Sky & Telescope February 2001 [antikvár]

Unfinished Businessn 1964, when in the third grade, I made a poster showing the nine planets of our solar system. 1 could find decent photographs of only Mars, Jupiter, and Saturn. Astronauts wouldn't photograph the Earth from lunar orbit for another four years. Mercury and Venus showed phases like the Moon's but were otherwise unremarkable when seen through a telescope. Uranus and Neptune were bland, blue-green disks. And Pluto was just a dot.By the time I had a son in the third grade, robotic explorers had beamed back close-up views of all the planets from Mercury to Neptune, dozens of their moons, an asteroid, and Halley's Comet. If 1 were making my poster today, it would be plastered with images of ragged canyons on Mars, dark storms on Neptune, and countless other wonders. But Pluto would still be just a dot OK, two dots: one for the planet and another for its moon, Charon, discovered in 1978.Aside from a few markings, a wispy atmosphere, and hints about its surface ices, we know little about this remote and frigid world. So, to complete the initial reconnaissance of the Suns family, scientists want to dispatch the Pluto-Kuiper Express (PKE) to the planet, its moon, and some icy cousins in the Kuiper Belt beyond. Following its launch in 2004, the plucky spacecraft would head for Jupiter to pick up speed, then zip past Pluto and Charon in 2012.At least that was the plan until last September, when NASA managers issued a "stop work" order that brought the effort to a grinding halt.PKE and an orbiter for Jupiter's moon Europa were being developed jointly, using similar technology to keep costs down. But the pair have now gone way over budget, so one has to be delayed. Consistent with its emphasis on astro-biology, NASA picked a detailed study of Europa's putative and possibly life-bearing subsurface ocean over a quick glance at some big iceballs.This shortsighted decision should be reversed, and here's why: Europa can wait, but Pluto cannot. The ninth planet sports an atmosphere only when nearest the Sun, as now. Soon experts aren't sure exactly when the thin Plutonian air will snow back onto the surface and remain there, inert, for two centuries. Europa's ocean (if it indeed has one) can be explored whenever we wish.We must launch a mission to Pluto in 2004. For a later departure Jupiter will no longer be positioned to act as an accelerating slingshot, so the trip will take years longer. In that case we might not see Pluto up close before 2020, and by then its atmosphere may be frozen and beyond the ken of everyone alive today. I think this would be a tragedy, and I'm not alone. The Planetary Society has delivered 10,000 letters pleading with Congress to get a Pluto probe back on track. And Ted A. Nichols II, a Pennsylvania high-school student, has posted an Internet petition (wvAv.PlutoMission.com) that's getting NASA's attention.Let s finish what we started in the '60s. Write to NASA! Write to Congress! Make 'em show us Pluto!