January 19 – Launch of New Horizons (2006)

We have two quick asteroids to start us off today.  Asteroid 502 Sigune was discovered on January 19th 1903 by old hand Max Wolf at Königstuhl Observatory near Heidelberg.  On the same day, young whippersnapper Raymond Smith Dugan, also working at Heidelberg, discovered the second asteroid of his career, 503 Evelyn (named after his mother).


On January 19th 2006, NASA launched the New Horizons probe to Pluto, so long ago it was still a planet at the time (and always will be for some of us).  I clearly remember thinking back then that it was going to take such a long time to arrive that I’d probably have forgotten all about it, but here we are more than a decade later and the visit is now on the cusp of becoming a fond and fading memory.

New Horizons (image credit: NASA)
New Horizons (image credit: NASA)

New Horizons was a fairly large program by today’s standards, costing about $650m, which sounds expensive, but it’s actually only about $5 per US taxpayer, and spread over the 15 years of the project it’s a mere 33 cents a year: a bargain!  The mission has also visited Jupiter, and once Pluto had been passed there was a rendezvous with a Kuiper Belt Object in 2019.  The object chosen didn’t have a particularly catchy name at the time (2014 MU69), and was apparently also known in New Horizons circles as PT1 (and yes, it did stand for “Potential Target”).  PT1 later got the nickname Ultima Thule (it’s two planetesimals stuck together with one name each) but is now officially named 486958 Arrokoth.  From a typing point of view I think I prefer PT1.

The Jupiter flyby, as well as being a scientific mission in its own right, and a useful testing-ground for the instrumentation before an extended period of hibernation for the long journey to Pluto, was used to increase the speed of New Horizons by “gravity assist” to 9,000 miles per hour.  I think I’ll have to get myself one.  At that speed I could travel across the Atlantic to visit my friend Joanne in Arizona in about 20 minutes.

During the visit to Jupiter, New Horizons imaged the moon Callisto, and studied Jupiter’s ring system, magnetosphere, and the atmospheric conditions on the planet.

Calisto from New Horizons (image credit: NASA)
Calisto from New Horizons (image credit: NASA)

Scientific instruments on New Horizons are under the command of the Clyde Tombaugh Science Operations Centre in Colorado, and a small quantity of the ashes of the centre’s namesake, the man who discovered Pluto in February 1930, have been sent along for the ride.  Tombaugh died on January 17th 1997.

Imaging of Pluto using New Horizons LORRI imager began in January 2015. Hundreds of photographs were taken of the Pluto system, enabling navigators to fine tune Pluto’s exact position, and calculate the precise distance between New Horizons and its target.

And at the time we thought these images were pretty impressive; but they were nothing compared to what we got when the Pluto system was finally reached.

 

Pluto from the New Horizons probe (image credit: NASA/APL/SwRI)
Pluto from the New Horizons probe (image credit: NASA/APL/SwRI)
Surface detail of Pluto from New Horizons (image credit: NASA)
Surface detail of Pluto from New Horizons (image credit: NASA)
Pluto (image: NASA)
Pluto (image: NASA)
Charon (image: NASA)
Charon (image: NASA)
Nix (image: NASA)
Nix (image: NASA)

See what I mean?


1747Birth of Johann Elert Bode in Hamburg. The “law” named after Bode uses a formula to predict the distances of the planets from the Sun. It’s great for the first six, and was hailed a success when Uranus (a name suggested by Bode) was found in the right place. Unfortunately, the existence of the asteroid belt and Neptune were not part of the plan. Bode has a comet, an asteroid (998 Bodea) and a galaxy (M81, Bode’s Galaxy) named after him (though I suspect any inhabitants of M81 might disagree).


1965Launch of Gemini 2 from Cape Canaveral. This was an unmanned flight, but it did include a practice ingress (clambering in) and egress (being pulled out) by crewmembers of Gemini 3. Following two occasions on which the launch assembly had to be dismantled (for hurricanes Cleo and Dora) and an aborted launch on December 9th, 1964, the eighteen minute flight took place on the morning of January 19th, 1965, and was only slightly inconvenienced by a power outage at Mission Control caused by the electricity demands of the television coverage.


 

September 23 – Discovery of Neptune (1846)

Officially, Neptune was discovered visually on September 23rd 1846 by Johann Galle, but its existence had been proposed by Alexis Bouvard years before, and its position was predicted by Urban Le Verrier on August 31st 1846, and by John Couch Adams a couple of days later.  James Challis at the University of Cambridge was also in the running, and observed Neptune twice before the discovery was announced, but failed to realise what was going on.  And Galileo had seen and noted Neptune himself, but even he had no idea what it was.

Neptune from Voyager 1 (image credit: NASA)
Neptune from Voyager 1 (image credit: NASA)

The first suggestion for a name for this new planet came from Galle, who thought Janus might be a good idea, after the two-faced Roman god of beginnings, from whom we get the name of the first month of the year.  Challis, no doubt anxious to make up for being beaten to the finishing tape, suggested Oceanus, whose children we have been meeting all year in these pages in the guise of asteroids.  Oceanus married his sister Tethys, and their children numbered at least three thousand, which, as they were immortal, might not have put as much of a strain on Tethys’ plumbing as I might imagine, because I have no idea how long it took them to complete their family.

Le Verrier was the first to suggest naming the new planet Neptune, the Roman god of the sea, and appropriately a brother of Jupiter and Pluto (he also suggested, modestly, Le Verrier, but this idea didn’t gain much support outside France).  The name is used almost universally, although as Neptune was the Roman equivalent to the Greek Poseidon, Greece is, as far as I’m aware, the only western country to use that name instead.

Neptune is a small giant (yes, I know what I just said).  It is 17 times more massive than Earth, but only about 5% as massive as Jupiter.  It is similar in composition to Uranus, and the two of them, while still coming under the “gas giant” umbrella, are sometimes also referred to as “ice giants”.

As with the other giants, Neptune has a ring system, but not one that’s going to be used as a backdrop to an episode of Star Trek anytime soon.  The rings are fairly thin, and few enough in number to have been named after some of the players in Neptune’s discovery (the Adams, Le Verrier, Lassell, Galle and Arago rings).

Neptune's Rings (image credit: NASA)
Neptune’s Rings (image credit: NASA)

At last count Neptune was known to have fourteen moons, all named after water deities.  I’ll just briefly mention that the biggest are Triton (way bigger than the rest at 2,700+ km diameter), Proteus, Nereid, Larissa, Galatea and Despina, but as all fourteen will probably be turning up in these pages over the next twelve months, we will leave it at that for now.

Just as an aside, it has been speculated that in the dim and distant past of the solar system there might have been a fifth gas giant, which was flung out of orbit by a strong gravitational kick from Jupiter or Saturn.


ALSO TODAY . . . .

1791  –  Birth, in Hamburg, of Johann Franz Encke, comet hunter, and expert at predicting when they were going to return. Encke also has a gap in Saturn’s rings named after him, in recognition of his observations of that planet.


June 02 – Launch of Mars Express

Mars Express, launched on this day in 2003, was the first visit to another planet by the European Space Agency (ESA). And, unlike many of the modern long-range voyagers mentioned in these pages, the name “Express” is there to denote speed; it is not a highly-convoluted acronym describing the mission.

Artist’s impression of Mars Explorer. (Credit: Spacecraft: ESA/ATG medialab; Mars: ESA/DLR/FU Berlin)

The journey to Mars began at the Baikonur Cosmodrome and ended six months and 23 days later in orbit around the red planet. With seven instruments on board, Mars Express was able to study just about all physical aspects of its new home, including geology, mineralogy and atmosphere.

Highlights of the mission have included the discovery of minerals which only form in the presence of liquid water, radar detection of subsurface water ice, the possible detection of methane in the atmosphere, and evidence for an ancient system of underground lakes.

Another impressive result was how close Mars Express managed to get to the larger of Mars’ two moons, Phobos. The image below was taken from 351 km, but closest approach was 67 km.

Phobos, photographed by Mars Express. (Image Credit: ESA/DLR/FU Berlin).

The Mars Express orbiter is still going strong, and is expected to remain in service until 2022. Which is more than can be said for the British component of the package, the Beagle 2 lander, which landed on the surface in an impact crater called Isidis Planitia on December 25th 2003, and was never heard from again. More than a decade later a camera on board NASA’s Mars Reconnaissance Orbiter spotted Beagle 2, and close inspection suggested that not all of Beagle’s solar panels deployed successfully.

Image from the HiRISE camera, interpreted as the missing British Beagle 2 lander. (Image credit as in photo).

There’s plenty more to read about this mission at the ESA Mars Express website.


ALSO TODAY

1967 — The unmanned US probe Surveyor 1 landed on the Moon.

1998 — Launch of space shuttle Discovery mission STS-91, carrying the prototype AMS-01, the first of two Alpha Magnetic Spectrometer missions.