Rendezvous Part 6 – A Tricky Problem

In my book Shuttle, Houston: My Life in the Center Seat of Mission Control, I bring readers deep into the middle of how Mission Control worked during the Space Shuttle era. I give readers a glimpse of both the technology and the humanity required to put humans in space on a routine basis. There are many parts to this thirty-year story, and only a small portion of the tales fit into the book – so here is an excerpt from an unused chapter on the process of rendezvousing the shuttle with other objects in orbit. 

I flew countless rendezvous cases in my years as the Flight Director, and one that sticks out specifically was a generic sim where we got to Ti with all of the minimum equipment running. In fact, we pretty much had all the nominal stuff working. We executed a Ti burn as near perfect as I have ever seen – the residuals were zero in all axes, and no mid-course were going to be required. It was just dumb luck, of course – the numbers just randomly all lined up that day, and the various errors all cancelled each other out. Of course, that makes for a very, very boring sim case – so the training team decided to improvise. They broke up the “Set” – the three GNC computers all running in lockstep. As I recalled, one failed outright, and the other two disagreed – so essentially, we were flying blind, towards a perfect intercept with the ISS. All we knew is that if we didn’t do something, we were going to hit the damn thing.

I let the trench, GNC and DPS flight controllers chew on the situation for a few minutes, the clock ticking, and the range counting down. It was quite a huddle down there in the front of the room – I could almost see smoke coming out of their ears. Finally, I called time – we had to make a decision, of some sort – and I was curious what they had come up with. DPS spoke first. “Flight, we can’t get the G2 set back up in time – we suggest activating the BFS. We can do that quickly by bringing up GPC 5 and giving it the strings”.

“OK, DPS – I get that. But hey – we don’t have any on-orbit rendezvous-type software in the BFS – it is just designed for ascent and entry…right?”

“Flight, GNC – the BFS does have an Orbit DAP that is pretty primitive, but it will allow attitude control and translation – we suggest that they use it to maneuver.”

“OK GNC – and what are we going to tell them about maneuvering – how do they do it with no onboard guidance at all?”

“Flight, RNDZ…we suggest that they look out the window and maneuver until they see the ISS in the forward windows”.

“OK RNDZ – that sounds like a plan – what do they do then?”

“Well, Flight, let’s just tell them to keep an eye on the Station, and do whatever burn they feel is necessary to miss it!”

Miss it – hey, that’s a good idea! So, that’s what we told them – and that’s what they did — pure manual, out the window, Mark 1 eyeballs flying. It worked fine – and then we got to spend the rest of the day rebuilding the set and re-establishing control. We never did get to the rendezvous, but everyone got to see recovery procedures and trajectory planning from a corner of the envelope they had never been. In fact, I don‘t know that ANYONE had ever been there!


We’ll bring you the next portion of “Rendezvous” next week right here! If you enjoyed this look inside the Shuttle program, you can find many more details and stories in the book – look for it wherever you buy your paper books, or add it to your favorite E-reader or audio book account.

Shuttle, Houston can be found at:

Speleobooks, who will provide autographed copies of the book at a great price:

Barnes and Noble:

Amazon hardcover:

Amazon Kindle:


Books2Read, which will give the user the option of multiple eBook sellers:

Great news! We have partnered with our pals Emily and Mike at Speleobooks to provide autographed/specially inscribed copies of

Ironflight’s book at a great price. Please go to their site to check out the details and order:

Christmas is coming!

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