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
Every Monday, the spacecraft team for the New Horizons mission “listens” for a signal from their fast-moving spacecraft. This grand-piano-sized probe is on its way to another object in the Kuiper Belt, called MU69. These beacons are important because they are the only signal the team gets while New Horizons is in hibernation. That means most (if not all) of its systems are powered down or in very limited-use mode. It conserves energy, equipment, and wear and tear on the electronics on the spacecraft while it’s en route to its next target.
Once the beacon is received, the team can get back to work on their planning. Alan Stern, PI of the team, usually tweets a “green beacon” announcement, letting the rest of the world know all is well. He described the beacon process in a “PI’s Perspective” blog entry in 2008.
What New Horizons Beacon Tones Mean
There are several beacon tones that New Horizons could send. Green is the best—it means that everything’s right on the nominal, that nothing is wrong with the sleeping spacecraft. It’s the equivalent of a text message saying, “Doing good, talk next week”. Anything not-green, particularly if it’s a red beacon tone, means there is (or could be) a problem. Luckily, throughout the mission, the green beacons outnumber the reddish ones. Right now the spacecraft is sleeping happily and will do so until mid-year 2018 when flyby operations start up again.
In the meantime, while New Horizons may be slumbering its way across the inner limits of the Kuiper Belt, its scientists and technical support staff members are busy rehearsing the next flyby, which will take place January 1, 2019. At that point, Earth and the spacecraft will be in the neighborhood of 43 astronomical units apart. That’s 6,432,708,440 kilometers, or 3,997,099,712 miles. Signals from the flyby will take six hours to get to Earth, making round-trip communication a 12-hour-long “conversation”.
New Horizons, Pluto, and Charon (artist’s concept). Courtesy NASA.
Our favorite outer solar system spacecraft is back on the job! New Horizons woke up from a five-month hibernation on its way to the distant world 2014 MU69. It’s still more than a year before the spacecraft gets to its next target, but it has a lot of work to do in the meantime. The current plan is to have it look at objects in the Kuiper Belt, measure the radiation environment it’s passing through, and check out the distribution and density of dust and gas. These are all “first-time” measurements of a regime of the solar system planetary scientists are eager to study.
New Horizons isn’t the first to transit the Kuiper Belt. The Voyagers and Pioneers passed through the same region and returned some data as their instruments would allow. Today, the Voyagers continue to measure the outermost region of the solar system and have crossed the heliospheric boundary to interstellar space. The Pioneers haven’t communicated back to Earth since 1995 and 2003, respectively. New Horizons is on a similar headlong trajectory out of the solar system and will return data for at least a couple of decades if all the instruments continue to work.
Mission Operations for New Horizons
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
Now that New Horizons is up and ready for a few months of work, the mission team will be outfitting it with new software packages and getting ready for a trajectory course correction. That will help refine its path toward its next target. This kind of “maintenance” is important. We want a healthy working spacecraft. By all accounts, New Horizons is functioning right on the nominal. Each week it has been sending back a little “I’m here” signal to let controllers know it’s doing okay. That beacon, speeding across more than 3.6 billion kilometers of space, is a signal from our planetary probe scout. It’s checking out the territory ahead and sending back critical updates along the way.
Next Up
In December, New Horizons slips into sleep again (still sending out its little signal). That happens December 9th. This time the spacecraft will snooze until June 4th. At that point, controllers will begin prepping it for the close flyby of 2014 MU69, which will take place on January 1, 2019. It’ll be another high-speed flyby, this time of a much smaller, dimmer world than Pluto. Nothing is known first-hand about any other Kuiper Belt world than Pluto and its moons. Pictures and data will really open a window into the kinds of worlds that populate this distant region of space. There are
There are many more M69-type worlds out there, and the next flyby is sure to provide some surprises about what they look like. There’s so much to learn about the Kuiper Belt — from the compositions of distant KBOs — to their origins and evolution. Sure, planetary scientists have a good general idea of how these places formed and changed over time, but actual images and data will help cement that understanding.
Exploring Distant Reaches
We’ve come a long way in our perception of the solar system since the first time Galileo trained a telescope on Jupiter in 1610. Today, the Kuiper Belt is the third regime of the solar system and it’s huge. Its inner boundary is at 30 astronomical units and stretched out to beyond 50 astronomical units. In linear measure, that’s a range of 20 astronomical units, covering a straight-line distance of 2,980,000,000 kilometers. Another way to think of it is about the distance between the Sun and planet Uranus. The Kuiper Belt surrounds the Sun at that far distance. It’s the vast wilderness of the solar system, compared to the better-explored areas of the terrestrial and gas giant planets. Who knows how many worlds are out there? For now, we have New Horizons to explore it, along with a cadre of Earth-based (and orbiting) telescopes. Stay tuned!
