I think that perhaps one of the communications issues is folks trying to fit the Traveller universe into the current world, where most of the useful parallels are with the 18th century "Age of Empire". A number of the rest are due to not grasping just how accurate (and powerful) weapons with light second engagement ranges are
So on to the 18th century parallel: the scout is the equavalent of a small packet ship, carrying a couple of 9 pound cannon. The grav tanks can be represented by a company or two of infantry. The packet ship (if there are no other naval forces in support) can handily shell the infantry into oblivion: if the packet is overly foolhardy the infantry can strip its decks of crew. If the packet spends too long shelling the infantry, there is probably some horse-drawn artillery that will blow nice holes in said packet ship if it notices the noise. I found the actual result of the engagement to be satisfyingly appropriate: the packet ship tried to run a blockade to the port, and got shredded for its trouble (eliminating the tanks on the way). The command crew escaped and are trying to infiltrate their way into the port to await rescue by their (less foolhardy) friends.
So shifting the viewpoint here from discussions of "DC-10 vs tank" to the age of sail. "detection equipment" and "defensive armament" of an east indiaman were *identical* to those used by ships of the line, and often manufactured in the same foundries. Why? because piracy and privateers were a common problem at the time, and east indiamen often had BETTER crew, since they could afford to pay them significantly better. Thus the difference between a "civilian" design and a "military" one boils down to a comparison of cargo/gun ratio, not more or less capable systems. If the modern world had a severe piracy problem then merchants would be packing a LOT more sensors and firepower, since NOT doing so would impact their profits a LOT more than the cost of outfitting their ships. Remember that this is the game where several AHL class *Cruisers* were sold to merchant cartels a surplus while the rest of the class remained in service.
Before getting huffy about the fact that there are "pirates" today remember that the US navy was basically formed to deal with the Barbary pirates. This is where the USMC gets "the shores of Tripoli" from, and the barbary pirates were not dealt with by Britain, France, Germany or any of the other "first tier" empires of that era, since the cost of "solving" the problem wasw percieved as being more than the cost of bearing it. The "pirates" we have now are pretty anemic in comparison.
Next up: why does that scout still have its excellent sensor suite.
1) Because no-one is ever going to buy a scout for shipping cargo. (Aren't these used for prospecting, where a top-notch sensor suite is more important than how much cargo you can haul?)
2) Because it's in use by a scout *on detached duty* remember that old book 1 stuff where the scout doesn't actually own the scout, but it is "on loan" from the Imperial Scout service? Maintenance and fuel is provided for free in exchange for Imperial access to logs?
Why the hell would the imperium degrade the intelligence it gathers by "downgrading" the sensors, especially when said sensors are available on the common market?
As for the "stealthiness" of a grav tank, you do know that it's running a fusion power plant right? One of the major issues with the Abrams is that when it is running it can be picked up by a blind man using IR imaging, and its IR signature is *at least* a couple of orders of magnitude smaller than that of a grav tanks plant. You can wave your hands and mumble magic ju-ju about dumping waste energy into a gravitic field or some other technobabble, but I bet if you have the technology to dump it there, I have the technology to notice the (multi-megawatt) signature. By the way, a megawatt signature is detectable (with existing technology) waaaaaay past a light second. For intellectual violence "By a passive sensor. The Space Shuttle main engines could be detected past the orbit of Pluto. The Space Shuttle's manoeuvering thrusters could be seen as far as the asteroid belt." you may want to check out
http://www.projectrho.com/rocket/rocket3w.html for "real world" detection. Even giving the tank the benefit of hiding in ground clutter, lookinng for the (several hundered degree above ambiant) exhaust will have it stick out like a sore thumb. And yes, you could power it down, but then it doesn't get to maneuver or shoot, which I'm sure would make the scout crew even happier than picking it off from the orbit of the moon.
If you want to pretend you can engage me at that range, check out the sme site for why plasma weapons suck in space (and note that TNE dumped space plasma weapons for a reason...)
And before we get into "The Trepidia isn't really a tank, it's a theater superiority weapon" discussion, I think that enough folks have already pointed out that by calling it a "tank" and defining its role (and design) in several versions of Traveller, it is *not* intended to engage space capable targets unsupported.
I won't even get into the issues with targetting a "huge" target from a light second out, or what teeny-tiny fraction of an arcsecond this target represents compared to (as an example) a human-sized target on the horizon at 100 naval miles . And no, I don't care about laser attenuation through the atmosphere: with 150 Mj or so I'll just deal with losing half my delivery energy in the form of atmospheric ionization: the remainder will probably result in a mission kill of one kind or another.
Ran is correct however in postulating that a hit from the grav tanks gun will punch a hole through the (relatively) unarmoured scout.
Scott Martin