BROOKTONDALE, N.Y. — Ann Harch woke up at 6:30 a.m. and sat in the makeshift office of her Maryland hotel room, a short distance from the Applied Physics Lab but a long way from her Brooktondale home.
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NASA commissioned the APL, which is based in Laurel, Maryland, to direct New Horizons, an un-manned mission to Pluto that launched in Jan. 2006.
As the sun rose, Harch pulled up a spreadsheet on her computer containing thousands of commands that had been uploaded to the New Horizons spacecraft.
It was the morning of July 14, and the vessel was preparing to travel closer than 8,000 miles to Pluto’s surface, the first mission ever to fly by the dwarf planet.
Harch watched the clock and imagined the spacecraft performing each scheduled motion: executing the commands she and her team had authored, rotating its instruments and snapping pictures of an unexplored landscape.
“I pretty much just watched the whole event in my mind,” said Harch, a former research specialist at Cornell University who has lived in Brooktondale for more than 20 years. “It was a beautiful thing. For two hours or so, I really felt like I was out there sitting on the spacecraft.”
How was the spacecraft able to perfectly capture its target? The answer is in hundreds of thousands of commands sent to the ship’s processors since its launch nine years ago, many written by Harch, the lead sequencer of science instruments for New Horizons since 2002.
A sequence is a large set of instructions that is uploaded to the vessel, telling it what direction to face, where to point its camera and when to take pictures, among other things. In an eleven-day period that contained the Pluto flyby, for example, the spacecraft was carrying out a sequence that included 30,000 individual commands.
“I liken our job sometimes to a videogame, where you have to work within the constraints of the spacecraft itself,” said Harch. “But the spacecraft costs half a billion dollars and the encounter is 3 billion miles away, so it’s a little bit more scary.”
Harch was raised in Irvine, Calif., and graduated from UCLA with a degree in geology. Her resume is full of various outer space endeavours, beginning immediately after college when she was hired to sequence for the Voyager 2 team, a mission that flew a spacecraft by Uranus and later Neptune.
Also on her resume is the Galileo mission, which took the first pictures of an asteroid up close; the NEAR mission, which was the first time a spacecraft landed on an asteroid; MESSENGER, a spacecraft that flew by Venus twice and has been orbiting Mercury since 2011; and many others.
“They’re starting to add up, all the comets and planets,” said Harch. “I think I’m only missing Mars and Saturn. I have two more notches on my belt and I’ll have the whole family. I don’t think there’s any other sequencer who will have worked on all of them.”
Harch grew up in the heat of the Space Race, and she witnessed Americans landing on the moon before she turned 10. As a child, she loved Star Trek and dreamed of becoming an astronaut, but later thought she wouldn’t be able to handle the zero-gravity simulators. Growing up, her three brothers were science-oriented and she has always been fascinated by outer space.
In a male-dominated field, where, for example, women make up only 34 percent of full-time NASA employees, Harch noted that the New Horizons team had many women in high-profile positions. In fact, a team of five women, including Harch, actually wrote all of the commands for the science and pointing instruments.
“I didn’t see being a woman, ever, as an obstacle,” she said, although she did recall accounts from her friends and colleagues of condescension and upfront sexism by other men in their field.
Harch made it clear that while the mission was exciting, the final months leading up to the flyby were incredibly stressful. “Because of the high-visibility of this flyby — in terms of the media — and also just the great distance and the fact that we’re not going back there in our lifetime, it was a lot of pressure,” said Harch.
She recalled being at a Fourth of July party with a fellow New Horizons scientist 10 days before the encounter, when they received a notification of an emergency meeting to discuss an anomaly on board.
“You don’t want to hear that,” said Harch. “It was about the worst thing that you want to have happen a week before a flyby that you’ve waited nine and a half years for.”
Because NASA keeps the specifics of its missions under tight wraps, Harch and her colleague couldn’t even explain why they had to abandon the party early. “We just said, ‘Oh, we have to go,’” she recalled, laughing.
It turned out that the spacecraft’s processors had overloaded with information, forcing it to default to a “safe mode.” Harch said the engineers labored to get the spacecraft back on track, some not sleeping for 50 hours, and were ultimately successful.
In the final week, as the spacecraft approached Pluto, Harch and other sequencers began to dread that the cameras would miss the planet, leaving the team with pictures of empty space. “You think about all the black sky that you could be pointed at instead of exactly where you’re supposed to be, and that makes it a little bit terrifying,” said Harch.
The sequencing team, made up of only four full-time sequencers, proposed an update in the final week, but the New Horizons scientists voted against uploading it, worried that any change to the delicate code could have an unexpected, adverse effect on the spacecraft.
At that point, the flyby was out of Harch’s hands for the first time since the mission began, and tortuous anticipation set in: “It was a very long time to wait for an event that took place on one day, 3 billion miles away, with a sequence that was on board and executing that you couldn’t touch anymore.”
At 7:48 a.m. EDT, the spacecraft reached its closest point to Pluto, and the next day about 10 photographs were released of the dwarf planet. No empty space. No blacked-out pictures.
“It’s still settling in that it most likely worked,” said Harch, who added that most of the high-quality images will be received by the lab in September.
As for her next quest, Harch has more than a few ideas, most of which are under tight wraps.
Although she loves space, Harch is also looking forward to focusing on terrestial matters for the first time in a while, like enjoying summer at her Brooktondale home overlooking the gorge. She said the worst part of traveling was missing summer in Ithaca. “It’s beautiful three months a year, maybe four,” Harch said of the area. “The rest of the time, you work very hard.”
Finally, Harch can relax and enjoy the relief that comes with successfully completing almost a decade of work. “Mostly, I want to play a lot of music and racquetball right now,” she said.
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