When SOFIA took off from a runway at NASA's Dryden Aircraft Operations Facility in Palmdale, Calif., on the evening of May 25, the dozens of researchers behind the mission likely felt a few first-time jitters.

But while the flight was a major milestone in infrared astronomy, most of its elements had already been rehearsed -- many times -- on the ground.

For the scientists and engineers on the flight and the support staff on the ground, the week before the flight is dedicated to line ops (line operations) -- long nighttime sessions of testing and retesting systems, observing and collecting data on target objects, and getting to know each other. All from inside the modified 747 -- without leaving the tarmac.

"The ground rule is, you never do anything on the plane that you can do in the lab; you never do anything in the line op that you can do in the hangar; and never do anything on the flight that you can do on the line op," said Cornell astronomer Terry Herter, principal investigator for FORCAST, the Cornell-built infrared camera that will take the first images.

In other words: Make the best possible use of every minute of the six- to seven-hour flight.

The line ops begin at sunset. Once researchers have chosen a target object -- one that can be seen in the infrared from the ground -- a crew positions the plane with the telescope pointing toward the object's projected path.

While they wait for the object to enter the telescope's viewing range, team members prepare their instruments and review procedures. The first target is Mars -- the researchers have half an hour to collect data before it moves out of the telescope's range.

When Mars comes into view, tracker operator Allan Meyer sets a timer to 30 minutes and places it next to Herter's computer. And the data collection begins.

At a console facing the telescope, project scientist Joe Adams operates the camera and relays information to Herter. Data from the instrument appears on Herter's computer, where he analyzes it quickly and directs Adams and the telescope operator on the next steps. Using two guider cameras on the telescope, the telescope operator tracks Mars and coordinates with Adams.

On the flight, team members used headsets and communicated on selected channels. The audio system is not quite ready during line ops, though, so commands are called back and forth. For the first hour or so, there is confusion -- but after that, the team settles into a rhythm.

"When you're into it, you don't even remember you're on an airplane," Herter said later.

When the first image of Mars appears on computer screens, there is a quick moment for cheers. Then it's back to work. They perform a series of maneuvers, called chopping and nodding, to measure background radiation, which is then subtracted from the radiation of the target object.

Then, the timer beeps, and Mars is out of range. The team prepares for the next object, a bright star that will pass through in about an hour.

The process continues: tracking, imaging, chopping, nodding. Adams has prepared a checklist of tasks for the first night, and by 2 a.m. the last star has passed for the night and the checklist is complete.

Over dinner the next day, Herter said seeing that first image was a thrill -- but only a brief one. "There is a little bit of adrenaline," he said. "But it's all about getting the next thing done. You really focus on the moment ... on doing what you've got to do. This is what we've been prepping for.

"You want to be efficient about doing things, and do the best job you can," he said. "And the higher the hurdle, the better it feels when you succeed."