Monday, July 13, 2015

Tuesday's Pluto Flyby: How to Follow Mission

The most recent image of Pluto, taken at a distance of two and one-half million miles by NASA's New Horizons spacecraft, shows four dark spots of unknown origin on the side of Pluto which always faces the largest moon, Charon.
(Image Sources: NASA, Johns Hopkins University Applied Physics Laboratory)

By Glenn A. Walsh
Reporting for SpaceWatchtower

Civilization's first close-up exploration of Pluto occurs this week. NASA's “New Horizons” spacecraft is expected to make its closest approach to Pluto on Tuesday Morning, 2015 July 14 at 7:49:57 a.m. Eastern Daylight Saving Time (EDT) / 11:49:57 Coordinated Universal Time (UTC).

New Horizons' flyby of Pluto comes exactly fifty years after the first successful spacecraft flyby of the Planet Mars, by NASA's Mariner 4 on 1965 July 14. This was the second successful planetary flyby mission, the first being a flyby of Venus in 1962 by NASA's Mariner 2.

New Horizons launched, as the first space probe to Pluto, from Cape Canaveral on 2006 January 19. At an Earth-and-solar-escape trajectory of 16.26 kilometers per second / 36,373 miles per hour, New Horizons' Atlas V rocket set the record for the highest launch speed of any human-made object sent into outer space.

Due to this great speed, New Horizons passed the orbit of our Moon in just nine hours! It took three days for the Apollo astronauts to reach the Moon in the late 1960s and early 1970s. New Horizons also passed the orbit of Mars in less than three months. It normally takes spacecraft between five and  ten months to reach Mars from Earth, depending on the speed of the launch and how close Mars is at the time of launch.

Serious consideration for an unmanned probe to fly by Pluto began 25 years ago with a project called “Pluto 350.” This was followed two years later by the Jet Propulsion Laboratory's “Pluto Fast Flyby,” inspired by a U.S. Post Office stamp that called Pluto, “Not Yet Explored.” This mission again evolved into the “Pluto Kuiper Express,” to explore Pluto and other Kuiper Belt objects (objects in a region beyond the known planets, home to small asteroid-like bodies and other remnants of the Solar System's formation). However, funding for all of these attempts was elusive.

Finally, after NASA established a New Frontiers space research program in 2001, the following year the Johns Hopkins University Applied Physics Laboratory was given the go-ahead to prepare a New Horizons spacecraft for a mission to fly by Pluto, as well as seek other nearby Kuiper Belt objects to explore.

After leaving Pluto, it is hoped to find other Kuiper Belt objects to explore within New Horizons' flight path. However, which other planetary objects, which are close enough to the flight path to be explored, has yet to be determined.

After launch, New Horizons first encountered the small Asteroid 132524 APL, which the spacecraft determined was an S-type asteroid. Then, in 2007, New Horizons was sent to Jupiter, for a gravity-assist from the Solar System's largest planet that increased the spacecraft's speed by 4 kilometers per second / 9,000 miles per hour. Additionally, New Horizons' scientific equipment was used to send back data regarding Jupiter's atmosphere, magnetosphere, and natural satellites.

After spending some years in hibernation, New Horizons began its approach to Pluto in January. NASA's Goddard Space Flight Center, using a supercomputer called “Enlil,” has tracked the motions of solar storms since January, to predict the space weather in the Pluto region for this month. According to their prediction, Pluto should have very low solar wind densities this month, while this could be followed by a more dense solar wind which could “significantly compress Pluto's atmosphere.” The problem is that this is the first attempt at a space weather prediction so far away from Earth, so the prediction could be off by a few weeks.

On American Independence Day, nine days ago, the New Horizons spacecraft experienced a computer overload and automatically shut-down. Although this situation seemed critical at first, it turned-out that the spacecraft's computer did exactly what it was programmed to do. When it experienced an anomaly, it went into a "safe mode" which includes ensuring that the antenna is facing Earth and communicating the problem to ground controllers. Within a few days, the New Horizons computer was back to normal operation. During the two and one-half days of "safe mode," about 30 scientific observations were lost, of the 500 observations expected during the Pluto encounter.

Discovered by Clyde Tombaugh (about 30 grams / 1 ounce of ashes of his remains are on the New Horizons spacecraft) in 1930, as a consequence of the Lowell Observatory's decades-long search for “Planet X,” Pluto was named after a suggestion offered by an 11-year-old school girl in Oxford, England, Venetia Burney (1918 to 2009). It was soon determined that Pluto was too small to be the “Planet X” that disturbed the orbit of Uranus.

It is said that Walt Disney was inspired by the planet, to name Mickey Mouse's canine companion Pluto. The 1951 Nobel Laureate in Chemistry, Glenn T. Seaborg, had named, in 1941, the newly created element, plutonium [which actually is used to power the New Horizons spacecraft in a Radioisotope Thermoelectric Generator (RTG)], after Pluto, in keeping with a tradition of naming new elements after newly-discovered planets.

Upon its discovery, Pluto was named the Solar System's ninth planet. However, with the discovery of other sizable objects in the Kuiper Belt such as Eris and Makemake, in 2006 the International Astronomical Union (IAU) defined the word “planet” for the first time, consequently reclassifying Pluto, Eris, and Makemake as a new kind of Minor Planet called a “Dwarf Planet.” Reclassifying Pluto as a Dwarf Planet, after all these years since discovery, caused a great deal of controversy among both astronomers and the general public, a controversy which continues to this day.

The Johns Hopkins University Applied Physics Laboratory, which administers the New Horizons spacecraft for NASA, as well as NASA itself, have good web sites for following New Horizons during the spacecraft's encounter with Pluto.

Johns Hopkins University Applied Physics Laboratory Web Site on New Horizons:
Link >>>

NASA Web Site on New Horizons:
Link >>>

NASA New Horizons Blog:
Link >>>

More on New Horizons: Link >>> 

More on Pluto: Link >>>

More on the Kuiper Belt: Link >>> 

Related Blog Posts ---

"Pluto & Moon Charon Close-Up Pix & Early Findings." 2015 July 21.

 Link >>>


"Pluto's Moons Spin Unpredictably in Orbit." 2015 June 9.

 Link >>>


"Public: Help Name Pluto & Charon Surface Features, New U.S. Rocket." 2015 March 30.

Link >>> 


"NASA Visits Pluto in 2015, Plans Visit to Jupiter Moon Europa." 2014 July 15.

Link >>>


"Pluto's Smallest Moons Receive Official Names." 2013 July 3.

Link >>>


"Captain Kirk: Name Pluto Moons 'Vulcan' & 'Romulus'." 2013 Feb. 14.

Link >>>


"Contest to Name Pluto's Newly-Found Moons." 2013 Feb. 12.

Link >>>

"Pluto Discoverer's Wife Dies at 99." 2012 Jan. 16.

Link >>>

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.

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