Pluto is so far away (3 billion miles) and so small (about two-thirds the size of our moon) that we’ve never had a good look at it, not even with the Hubble Space Telescope. In Hubble images, Pluto has always been a tiny, pixelated blob.

Until now.

A NASA spaceship, New Horizons, is bearing down on the dwarf planet at 32,000 miles per hour. The robotic probe, which weighs half a ton and is shaped like a vacuum cleaner attachment, will fly past Pluto, cameras and instruments ravenously gobbling data, at 7:49 a.m. Eastern time on July 14.

That, at least, is what we can expect to happen given the current trajectory of New Horizons and the laws of physics. But this is not a mission free of hazard. A spaceship traveling so fast – New Horizons is the fastest spaceship ever launched from Earth – can be disabled by a collision with something as small as a grain of sand.

Pluto had been left out in the cold for decades as NASA probes explored larger and flashier planets. Recently, it endured a downgrade among astronomers who declared that it wasn’t a full-blown planet at all. But it’s definitely something intriguing – easily the most famous of the small, icy worlds that inhabit the exurbs of the solar system.

“We are running the anchor leg in a 50-year exploration of the planets,” says Alan Stern, the principal investigator – the leader – of the New Horizons mission. “I tell people, this is it, it’s the last picture show, it’s the last train to Clarksville. Better watch!”

That’s vintage Alan Stern: He is a tireless promoter of New Horizons. You could call Stern “mercurial” if that weren’t inappropriate for a planetary scientist focused on Pluto.

In a world in which scientists tend to speak in jargon, and where project managers default to bureaucratese, Stern, 57, a former NASA associate administrator who is now at the nonprofit Southwest Research Institute in Boulder, Colorado, speaks in tweets, news alerts, sound bites, headlines and pull-quotes.

“This” – he pauses dramatically – “is a moment. People should watch it. They should sit their freakin’ kids down and say, think about this technology. Think about people who worked on this for 25 years to bring this knowledge. . . . It’s a long way to go to the outer edge, the very edge of the solar system.”