NASA’s New Horizons spacecraft has reached its closest point to Pluto, and now is heading … beyond.
After a decade-long journey through our solar system, New Horizons made its closest approach to Pluto Tuesday (July 14, 2015), about 7,750 miles above the surface – roughly the same distance from New York to Mumbai, India – making it the first-ever space mission to explore a world so far from Earth.
Per the plan, the spacecraft on Tuesday was in data-gathering mode and not in contact with flight controllers on Tuesday, but by mid-day Wednesday scientists were gathered again with press, talking about first results from the Pluto mission. The mountains likely formed no more than 100 million years ago — mere youngsters relative to the 4.56-billion-year age of the solar system — and may still be in the process of building, said Jeff Moore of New Horizons’ Geology, Geophysics and Imaging Team (GGI).
That suggests the close-up region, which covers less than one percent of Pluto’s surface, may still be geologically active today.
Moore and his colleagues base the youthful age estimate on the lack of craters in the image above. Like the rest of Pluto, this region would presumably have been pummeled by space debris for billions of years and would have once been heavily cratered — unless recent activity had given the region a facelift, erasing those pockmarks. Moore said in a statement from NASA:
This is one of the youngest surfaces we’ve ever seen in the solar system.
Unlike the icy moons of giant planets, Pluto cannot be heated by gravitational interactions with a much larger planetary body. Some other process must be generating the mountainous landscape. GGI deputy team leader John Spencer of the Southwest Research Institute in Boulder said:
This may cause us to rethink what powers geological activity on many other icy worlds.
The mountains are probably composed of Pluto’s water-ice “bedrock.”
Although methane and nitrogen ice covers much of the surface of Pluto, these materials are not strong enough to build the mountains. Instead, a stiffer material, most likely water-ice, created the peaks. Deputy GGI lead Bill McKinnon of Washington University, St. Louis, said:
At Pluto’s temperatures, water-ice behaves more like rock.
Earlier, scientists had waited for New Horizons to “phone home,” showing the craft had survived its passage through the Pluto system. The “call” came from a healthy New Horizons at 8:52 p.m. EDT on Tuesday evening (00:52 UTC Wednesday).
— NASA New Horizons (@NASANewHorizons) July 15, 2015
The Pluto story began early in the 20th century when young Clyde Tombaugh was tasked to look for Planet X, theorized to exist beyond the orbit of Neptune. He discovered a faint point of light that we now see as a complex and fascinating world.
John Grunsfeld is associate administrator for NASA’s Science Mission Directorate in Washington. He said:
Pluto was discovered just 85 years ago by a farmer’s son from Kansas, inspired by a visionary from Boston, using a telescope in Flagstaff, Arizona. Today, science takes a great leap observing the Pluto system up close and flying into a new frontier that will help us better understand the origins of the solar system.
New Horizons’ flyby of the dwarf planet and its five known moons is providing an up-close introduction to the solar system’s Kuiper Belt, an outer region populated by icy objects ranging in size from boulders to dwarf planets. Kuiper Belt objects, such as Pluto, preserve evidence about the early formation of the solar system.
New Horizons’ almost 10-year, three-billion-mile journey to closest approach at Pluto took about one minute less than predicted when the craft was launched in January 2006. The spacecraft threaded the needle through a 36-by-57 mile (60 by 90 kilometers) window in space – the equivalent of a commercial airliner arriving no more off target than the width of a tennis ball.
Because New Horizons is the fastest spacecraft ever launched – hurtling through the Pluto system at more than 30,000 mph – a collision with a particle as small as a grain of rice could incapacitate the spacecraft.
Now that it has reestablished contact, it will take 16 months for New Horizons to send its cache of data – 10 years’ worth – back to Earth.
[July 13] In a late-day announcement on Monday, astronomer Alan Stern – who is New Horizons principal investigator – said measurements by New Horizons in the past few days have now confirmed that Pluto is the biggest object in the Kuiper Belt beyond planet Neptune. Pluto measures 1,473 miles (2,370 km) in diameter. Other comparably sized bodies Kuiper Belt bodies – for example, Haumea, Makemake and Eris – had at various times been contenders for the biggest Kuiper belt object title, but now … Pluto wins!
Until we get new images, here are the best images and a sampling of information from New Horizons’ past two weeks, as it made its final approach to the Pluto system.
New Horizons normal operations resumed July 7 after July 4 anomaly
[July 6] The New Horizons spacecraft experienced an anomaly the afternoon of July 4 that led to a loss of communication with Earth. Communication has since been reestablished and the spacecraft is healthy. Preparations are ongoing to resume the originally planned science operations on July 7 and to conduct the entire close flyby sequence as planned on July 14.
The mission operations center at the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, lost contact with the unmanned spacecraft at 1:54 p.m. EDT, and regained communications with New Horizons at 3:15 p.m. EDT, through NASA’s Deep Space Network.
During that time the autonomous autopilot on board the spacecraft recognized a problem and – as it’s programmed to do in such a situation – switched from the main to the backup computer. The autopilot placed the spacecraft in “safe mode,” and commanded the backup computer to reinitiate communication with Earth. New Horizons then began to transmit telemetry to help engineers diagnose the problem.
An investigation into the anomaly has concluded that no hardware or software fault occurred on the spacecraft. The underlying cause of the incident was a hard-to-detect timing flaw in the spacecraft command sequence that occurred during an operation to prepare for the close flyby. No similar operations are planned for the remainder of the Pluto encounter.
The mission science team and principal investigator have concluded that the science observations lost during the anomaly recovery do not affect any primary objectives of the mission, with a minimal effect on lesser objectives.
New Horizons Principal Investigator Alan Stern said:
In terms of science, it won’t change an A-plus even into an A.
Adding to the challenge of recovery is the spacecraft’s extreme distance from Earth. New Horizons is almost 3 billion miles away, where radio signals, even traveling at light speed, need 4.5 hours to reach home. Two-way communication between the spacecraft and its operators requires a nine-hour round trip.
Time-lapse movie of Pluto and Charon
Bottom line: The New Horizons spacecraft’s flyby of the Pluto system is on July 14, 2015. Newest images and updates.