A quick preview of upcoming events on the spaceflight front:
The USAF has announced that the X-37B will be coming home, probably on Tuesday. This is the third X-37B mission (OTV-3), using the same vehicle as the first X-37B flight and the first to last this long — about 22 months. This blows away the endurance record for a reusable spacecraft, which was previously held by the last two X-37 missions, and before that, by the Space Shuttle’s STS-80 mission, at 17 and a half days. The big difference is that Shuttle ran on fuel cells, so endurance was limited mainly by the amount of reactant they could carry, whereas X-37B is solar powered. The Air Force isn’t saying what it’s been doing up there or why it took this long, but in theory mission duration would only be limited by propellant margin or whatever restrictions the payload has. And obviously we don’t know what the payload is.
Next up after that is Comet Siding Springs’ astonishingly close pass by Mars — close enough that there is some concern about damage to the fleet of Mars orbiters. They’ll take some precautions, like feathering themselves to present the smallest possible target to the comet’s debris stream, but there realistically isn’t much they can do. Those which can, however, will be seizing the opportunity for some amazing comet viewing. At closest approach, it will be only 82,000 miles away. For comparison, the Earth’s geosynchronous ring is 22,000 miles up, and the Moon is a quarter of a million, so if this were flying by Earth at the same distance, it would be much closer to us than the Moon, and would be a staggeringly beautiful sight in the night sky. Closest approach will be October 19.
And then on October 23, the next new moon, we’ll get the buddy to our recent lunar eclipse. Only visible to folks in northwestern North America and a teensy bit of Siberia, this partial eclipse will still be worth watching if you’re in the viewing area. Click here to decide if it’ll be visible from your area.