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Titan's Alien Thunder
An anonymous reader writes "What is not being reported much about the fascinating Huygens descent to the surface of Saturn's largest moon, Titan, is its remarkable microphone. In the silence of space, the probe offers a platform for listening to alien thunder while watching the lightning strike on this alien world--the only moon with an atmosphere thicker than our terrestrial one. The probe detaches from Cassini on Christmas for its atmospheric entry on 14 January 2005. The landing target on Titan borders a bright-dark region thought to be an oil-rich shoreline. Huygens can float for a few hours while still broadcasting if it lands in a lake of oil."
...that crop up around here from time to time after setbacks, you HAVE to be amazed by what they have accomplished on an ever-shrinking budget.
Kudos, NASA! Some of us are still impressed!
There's a Mercedes gap too. I want one and can't afford one, but it's not government's job to do anything about it.
"What is not being reported much..."
That's because it hasn't happened yet. I look forward to downloading the audio once Huygens lands, and if there happens to be a thunderstorm at the time. But until then, I'm not sure what the point of this story is.
Give me Classic Slashdot or give me death!
Are all the WMD and "Invade!" and "Haliburton!" jokes even funny any more? They're about as predictable as the Soviet Russia troll, but not nearly as funny.
I want to delete my account but Slashdot doesn't allow it.
Calling it alien thunder is quite a geocentric perspective. The thunder there is native, Huygens is alien.
500GB of disk, 5TB of transfer, $5.95/mo
It's rather darn good evidence that oil doesn't come from dead dinosaurs...
Oxygen is an explosive gas...
Actually, the idea is to combine oxygen with hydrocarbons and use the surplus energy. In our atmosphere (with plenty of oxygen), you bring the hydrocarbons. On titan (apparently with plenty of hydrocarbons), you would bring the oxygen. Same result.
2) It's antennea is too small to talk to anything but Cassini, which will promptly be flying off.
This probe is designed to be expendable. That is really the right move for an environment about which you no nothing accept "Mostly orange."
...or maybe not.
As mentioned, battery life is the issue here.
Most likely the probe is designed to float, and WILL continue floating for quite a long time. But since Cassini will be gone and the batteries will be dead, it won't matter.
retrorocket.o not found, launch anyway?
I was under the impression that the camera package on Cassini has two cameras - one very long focal length [very small field of view] and one wider focal length with 10x the field of view of the other camera.
Yes, they are 1 megapixel chips, but you have to remember, the design for this started in 1990 and it was launched in 1997, so its not going to be up-to-the minute technology.
Also, if you are going to send a probe all of the way to Saturn, you want to cram as much instrumentation on board as you can whilst being constrained by weight, size, payload, fuel, electrical power etc. Sure Cassini is massive, but when is the next time we will send a probe to Saturn - 20 or 30 years in the future ? As for using ION Propulsion, Deep Space 1 wasn't launched until Oct 24th 1998 - that's a year after Cassini. I'm not an expert on this, but I always through Ion propulsion was for slow acceleration up to speed - Cassini needs manouvering and I presume slowing down to insert itself into orbit around Saturn - can ion propulsion produce such deacceleration ?
Finally, as for Huygens staying around on Titan, is the knowledge about the atmosphere pressure/density/temperature/wind speed or surface composition sufficient to plan for an extended stay ? If not, then surely plan for an exciting but short lifespan for the probe. If the atmosphere or surface is more benign than was thought, then future missions could be planned to stay longer.
Simply put, you can't have your cake and eat it too. Have you taken a look at the number of instrument packages on Cassini and Huygens? It's HUGE. You get what you pay for. Especially in terms of reliability, if you're sending a probe on an 8 year journey you kinda want to be absolutely certain it works when you get there. Double redundancy on everything and money for insane amounts of testing does that for you. As for the one megapixel thing. This misconception has been debunked many times before. Imaging spacecraft don't keep up with the latest best buy "5 megapixels for under 300$!!" race because it's irrelevant. It's the optics that matter and the more pixels you have the more data you have to transmit back to Earth per image, therefore the higher the bandwidth and the bigger the radio transmitting dish (higher gain) has to be, increasing weight and onbaord propellant requirments...see where I'm going with this? That's right, nuclear propulsion. Because if you want to do these things you need POWER to do them and an onboard nuclear reactor does that for you.
- "Hear that?! The percolations are imminent! Cease your ingress!"
I took a look at some of the artist impressions of Titan and the probe coming down.
o rk/index.cfm
http://saturn.jpl.nasa.gov/multimedia/images/artw
At first I wondered if daylight would be that bright on Titan. That made me study the way light is depicted.
If you study the light source in several of the artistic renderings, the light striking Saturn in the background has nothing to do with the light on the surface of Titan. One image (Probe over Titan) shows Saturn getting light from a direction low on Titan's horizon, and yet there seems to be a bright halo around a dark cloud overhead, as if the sun were behind it.
I like the fantasy aspect of this, but I'm afraid we are going to be in for a big let-down when the real images arrive. I'd say that part of the interest in Titan is not science, but pure wonder lust.
Also,
the CCDs on the mars rover (and probably others) are monochrome CCDs. So, for every color picture, 3 are taken, filtered at 3 specific wavelengths (which happen to be, R, G, and B.) The image data is then recomposed into a full-color image here on earth.
"consumer" CCDs, for the most part, may be "5 megapixels" but they count an individual red, green, and blue sensor element as a pixel, and then interpolate to get the full resolution they claim.
NASA's way of doing it with a monochrome CCD and filters means you get a true 1 mpixel image in stunning detail.
Optics do matter, but it is wrong to say that the sort of quality of optics on this craft would not benefit from a higher resolution CCD.
Make the missions faster & smaller in scale, you turn it around quicker (and more often) & hence deliever more up to date tech for any given timescale..
"You lied to me! There is a Swansea!"
Everything is a trade-off.
No matter what you do, it takes a huge amount of resources to orbit Saturn, so it made sense to load up as many instruments as you can for economy of scale. It's 22 feet x 13 feet and weighs six tons. It's taken it seven years to get to Saturn. The cost of building, launching, and staffing 3 or 4 smaller devices would be a great deal more.
Cassini's two cameras are only one megapixel (1024 pixels square) but their versatility far outweighs this "low resolution". They are wide-angle and narrow angle with a range of filters that can see in visible, infrared, and ultraviolet. The narrow angle can see a penny at a distance of 4km. The biggest problem with Cassini is that it's only got a 140 Kbps data rate back to earth. All 12 of Cassini's instruments have to share this pipe, so there isn't any spare bandwidth. To make things worse, Cassini doesn't have a scan-platform so you have to aim the whole thing to transmit and take pictures. A higher resolution camera wouldn't give you that much benefit at the cost of a lot longer transfer time. That was the point of the dual cameras. Wide-angle to look at everything and narrow-angle to zoom in on the interesting stuff.
The Mars Rovers are even more limited. They can transfer 11 Kbps direct to earth, or 128 kbps relayed through the Mars orbiters.
It all comes down to one of those old military sayings. Armchair generals discuss tactics. Real generals discuss Logistics. The supply lines in space are very long or non-existent.