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Posted by Max Power on July 16, 2006, 6:31 am
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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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Posted by (null on July 19, 2006, 2:35 pm
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>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).
1) Hard drive heads need air to keep them from bouncing on the platters.
2) HDs are guaranteed to work only in a narrower temperature range than
they'd see on spacecraft.
Francois.
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Posted by Damon Hill on July 19, 2006, 9:50 pm
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Posted by American on July 20, 2006, 1:06 pm
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Max Power wrote:
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> 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.space.policy/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/messenger/oldmess/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/0,1282,61009,00.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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Posted by Paul F. Dietz on August 12, 2006, 5:55 pm
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> No, the storage mediums are too allergic to magnetic field disturbances
> in the solar radiation field, as well as in the vicinity of Jupiter:
Utter bullshit. The magnetic fields in the interplanetary medium
are much weaker than the magnetic field at the Earth's surface,
let alone the magnetic field needed to affect a hard drive.
Paul
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>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).