NASA's Mission to Pluto and the Kuiper Belt
May 23, 2019
The first published results from New Horizons' flyby of 2014 MU69 appeared May 17 in the journal Science.
Image credit: AAAS/Science
The New Horizons spacecraft and its seven scientific instruments are performing well, with no problems. New Horizons is now more than 100 million miles past our first KBO flyby target, 2014 MU69 (nicknamed Ultima Thule, or UT), and plowing deeper into the Kuiper Belt every day. Estimates are that we won't leave the Kuiper Belt for eight more years.
Meanwhile, after almost four months of intensive data downlink to Earth, about 25% of all the bits collected during the flyby are now on the ground. More data comes back every week.
Following the intense activity of the flyby over the holidays and New Year's, the New Horizons science team buckled down to begin the hard work of data reductions and analysis. By late February, we had collected dozens of discoveries and a handful of mysteries into an omnibus (9,000-word) technical paper that we submitted for peer review – in effect, a certification of the results – to the prestigious international journal Science, of the American Association for the Advancement of Science (AAAS). Amazingly, that paper completed peer review in early April, less than 100 days after the flyby, and was published on May 17 – gracing the cover.
As I told our famous science team collaborator and Queen rock star, Dr. Brian May, "we just made the cover of the Rolling Stone — for nerds!" In fact, the entire article was published open access, so anyone, even those who aren't AAAS members or Science subscribers can read it; just click here to read it yourself!
But that's only the start for our analysis and publication plans from the flyby. Already four more papers are in preparation for another issue of Science that will appear late this year, and a special New Horizons issue of the planetary science journal Icarus is set for publication in 2020.
On the bird itself, in March, New Horizons paused its data downlink to make observations of two passing KBOs, including our alternate flyby target and the closest KBO we will approach (other than MU69) in this first extended mission. That KBO is called 2014 PN70; results from those observations should be forthcoming once all the data are on the ground. Also in those March observations was a look back at Pluto to study its hazy atmosphere — from over a billion miles away.
Initial geomorphological map of the KBO 2014 MU69 based on New Horizons flyby imagery.
Image credit: NASA/Johns Hopkins Applied Physics Laboratory/Southwest Research Institute
And while our team is downloading and analyzing data, and making new Kuiper Belt observations, we're also planning for our expected 2020 proposal to NASA for a second extended mission beginning in 2021. Most of that proposal planning begins this fall, but a couple of noteworthy activities are already helping us prepare for that.
One was a hard look at the amount of unusable propellant that will be trapped in the spacecraft's propellant lines at the end of mission. Working with the New Horizons propulsion system manufacturer Aerojet Rocketdyne, our propulsion engineering lead at the Johns Hopkins Applied Physics Laboratory, Stewart Bushman, found that our previous estimates of this quantity had been overly conservative – and that we could "gain" back about a kilogram of fuel to use in future extended missions. You might recall that we gained back another kilogram after the flyby because we didn't spend all the propellant we'd budgeted to refine our course to UT. Two kilograms may not sound like much, but that's enough to run an active extended mission for more than two additional years, or about what it took to execute the UT flyby. So those savings are big news to us and brighten our expectations for important science we can accomplish with the next extended mission proposal.
In addition, we also found that a simple software change to the Long Range Reconnaissance Imager (LORRI), which we use for most distant KBO observations and searches, will allow the instrument to downlink data more efficiently and improve its observations of KBOs in the distance. We have already implemented the software change on our testing simulator, and will upload to the spacecraft this summer. We then plan to begin using it for new KBO observations beginning around Sept. 1.
This sequence of images from the Long Range Reconnaissance Imager (LORRI) shows UT from behind as New Horizons departed shortly after flyby.
What else is coming up for New Horizons?
With all of the planning these activities require, it's easy to see how we on the New Horizons team are very busy turning 1's and 0's into discoveries and other kinds of results.
And that's my report for now. I plan to write again in the late summer. Meanwhile, I hope you'll keep on exploring — just as we do!
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