Monthly Archives: August 2017

Kuiper Belt, New Horizons mission

The Shadow of 2014 MU69 Tells a Tantalizing Tale

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Is MU69 A Double-lobed World?

In just under a year and a half, the New Horizons spacecraft will pass by a distant Kuiper Belt Object called 2014 MU69.

No one was quite sure what shape this tiny world is, and the mission scientists needed to know. So, they put together an ingenious plan.
Earth-based observations gave the New Horizons scientists a tantalizing look by watching what’s called a “stellar occultation”. They watched as MU69 passed in front of a star on July 17, 2017,  watching a little eclipse-type event more accurately called an “occultation”. This was after a first occultation observation mission on June 3, 2017, was set up for observers in South Africa and Argentina, and a crew aboard the airborne Strategic Observatory for Infrared Astronomy (SOFIA) watched the event on July 10. The observations, plus high-resolution scans using Hubble Space Telescope (which looked for debris in the area right around MU69) gave clues to this little world’s shape.

Unlike eclipses, which can last for minutes, the MU69 occultations lasted only a few seconds. That was precious little time to gather information about the size and shape of the object. Scattering observers along pre-selected sites from where the event could be seen (and imaged) gave the New Horizons team much more data. That gave a better feel for what MU69’s shape must be.

What Does 2014 MU69 Look Like?

MU69
The Kuiper Belt object 2014 MU69 may be a double-lobed object or possibly a more spherical one with a chunk missing. The New Horizons spacecraft will fly by this object in January 2019. Courtesy JHU/APL/SWRI/Alex Parker

It turns out 2014 MU69 is pretty weird-looking, at least from our great distance from it. The measurements reveal what looks like a double-lobed object or maybe a tiny world with a big bite taken out of it. It’s not a perfectly round place. It’s also possible that 2014 MU69 could be two objects orbiting very close to (or even touching) one another — too close to be distinguished from each other. Right now, MU69 is more than 6.5 billion kilometers from Earth and its tiny size (about 30 km) makes it difficult to get a final answer about that oddball shape. Still, it’s a pretty amazing feat to use occultations and high-resolution measurements to get this far 17 months ahead of the flyby. It will be interesting to see how it all pans out as the spacecraft gets closer and returns better images. That won’t happen until later in 2018.

Threading the Needle at MU69

Not only is this information pretty cool to know for its own sake, but the observations made this summer also help the New Horizons mission planners do a more accurate job of targeting the flyby. That’s set for January 1, 2019. The closer they can get for a safe flyby, the better the science will be. However, it’s like threading an incredibly tiny needle. Obviously, it’s good to know if there’s a debris field orbiting along with 2014 MU69. We don’t want to see New Horizons whack into something that could be avoided.

Mission Science

The science to be gained at MU69 itself is incredibly important. However, the upcoming flyby will also tell us a lot about its environment. The Kuiper Belt, the third “regime” of the solar system, contains many objects that range in size from fairly small to some larger than Pluto. This one is among the smaller worldlets out there. The short-period comets also come from this region, and Pluto is among its more famous planetary bodies. MU69 lies on the way “out” of the solar system along the New Horizons trajectory from Pluto (which it explored on a quick flyby in July 2015). The mission is essentially sampling KBOs as it goes. From its data, we may see more than just this oddball world; if there’s debris, then that will also give clues to the population of objects in the neighborhood.

Questions about 2014 MU69

I can imagine all kinds of questions to be answered by the next flyby, all aimed at figuring out just how MU69 (and any companions) formed. Is nearby debris the result of an ancient collision? Or, could it be left over from MU69’s formation (which itself could be the result of a collision)? What’s it all made of? Are they mostly rocks? Mostly ice? A mix? If so, which ices are predominant out there? What do the surfaces look like? These are all questions to be answered with images and data from the flyby. New Horizons is our “forward scout”, exploring the territory ahead and giving ever-more-detailed answers about the outer frontiers of the solar system.

Addendum:  Check out the comments below, where artist Adolph Schaller shares his interpretation of the occultation data for MU69. He does a remarkable job of extrapolating the possible shape of this object.

astronomy, voyager

Voyager: Exploring the Realm of the Giants

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The Voyager Mission

the Voyager spacecraft
The Voyager spacecraft twins are still working and still returning data, 40 years after their launch. Courtesy NASA/JPL-CalTech

I’ve been thinking about the Voyager mission lately. Last week marked the 40th anniversary of the launch of these two hardy spacecraft to explore the gas giants of the solar system. They weren’t the first spacecraft to get “out there”. That honor belongs to the Pioneer 10 and Pioneer 11 spacecraft that preceded them. Those two explored Jupiter and Saturn, whetting our appetites for more.

The Voyager 2 mission is the first one I ever covered as a science writer, so it holds a very special place in my memories. I flew out to JPL in August of 1981 to watch the images and data come flowing back as the spacecraft whizzed past Saturn. I returned two more times to cover the flybys of Uranus and Neptune in 1986 and 1989, respectively. Those were seminal experiences for me and led me directly back to school to study more science.

Voyager’s Achievements

For the scientists involved, the Voyager mission is their life’s work. The data the spacecraft returned are still contributing to our knowledge of the gas giant planets. These flagship missions inspired others to follow. The Cassini spacecraft is currently ending its mission to Saturn. The Galileo mission went to Jupiter and did in-depth studies there. The New Horizons spacecraft to Pluto broke many records and is well on its way to the next target. Finally, the Juno mission that arrived at Jupiter last year is sending back even better looks at the largest planet and is winding up its last orbits this year. Planetary science has never had it so good, and I hope it gets even better!

Voyager’s Achievements

voyager targets
The planets visited by the Voyager spacecraft; Voyager 1 flew past Jupiter and Saturn; Voyager 2 flew past all four gas giant planets. Courtesy NASA/JPL

Both Voyager spacecraft are still working, still sending back data from just beyond our solar system’s heliospheric boundary. Voyager 1 is the first to actually leave the heliosphere behind and is headed to deep space. Voyager 2 is not far behind. And, incredibly, they’re both still working pretty well and will continue to do so until their energy runs low within the next decade.

Along the way out toward the stars, they showed flew past four gas giants, sending back glorious images of planets, moons, rings, and massive atmospheres. They revealed dozens of new moons and provided incredibly detailed close-up looks at cratered surfaces, turbulent clouds, lightning storms, aurorae, and much more.

Personal Reflections on Voyager

I have to admit that when I first asked if I could go cover the Voyager 2/Saturn flyby for the Denver Post, I was motivated more by the chance to visit the world-famous JPL and hang with scientists than I was by the chance to learn the science. By that, I mean I already knew that there’d be cool science. But, the rare chance to meet and mingle with people such as Carl Sagan and Ed Stone and other Voyager scientists (including a few from Colorado who I knew from my undergraduate days there), was just too much to pass up. And so, off I went and spent several days absolutely immersed in planetary science. I wrote a couple of stories that I had to phone into the copy desk at the paper, and in the process, gained a nickname I still have: Spacewriter. I was also called “The Planet Lady” by the copy desk folk. All because I had the audacity to ask if I could go cover something bigger than anything I’d imagined. And, my editor, an amiable guy named Bob, told me to be good and do good. So, I did. And, I was dazzled by the science, the pictures, the sights and sounds of the flyby, and the absolute dedication of the science teams doing the work.

I’ve been back to JPL many times since then, covering various missions. I’ve also covered a few at the Kennedy Space Center and Johns Hopkins Applied Physics Lab (for New Horizons). Make no mistake about it: they’ve all been exciting. Perhaps because it was my first, Voyager 2 at Saturn will always stand out in my mind slightly above the rest — not because the others were bad, but because it opened doors for me. It taught me a lot about the planets, but also about the science teams and the science itself. I’ll always want more.

Want to see more about the Voyage achievements? Check out JPL’s story about this set of missions.