1. Quotes from the TESB Radio Drama prove that probe droid capsules have hyperspace capability!
This claim is the strongest counterclaim available, but unfortunately that is not saying much. It is based on the following quote:
NEEDA: Lord Vader has also revised the targeting list. Have the operations people retarget probe droids for the planets Allyuen, Tokmia, and Hoth. IMPERIAL OFFICER: Hoth, sir? But Captain Needa, that's an ice planet! NEEDA: I am aware of that, Lieutenant.
The quote is purported to come from the TESB Radio Drama, which would make it part of the canon. Of course, since the Radio Dramas are effectively only quasi-canonical (useful for clarification of on-screen events and not re-writing of them) the utility of the claim is a bit iffy.
However, we needn't trouble ourselves to engage in any sort of canon calculus for a very simple reason: The quote above never appears in the TESB Radio Drama. It is a falsehood. There's no telling if it's one based on lazy research, or just a plain old lie. My loyal opponents have used both frequently, so there's no way to tell for sure.
Update: In perusings online, I've found that the Allyuen and Tokmia quote -- if it exists -- probably comes from the scripts of the radio dramas published in book form by Del Rey. However, those lines didn't make it into the finished audio product. So far as I know the scripts of the radio dramas aren't considered canon, and so they are EU material only.
In reality, the following conversation appears in the TESB Radio Drama (Part One), for what it's worth:
Lieutenant: Captain Needa? Capt. Needa: Yes, Lieutenant. Lieutenant: Sir, Imperial Headquarters reports that a Rebel convoy has been completely destroyed near Derra IV. Capt. Needa: Ah, at least someone is seeing a little action. Let's hope that we do before the Rebellion is completely obliterated. What is the status of our probe droid operation? Lieutenant: The probe droids we've launched so far report no Rebel activity. No human activity, for that matter, on any of the planets they've reconnoitered. Capt. Needa: And the next launch group? Lieutenant: All the probes are targeted and ready to go. The ship is now in position, shall I give the order to launch? Capt. Needa: No, Lieutenant. I just received priority signal from Lord Vader's flagship. We have new information to program into the probes' databanks and sensors. Lieutenant: That could delay the launch for some time, Captain Needa. May I ask what the new information is? Capt. Needa: It seems that Lord Vader is more eager than ever to locate this Skywalker. He's also placed great emphasis on discovering the whereabouts of a starship called the Millennium Falcon. Lieutenant: I'll have the new material programmed into the probes immediately, sir. Capt. Needa: Very good.
The above would seem to suggest either that the ISD seen in the Hoth system was Needa's, or else that Needa's lieutenant was overseeing other ISDs that were depositing probes. In any case, it's interesting that the ship has to move to a particular position to launch, isn't it? I, for one, have a few ideas on where that position is. Sounds to me like the Radio Drama supports my page, for all both are worth.
2. "[Y]ou'd have to be delusional in the first place to think that an Imperial Star Destroyer would drop off eight probes in a single system"! And what of the others that head in the direction of the blue glow that reflects off the ISD?
The argument above is quite silly. First, it assumes that the Empire must only use one probe droid per planet. Given the breakneck speed of a few miles per hour seen from the probe droid on Hoth, I don't see how anyone could seriously think the Empire would deposit one droid only. This would be about the same as exploring Earth by having a guy on a bicycle tool about the countryside at random looking for interesting stuff. Sure, you'll find interesting stuff, but it's gonna take you a long while.
As example, the Lewis & Clark expedition that explored the then-new Louisiana Purchase (which doubled the size of the early United States) and points all the way to the Pacific departed St. Louis, Missouri in May, 1804. Travelling mainly by water and assisted by pre-existing penetrations by fur traders and such, along with help by local native guides, the trip to the Pacific took them until November, 1805 (at least if we count as of when they were 20 miles distant). That is eighteen months. A probe droid would almost certainly be faster, but exploring an entire planet is a much grander undertaking than exploring a small line through half of a continent.
Or, just consider Texas. The state of Texas consists of over 268,000 square miles of territory. Now, let's assume that the probe droid has a three mile scan radius (and do please suppress your giggles at my generosity). So, for the sake of ease, let's bend Texas into a single long line three miles across and 89,333 miles long. The probe droid can thus make one straight shot without diversions or curves . . . but still, it has to cover those 89,000+ miles. Even if we assume the probe droid can make 30mph (again suppressing our giggles, since this is several times what we actually saw it capable of performing), then it will take almost 3,000 hours to make the trip. That's 125 days of travel without stopping just to scan the whole of Texas with a faster probe equipped better sensors than we saw.
3. The Rebels had found life on Hoth in the form of the Tauntauns.
Evidently my saying that the Rebels found no life after a month was offensive to some. However, it is also absolutely correct.
Although Han says there wasn't enough life to fill a space cruiser (indicating that there might've been at least a little bit), other statements from the Rebels call Hoth lifeless, such as Han reporting to Rieekan (in the film and Ch. 1) that there is "no sign of life" and "there isn't a hint of life in the area", not to mention Luke saying he hadn't detected any life right before a wampa beat the crap out of him. (Note that this contradicts the Radio Drama's assertion that the Rebels were aware of wampas and had found carcasses indicative of its prey, another radio drama detail the opposition tried to use to countermand the higher canon. Interesting that they'll then ignore the Radio Drama when it supports condemning the probe droid's sensors, but then we should expect nothing less.)
There is also no suggestion anywhere in the canon that tauntauns are native to Hoth. For starters, tauntauns are trained animals. The Rebel base had only been there for a month. While I'm sure there could've been more than a few animal herders among the Rebels, it seems odd to me to assume that without benefit of usable vehicles the Rebels could've captured, pacified, and trained several tauntauns within 30 days. Second, these are described as "snow-lizards" and "reptiles" . . . hardly the sort of lifeform one would expect on a frozen waste. Indeed, the fact that warm-blooded lifeforms (in the form of humans) outlasted the tauntauns makes it pretty clear that they weren't exactly well-adapted to the environment, and thus that they probably came from some other world's cooler regions.
Of course, the obvious (if silly-sounding) counter to the two ideas above is that perhaps there was a small, more temperate region or band near the equator of Hoth, and the Rebels (with speeders functioning there) managed to collect tauntauns and take them to their base at some other, colder location. This begs the question of why the Rebels would not place their base in the more pleasant area, but whatever.
The problem with this idea has to do with guts. When Han cuts open the dead tauntaun with Luke's saber, a rather icky assortment of creamy white guts splooch out. However, the wampa that attacked Luke (and the prey it was nibbling on as an appetizer) featured red blood. Although some fairly decent-size insects and invertebrates on Earth have used alternate blood chemistry (in the form of clear/yellow/green hemolymph, pink hemerythrin, or clear/blue hemocyanin), the larger creatures . . . up to and beyond man-size . . . all feature the same hemoglobin-based chemistry. Given that we have no claim or suggestion that tauntauns are native to Hoth, I see no need to try to jump through the hoops of rationalization necessary to try to explain the completely disparate evolution of a tauntaun on Hoth compared to that of its neighbors like wampas . . . wampas who don't seem to find tauntauns appetizing in the first place. As such, the two are most likely from different worlds altogether.
Update: Entertainingly, even some at Stardestroyer.Net's forums concur with the above. (http://bbs.stardestroyer.net/viewtopic.php?t=97430&start=25):
"RedImperator": "Add that to the fact that the tauntaun didn't run away immediately when it smelled its "mortal enemy". And that it froze to death in its supposed native habitat, and didn't attempt to take shelter or dig a nest into the snow. And that they even allowed humans to ride them at all. The tauntauns behaved exactly like an imported domesticated animal, not a recently tamed native life form--the idea that the Rebels could have tamed wild animals to that degree of docility and gotten them to ride into mortal danger in a few years, at the absolute outside, is absurd on its face. You can work a horse to death, but even a tamed zebra will quit, and probably bite its rider, long before it gets anywhere near that point. [...] It would have been trivial to write "Tauntauns are native to, and were domesticated in, the arctic regions of [Planet], and were imported to Hoth by the Rebels when they realized their vehicles functioned poorly in the extreme cold." The problem is that too many EU writers are scientific ignoramuses who, left to their own devices, make the same kind of moron mistakes with which Star Trek writers have assaulting its fans for years."
"Wyrm": " Domestication takes generations, and for large animals like tauntauns would take decades if not centuries or millennia [...] Now, if tauntauns are domesticated, where were they domesticated? Hoth is an uncharted system, "devoid of human forms" by Captain Piett's (?) report, yet tauntauns allow humans to ride them. They must be domesticated by humans, ergo, they are not native to Hoth, no matter what the EU says."
More to come . . .