Clyde Tombaugh Discovers Pluto

*click* ….. *click* …. *click* …. *click*

On this day in 1930, a 24-year-old man named Clyde Tombaugh was squinting into the Lowell Observatory’s Zeiss Blink microscope. The unique device, also known as a blink comparator, held two photographic plates that each contained the image of a star field taken the previous month–the images showing the same section of sky, taken a few days apart. Tombaugh could rapidly switch between the two images by rotating a dial, allowing him to quickly compare the images and watch for any variations between the two that would indicate a body moving more rapidly than the background stars (eg. planets, asteroids, etc.).

*click* ….. *click*

Late into that February afternoon, a subtle difference between the two images caught his eye.

Animation comparing Tombaugh's star fields.

Can you spot Pluto?  Click on the image to see a version with Pluto identified.   Image Credit: National Air & Space Museum

 

*click* … *click* … *click* .. *click* . *click* *click*

He spent 45 minutes comparing the two images. Convinced of his findings, he contacted his supervisors. Over the next couple of weeks, the observatory focused its attention to the object before confirming Tombaugh’s discovery. On May 1st, 1930, a new planet was introduced to the world: Pluto.

And of course, in 2015, we got to see Pluto in a way that Mr. Tombaugh himself could only have imagined.

NASA’s New Horizons spacecraft captured this high-resolution enhanced color view of Pluto on July 14, 2015.

NASA’s New Horizons spacecraft captured this high-resolution enhanced color view of Pluto on July 14, 2015.        Source: NASA

New Horizons Awakens

If everything has gone according to its meticulous plan, by the time you are reading this NASA’s New Horizons spacecraft will have awoken from its electronic hibernation for the last time and begun its careful preparations to encounter Pluto in July of 2015.

Maybe I should back up for those that aren’t familiar with New Horizons, or just want a little recap:

New Horizons is the name of a NASA spacecraft and mission to complete a fly-by mission of Pluto and its moons, and then on to view other Kuiper-Belt objects. New Horizons will give us shiny new photos of our favorite dwarf planet and a wealth of other scientific data. It’s about time, too. I mean, just look at the current best image we have of what we–at least  used to–consider 1/9th of our solar system’s planetary awesomeness:

Pluto as imaged by Hubble in 2010.

Pluto as imaged by Hubble in 2010.

Yuck! And NASA was impressed enough to brag about these “most detailed and dramatic images ever taken of the distant dwarf planet“. I’m looking forward to which adjectives they’ll use when we get real images courtesy of New Horizons. But I digress.

On January 19, 2006, New Horizons lifted-off from its Cape Canaveral launchpad and screamed into the heavens. In fact, nothing before or since has left the Earth with such a sense of urgency. New Horizons holds the record for the fastest launch of any spacecraft. It left the Earth with a velocity of 36,373 miles per hour (58,356 kilometers/hour), fast enough to propel it not just out of the Earth’s orbit, but completely out of the solar system (referred to as a solar escape velocity).

Subsequently, New Horizons continued to voyage towards its 2015 encounter with Pluto. Along the way, it came within 1.4 million miles (2.3 million kilometers) of Jupiter, on February 28, 2007, and actually used its proximity to gain a gravity assist boost from the massive gas giant. This gave New Horizons a speed boost of about 9,000 miles per hour (14,000 kilometers/hour). Taking advantage of that graviational slingshot, the voyage to Pluto was shortened by three full years. Score! Free energy!

New Horizons zoomed along, passing Saturn’s orbit in June of 2008, Uranus’s in March of 2011, and then Neptune’s in August of this year.

Next up: Pluto.

Throughout its journey, New Horizons has gone through hibernation/wake cycles more than a dozen times, in fact, spending about 2/3 of its time in an electronic slumber. During hibernation, most of the craft’s systems are powered down or entered into an extremely low-functioning state. This “reduced wear and tear on the spacecraft’s electronics, it lowered operations costs and freed up NASA Deep Space Network tracking and communication resources for other missions”.  Today, however, New Horizons is waking for good.

Beginning in February, the main observation objectives begin. Around the beginning of May, New Horizons will be capturing images of Pluto exceeding the resolution that Hubble was able to produce. For the next two months, Pluto will become more accessible to all of the spacecraft’s instruments. The closest approach is projected for July 14, where New Horizons will be within 6,200 miles (10,000 kilometers) of Pluto. New Horizons’s Long Range Reconnaissance Imager (LORRI) is expected to capture images on the scale of 50 meters per pixel and accomplish a handful of other primary and secondary scientific objectives.

But wait, there’s more!

In addition to Pluto, New Horizons will be observing and recording images and data from Pluto’s known moons: Charon, Hydra, Nix, Styx, and Kerberos.

And that’s still not all. Remember how I mentioned that New Horizons is on a solar system escape trajectory? That means the craft is going to continue hurtling away from the Earth and Sun, away from Pluto, and out beyond the ends of our solar system and into intergalactic space. Included in the craft and mission design, is fly-by opportunities for one ore more Kuipier-Belt Objects (KBOs), the residents of the Kuiper Belt. If you’re not familiar with the Kuiper Belt, think asteroid belt except much larger but instead of rocky asteroids, these bodies consist more of frozen gases such as methane, ammonia, and water. (Some of the moons of our solar system are believed to be former residents of the Kuiper Belt, but that’s another story for another time.) The ability to complete this mission will depend on targetable candidates and remaining fuel supplies.

After all of this, New Horizons slips into the furthest reaches of the Sun’s influence, the fascinating realm known as the outer heliosphere, including the heliosheath and heliopause (again, another story/another time). If the craft is still alive at this point, New Horizons will continue the work of the Voyagers in mapping this interesting environment.

That’s it for today. Stay tuned for updates on this historical mission, and much, much more!


Awakening

 

But that’s not all that will reawaken on December 6th.