Watch out Phoenix! Don't Scratch the CD!

by Ian O'Neill (June 26, 2008)

I've just written an article over on the Universe Today about the stunning discovery that Mars regolith actually bears very close resemblance to terrestrial soil. This is very cool as this shows Mars may be capable of sustaining life (as we know it) and it has implications for the future of manned Mars missions (we might be able to use this mineral-rich soil for growing plants for instance). So rather than replicating the article here, I urge you to pop over to the Universe Today article (Phoenix: Mars Soil Can Support Life) and enjoy (I was quite proud of pointing out the huge difference between "soil" and "regolith" in the final paragraph!). But that's not the point of this Astroengine post, I have a far more pressing issue to voice…

The Phoenix Mars lander has a CD attached to its deck. It's not your average run-of-the- mill CD though, it's actually one of the most advanced DVDs ever manufactured. It contains a vast number of literary, visual and audio science fiction works about the Red Planet including 161 novels and stories, 63 pieces of artwork and four radio broadcasts related to Mars. The library totals over 1.43 GB of data. For the full play list, have a look at the Space.com article about the "Visions of Mars" DVD.

According to NASA, the DVD is has its data stored in a robust silicon glass disk, designed to withstand extreme temperatures and freezing carbon dioxide damage. According to the scientist that oversaw the DVDs construction, it should remain undamaged for 500 years. When attached to the spacecraft before launch, the DVD was even baked to remove any explosive CO2 bubbles. Sounds like an impressive piece of kit.

However, I can see a possible design flaw. As an avid collector of music CDs and data DVDs for computing and films, I've often experienced frustrating scratches forming inexplicably on the laser-reading side of my CDs and DVDs. Even disks slid out of harms way inside a protective case have formed small abrasive marks and sometimes corruptible scratches. I remember my treasured limited edition gold-plated Enigma CD succumbing to a nasty score right through the middle. No matter how careful I was, scratches would appear (having said that, I'm surprised most of my collection is still functioning after the chaos of eight years in university digs!).

More at www.astroengine.com