To Pluto and Beyond

With the successful flyby of Pluto this week, the human race has now visited all the 'classical' planets.

Pluto and Charon Show Exactly Why They Are Dwarf Planet and Satellite ....

 

Of course technically Pluto ceased to be classed as a planet, as it was just too small, especially after the discovery of Eris and Orcus alongside it in the Kuiper Belt.

  

This fate was compounded when other similar size bodies such as 'Makemake' and 'Haumea' and 'Sedna' were found, with a real prospect of even more being found in the same size range .... so in 2006, Pluto was demoted from the classification of planet to that of 'dwarf planet'.  

 

Officially this demotion was because it failed one of the three new tests of what defines a planetary celestial body, which are that:

1. It is in orbit around our Sun.
2. It has to have sufficient planetary mass for its own self-gravity to overcome any internal forces and achieve a nearly round shape (aka hydro-static equilibrium), and
3. It has to have cleared the neighbouring space around its orbit.

..... it failed on point 3 (as did Eris and Orcus etc), because its orbiting as part of the Kuiper Belt Objects, and so has not either "vacuumed up", or ejected, the other large objects in its vicinity of space. In other words, it has not achieved gravitational dominance of its orbit .... so does this mean that all those other large objects in the Kuiper Belt, and that are also classed as dwarf planets, should now be renamed as sleepy, dozy, grumpy etc?

Our First Photograph of Pluto .....

Brevity, and the reclassification of Pluto aside, the achievement of humanities successful visits to all the original planetary bodies, really is something to waive the (American) flag about, especially when its been done inside 60yrs. By the way I class 'successful' as any probe that:

• Makes it to the planet or target,
• Doesn't crash into it, and
• Sends back relevant data.

Just for the record, and to illustrate why I alluded to the American flag, the planets, the first successful probes and dates, are as follows:

Solar Probes:

The Pioneer 5 probe from the United States (NASA/Dept Of Defence) in the period March–April 1960 ~ which was an orbiter success, and which measured magnetic field phenomena, solar flare particles, and ionization in the interplanetary region.

Lunar Probes:

The Luna 2 probe from the Soviet Union (USSR) which on the 14th of September 1959, was an impactor probe with the first impact on the Moon followed by Luna 3 on 6 October 1959, which was a flyby success with the first images from the lunar far-side. Then the Luna 9 probe from the 3rd of February 1966 – to 6th of February 1966, which was a lander success being the first soft landing; It also provided the first images from the surface of the moon. How close the USSR came to being the first to land on the Moon, we will never know.

Mercury Probes:

The Mariner 10 probe from the NASA, which on the 29th March 1974 was a flyby success at a minimum distance of 704 km, and then again on the 21st of September 1974 at a distance of 48,069 km, finally closing to 327 km on the 16th of March 1975, as its orbits swung it by the planet.

Venus Probes:

The Mariner 2 probe from the NASA, which on the 14th of December 1962, was the first successful Venus flyby probe; at a minimum distance 34,773 km, but the Venera 7 probe by the Soviet Union (USSR) on the 15th of December 1970, was the first lander, and was also the first successful landing on another planet; signals returned from surface for 23 minutes.

Mars Probes:

The Mariner 4 probe from the NASA on the 15th July 1965, was the first flyby probe success with the first close-up images of Mars. This was followed by the Mariner 9 probe by NASA on 14th of November 1971, which was an orbiter success. The first spacecraft to orbit another planet.

Ceres Probes:

Dawn a NASA probe on the 6th of March 2015, was an orbiter which was the first spacecraft to orbit two different celestial bodies; previously visited Vesta.

Jupiter Probes:

The Pioneer 10 NASA probe which on the 3rd of December 1973, was a flyby success and the first probe to cross the asteroid belt; first Jupiter probe; also the first man-made object on an interstellar trajectory; now in the outer regions of the Solar System but no longer contactable.

Saturn Probes:

The Pioneer 11 probe, NASA, which on the 1st of September 1979 was a flyby success, having previously visited Jupiter.

Titan Probes:

Huygens Europe ESA 14 January 2005 atmospheric probe, lander success deployed by Cassini; first probe to land on a satellite of another planet.

Uranus Probes:

The Voyager 2 probe, NASA, which on the 24th of January 1986 was a flyby success previously visited Jupiter and Saturn; went on to visit Neptune.

Neptune Probes:

The Voyager 2 probe, NASA, which on the 25th of August 1989, was a flyby success after having previously visited Jupiter, Saturn and Uranus.

Pluto Probes:

The New Horizons probe, NASA which in July 2015 was a flyby success for Pluto and then hopefully a flyby success for other Kuiper Belt Objects which may follow (targets yet to be decided).

Comet Probes:

The 21P/Giacobini-Zinner ICE (formerly ISEE3) probe, NASA, which on the 11th of September 1985 was a flyby success which went on to observe Halley's Comet.

Asteroid Probes:

The 951 Gaspra Galileo probe, NASA which on the 29th of October 1991, was a flyby success en route to Jupiter; minimum distance to the object was 1900 km.

Extra Solar Probes:

The Pioneer 10 probe, NASA, which left Jupiter in December 1973. Mission ended March 1997. Last contact January 23, 2003. Craft now presumed dead; no further contact attempts planned.

The Pioneer 11 probe, NASA Left Saturn in September 1979. Last contact September 1995. The craft's antenna cannot be manoeuvred to point to Earth, and it is not known if it is still transmitting. No further contact attempts are planned.

Voyager 1 probe, NASA, Left Saturn in November 1980. Still in regular contact and transmitting scientific data (as of December 2014). Contact hoped to be maintained until at least 2020.

Voyager 2 probe NASA, Left Neptune in August 1989. Still in regular contact and transmitting scientific data (as of December 2014). Contact hoped to be maintained until at least 2020.

New Horizons probe, NASA, Left Pluto July 14th, 2015; Pluto mission to last until early 2016, proposed Kuiper Belt missions to begin in 2018/2019.

The words of the Fireball XL5 theme tune get closer every day .....

We'd take the path to Jupiter
And maybe very soon
We'd cruise along the Milky Way
And land upon the Moon
To a wonderland of stardust
We'd zoom our way to Mars
My heart would be a fireball, a fireball

'Cause you would be my Venus of the stars'