November 2004

Saturn is going to make the headlines again, or rather it's impressively large moon Titan is. Up until now, even the best close-ups from the probe have revealed little more than pictures that you could easily confuse with a brown hen's egg. But the Cassini-Huygens spacecraft is going to come within 1280km of Titan's surface and have a good look at it with optics and fog-penetrating radar. Bearing in mind that the Huygens part of the craft will be landing on it in January, we'd like to know if it'll land with a thud or a splash for a start, though a splash will more likely indicate liquefied natural gas rather than water.

I've been at the NASA website where they thoughtfully store the raw images as they come in. I don't have access to all the tools and calibration information that NASA have, but I have Linux and the image on the right is the most recent one I could find. I've manipulated it to bring out contrasts and added fake colouring based on that. Note the circular bit in the bottom right corner – probably a crater; definitely not my digital paintbrush or a tea mug ring. But volcanic, or done by a falling rock? What's the dimple in the middle?

We're still a bit sketchy on the details of surface conditions, but we know the pressure is slightly higher than Earth's, and it's likely to be pretty cold down there; 178°C below zero or thereabouts. At that point water is a stable solid, and carbon dioxide is very definitely a kind of snow. Huygens is in for a frosty reception. Cassini did a fly-by back in July this year, and snapped an image that was subsequently enhanced (left) revealing light and dark areas and possibly a polar ice cap of some kind. We don't know if the light and dark areas are dry, wet, or simply patches of a tar-like organic rain called tholin that is also found on comets and distant asteroids. On Christmas day, Huygens will be released from Cassini to land on Titan, and a month or so later we may know the answer.

The Brazilians finally got their rocket off the pad at Alcantra after a previous attempt 14 months ago which detonated catastrophically and unexpectedly on the pad claiming the lives of 21 technicians. Investigations blamed a wiring fault that caused the solid rocket motors to ignite prematurely. The rocket is creatively named the VSB-30, or the Brazilian Exploration Vehicle – the girls at the beauty salon will think this is hilarious. Brazil has plans to sell 15 of the rockets, which can carry 395kg up as far as 250km. This one was just a prototype, and provide 7 minutes of microgravity with a maximum altitude of about 100km . As the launchpad is so close to the equator, the higher launches tap the Earth's spin and need less fuel to reach orbit.

NASA Are using an old military surveillance satellite as target practice for their DART - Demonstration of Autonomous Rendezvous Technology shown on the left, which has recently completed successful ground tests. They've developed a manoeuvrable satellite – 22 manoeuvring thrusters, no less - with some cunning software that can automagically seek out a satellite and dock with it. Now, there are a couple of ways this can go: The primary reason given is to send up spacecraft in small chunks and have them assemble themselves in orbit without all that tedious manned space station stuff. Satellites can be refuelled or topped up with coolant, supplies sent up, yada yada.

But they'll put DART in a polar orbit, and polar orbits are where you put spy satellites because as the loop over the poles they take pictures of the whole Earth rotating underneath them. Having a spacecraft that can seek out other spacecraft and get close to them autonomously could be very handy in the spying business. The old USSR used to play that game with satellites carrying a payload of high explosive and ball bearings. Bear in mind that the US government published a report titled "Air Force Doctrine Document 2-2.1: Counterspace Operations" this October, which makes two things perfectly clear: First, the document declares that the U.S. Air Force is duty-bound to slap down other countries' space efforts, should the need arise. Second, the US Air Force announced that it has a new job; to maintain America's "space superiority" - the "freedom to attack as well as the freedom from attack" in orbit. That should go down well as a starting point for future international joint missions, eh?

The two Mars rovers are still going strong, although Spirit proceeds with a slight limp out of Gusev Crater into the Columbia Hills having travelled 3647 metres so far. The other lander, Opportunity, has now travelled more than an old-fashioned mile, having just clocked up 1619 metres. Opportunity has had a spot of good luck recently, with its solar panels suddenly upping their power output from about 550W to 700W. Nobody is sure why, but guesses range from wind blowing the dust off to frost making the dust clump together, revealing more solar cell in the gaps. It'll be interesting to see how long the rovers can hold out for.

And finally, the reason behind the Genesis probe's tendency to forget about its parachute and burrow into the Earth has been identified: They built the gravity sensor downside-up. The chaps with the screwdrivers assembled it all correctly, but someone had a “senior moment” and the sensors were put in their little pre-pack boxes the wrong way up. I bet Newton never had this problem when he invented gravity.

This edition is also on the web, just point your web browser to http://olliver.family.gen.nz.   vik@olliver.family.gen.nz
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