CAPCOM (Capsule Communicator) at Mission Control Houston for the International Space Station. I said, “It’s like in Apollo 13, when the crew calls down and says, ‘Houston, we have a problem!’ I’m the one that says ‘Stand by!’”

The very next day, during a routine detachment from the ISS of the Japanese H-II Transfer Vehicle-3 (HTV-3) supply ship bound for reentry into Earth’s atmosphere, it aborted its trajectory after being released from the Canadian robotic arm. We were Houston, and we would have had a problem -- if we didn’t DO WHAT WE DO. We are explorers: We imagine - we build - we train - we fly. It is what we do.

We also take risks. To manage those risks - to make sure that we accomplish the mission and bring the crews home safely - we are constantly thinking, “What if this happens?” “What if that doesn’t happen?” And then we practice every scenario. And then we practice some more, so that on the real day, we are ready.

So what happened with the HTV, named Kounotori (meaning stork)? Precise conditions that keep the space station safe were not met, so the process aborted.

After the crew released the HTV with the robotic arm, it appeared that the 16-ton supply ship (the size of a large school bus) was slowly coming closer in our camera view. However, our data indicated that the HTV was slowly headed away from the ISS. We asked the crew with their bird’s eye view to confirm what we were seeing: that the supply ship was slowly drifting closer to the robotic arm.



In retrospect, all of our hearts were probably beating quickly as our training kicked in. Our team on the ground and the crew in space train for this kind of situation. What are we seeing? What are our options? What do we need to do?

Robotics Officer Jason Seagram was monitoring the distance to the arm and plotting how best to move it away from the HTV. Visiting Vehicle Officer Jerry Yencharis called out that he saw a positive rate away from the ISS but was puzzled by the rate toward the arm. Attitude Control Officer Greg Anderson confirms that the ISS is indeed stable, and it is the HTV that is moving.

Outside that day, the weather in Houston was terrible. We never even knew, because inside Mission Control-Houston and Mission Control-Japan we had a storm of our own. Everyone was at the top of his or her game. It is who we are, and it is what we do.

David Korth, the NASA HTV3 flight director, quickly collected the options and weighed the pros and cons. He may not have been wearing a vest and smoking a cigar like in Apollo 13, yet he was every bit the force behind our team’s cohesion on the road we were traveling.

We were just moments away from telling Joe Acaba on the ISS to maneuver the arm further away from the approaching ship, when, just as it was designed to do, the HTV-3 itself analyzed the situation, predicted that it would soon be closer to the ISS than was planned, and aborted to a safe path away from the ISS.

The crew onboard ISS, Joe Acaba, Aki Hoshide and Suni Williams, were ready on the arm and helped us follow the path of the HTV as it sailed away from the ISS.

Maki Kawashima and her crack team in Japan fired emergency commands at the departing HTV to ensure that it continued on a good path away from the ISS. HTV was gone, free and clear. But was it really? Was the ISS really safe? Could orbital mechanics bring the ship back on a collision path with ISS?

Math - math - math - math - math. I can’t say it enough times: it is what keeps us safe. Jerry reassures the flight director that HTV-3 is already 700 feet in front of the ISS and increasing its distance.

At the end of the day, HTV-3 is on a safe path away from the ISS, the crew is asleep, and we left the next shift of folks at mission control busy planning the crew’s experiments the next day, next week, next year. The stressful part only took a few hours, but it was the longest day that I can remember in quite a while. What happened? Why did it happen? What does it mean? It takes time to sort it all out, and that’s also what we do. When things don’t go according to plan, we learn something. But for the moment, our work was done.

The HTV team and I shared something that day. Some of us are from the US, some are from Japan and some are from the rest of our cadre of international partners. But we are all part of the space station world, and we are all people that make exploration work.

All the experiences that I have had over the years at NASA add up to that kind of day, and HTV-3 safely completed its journey on 14 September 2012 when it re-entered the atmosphere. The cycle begins anew.

Editor's Note: For another point of view, here's what space station Commander Suni Williams has to say about the undocking and release ...