Tag Archives: New Horizons

What we’ve learned so far from New Horizons’ trip to Pluto

After a trip of 3 billion miles, the NASA spacecraft New Horizons has finally reached it’s closest orbit of the much-beloved planetesimal Pluto today at 8:45am. Powered by Pluto’s namesake element, Plutonium, New Horizons is Humanity’s first meet-and-greet with the famed body. What it saw in those fateful moments, only a few at NASA know about for now. It may be until 9pm before we get new images, but those images may also be the first-ever full-color images of the mini planet.

“This is real exploration,” intoned NASA Associate Administrator for Science John Grunsfeld. And indeed, we will still be waiting some time to find out if the spacecraft survives the full experience of flying by Pluto.

This is largely due to the fact that space missions have to run on shoestring-and-less resources in order to be able to make the journeys they do make. New Horizons has to split it’s time between taking measurements, then turning, and sending it’s data payload back to Earth.

In fact,  one interesting observation that helps us understand just how far the New Horizons spacecraft has traveled, it takes 8 minutes for light from our sun to reach the Earth, but speed-of-light communications from the New Horizon craft will take about 4.5 hours to reach Earth.

Still, Principle Investigator Alan Stern doesn’t think New Horizons is in much danger of failing. NASA calculates that there’s about 2 chances in 10,000 that the mission will fail. After that, New Horizons has enough power to continue it’s mission until as late as 2030. By that time, New Horizons may even have passed out of the heliosphere – the region of space affected by solar radiation – just as Voyager 1 and 2 have done. But this time, it will be with much more sophisticated technology.

Pluto: a world of surprises

We’ve yet to find a planet in our solar system that’s a snoozefest. And if it was going to happen, most predicted it might be Pluto. After all, it’s just a hunk of rock in the distant Solar System that has even been stripped of it’s planet status. Many of us still bristle at the prospect of Pluto the “Planetesimal,” yet that’s exactly what it is.

Still, early indications predict a much more active planet than we’d thought. Alan Stern points out that the dichotomy of Pluto and it’s moon Charon could not be more striking. Since Pluto’s surface looks much less crater-ridden than it’s neighbor, indications are good that there might have been or may still be geological activity on the planet. There are also striations on the surface that suggest more seismic or tectonic activity.

A planet that gets regular quakes, volcanic activity or other geological processes tend to cover up their asteroid strikes. That Charon has these marks but Pluto does not seems to suggest that it’s been at least that active.

We’ve known for a while that Pluto has a very thin nitrogenous atmosphere. The idea that this atmosphere might obscure surface features has been a real worry for scientists embarking on this mission. But on close inspection, this atmosphere seems to be extremely thin with almost no differentiation. Thinning and thickening clouds would indicate weather patterns, but none are present. Still, when asked if it snows on Pluto, scientists seemed confident.

“It sure looks that way,” exclaimed Stern.

So, there may not be an active atmosphere on Pluto, but like Madison Square Garden, you can still occasionally get some precipitation.

We will be spending months and years analyzing the data brought back to us by New Horizons, but for now, we will need to wait on a lot of it. It’s not just distance alone that makes the wait: it’s also the technology. To say the least, transmitting data through 3 billion miles of space is “lossy.” Thus the transfer rate from New Horizons is in the range of about 1000 to 4000 bits per second. Literally fractions of the speed that your old dialup modem enjoyed.

On top of that, NASA’s means of transferring data is based on the already successful model put forth by the Apollo missions. Namely, that data is sent twice, first as a “contingent data” stream, in case the mission goes south later. Then again as fully-fleshed out data. We’ll get full-color pictures tonight, but they won’t be full-resolution for some time.

What’s next for the New Horizons probe? Well, it’s currently traveling on the night side (opposite the sun) of Pluto. Boffins were able to plan the trip to coincide with Charon’s travel across the same night side, so that reflections from Charon will illuminate the surface of Pluto in much the same way that our Earth’s Luna does. After that, it’s off to interstellar space, perhaps with another flyby of one of our outer Solar System’s many mysterious planetesimals.