NASA's New Horizons probe flew past Pluto two years ago, documenting our Solar System's former ninth planet, but the mission always intended to go farther.
Though New Horizons launched in 2006, NASA and San-Antonio based Southwest Research Institute didn't know where the probe would explore after its primary mission to Pluto.
In 2014, scientists settled on Kuiper belt asteroid MU69. Only now are they figuring out exactly the best route and how big the icy rock is.
"The estimates range from as small as five kilometers in diameter to potentially 50-60 kilometers in diameter," says Alejandro Soto with Southwest Research's Boulder, CO office.
Soto is a planetary scientist, but in the wee hours of Monday morning, he was just one more guy staring into the sky from Argentina's Patagonia region. His and 24 others telescopes were paramount in gathering the best data possible for figuring out where MU69 is and where it's going to be.
"We're staring at this star, and we have a prediction of the moment when this icy rock --super distant from here -- is going to pass in front of the star at this very precise moment," Soto says.
It's called an occultation. Based on existing data, scientists predicted stars that MU69 would pass in front of, so they could gather information about it and its path. They knew where to look at and what part of Earth it would be observable from.
Over the past two months they have done three occultations, sending as many as 60 people to regions from South Africa to last night's site, outside the city of Comodoro Rivadavia. All to grab 200 milliseconds of observation. With that they hope they can fine tune their approach route for an asteroid more than 50 times farther away than the distance from the Earth to the Sun.
The week prior, NASA flew a specially designed plane over the South Pacific in order to observe MU69's shadow.
Monday morning was the final chance scientists had to collect data to adjust their course.
Soto says it went well, which was a relief after a week of battling the wind.
"Turns out this is one of the windiest cities in the world, which is not good if you want stable observations of stars," says Soto, but 23 of 25 telescopes were able to collect data.