Macs In Space II

MasterOfDisaster writes: "Some nut is planning to make a global wireless network using apple's Power Macintosh G4 Cubes. Here's the story." We ran a story about this guy last year, but this one has a bit more detail and he's progressed further in his plans.

Comments

Airports are x86-powered

[maggard]

Yep, you heard me right: Apple's very popular line of AirPort wireless base-stations use x86 processors, not PowerPC ones.

Really the thing is little more then a FlashROM, an off-brand x86 and of course Lucent's Orinoco PC-Card. The code running it is exemplarily, folks have found lots of goodies in it and Apple's put out several revs. of improvements, but not a PPC to be found.

Since the article talks about flying boxes with MacOS on PowerPC's then clearly the existing AirPort base-station technology is NOT the subject. There'd be nothing in common with either the hardware or the code. It'd be easier to start with a BSD underpinning (MacOS X) or something like Sustainable Software's products (MacOS >X.)

Thus, moderators, please bring down those postings that refer to flying AirPorts.

BTW, a good (though dated) AirPort technology link is http://www.msrl.com/airport-gold

Solar wind will kill this thing

[Argyle]

The solar radiation will degrade the hard drive and RAM to the point of unusability. Long term solar radiation studies have shown that that extended exposure in orbit subjects electronics to solar storms and other destructive environments that harm non-shielded systems.

There are also the issues of microgravity and vacuum. Metals behave differently in orbit. Several communications satellites have failed because of the growth of zinc solenoids in the spacecraft in orbit. Plastics will outgas, changing their structure. The air trapped in the hardrive will exert a constant pressure on the seals holding it in, increasing the chance of hard drive failure. All the rules are different in space.

The temperature differential between the light and dark sides of the satellite are approx. 200 F. With all that thermal stress, all components will be mechanically stressed.

While I applaud this guys gung-ho spirit, I think he underestimates the harsh environment of space.
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Re:Solar wind will kill this thing

[Chairboy]

Most of these (very valid)concerns can be addressed cheaply. He probably intends to shield most of the hardware. He can avoid most of the plastics problems by removing the Cubes from their boxes and putting the components in a special case, and by filling the sealed case with nitrogen at low pressure, he can avoid having too large of a pressure differential between the components and their surroundings. He'll need to do this anyhow so he can install special heat transfer sinks to pull heat out to radiators.

Finally, by choosing a super-low albedo material for the outside (polished silver or white, for instance) he can reduce the mechanical stressing (which is caused by the temperature differential) by a lot, making this a viable cheap satellite.

hm - READING

[jafac]

after READING the article, (wot a concept!) I start to see a method to his madness.

Nowhere does it say that a Mac cube will be used. Nowhere does it say that MacOS 9 will be used.

It's a 120 lb satellite, not engineered to withstand launch stresses, because it will be assembled in orbit. Many of the parts are off the shelf - including probably not more than a motherboard and CPU of a macintosh (much cheaper than designing a controller) - which will probably THINK it's running an Airport - but I'm betting it will be fooled into thinking that it's running airport when it's running some higher-powered device (airport range = 150 feet on disputed radio bandwidth (in France)), (his satellite range, altitude of 120 miles plus azimuth. . .).

In fact, I bet it will run Darwin, probably without a hard-drive, (probably some sheilded flash RAM device instead), and probably with lots of custom software (like TiVo runs Linux). (I'm guessing Darwin because it would be much easier to run the transceiver as Airport that way than trying to hack together something with Linux - BSD is supposedly more reliable than Linux anyway, but I digress and risk a flamewar).

Cooling will be an issue, and so might radiation, but a PPC chip will give him some pretty good computing power without worring about heat as much as with SOME OTHER solutions.

Of course, part of the 120 lbs will probably be gyros, solar panels, the transmitter and amplifier,

but the main gimmick here, is that he's using off the shelf parts, and assembling them in orbit, in an attempt to reduce costs. (in other words, he probably plans on all devices being launched from ISS or Shuttle, assembled in orbit). Yeah, the labor of assembling in orbit is probably LOTS higher, but you end up reducing the overall weight by bunches, by not having to design solar-panel deployment systems, shrouds, and shock-resistant innards.

If he's planning on spending $10 million on the first device (instead of hundreds of millions for standard communications satellites), it sounds like a worthy project to me (*cough* irridium)