Monday, March 22, 2010

Whale of a story

Eli had previously recounted the amazing story of how Denis Wingo and Keith Cowling had brought Lunar Orbiter tapes back from the dead, digitizing the high resolution analog images of the moon and the first blue (ok, greytone) marbles. Word got around, and soon data archivists who had pallets of old tapes from early satellite missions came calling.

The Lunar Orbiter Image Recovery Project (LOIRP) is moving on to NIMBUS tapes from the 1960s. Among other things, once these tapes are analyzed it will be possible to follow ice extent back almost 20 more years. The National Snow and Ice Data Center believes it will be possible to figure out monthly averages as far back as the mid-60s.

The figure to the right show a thermal map from 23 September 1966. The blue area in the center is cold clouds over the Indian Ocean.

But why is Eli posting this you ask. Well there finally is an answer to why many of the tapes were recorded over. Turns out, that the highest quality tape used whale oil in the tape binder which held the iron oxide. Eli speculates that this lubricated the tape as it moved quickly through the transport. When commercial whaling stopped in the 1980s, new tapes were not available.



Anonymous said...

Tut, tut! Those pesky people at Greenpeace, eh. It's all their fault.

Have they no idea of the importance of gathering data and the need to archive it.

Cymraeg llygoden

Hank Roberts said...

So much for the idea that technology can come up with substitutes for resources being depleted.

If those ecologists who made that bet with that economists a few decades back about prices had just bet on whale oil instead of metals, they'd have won.

I'm sure we'll be hearing from the Japanese Whaling and Space Agency soon offering a solution to this problem.

PS, not to express any hint of lack of trust, but, er, linky? Please?
Purely for citation purposes?

dhogaza said...

Well, apparently whale oil was used as in the binder as a lubricant, this patent on improving magnetic tape references it (along with a slew of other binders):

And there are tons of references to whale oil and magnetic tape, but I didn't find anything authoritative (Google is Hank's job, after all! :)

EliRabett said...

Also great for the Millikan Oil Drop experiment

Hank Roberts said...

Now don't start rumors, Dhog. Googlewhacking is a minor hobby, not my job. To the extent anyone waits for me rather than looking things up for herself, I'm doing it wrong.
Didn't _everybody_ study those Venn diagrams in high school? That's all there is to it.

Anonymous said...

Very cool! Look forward to seeing the monthly sea ice data. Wonder how long it will take to produce the stats?


Anonymous said...

in Wingo's account it sounds like they are close to getting files on line.
Snow Bunny

Anonymous said...

Thanks snow bunny @8:38.


dhogaza said...

"To the extent anyone waits for me rather than looking things up for herself, I'm doing it wrong."

Heh. In this case googling for whale oil and magnetic tape returns a bunch of links to hearsay evidence, along with a couple of markers that make it clear that at least some manufacturers used whale oil. But not enough to confirm the story as told by the Eli in a couple of minutes of poking around.

Anonymous said...

Eli may be referring to Heather Pringle's Science News Focus article entitled 'NASA Dives Into Its Past to Retrieve Vintage Satellite Data' (not read it, as sub required), in which whale oil use is mentioned.

I doubt its use as a binder mind you, but accept its use as a lubricant to overcome things like stiction and preventing the heads stripping the tape bare.

I can also see that little other than hearsay evidence would be present in literature from that era, as tape formulations probably were (are) proprietary information. That whale oil was used in tapes is almost certain (and don't think it's seriously debatable), especially those of Japanese origin. Patents make reference to its possible use, along with a long list of other fatty acids, etc.

I can also imagine that the US 1971 Pelly Amendment made the importation of whale products and derived products almost impossible in short order and led to formulation changes by tape manufacturers who used it. (Sperm oil was big business, and I think at one stage it was stated as being a strategic product by the USA and stockpiled prior to Pelly.)

I did find this (you can skip the intro para); the first answer to the unintelligible question is informative. It casts some doubt on the whale tale, but I wouldn't say that was definitive, because it is at least conceivable that a minor change in one aspect of tape formulation after Pelly might well have exacerbated or caused the later (earlier?) hydrolysation problems found with tapes.

Cymraeg llygoden

Anonymous said...

Oh, I found this too, but it requires a sub and so I've not read it:

Tape Degradation Factors and Predicting Tape Life

Perhaps it would illuminate and provide refs.

Cymraeg llygoden