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Hard drives on 'Deep Space' missons: any idea why they are never used?
Hard drives on 'Deep Space' missions: any idea why they are never used?
4 x 100 Gb drives could store enough data such that it could take up to 6 months to trickle the data back at 24,000 kbs (assuming high power downlink and turbo codes). |
#2
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Hard drives on 'Deep Space' missons: any idea why they are never used?
Max Power wrote: Hard drives on 'Deep Space' missions: any idea why they are never used? 4 x 100 Gb drives could store enough data such that it could take up to 6 months to trickle the data back at 24,000 kbs (assuming high power downlink and turbo codes). No, the storage mediums are too allergic to magnetic field disturbances in the solar radiation field, as well as in the vicinity of Jupiter: from thread: [...http://groups.google.com/group/sci.s...icy/browse_frm /thread/c908cbed581e70/6501c0af54ba70bd?lnk=st&q=&rnum=7# 6501c0af54ba70bd...] Radio and Plasma wave data were obtained on December 3, 2000 by the Cassini Radio and Plasma Wave Science (RPWS) investigation from a distance of just over 27 million kilometers from Jupiter: During this time period, the RPWS captured radio emissions generated in the vicinity of Jupiter. These emissions included decametric radio emissions originating in the auroral regions of Jupiter. (Decametric refers to approximate wavelength of radio emissions (10 meters). At somewhat lower frequencies, near 1 megahertz, the hectometric radiation, around 100 meters, is generated as a part of the auroral process at Jupiter. Lower in frequency, near 100 kilohertz, are examples of two types of kilometric radiation. (Kilometric refers to wavelengths around 1 kilometer or 1000 meters.) Even though these two types of emissions are centered at about the same frequency, they are thought to originate in totally different locations and by totally different mechanisms. The broadband kilometric radiation near the center of the display is again believed to be generated on field lines associated with the aurora and probably generated by the same or similar mechanism as the decametric and hectometric radiation. The narrowband kilometric radiation is generated near the outer edge of the Io torus, which remains on a different orbital path than Europa. Data on Quasi- periodic bursts below about 10 kilohertz consist of brief bursts and sometimes occur at about 15-minute spacing, and sometimes at about 40-minute spacing. Even though these emissions were discov- ered by Voyager and studied by Ulysses and Galileo. Very little is known about where and how they are generated. (From: http://www2.jpl.nasa.gov/galileo/mes...ess/Ion.html): On Jupiter's moon, Io, volcanoes constantly erupt, spewing forth oxygen and sulphur, which then settle on Io's surface. The inter- action of Io with Jupiter's magnetosphere strips the oxygen and sulphur from Io's surface at the rate of 900 kg (1 ton) per second, tearing these particles from Io's gravitational influence and expel- ling them into Jupiter's magnetosphere. These particles become elec- trically charged and many diffuse outward to 1.5 to 3.6 million kilometers (0.9 to 2.2 million miles) from Jupiter, where they are accelerated by an interaction with the massive Jovian magnetic field. Ed explains, "About 0.2% of the original particles, now highly energized, diffuse back toward Jupiter. The ions may have left Io at one-thousandth the speed of light. By the time they have returned to within 700,000 kilometers (420,000 miles) of the planet (near Europa's orbit), these ions have accelerated to one-tenth the speed of light (about 30,000 kilometers/second (18,000 miles per hour))!" Some of these ions travel along Jupiter's magnetic field lines and spiral into the planet's polar region. In fact, these heavy ions falling into Jupiter's atmosphere may be the single largest contributor to Jupiter's auroras. So what do we replace "Hard Drives" with? Try the new optical storage medium that was invented by the Israelis, whose link is now defunct, but can also be read at the Wired website: http://www.wired.com/news/technology...,61009,00.html Also try typing in the Google Search engine the words "optical storage" and "optical processing" and see what Taiwan has been up to, as well as the rest of the world trying to play "catch up". |
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Hard drives on 'Deep Space' missons: any idea why they are never used?
PLease clarify what you are saying, cause last time i checked all our
space vehicles had hard drives. peace zonker http://2000ah.blogspot.com Max Power wrote: Hard drives on 'Deep Space' missions: any idea why they are never used? 4 x 100 Gb drives could store enough data such that it could take up to 6 months to trickle the data back at 24,000 kbs (assuming high power downlink and turbo codes). |
#4
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Hard drives on 'Deep Space' missons: any idea why they are never used?
Max Power wrote: Hard drives on 'Deep Space' missions: any idea why they are never used? 4 x 100 Gb drives could store enough data such that it could take up to 6 months to trickle the data back at 24,000 kbs (assuming high power downlink and turbo codes). My guess is that Hard Drives are too prone to magnetic turbulence both in the Van Allen Belt and Jupiter, therefore not a good storage/processing medium. There are several methods for holographic storage, one interesting one being 3D Atomic Holographic, as seen by one Colossal Storage Corp.: http://www.i4u.com/article481.html While there are currently lesser technologies that are exploring holographic storage and processing, this technology seems to be at the cutting edge. My belief is that these technologies will advance in tandem to some kind of FTL propulsion technology, unless, of course, our currently antiquated types keep us earthbound. |
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Hard drives on 'Deep Space' missons: any idea why they are never used?
Max Power wrote:
Hard drives on 'Deep Space' missions: any idea why they are never used? Reliability. Tape drives and solid state storage have demonstrated endurances of decades. The moving platters of hard drives do not yet have the same reputation for reliability. Mike Miller |
#6
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Hard drives on 'Deep Space' missons: any idea why they are never used?
Hard drives on 'Deep Space' missions: any idea why they are never used?
Reliability would probably be a problem. But more interestingly, spinning a drive would change the attitude of the spacecraft (a la reaction wheels). I think there may have been at least one mission which avoided this by having two drives spinning in opposite directions. But given the alternatives to hard drives these days, I'd be quite surprised to see this done now. |
#7
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Hard drives on 'Deep Space' missons: any idea why they are never used?
Max Power wrote:
Hard drives on 'Deep Space' missions: any idea why they are never used? 4 x 100 Gb drives could store enough data such that it could take up to 6 months to trickle the data back at 24,000 kbs (assuming high power downlink and turbo codes). Well there you go. Since you're not likely to collect 400 Gb all at once, that means you put too much storage on board. (We tend to not do a whole lot of flybys anymore, so there isn't one giant burst of data collection.) So the basic reasons a 1. The data rates from deep space are low, limiting the sustained collection rates. You simply don't have any use for storing months worth of collected data, so you don't really need that much storage. A few weeks worth is plenty. 2. Qualifying (and possibly making design changes to) hard drives to survive the launch, and in some cases landing environment, not to mention working in a either a vacuum or a pressure vessel and working in zero-G, would be an expensive proposition. I haven't heard of such a qualification having been done, but it may have. 3. On the other hand, flash memory is already qualified. The higher $/GB of flash memory is not a factor for spacecraft, and the kg/GB is comparable or better for flash (depending on packaging). 4. The fewer critical mechanical devices on a spacecraft, the better. Hard drives crash, flash memory doesn't. That doesn't mean that some deep space application won't come along that makes putting a hard drive on it worthwhile somehow. It's conceivable, for some application with very high bursts of high rate data. Even in that case, I still think the trade between hard drive and flash will be a close one. It would basically come down to mass vs. reliability. I'd bet on the flash. mark |
#8
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Hard drives on 'Deep Space' missons: any idea why they are never used?
On Sun, 16 Jul 2006 03:31:14 -0700, "Max Power"
wrote: Hard drives on 'Deep Space' missions: any idea why they are never used? Mostly because hard drives have moving parts, and moving parts are a serious annoyance to engineers who have to design hardware that absolutely must work for years at a time with absolutely no possibility of repair or servicing. Also, hard drives require air to work - it's guaranteed head crash time if you try to spin one up in vacuum. You can seal them inside a pressurized container, of course, but now you've got a set of seals that absolutely must not leak, again for years at a time with no maintenance. Usually, it's easier to go with some sort of no-moving-parts memory; several technologies to chose from, and they'll hold enough data to keep the scientists and journalists happy until the next mission. -- *John Schilling * "Anything worth doing, * *Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" * *Chief Scientist & General Partner * -13th Rule of Acquisition * *White Elephant Research, LLC * "There is no substitute * * for success" * *661-951-9107 or 661-275-6795 * -58th Rule of Acquisition * |
#9
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Hard drives on 'Deep Space' missons: any idea why they are never used?
"Max Power" wrote in message ... Hard drives on 'Deep Space' missions: any idea why they are never used? 4 x 100 Gb drives could store enough data such that it could take up to 6 months to trickle the data back at 24,000 kbs (assuming high power downlink and turbo codes). power requirements, or perhaps the need to "float" the head on a cushion of air to prevent head crashes. |
#10
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Hard drives on 'Deep Space' missons: any idea why they are never used?
see the thread on hard drives at 30,000 feet. Also consumer grade hard
drives are just not realiable enough. Its cheap to replace them here on earth... but up there, on mars? or at Pluto? Solid state looks like the way to go for deep space applications. IIRC However i do belive that some LEO satlites may have use them. But i could be totaly wrong there. greg Max Power wrote: Hard drives on 'Deep Space' missions: any idea why they are never used? 4 x 100 Gb drives could store enough data such that it could take up to 6 months to trickle the data back at 24,000 kbs (assuming high power downlink and turbo codes). |
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