Carrying Buckeye technology, New Horizons probe zeroes in on mysterious Ultima Thule after Pluto success
The scheduled New Year’s flyby of a mysterious Kuiper Belt object (or objects) known as Ultima Thule follows up on the mission’s first act, which hit a climax three years ago with a history-making flyby of Pluto.
The probe’s most prominent feature was partially designed, constructed and tested at The Ohio State University ElectroScience Laboratory (ESL) beginning in 2002.
Ohio State electrical and computer engineering alumni Ron Schulze and Willie Theunissen, now distinguished engineers with the Johns Hopkins Applied Physics Laboratory (JHAPL) and Lockheed Martin Space Systems, respectively, both played an integral part in the New Horizons mission.
As JHAPL lead engineer for the high gain antenna dish project, Schulze coordinated its design and worked for months with Theunissen, as well as Ohio State faculty and staff at ESL’s anechoic chamber. Considered the largest university-owned anechoic chamber worldwide, ESL’s facility is 60 feet by 40 feet by 20 feet and operates from 400 MHz up to 100 GHz.
High gain antennas provide focused and narrow radio wave beam widths, allowing for more precise targeting of radio signals. The antenna, created and designed in a partnership between the Johns Hopkins Applied Physics Laboratory and Ohio State, remains one of seven instruments on the probe currently gathering scientific information being transmitted back to Earth. Without the dish, NASA could not communicate or receive signals from New Horizons.
ESL Research Scientist Teh-Hong Lee put the project in some perspective.
“Because a spacecraft is spinning while it is traveling, they need to maintain the accuracy of pointing the antenna to the Earth. I was told they required the accuracy of pointing to the Earth at .001 degrees. It’s amazing that they can achieve that,” Lee said. “We were also very excited that our antenna facility could accommodate their need.”
Launched in 2006, New Horizons was never meant to be a one-shot deal. Even before the Pluto flyby, mission managers used the Hubble Space Telescope to identify its next quarry, a billion miles farther out in the Kuiper Belt. Now it’s crunch time for New Horizons principal investigator Alan Stern and his team.
“This flyby is a lot harder than Pluto,” Stern said. “Ultima is tiny, and faint, much harder to navigate on. … Another difficulty, or challenge, really, is that we’re farther away, and that means communication times are longer. Bit rates are lower.”
“It’s a one-shot, ‘get it right or go home’ deal, because there’s no U-turn to go back and have a re-do. … You have to plan every chess move with the spacecraft more carefully,” said Stern, a planetary scientist at the Southwest Research Institute.
Dozens of scientists and engineers are due to converge on Johns Hopkins University’s Applied Physics Laboratory in Maryland to get set for the flyby, which is scheduled to come closest to Ultima Thule at 12:33 a.m. ET Jan. 1 (9:33 p.m. PT Dec. 31).
If all goes according to plan, New Horizons will pass by Ultima at a distance of 2,200 miles, or less than a third of the distance used for the Pluto flyby, But the mission team is on the watch for any mini-moons that would force a shift to a safer, more distant trajectory.
During a recent rehearsal, the team had to cope with a worst-case scenario in which New Horizons spotted 11 satellites in Ultima’s vicinity. “It was just flying into a hornet’s nest,” Stern recalled.
Neither Stern nor anyone else knows exactly what New Horizons will actually see.
“We don’t know what a primordial, ancient, perfectly preserved object like Ultima is, because no one’s ever been to something like this,” Stern explained. “It’s terra incognita. It is pure exploration. We’ll just see what it’s all about — if it’s got rings, if it’s got a swarm of satellites.”
The Hubble imagery suggests that Ultima Thule (also known as 2014 MU69) measures roughly 20 miles wide — and might consist of two or more mutually orbiting objects. The dearth of knowledge leaves plenty of room for surprises.
“Considering how much we knew about Pluto, and how much it astounded us, here we’re starting from complete scratch,” Stern said. “We barely know its size and its color. We can’t tell you anything about its composition or its atmosphere, or satellites, any of that. But we’re going to find out.”
To find out, the plutonium-powered New Horizons probe will employ the same suite of scientific instruments that worked so well to study Pluto and its moons more than three years earlier.
New Horizons’ long-range camera, known as LORRI, currently sees Ultima as a mere speck, but it should be able to make out its shape starting a few days before the flyby. During the closest phase of the encounter, LORRI could detect features as small as the boats floating on the lake in New York’s Central Park, Stern said.
New Horizons will make use of an ultraviolet imager called Alice and an infrared and visible-light imaging spectrometer called Ralph to characterize Ultima’s composition. A radio science experiment will take its temperature, and other instruments will analyze particles in Ultima’s cosmic neighborhood.
It’s likely to take months to send back all the data from the Ultima flyby, just as it did in the wake of 2015’s Pluto flyby. But eventually, Act Two of the New Horizons mission is expected to add to Act One’s already-substantial record of revelations about the icy worlds on the solar system’s edge.
Will there be an Act Three? Stern said he and his colleagues fully intend to ask NASA for another mission extension once Ultima is behind them.
He noted that at its current speed, New Horizons will be flying through the Kuiper Belt for almost a decade longer.
“We’re going to look for another flyby target, and we’re going to continue to observe Kuiper Belt objects with the telescopes on board,” he said. “If NASA approves that, there will be a third act.”
Article updated via Alan Boyle, GeekWire’s aerospace and science editor, which originally ran here.