Tag Archives: solar system names

P–38 days: Navigating Pluto

Pluto and Charon artists impression

Pluto and Charon: Xanthine/Wikipedia

Pluto. A cold distant place we’ve never needed to think much about. Until now. Pluto and Charon (his ferryman of the dead): bodies at the outskirts of our traditional solar system which will soon have names of dead astronomers, poets, goddesses, writers, characters from literature, and other hoi polloi plastered all over their surfaces; names for everybody and every thing, real or fictitious, except for the very thing taking us there: New Horizons.

New Horizons. The spacecraft I helped launch nine years ago. New Horizons: the mission led by Alan Stern and guided by a host of dedicated engineers and scientists, navigated by Bobby Williams and his team, augmented by an independent Navigation team at JPL (the Jet Propulsion Laboratory).

Pluto moons and orbits

Pluto Satellites, NASA / Wikipedia

Unfortunately, New Horizons will not have its name on a single feature that it discovers on the surface of Pluto, Charon, Styx, Nix, Kerberos, Hydra, or any of the likely more-to-be-discovered satellites. So says the IAU (International Astronomical Union), the self-appointed official namer of names for all things astronomical. What a shame! Let’s have a waiver. Name something big on Pluto—a major crater, chasm, scarp, plain, mountain, sea, valley, whatever—for the spacecraft what brung us. It would be an insult not to do so.

I’m proud to be associated with the mission, and honored for an invitation to help out on the KinetX Navigation team at the Applied Physics Lab in Maryland next month in whatever small way possible to usher the spacecraft through its brief fling with the Plutonian system. This post and any others following it, if there’s time and wherewithal, are dedicated to Navigation and the process of getting there, true to the spirit of “The journey is more than half the fun.”

The journey is the important thing; the destination … not so much!

Project scientists will quibble with that. Many have expended a good fraction of a career to seeing what’s at the end of this particular tunnel, and that’s a perfectly good reason for them to celebrate an arrival. It’s just not the Navigators’ thing. The Navigators get us there, so their concern is Where are we? Where are we going?

Let me rework the statement above: We almost always get you there! is an unofficial and seldom mentioned motto of this particular Navigation team, because there is an example or two in history, like the Mars Climate Observer’s unanticipated and unwelcome arrival at the surface of that planet, to remind us that there is some justification for the modifier “almost.” (An almost that was barely avoided by the JPL Navigators for the Mars Polar Lander that augered in a few months later. Through a lot of effort they barely avoided missing the Martian reentry aim point only to see an onboard software failure late in the descent smear the spacecraft over the south polar region. See Embracing the Future.)

Will New Horizons accidently smack into Pluto? No. The flyby is too far away to make that kind of error. The more likely bad karma for Navigation would be to incorrectly estimate the position near the closest approach time and cause the cameras to point the wrong direction and snap pictures of empty space. Or to miss the dual occultations of the Sun and Earth when the spacecraft passes behind Pluto and Charon. To quote a character from literature (a likely candidate for a name on Pluto) Harris Mitchel in The Darkest Side of Saturn says, of the possibility of blowing a similar encounter at Neptune, “You’re totally humiliated because you said you could do this and you didn’t. As a consequence, you lose all your credibility and live the rest of your life in shame and degradation…. [And] you get pelted by the scientists. They throw outdated textbooks at your head because you lost a science opportunity, probably the only [one] in our lifetime.”

So, the pressure is on the Navigation team, as it always is for encounters like this, to get us there safely, surely, and without error. Well, at least not any major error, because there is never any surety in human activity, and the best we can do is keep the inevitable and ineradicably small errors from turning into big ones.

Here’s the Navigation process, also described in the literary masterpiece mentioned above, paraphrased to befit the occasion: Dump the tracking data into a large black cast-iron pot, metaphorically speaking—actually the pot is a computer—along with other ingredients such as data calibrations and satellite and planet ephemerides. Stir vigorously. Incant technobabble and taste frequently, adding spices, a priori covariances, and toad tongues now and again until the brew is complete and the answer apparent: we know where New Horizons is and where it’s going. The encounter will be a success.

Sorry to trouble you with the technical description above. In future posts I’ll try to put things into more down-to-earth easily-understood terms such as the interpretation of dynamic events from signatures in the Doppler tracking data, the use of Very Long Baseline Interferometry data—spacecraft versus quasars—to nail down the trajectory in heliocentric space, and the number of pixels that can dance in the frame of an Optical Navigation image to determine the solution in Plutonian-centric space. By-and-by it will all become clear as a bell.

The Navigation Team, led by Bobby Williams (the first to navigate a spacecraft, NEAR, to a landing on an asteroid), determines the spacecraft trajectory and the orbits of the satellites circling the Plutonian system, designs maneuvers to redirect the spacecraft to whatever target the mission desires, and provides the rest of the numerous New Horizons project folk—engineers and scientists—with last minute updates on positions so that the cameras and other instruments will point the right direction at closest approach, and not click pictures or take data of empty space.

One last topic to end this ever-rambling post:

Pluto the Dog

Photo: Leo Reynolds (modified)/ CC BY-NC-SA

Is Pluto a planet?

Used to be, but not any more. Why is that? Well, besides a few technical things like how it was formed, and that it doesn’t clear its orbit of debris like all the other prim and proper planets do, I think there is a much more down-to-earth reason. It resides with the schoolchildren of our planet. Since there are probably scads and scads—hundreds and thousands or more—of new Pluto-sized bodies in the Kuiper Belt and Oort Cloud far outside the traditional bounds of our solar system, don’t you think it would be cruel to commit our school kidlets to the memorization of hundreds and thousands of dubious planetary bodies when it’s already difficult enough to name the eight already out there, even using the awkwardly unusable mnemonic “Men Very Easily Make Jugs Serve Useful Needs”?

I’d propose granting Pluto, for reasons of history and tradition, the status of “Honorary Planet.” It’s the least we could do to ease the pain of Pluto-is-a-planet advocates such as Alan Stern, the New Horizons leader (who has spoken quite nicely of Navigation in one of his own blog posts.) That way, with this mission we could then say that we’ve finally explored the last planetary outpost of our traditional solar system.

Where are we going? Pluto! That faint blob in our telescopic sky, that last place of mystery and darkness, the place we go to die, crossing the river Styx, and yet also the place we go in these last 38 days to come alive and understand ourselves and our universe a bit more.

But Pluto is only another milestone in a longer trip that the human race will ultimately celebrate in the far future if we don’t kill ourselves first. Let the journey continue.



Naming Pluto


Image credit: NASA-JHU APL/New Horizons

Update 2015/04/14! The voting is extended to April 24th. Here’s your chance!

Pluto – 113 days and counting as of 2015/03/23. The New Horizons spacecraft flies close by Pluto this July 14th—the first encounter in history and probably the last in your lifetime.

Looking for a link to the blessed event, I ran across this site, http://www.ourpluto.org, describing itself as a public campaign to name the surface features on Pluto and Charon. “Working with the International Astronomical Union (IAU), the New Horizons team plans to assign names to the features on the maps of Pluto and its large moon Charon, once we have seen them in sharp detail this summer. At this site, you can suggest your ideas for names and vote for your favorites. The team will use your best ideas in their proposal to the IAU.”

In other words, you get to suggest names, but the IAU gets the last word, and if your proposed name doesn’t fit into its naming policy, out it goes.

Well, maybe that’s as it should be. We certainly don’t want corporate sponsors naming craters after automobiles, religious organizations naming mountains or valleys after holy names in the Quran or Bible, or politicians naming smoking fumaroles after themselves. What better way to handle it than let an international organization of astronomers fairly and impartially dictate the terms?

The only problem is that the IAU rules for naming features on solar system bodies seem to preclude naming anything for the spacecraft or mission that discovered those features in the first place.

The only exception I know is Valles Marineris (Mariner Valley) on Mars, named after the Mariner 9 Mars orbiter that discovered it. This instance seems to have irked the IAU because you’ll have a hard time finding the names of spacecraft for features on any other planets or their satellites since then. Not Viking or Voyager or Cassini or Galileo or MESSENGER, or apparently now, New Horizons. Hardly a valley, scarp, crater, hollow, chasm, knob, ridge or volcano has been named for the spacecraft or mission that found it.

There are plenty of deceased astronomer names plastered over those terrains, gods and goddesses, fictional characters, writers, and other hoi polloi, but exceedingly rarely, or maybe never, will you find the name of a spacecraft or mission or its engineers or scientists.

To qualify, if you’re a person, you have to be both famous and dead. This precludes having anything you’ve discovered being named after you at the time of discovery. Maybe you’ll get a tiny crater fifty years from now if there’s anything left over, but certainly nothing big. Perhaps this is as it should be, but this exclusion of mission names and the names of the scientists and engineers that run them violates, in spirit at least, the moral dictum “You gotta dance with the one that brung ya.”

A literally down-to-earth historical precedent is seen in the many geographical features on earth named for their discoverers. Why should this not also be the case for the solar system?

Check it out. Go to http://www.ourpluto.org and nominate a name for a Pluto feature (voting closes on April 7th), but at the same time notice the categories of names that the IAU will allow, and note that you won’t find New Horizons or any of its live participants in any of the “allowed” themes. Go ahead and suggest names, but please also entertain the question of why mission names are not allowed for the features they’ve discovered. And of course if you like the idea of something big on Pluto or Charon being named for the mission that brung us, the public, along on this long distance voyage of discovery, then certainly write it in.