Q&A with John Mackin, a Man Very Very Close to the ISS

Image credit: NASA/Lauren Harnett

The International Space Station has been soaring above our heads since 1998. It's easy to forget that this marvel is falling around the Earth until we wake our sleeping children to see its night-time majesty, or as we've seen in past weeks, it shows up on the pages of every news source everywhere. With the recent Soyuz and Dragon launches, I had a few questions remaining despite all the coverage. Here to tell us a little bit more about it is John Mackin, fellow Illini and ADCO for United Space Alliance.

(News Flask) :How long have you been with NASA and what is your position there?

(John Mackin): I started at United Space Alliance (USA) in November of 2008.  USA is NASA’s prime contractor for International Space Station and Space Shuttle operations. 

I serve as the Attitude Determination and Control Officer (ADCO) for ISS.  I manage the onboard systems that are used to determine where ISS is, how fast it is going, and how it is orientated (We refer to orientation as attitude).  The second part of my job is making sure the ISS is maintaining the attitude which we command to it.  This is very important because if the vehicle is not pointing in the correct direction or spinning out of control, it makes it really hard to generate power from solar arrays, or point antennas at communication satellites.  Without a stable platform, we would not be able to do the scientific research that the station was created for. 

This attitude control is either performed by firing thrusters located on the Russian modules and the attached logistics vehicles or by moving very heavy spinning discs to impart a torque on the station.  The discs are referred to as Control Moment Gyros (CMGs) and are electrically powered.  The latter type of control is used at least 90% of the time because it uses electricity generated onboard instead of propellant that has to be delivered.  Different activities require different types of control and part of my job is managing the transition, or handover, from one control type to another.  I interact a lot with our Russian counterparts because the thrusters are on their part of the ISS.

(NF): Recently the ISS has had a lot of new traffic with the Soyuz a couple weeks ago and now the SpaceX Dragon vessel. Does this mean good things for the future of the space station program?

(JM): In the last year, ISS has seen four regular crew launches on Soyuz, and a variety of resupply vehicles (Russia’s Progress, the European Space Agency’s Automated Transfer Vehicle (ATV) and Japan’s HTV). With the shuttle program completed, the only way to get materials back to the ground is strapping them in with the crew in the Soyuz (Progress, ATV, and HTV are all loaded with trash and burned up on re-entry).  The Soyuz return segment is just large enough to fit 3 people, so it is very challenging to return experiments or used equipment.  With the success of SpaceX’s Dragon, experiments on ISS can be packed up and returned to ground. Within two weeks, the experiments will be in the hands of the scientists who designed them. Some experiments will even be returned within 48 hours of returning to earth.  NASA has purchased 12 more Dragon launches.

(NF): You said you played a role in the recent docking of the Soyuz. Can you tell me a little about that, what role you played and the work that goes into such a feat?

(JM): This was one of the most complicated Soyuz Dockings we’ve done. Before every major event on ISS, the engineers run analysis on how the structure of the ISS will respond to certain types of thruster maneuvers.  For the Soyuz docking, it was found that part of the two required thruster maneuvers could cause problems for ISS. To work around this problem, we did four  maneuvers instead of the normal two.   Half of those maneuvers were performed by US computers.  In between the maneuvers we had periods of CMG control and during the docking itself, ISS was in free drift.  All in all, we changed how ISS attitude control was performed 10 times in 3 days. Furthermore, all of the attitude details change whenever a launch moves, so when SpaceX delayed until after Soyuz docking, the whole plan had to change.  I worked a few shifts while we were developing the plan and I did a lot of the initial detail work.  When I was done, seven days of shifts reviewed and improved the plan before it was finally executed.

(NF): How closely did your team work with the SpaceX program to guarantee success in launch and docking of the Dragon?

(JM): My position had a flight lead for Dragon, who had been working with a flight director and the SpaceX folks for over two years. My involvement was as a GPS specialist for ISS.  We GPS to determine position, velocity, and attitude on ISS.  SpaceX Dragon also uses GPS,  and when GPS data is shared between vehicles,  the relative distance can be determined with high accuracy.  This is very important for rendezvous, so ISS has to maintain redundancy in the GPS system.  After one of the two 10 year old ISS GPS units failed last year, we  replaced both of them to be prepared for Dragon.  One week out from dragon launch (on the day I was switching from night shift to day shift) one of the new GPS units failed.  The next morning I came in for meetings with the engineers and over the weekend I was on call as plans were hammered out. Monday morning I arrived at 4am local as astronaut Don Petit was opening up the interior walls of ISS to remove and replace the failed GPS.  Once the new GPS was up and running, we put it through its paces to make sure it was producing good data for dragon rendezvous. It started having some anomalous behavior just hours before dragon was ready to launch, so I got a couple middle of the night phone calls.  We recovered the GPS unit and were go for Dragon launch with about an hour to spare.  

(NF): Some say SpaceX is a threat to NASA, and some say it will bring much needed public attention to human space flight. With drastic budget cuts to NASA over the last few years, do you feel like private space travel will help or hurt the NASA programs?

(JM): SpaceX success is NASA success.  They are providing a needed service to the space station program, by delivering and returning cargo to and from ISS.  Also, by controlling their costs, they’re allowing NASA to free up money to build a human vehicle that can go further than low earth orbit.  I think it’s great that it has brought some excitement to the general public, since so many people think that America is out of the space business. 

(NF): Do you think that private cargo launches add anything to the world of space flight or how the ISS operates, or is it all just hype?

(JM): I think they’re providing a service and I look forward to the day when you don’t have to work for a government to research in low earth orbit.  I am waiting to book my trip!

(NF): What's your favorite part of working at the Johnson Space Center in Houston?

(JM): There’re a lot of things I enjoy: problem solving, developing new and better ways to do things, flying the space station at night, giving tours to friends and family, really just being in mission control is one of my childhood dreams.  The best part is that I get to contribute to the future of human space flight, it makes the graveyard shifts and late night GPS phone calls worth it.

(NF): Once you told me you eat lunch in the old mission control room. Is it true that it's encouraged for staff to take breaks in there as a tourist attraction?

(JM): I actually do a lot of training simulations in a room next to the old Apollo mission control.  I like to stroll through there on my way to the fridge to pick up my lunch, it’s nice to see the tourists behind the glass, excited to hear about Apollo and men walking on the moon. I don’t actually eat in there though, my breaks only last as long as the ISS is not communicating to mission control, so it’s only a few minutes at a time.  Also it’s a piece of history and technically the Smithsonian owns the room, so I don’t want to mess it up!

Thanks again, John, for taking some time out to talk with me!  I hope someday you do get the chance to book your space flight trip!

Be sure to check back in the next few days for a closer look at budgetary threats to the ISS program and what it might mean for the future of the station; the last installment in our short space series.