New Horizons releases best Pluto images as encounter officially begins
NASA’s New Horizons spacecraft returned to normal science operations on Tuesday, July 7, the first official day of its long-anticipated Pluto encounter mode, with all of its seven instruments now active. In the early hours of July 8, on its second official day of the encounter, mission scientists received this latest picture of Pluto, featured above, as seen by New Horizons’ Long Range Reconnaissance Imager (LORRI) – the most detailed yet of the dwarf planet.
New Horizons acquired the image on July 7 when the spacecraft was 5 million miles (8 million km) distant from Pluto.
Earlier, at a July 6 media briefing, NASA officials and mission team members had revealed the good news that the spacecraft is healthy and operating “flawlessly”. Rapid, round-the-clock work by the mission team had hastened the mission’s swift resumption after a computer glitch had sent the spacecraft into “safe mode” on July 4.
The anomaly had resulted from software uploaded the day before, which had inadvertently required New Horizons’ onboard computer to do two tasks: compressing data and writing command sequences – all at once.
Entering “safe mode” and switching to the backup computer were exactly what the spacecraft is programmed to do under such circumstances.
Unfortunately, thirty observations were lost during the three-day recovery period, but that constitutes less than one percent of the data scheduled to be collected between July 4 and 16.
However, since no similar software uploads are planned between now and the July 14 encounter, the mission team is confident there will be no further anomalies like this one.
Even before the spacecraft resumed normal science activities, the mission team released the then latest and best images of Pluto taken by the Long Range Reconnaissance Imager (LORRI ).
The above three images were taken between July 1 and 3 of 2015, prior to the July 4 anomaly, from a distance of 7.8 million miles (12.5 million km). The left image shows, on the eastern limb of the disk, a bright area on the hemisphere of Pluto that will be imaged in close-up by the New Horizons flyby on July 14. Collectively, the three images shows the entire range of what appears to be a continuous belt of dark terrain that encircles most of Pluto’s equatorial region.
Variations in contrast and surface texture are clearly visible in these latest photos, as are the four strange dark spots (in the right and the above right images) slightly below and to the left of the equator on the side of the planet opposite to the one that will be photographed in the highest resolution.
Some of the features resemble craters or cryovolcanos (ice volcanoes) seen elsewhere in the outer Solar System, but planetary scientists are holding off any speculation as to what are these features until more visual data becomes available during the course of this coming week.
Using images taken by LORRI between June 27 and July 3, along with lower resolution color data from the Ralph instrument, mission team members created a map of the encounter hemisphere of Pluto.
The map will be an important tool in efforts to understand the dwarf planet’s starkly contrasting bright and dark areas, making it easier to compare their shapes and sizes.
The above map shows (at the left) an elongated dark area that some have dubbed “the whale” – a region 1,860 miles (3,000 km) in length. In the center of the map, at about 180°E, is a very bright feature with a width of approximately 990 miles (1,600 kilometers), which may be a region of methane/nitrogen/carbon monoxide frost. At the left of the map, about 30°E, near the ‘tail’ of “the whale”, is the doughnut-shaped region seen in two of the above images, and it is approximately 200 miles (350 kilometers) in diameter.
John Spencer, of the Southwest Research Institute in Boulder, Colorado, and deputy leader of the mission’s Geology, Geophysics, and Imaging team, emphasized, “[…] It’s too early to know what these features really are.”
During the encounter phase, New Horizons is programmed to reboot itself without contacting Mission Control back on Earth in the event of any problems. Within seven minutes of any anomaly, it can put itself into safe mode to preserve as much science data as possible. This will enable it to circumvent delays caused by the nine-hour round trip travel time for radio signals to travel to Earth and back.
“The spacecraft is in excellent health and back in operation. New Horizons is barreling towards the Pluto system,” emphasized NASA’s director of planetary science Jim Green.
Principal investigator Alan Stern confirmed, “The New Horizons spacecraft and science payload are now operating flawlessly.”
In the extreme cold of the outer Solar System, the spacecraft and its instruments are kept warm by the radioactive decay of plutonium-238 in its power source – a Radioisotope Thermoelectric Generator (RTG).
In just one week, the probe will speed past the Pluto system at 30,000 miles per hour (48,000 km/h), passing within 7,800 miles (12,500 km) of the planet’s surface.
Just in time for the encounter, Mark Showalter of the SETI Institute announced that the “Our Pluto” campaign to name features on the surface of Pluto and Charon has submitted a formal proposal to the International Astronomical Union (IAU) based on the results of a public online vote earlier this year. Approximately ten names were submitted within each of 14 themes – six for features on Pluto, four for features on Charon, and one for each of the other small moons. The proposal is viewable as a Google spreadsheet.
As expected, top contenders in the theme of scientists and engineers include Clyde Tombaugh and Percival Lowell. Sputnik, Challenger, and Columbia drew the highest vote count among space missions.
Both Star Trek and Star Wars topped the lists for fictional explorers and locations. Top vote getters in these categories include Kirk, Spock, Uhura, Vulcan, Leia, Skywalker, and Tatooine.
Also popular were names from the TV show Dr. Who, the Cthulhu mythos by H.P. Lovecraft, and the Lord of the Rings books by J.R.R. Tolkien.
Additional names will be submitted in the future, Showalter said.
Video courtesy of NASA
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.