Today in space exploration…
January 19, 2006, saw the launch of the New Horizons probe. It was the first probe in a program called New Frontiers, that was designed to explore various aspects of the outer solar system. New Horizons is also among the fastest artificial objects ever made, and is the fifth human made object to achieve escape velocity from the solar system.
The primary objective for New Horizons was the enigmatic dwarf planet, Pluto, and it’s frozen companion, Charon. In this respect, New Horizons picked up where the Voyager program left off. Pluto and other objects beyond the orbit of Neptune weren’t included in the Voyager program, though I remember hopeful talk on this point. The Voyager probes made frequent use of gravity assisted slingshot maneuvers around the outer planets to reach their next target. It’s likely that Pluto just wasn’t in a location where a slingshot off one of the ice giants (Uranus or Neptune) would be effective. So, Pluto ultimately had to wait for a dedicated mission.
New Horizons was launched at 2:00pm EST (19:00 UTC) from Cape Canaveral, on a rapid trajectory toward the outer solar system. It cleared the Earth-Moon system a mere nine hours after launch. Its first stop was Jupiter, where it received a gravity assisted speed boost from the gas giant, to hasten its journey to the outer solar system.
New Horizons completed it’s slingshot maneuver around Jupiter on September 4, 2006. While in the Jovian system, the probe took several readings and photographs of Jupiter and its moons, mostly to answer questions raised by previous missions. At the speed it was going it couldn’t do a lot of research, but since it was in the area, why not take a quick look?
After barnstorming Jupiter, the probe went into sleep mode for the bulk of its journey. On January 4 of 2015, the first clear images of Pluto were being relayed, and the probe was fully awakened by mission control. At the same time, New Horizons was receiving navigational support from the Hubble telescope back at Earth. Pluto was found to have not one, but a total of five moons. All of them are very small, and along with Pluto they perform a complex square dance around one another. I suspect navigating through such a place would be a nightmare!
The direct flyby of Pluto and its companions occurred in July of 2015, and provided not only excellent photographs of the distant world, but extensive information about atmosphere and geology. Scientists were also provided with insights into the early ages of the solar system, and the nature of the interstellar void. NASA scientists considered all of the primary and secondary objectives, and most of the tertiary objectives, of the Pluto flyby to be a success. The information gathered by New Horizons is still being analyzed today, almost ten year later.
There was a contingency for additional targets for New Horizons, if circumstances permitted. The Kuiper belt is the collective name for a torrid (doughnut) shaped cloud of materials orbiting beyond the orbit of Neptune. There was hope that New Horizons could do a flyby of one of these objects, after visiting Pluto. Again with some help from the Hubble telescope, such a target was located. The Kuiper belt object 486958-Arrokoth was visited by New Horizons on January 1 of 2019, providing even more insight into the nature of the interstellar void, and the various materials within the Kuiper belt.
Controllers predict that the onboard power cells will allow New Horizons to continue operating until the early 2030’s, so an additional flyby of a Kuiper belt object may be possible. Both the Hubble telescope and the Webb telescope have periodically searched for a suitable and reachable targets. But at this writing, such a target hasn’t been found.
Currently, the craft is collecting data on deep space radiation, heliophysical data, and other characteristics of the Kuiper belt. It has also been conducting long-range observations of two nearby stars, Proxima Centauri and Wolf 359. Most of its instruments are currently in sleep mode, but if a suitable flyby target is located, they can be restarted. New Horizons will exit the Kuiper belt some time in 2028. At that point it will join Pioneer 10, Pioneer 11, Voyager 1 and Voyager 2 in the interstellar void. It should be noted that the two Voyager probes still occasionally send back data, decades after they were expected to shut down. We may continue to hear from New Horizons for many years to come.
Several follow-up missions for the exploration of Pluto have been suggested. While such a mission has not yet been scheduled, the most popular plan under consideration is modeled on the highly successful Cassini-Huygens mission that visited Saturn. It involves a “mother probe” settling into an orbit around Pluto or Charon, and then use the gravity of those two bodies to bounce around the planetoid cluster visiting points of interest. Small drones, or even a lander, would be dispatched along the way.
I suspect distant Pluto and it’s posse of tiny moons still have many stories to tell.
All images are from Wikipedia and Wikipedia Commons.