Finding Pluto is really New Horizon’s biggest problem

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As New Horizons speeds towards its planned fly-by of Pluto on July 14, the biggest problem faced by its engineers is making sure the spacecraft actually finds and photographs the planet.

Because astronomers discovered the dwarf planet in 1930, they have seen only part of its 248-year path around the Sun, and they don’t know exactly where Pluto is. And New Horizons is so far from Earth that it takes 9 hours to send and receive a signal, making the spacecraft hard to direct in real time. “Everything is pushed to the extreme,” says Bobby Williams, an engineer at KinetX Aerospace in Simi Valley, California, who heads the mission’s navigation team.

This fact, which has not been mentioned previously as far as I remember, suggests that there is a good chance that New Horizons might fly through its planned window and aim its cameras at the wrong spot in the sky, missing Pluto entirely. It also explains partly why the images released so far have been so fuzzy: They are focused mostly on doing navigation work, and are taking wide angle shots to make sure they catch Pluto in their picture frame. Zooming in too close might actually miss Pluto as they don’t exactly know where it is.

All this only makes the July 14th fly-by even more exciting. Let us hope they do due diligence and get the pictures we all want!


  • Nick P

    Bob, I have been a little surprised by how fuzzy the images so far have been but your explanation must explain it. Do you have any idea what the aperture is of their main camera? A relatively small telescope can get a clearer image of Mars at similar distances and our telescopes have to contend with the earth’s atmosphere.

  • mivenho

    Apparently my fingernails weren’t bitten down quite enough yet.

  • Ben K

    Is there evidence of massive objects in the kuiper belt, or beyond, causing perturbations in Pluto’s orbit?

  • No. The reason they do not know Pluto’s exact position is simply because its 248 year orbit has only been tracked for less than 80 years. We simply don’t have enough information yet to precisely plot out the orbit. We can make some very good estimates, and every minute that New Horizons gets closer to Pluto those estimates improve, but they are still nonetheless estimates.

    Note that we are not talking about gigantic errors. The problem is that to point New Horizons precisely, at the speed it will be traveling as it flies past Pluto, requires a level of precision that we simply might not yet have.

  • PeterF

    Perhaps now is the time to start taking progressively narrower field-of-view so that a more precise location can be determined and they can more accurately point the camera at closest approach?

  • Maurice Levie

    Up to last week, all pluto imaging came from OpNav Campaigns that LORRI was used for. I would hope that the KinetX team that actually controlls the probe’s trajectory has a solid backroom of engineers, or can reach out to other outsourced teams that serve NASA. If that is wishful thinking on my part, maybe JPL could be pulled in to tap their vast knowledge (New Horizons is ran by APL not JPL) ?

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