As New Horizons probe approaches Pluto, Eldersburg resident rejoices

As New Horizons probe approaches Pluto, Eldersburg resident rejoices
Sarah Bucior is a flight controller for the New Horizons mission. (KEN KOONSSTAFF PHOTO, Carroll County Times)

It's about 3 billion miles from Earth to Pluto. It took NASA's New Horizons spacecraft nine years to traverse that vast distance — for Eldersburg resident Sarah Bucior, a single afternoon seemed to stretch almost as long.

The mission flight controller had been up at 6 a.m. to see the last photo of Pluto the spacecraft sent back to Earth before falling silent in order to concentrate on taking photos during it's flyby of the dwarf planet.


The probe would not signal Earth again until 9 p.m., when Bucior and the rest of the team would learn whether the near-decade-long mission was a success.

"I am kind of in a holding pattern. My shift ends at 4 p.m., but none of us want to leave before tonight," she said at about 2:30 p.m. Tuesday afternoon. "I was going to take a nap, but I don't think it is worth it now."

Speeding far faster than a bullet at more than 30,000 mph, the New Horizons spacecraft passed within 7,800 miles of Pluto at about 7:49 a.m. Tuesday morning, its cameras and other instruments trained on the dwarf planet's surface and those of its five moons: Charon, Styx, Nix, Kerbos and Hydra. It would not be until hours later that the craft would signal Earth to let the mission team know everything went OK, and it would take 4.5 hours for that signal to reach Bucior and her colleagues.

"For the flight ops team, once we get that phone call home, it's a relief," she said. "We go back to what we were doing, making sure data is coming down, sending commands up to the spacecraft and keeping doing what we've been doing for nine years."

The images taken during the flyby will begin to be transmitted back to Earth in a compressed form, to be processed and released to the public by later Wednesday, Bucior said, but with the vast distance involved, it will take more than a year for the science team to receive the full compliment of high-resolution data from the Pluto encounter.

The New Horizons mission is managed from the Johns Hopkins Applied Physics Lab in Laurel. As a mission flight controller, Bucior's job is to make sure the spacecraft is safe, healthy and communicating normally. If something is wrong, it's up to her to alert the specialists who can solve the problem, and it's up to her to transmit their solution to the spacecraft.

"We don't know everything about the propulsion system, but we know a little bit about everything," Bucior said. "We know a little about ground control, a little about telemetry; we know a bit about everything so we can tell the team if something is wrong."

Sending corrections to a spacecraft the size of a baby grand piano hurtling away from you in space is not like sending a text message: Even at the speed of light, the round trip for a message is nine hours. With such a long communications gap, Bucior said New Horizons was designed to be resilient.

"Our entire spacecraft, except for the power source, which is nuclear power, is completely redundant," she said. "We have two computers, two guidance controls — two of everything. And we have this great software system that takes care of itself."

That software, the hardware redundancies and the nerves of the mission flight controllers were put to the test over the Fourth of July weekend, when the spacecraft unexpectedly shut down.

"Early that Saturday morning, on the Fourth of July, I came in and sent the command up that discovered the problem — I got an email that evening that said I should call in while I was at the fireworks," she said. "My next shift was Sunday, so I worked the whole next day doing the recovery. We only had until Tuesday morning until the encounter sequence needed to start."

The encounter sequence was the preset list of operations New Horizons would follow during its high-speed flyby of Pluto, and Bucior said the team worked through the weekend to get the craft back to ready status. It took 27 hours.

"The primary computer got overloaded, basically, and it did exactly what it was supposed to do — it shut itself down, switched over to the backup, and pointed the spacecraft back to Earth and waited to hear from us," Bucior said.

When the New Horizons probe was launched in early 2006, it was the fastest spacecraft ever launched into space, according to NASA, reaching the planet Jupiter by 2007 and using the gas giant's massive gravity to sling-shot toward Pluto at even greater velocity, all while grabbing some stunning images of the Jovian system.


Bucior joined the New Horizons team in 2008 when it was still close enough that communications took only two hours each way between the problem and earthly antennas. During its long haul toward Pluto, the communication lag became greater, but the need to check in became less frequent.

"For most of our cruise out to Pluto, we spent most of each year in hibernation. We usually wake New Horizons up for two to three months and it's called an annual check-out," Bucior said. "We wake the spacecraft up, check all the instruments, run it through its paces and then put it back to sleep again."

While the spacecraft was asleep, flight controllers only checked its progress once a month, so many flight controllers, Bucior included, would spend time working on other projects.

"In between, I have worked … on another launch and had two babies, but I always remained part-time on the [New Horizons] project because I always wanted to be here for this part," she said. "It's exciting for my kids, who are 6 and 4 and they know that mommy has a mission and they know about space, and I go to the kindergarten class and talk to the kids about space."

After New Horizons passes the Pluto system, the probe might be directed to explore farther into the Kuiper belt, according to Bucior. But before that mission can take place, New Horizons has to safely traverse the Pluto system.

At 8:54 p.m. Tuesday, NASA TV broadcast live from the New Horizons missions operations center as the team received the phone call from the spacecraft. It had come through with flying colors, and the team erupted into applause.

For Bucior, it made the wait of nine years, and many hours, completely worth it.

"I am really excited to be here, and there are a lot of people here that are excited about us," she said. "I knew it would be exciting, but it's been a long time, and sometimes you lose sight of what's in the seven year future."