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Interstellar craft’s navigator looks at New Horizons — and even beyond
Dr Shyamkumar Bhaskaran

His work at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, is rather like solving a mathematics problem on which a friend too, is working, says Dr Shyamkumar Bhaskaran — “If both have the same answer, then that is good enough.”

Dr Bhaskaran leads an independent navigation team at JPL that supported the Applied Physics Laboratory (APL) of Johns Hopkins University on the New Horizons Mission. On New Year’s Day, the mission presented the world with a pixelated blob that was the first image of Ultima Thule, a tiny, icy, trans-Neptunian object in the Kuiper Belt, which became, as the New Horizons spacecraft sped past it, the farthest object ever visited by humankind.

Later images brought Ultima Thule into sharper focus — a snowman-like object that could, along with the countless other objects in the Kuiper Belt, hold the key to our understanding of the origin of the Solar System.

It was by a pleasant coincidence that the New Horizons rendezvous with Ultima Thule took place on the first day of the year. “The flyby is determined by orbital mechanics, we can’t change it by very much, the dynamics of the Solar System does play a role,” Dr Bhaskaran said in a Skype interview. “These flybys are very critical, all you’ve got is one shot to get it right and if you don’t, you have sort of lost the mission basically.”

Bhaskaran was born in Mumbai to parents who both worked at the Bhabha Atomic Research Centre, and his fascination with space began in 1968 with first glimpses of the Apollo Mission on television after his parents emigrated to the United States. Reading science fiction and watching the Star Trek series further fanned his interest in space exploration. He now supervises the Outer Planets Navigation Group at JPL that focuses on planets beyond Mars.

The independent navigation team on the New Horizons Mission compared notes with the APL team over whether the navigation was on track. “We do the same thing that the main navigation team does, we take tracking data from antennae, we process that data, figure out where the spacecraft is, and where it is going and we give that answer to the APL. We would get our solution, they would get their solution, and we would come together and say here is where we think we are going, they would say here is where we think we are going, and the consistency of results will provide the project confidence that the navigation is going properly.”

Two weeks before crunch time, Bhaskaran’s team flew to APL in Maryland where the two teams worked together in a large room, meeting every afternoon to exchange notes and thrash out differences. Something similar had happened during New Horizons’s Pluto flyby in 2015 — this mission was, in fact, easier than that one, he said.

“The Pluto flyby was difficult… the reasons might be too technical to explain, though… But it was an interesting dynamic both times between the two teams… Let’s just say in the end, for the critical final moments, everything sort of came together,” Dr Bhaskaran said.

On December 30 (Sunday), the team had its last opportunity to tweak anything it wanted, since sending a signal to the spacecraft took six hours one way. “By Monday, we were done and celebrating. APL had a New Year’s eve party, we drank champagne, and counted down to 2019.” A half hour later, the spacecraft made its closest approach to Ultima Thule. “Even though we could not confirm that everything went well since we had to wait six hours for the images, we celebrated by marking that as well!” he laughed.

And what had New Horizons been up to between the time it flew by Pluto and reached Ultima Thule?

“After the Pluto flyby, the spacecraft has been flying in a straight line out, beyond the Solar System, pretty much. It had been travelling to this object (Ultima Thule) ever since… We were tracking it, actively navigating it… it’s like the drive between New York and Oklahoma, there is a lot of nothing in between, but you still have to steer the car,” Dr Bhaskaran said.

Since the Ultima Thule flyby would take place at a very high speed — 52,000 km/hour — “we had to sequence everything ahead of time,” Dr Bhaskaran said. “We knew the object was roughly 30 km across, and the flyby would take place at a distance of 3,500 km. You have a good plan, a rough idea, on how you will plan and make observations.”

New Horizons is taking a bit of a break now, with the Sun between it and the Earth, cutting off communication. But it will eventually float on through the Solar System into interstellar space forever. “It is our emissary from Earth,” Dr Bhaskaran said. “It will eventually leave our Solar System.”

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