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Old December 17th 17, 02:41 AM posted to sci.space.policy
David Spain
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Default Falcon Heavy test flight payload announced on Twitter

On 12/16/2017 8:17 PM, Sylvia Else wrote:

Do CDs, even pressed CDs, work after hundreds of millions of years?

Sylvia.


Well if you're going to go all out post-historic on me, probably not.

Interesting digression....

Space vacuum with protection from radiation helps a great deal, the real
issue is probably temperature regulation to prevent de-bonding. That's
probably a CD killer.

Here's a list of issues:

quote
How Do CDs or DVDs Rot?

As mentioned above, different types of optical discs contain different
layers and particularly the reflective layer is susceptible to damage.
Standard compact discs typically have a reflective layer made from
aluminum. When exposed to air, aluminum oxidizes, which naturally
happens around the edges of the CD. However, degradation of the
reflective layer is not the only cause of disc rot.

The causes of disc rot are manifold and can include one of the following:

oxidation or corrosion of reflective layer
physical damage to disc surfaces or edges
galvanic reaction between layers and coatings
chemical reactions with contaminants
ultra-violet light damage
breaking down of disc materials, e.g. de-bonding of adhesives
between layers

Interestingly, while most types of disc rot are caused by inappropriate
use and/or storage, there is one in particular, i.e. CD bronzing, which
is caused by a fault in manufacturing.
/quote

From:
http://www.makeuseof.com/tag/cds-tru...vity-mold-rot/

Being in vacuum takes care of item 1. Not being in the possession of
humans takes care of item 2. Item 3 is a limiting factor, being in space
won't change this. Item 4 highly unlikely if the capsule was prepped in
a "clean room", unless the disk was ill-manufactured. Item 5 is an issue
but gamma rays are probably far worse than UV in a space environment, so
assume disk would need rad shielding and would have it in a capsule.
Item 6 is probably the most significant problem, esp. if the disc is
exposed to extreme cold.

Dave