New Horizons and Pluto’s Space Debris

New HorizonsGiven the kinds of politics I write about, there wasn’t much going on over the weekend. Luckily, there days, there is always a lot going on with Pluto. New Horizons is still just under two months out from its ridiculously close approach to the planet, but there is something new all the time. At this point, the NASA scientists seem to be on a knife’s edge. They are afraid that New Horizons might be destroyed as it makes its rendezvous. There are a lot of things to worry about.

New Horizons was launched at the fastest speed ever for a NASA rocket. According to, the spacecraft is moving at 32,570 mph relative to the sun. So if it were to run into an object smaller than the head of a pin, the spacecraft could be destroyed. And New Horizons is headed into what looks like a pretty dirty planetary system.

When New Horizons was being planned, we only knew about one moon: Charon, which is so big (1,205 km diameter) that Pluto and it constitute a true binary system. By the time it launched in 2006, we knew about two more moons. In June 2005, 91 km diameter Nix was discovered, followed closely in July by 114 km diameter Hydra. And since then, two more moons have been discovered: ~25 km diameter Kerberos and ~15 km Styx. These last two moons indicate that Pluto may have a ring system. (Note that 15 or 25 km may not sound like much, but the Chicxulub impact, which killed the big dinosaurs off, was estimated to be just 10 km across.)

So Pluto is looking to be quite the space dump. And New Horizons would seem to have quite a chance to run into debris that is quite a lot larger than a pin head. As a result, NASA is using New Horizons itself to look for potential problems. In that effort, we have this processed image that includes all of the moons that we know about. Scientists think that as the the spacecraft gets closer, new (smaller) moons will be found. It should be interesting.

Pluto's Moons - New Horizons

The team working on New Horizon has a few options if it looks like the probe will be heading through a debris field. They could orient the probe so that it shields itself. Or better: it could take a different route. The team has come up with three alternatives — two very similar, but one that will take New Horizons so close to Pluto that it will compromise the images taken. But given that there are models of just where new moons and debris are likely to be, they think the current route is good.

I hope so.

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