Dawn Moessner joined the MESSENGER mission a bit too late to take any of the credit for the work that went into the overall mission trajectory design that had been done before launch. But since she was first assigned to MESSENGER, when she joined the Johns Hopkins University Applied Physics Laboratory (APL) in August 2008, she has helped with redesigns to optimize maneuvers and ensure that the orbit-phase maneuver plan allowed the science team to gather the type of data they wanted.
The Hubble Space Telescope repair mission in 1993 fascinated Moessner and was what first inspired her to become an engineer. “The fact that engineers could figure out what had gone wrong and come up with a way to fix the problem, and then, to top it all off, that astronauts could actually perform the repairs in space was incredible,” she says. “I was caught, hook, line, and sinker.”
Moessner grew up in Louisa County, Va., and attended Purdue University in West Lafayette, Ind., where she received both her bachelor’s and master’s degrees in aerospace engineering.
An incredible moment for Moessner came during MESSENGER’s second Mercury flyby shortly after she started working at the lab. “I was in the Mission Operations Center when the photographs of Mercury’s surface began to come down and I was just awed by the fact that no human being anywhere had ever seen what I was looking at right then,” she says. “In that moment I completely understood what drives us to explore our world and the cosmos.”
In the Mission Operations Center during orbit insertion, Moessner spent most of her time getting software ready for post-maneuver inputs and then waiting for the maneuver to begin. “My confidence was pretty high that everything would go as planned, but there was always that little nervous thought in back of my head that Murphy’s Law would strike,” she says. Unlike the second flyby, MOI gave her a definite sense of accomplishment because she had a much more substantial role in the maneuver’s design as well as relief that everything had run smoothly.
Now that MESSENGER has entered orbit about Mercury, there are several more products that the mission design team needs to deliver to other teams — many of them on a weekly basis. In addition, the pace of maneuvers has increased so that her team must produce designs every six weeks instead of once a year or so. “Prior to orbit there were also more opportunities to make the trajectory and maneuvers more efficient by slightly tweaking a planetary flyby or maneuver location,” she says. “Now that we are in orbit we don’t have that sort of leverage anymore.”
In addition to MESSENGER design work, Moessner has had the chance to perform some mission design work for a few proposals and internal research and development projects at APL, but unlike MESSENGER, these other projects have all been at pre-launch phases.
When not being a part of interplanetary exploration, Moessner enjoys camping, hiking, martial arts, reading, and the occasional sewing or arts and crafts project. “Although,” she adds, “ever since my son, Patrick, was born in July 2010, my husband, Mike, and I haven’t had much time for anything other than keeping up with the little guy.”
Moessner, her husband and their son live in Bel Air, Md.
By Lydia Zuraw