Gizmodo: solar wind

New Spacecraft Uses Starlight to Propel its Sails

Adam Frucci — Tue, 10 Nov 2009 10:40:00 EST

A new spacecraft is being launched in about a year, one designed to travel across the solar system. But instead of using rockets to propel itself, it uses sails. Sails pushed by light.

Starlight carries not only energy but momentum. Comet tails, for example, are the result of light blowing dust off the comet's core. It's not a lot of juice, but it's enough.

The force on a solar sail is gentle, if not feeble, but unlike a rocket, which fires for a few minutes at most, it is constant. Over days and years a big enough sail, say a mile on a side, could reach speeds of hundreds of thousands of miles an hour, fast enough to traverse the solar system in 5 years. Riding the beam from a powerful laser, a sail could even make the journey to another star system in 100 years, that is to say, a human lifespan.

We're pretty damned far off from a person riding the light to whatever planet Avatar is set on, but it's still a pretty neat idea. [NY Times]

IBEX Launches Today on Man's Most Depressing Space Mission Ever

Jack Loftus — Sun, 19 Oct 2008 17:00:00 EDT

The IBEX launch, which we previewed here at Gizmodo last Monday, went off without a hitch today. The ottoman-sized probe was strapped to a rocket that was strapped to the belly of an airplane, which carried it to 40,000 feet. From there, the rocket fired up and took IBEX to an orbit about 200,000 miles up. Fun! But it gets worse. Much worse. I hope everyone has their lead-lined fallout suits at the ready, because things could get a bit freaky in a few decades.

Now, just to summarize, before we get to the depressing part, the IBEX (Interstellar Boundary Explorer) was conceived to study the farthest reaches of our solar system. At the very edge is the termination shock, where the system ends, and deep space begins. Studying the unknown will always be cool, but it turns out the IBEX mission could also lead to a better understanding of our future doom.

The termination shock is also the point at which the sun's solar wind begins to taper off, and eventually end. Much like our atmosphere here on Earth, the solar wind protects the solar system from the deadly radiation that saturates deep space. It does this by hurling ions in every direction, at 1 million miles per hour, all the time. Scientists believe the solar wind stops about 90% of the radiation from reaching the planets housed within the termination shock.

The trouble is these winds have fallen to their weakest levels in 50 years. In the past 10 years, the wind's intensity weakened by about 25%. Why? Who knows. Hence, IBEX.

Said David McComas, IBEX chief scientist, "We don't believe we're in imminent danger, but we've only measured the solar wind for about 50 years." Reassuring, thy name be NASA. [Bloomberg]

Spiderweb Solar-Wind Sail Proves Jor-El Was Right

Wilson Rothman — Fri, 25 Apr 2008 10:15:00 EDT

Laugh all you want at the sea-urchiny ship Jor-El used to send Kal-El to earth, but it looks a lot like the new kind of solar-sail array developed by the Finnish Meteorological Institute in Helsinki. Instead of the standard solar panels, the Finnish scientists propose long thin strands, just microns in diameter, that stretch out from the spaceship, and use a positive charge to repel heavy positive ions in the solar wind that move at hundreds of kilometers per second.

Unlike Superman's ship, these strands have to be very long—even a test run will require a total of 10 kilometers of the strand, which is currently stitched by hand using ultrasound. Also, as they require solar wind, they won't be much for interstellar travel. Still, as you can see in the video below, it's wild stuff, promising to provide plentiful free "fuel" for fast travel around the solar system. [New Scientist via KurzweilAI]