Alumni ProfileTom Strikwerda '71
To Pluto ... and beyond

Tom StrikwerdaNear Baltimore, Md., a team of engineers under the supervision of Tom Strikwerda '71 is watching and listening to a small satellite named MESSENGER (Mercury Surface, Space Environment, Geochemistry and Ranging) as it takes an elliptical 5 billion-mile route to the planet Mercury. Before its launch in August 2004, they had calculated the precise speed and trajectory to send the spacecraft into orbit around the solar system's hottest, fastest planet. Now, given the actual flight path, the pull of other planets and the effects of solar radiation, they are carefully refining their calculations.

“Those calculations and the course correction maneuvers we make based on them determine whether MESSENGER will crash into Mercury, miss it altogether or enter orbit on March 18, 2011, at exactly 200 kilometers altitude,” Strikwerda said.

With a PhD in astronomy and a postdoctoral fellowship in astronautical engineering, Strikwerda is an engineer at the Applied Physics Lab (APL) at Johns Hopkins University. The lab contracts with NASA and the Department of Defense to design, build and operate spacecraft for various purposes. For the past 11 of his 26 years at APL, Strikwerda has supervised the mission design and guidance and control systems teams, tasked with determining a spacecraft's best route to its destination and how to guide it there. Besides MESSENGER, Strikwerda's team is also monitoring NASA's “New Horizons” spacecraft, now plunging through deep space toward Pluto with an arrival date of July 14, 2015.

Before becoming supervisor of the mission design and guidance and control systems teams, Strikwerda worked as the team's lead engineer on a number of projects, including a satellite that was part of the Defense Department's strategic defense, or “Star Wars,” initiative. Now, as a supervisor, Strikwerda says he “gets to dabble in all the projects. But I miss the rush you get when, as lead engineer on a project, it's your system up there.”

He's still in on the aspect of space missions that has appealed to him since he began at the lab, though. “Some people have the image that spacecraft scientists and engineers just sit alone at a console typing in commands. It's nothing like that. It's a multidisciplinary endeavor that requires many teams to work together, all precisely choreographed. It's amazing!”

An important part of Strikwerda's job is to ensure the choreography comes off. “We supervisors have to make sure everyone is communicating with each other. In fact, when I look for new hires, it's not always the smartest person who gets the job. I'm looking for the person who's going to communicate and fit well with the team.”

Though carefully choreographed and controlled, each mission surprises its designers and operators, Strikwerda said. “There's always something we learn. That's what makes this work so much fun.”

As for future prospects for his team, he said, “My concern is the balance between how much NASA spends on human exploratory missions versus the robotic missions that we, in our lab, do. The cost differential between what it takes to send a robotic spacecraft to Mercury and what it takes to send a human to the moon is enormous. I don't have the answer by any means, but robotics, in my view, can give us much more science return for the dollar. And there's so much out there to learn!”


To learn more about the MESSENGER or New Horizons missions, see or