New Horizons sends us a new photograph of Pluto

July 9, 2015 • 11:03 am

by Grania

The first space mission to explore Planet Pluto is now 5 days from target, the last of our solar system’s planets (or not-planets) to be visited. New Horizons will then pass within 12,500km of the surface. The mission hopes to uncover knowledge about its surface and atmosphere. There’s an in depth discussion of what the mission would like to uncover as well as questions about Pluto that are as yet unanswered over on the America Space website.

This was the image taken by the Long Range Reconnaissance Imager (LORRI) when New Horizons was woken from its accidental “safe mode” this week.

The dark patch is called “The Whale”.

There is also a competition running to name the mountains on Pluto’s moon Charon, and it appears that they’re going to end up being a character out of Star Wars or Star Trek.

Pluto & Charon seen from Hubble. Image Credit: NASA/JPL-Caltech
Pluto & Charon seen from Hubble. Image Credit: NASA/JPL-Caltech

I wasn’t kidding about the Star Wars characters.

Pluto is technically a Dwarf Planet, having been demoted from full planet status in 2006 on the basis that “has not cleared its neighboring region of other objects” according to the International Astronomical Union. Its demotion caused an upset, not least amongst young fans of the solar system who bombarded Neil DeGrasse Tyson with angry letters about it.

Credit: PBS NOVA
Credit: PBS NOVA

He’s apparently since made peace with Pluto, ot at least, that is his story and he’s sticking to it.

If you do Twitter, then you can follow the mission as it unfolds on @NewHorizons2015

39 thoughts on “New Horizons sends us a new photograph of Pluto

  1. I wonder why they didn’t design New Horizons to go into orbit around Pluto? Whizzing by at a distance of 12,500 km seems like only a quick glimpse. All that way for a drive-by and then onward forever into the dark.

    1. To go into Pluto orbit they’d have to slow down a heck of a lot, and that would take a lot of fuel. And fuel is heavy, so taking that amount of fuel all that way, and that far out of the Sun’s gravitational field, would have required a heck of a lot more fuel, et cetera.

    2. In space inertia matters so much more. Slowing down in space takes as much fuel and reaction mass as getting going in space. And then you’d need even more fuel than all of that to accelerate all that extra fuel.

      Think about how crazy things got when you held down the thrust button in the old Asteroids arcade game. It was the most realistic space game of all time, and even then it gave you infinite massless fuel and there was a small amount of drag in the game.

      1. Realism in space games has come some way since Asteroids. You might want to look into Kerbal Space Program, or even Orbiter. The former is a game first, the second a simulator first.

    3. Also bear in mind that most of the spacecraft’s speed comes from its flyby of Jupiter. To go into orbit around Pluto, all of that added speed would have to be shed using chemical rockets, at massive cost in fuel (and fuel to accelerate the fuel, etc). Unlike Mars, Pluto has no atmosphere to speak of, so aerobraking isn’t an option.

      Getting up to speed is hard enough; getting rid of that speed again is (literally) exponentially harder.

    4. I think they have the option of steering it to some extent in the direction they want to go after the fly-by, if they see anything interesting worth visiting in the Kuiper Belt.

    5. I’ll add one more thing to all of the above valid points.

      There is also a trade off between travel time. If decades or centuries of travel time were okay a much lower energy trajectory could conceivably be used that would put the probe at Pluto with a low enough relative velocity to be captured by Pluto. But, aside from that kind of time frame being impractical by itself, there are also the added technical challenges of making the probe and all its instuments robust enough to last that long.

      1. A comment I saw earlier today was that they could have launched a Pluto orbiter on a Delta or Atlas-something rocket already … if you didn’t mind waiting for another 50 to 70 years before getting and data.
        Which actually has major implications for things like the power source. You might need a different isotope ; you might need a different thermocouple pair to survive the longer duration of radiation damage ….lots of issues.

    6. Aerobraking would work…on Neptune. And while at Neptune a mission could report for years about interesting details about Triton, which is the most interesting moon in the solar system (probably a captured drawf planet) that will not be there in a couple of billion years.

    7. How about using a nuclear motor to reduce mass? But they are pretty low power. Probably you still have the problem of having to begin the deceleration early in the trip which would force a much longer trip and require, again, a more robust and expensive machine.

      1. The most likely option would be an electric engine (ion drive) powered by a nuclear RTG. Very low thrust, but negligible reaction mass requirements so you can achieve high delta-V by accelerating continuously for weeks or months. Higher peak velocity means shorter trip times overall, even if it takes much longer to get up to speed.

        For what it’s worth, a minimum-energy orbit from here to Pluto takes about 35 years (if I’m doing the math right).

      2. True, that would take a long time; probably greater than 30 years with an average velocity less than half of New Horizons. In any case, you still need to put mass in the opposite direction you are going to sufficiently slow down.

  2. …the last of our solar system’s planets (or not-planets) to be visited.

    Except we now know there are plenty of other not-planets out there beyond Pluto, some of them as large as or larger than Pluto (that’s why it was demoted).

    Nor is Pluto the last stop for New Horizons, which will fly by one or more small KBOs as it passes through the Kuiper Belt.

    1. Also, as it turns out, there’s a spacecraft called Dawn currently in a holding orbit around Ceres awaiting the resolution of a technical problem before beginning its primary mapping mission.

      Ceres was the first known member of the asteroid belt, just as Pluto is the first known member of the Kuiper belt. Like Pluto, Ceres was originally classified as a planet until other, similar objects were found in its neighborhood. Both Ceres and Pluto are now classified as dwarf planets.

      So a case can be made that since Dawn’s mission at Ceres has been delayed, Pluto is no longer the last dwarf planet (or former planet) to be visited.

    2. I was unaware NH was headed for another rendezvous after Pluto. Great. NASA is smarter than I thought. 😎

      1. They launched a KBO-detecting campaign of observations with Hubble about 2-3 years ago, specifically looking for KBOs in the region that New Horizons could reach, so they could optimise the encounter flight path.

      2. That collective genius, the U.S. Congress, imposes certain constraints. Also, I assume that an engineering/science degree is not always mandatory to ascend the NASA administrative/management ladder.

    1. You may be thinking of pictures of Uranus; it’s (often depicted as having) a striking blue color.

        1. Actually, the image I have from a dim childhood memory is of an artist drawing what the landscape on Pluto would be like I think, not the planet from space, which I have (prior to the above photos) only seen as a small disk. Perhaps the artist was trying to capture the ice that may be around there.

    1. The same spacecraft had earlier flown by other planets and took pictures. Your hope will be fulfilled since they are beautiful.

  3. I don’t do the twitter. I hope events like this coverage don’t become the norm- twitter exclusives. I wouldn’t want to be forced to be a twitt. 🙂

  4. Woah! Who knew?
    It seems New Horizons nearly crashed and burned on the 4th.

    “The APL team had to reconfigure New Horizons the way you would rouse a drunk on a Sunday morning to get him ready for church.”

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