Change the payload and you have a decent bunker-busting electronic weapon? Should get the arms merchants interested.
A successful speed-of-sound shot has powdered ten tonnes of ice, but much to the builders' delight the projectile used managed to retain its components and internal structure in spite of the massive g-forces involved in the test. Reported over at the BBC, the test is part of a “space penetrator” project, offered as a lower- …
They've already got working devices with slightly more substantial penetration that have been demonstrated to work. Naturally, such things are sensitive military technology and as such much of the useful research will be classified and inaccessible to mere academics, who will have to repeat the research on a significantly smaller budget and without the same amount of prior expertise. C'est la vie.
...They've already got working devices with slightly more substantial penetration that have been demonstrated to work. Naturally, such things are sensitive military technology and as such much of the useful research will be classified and inaccessible to mere academics, who will have to repeat the research on a significantly smaller budget and without the same amount of prior expertise....
The basic technology is already set down in Barnes Wallis's paper: "A NOTE ON A METHOD OF ATTACKING THE AXIS POWERS" (1940).
It is of interest to observe the US attempts to understand the principles involved. A key part of the Barnes Wallis concept was that, to deliver the maximum energy from an exploding projectile to the target, you needed to pass this energy through a substantial medium. Air was very poor for this purpose - it allowed the force of the explosion to vent along paths of least resistance. So his Tallboys and Grand Slams were designed to be dropped into solid ground (preferably rock) BESIDE the target, whereupon the explosion would emulate a major earthquake throughout the target's foundations, resulting in major damage.
I note that the US, having recently re-invented the Grand Slam as their 'Massive Ordnance Penetrator' (MOP) GBU-57A/B, are trying to fit a void-sensing fuse to the weapon, enabling it to go off when it arrives in an air gap. Face-palm time...
Maybe they think that if they set it to blow if it penetrates into a bunker, the blastwave will do more damage?
(It won't. And any bunker weak enough that the MOP can penetrate into can probably be knocked out with much smaller penetrators, too)
A thin-walled, extensive bunker system is probably better taken out with the MOAB.
"Maybe they think that if they set it to blow if it penetrates into a bunker, the blastwave will do more damage?
Are you sure about that? I reckon once this weapon gets into an airspace of a bunker *complex* (think: tunnel-linked multi-node setup) then perhaps the "line of least resistance" propagation becomes a very useful thing as the structure of the bunker is working for the weapon rather than against it.
Not only that, I suspect the heat involved will be as "useful" as the pure force of the explosion.
I can see where the idea is coming from. Whether it can be made to work at a price the armed forces will pay is another matter.
Of course, weapon manufacturers are scrambling for the Next Big Thing, wartoy-wise as the draw-down in Afghanistan and Iraq bleed away the justification for their products.
Which is a factor in the use of technotat to "monitor" the homeland of course.
"I note that the US, having recently re-invented the Grand Slam as their 'Massive Ordnance Penetrator' (MOP) GBU-57A/B, are trying to fit a void-sensing fuse to the weapon, enabling it to go off when it arrives in an air gap. Face-palm time..."
The problem is, the US designs and trains for the last war that it fought. Operative in this case is a desert war, where what was penetrated wasn't rock, but loads of sand, which disperse shockwaves quickly.
Of course, during Gulf War I, the US had to kludge up bombs made out of howitzer barrels to use as penetrators.
Never said we were bright, only highly enthusiastic. And eventually do the right thing, after trying everything else first.
"They've already got working devices with slightly more substantial penetration..."Well, that may be true, but most of them don't have to do anything useful after arriving, apart from blow-up. Another point is that the tech you speak of will not be available to us, or it will only be available with our eyes shut and no info. Isn't that what happened with the air-bag system that we received for Beagle? It's hard to design for something that you are not allowed to know anything about.
It was launched from a rocket sled. (That's what they're famous for at Pendine). The sled comes to the a dead stop and the penetrator was flung forward. Not the best way to ensure the correct accuracy but since they were testing deceleration rather then penetration depth the correct attitude is not important.
In practise I expect they'll have a small reaction motor that will accelerate them to impact speed, and probably put on a bit of spin for stability in the rarefied atmospheres
I'm sure you could find other lawyers (probably the human rights type) who would argue that it was a landing as Europa was the intended destination for the projectile. Don't forget for every fine legal mind arguing pro, there's a fine legal mind with low morals being paid stupids amounts to argue con.
If one of your goals is to eliminate any pesky parachutes and other decellerators.
Mars (for example) with an atmospheric pressure of 0.1% that of Earth is not likely to slow it down much from orbital velocity.
Venus is interesting. It's real hot so there's nowhere to dump the heat to and the atmosphere is very corrosive. So a fast entry might stop the capsule being eaten before it gets to bury itself in the ground and if it gets deep enough to start dumping heat into the soil.
Transmitting data back may be a bit difficult.
Thumbs up for this. But remember this is still low TRL. It's a long way from flight test.
The other goal is to look just under the surface, so this also avoids having to take a 2m drill with you. It's a happy win-win.
However 24,000G is a bit more than any of my stuff will currently survive, so I've got a bit more work to do - oh and that's on top of surviving 400krads!
An impactor for Europa is going to be travelling iro 45,000-50,000mph when it hits the surface, which is iro 20-23 km/s or 20,000 - 23,000m/s.
About 58-65 times more energy than this test, with corresponding increase in G loading, not to mention, as Europa is so cold the ice is harder than steel.
"Venus is interesting. It's real hot so there's nowhere to dump the heat to ..."
Unless you do what we used to do before the shuttle and will probably start doing again: dump the heat by ablation (usually of molten iron). Coat the projectile in a sacrificial ablative material.
Of course, you'll tend to get tumbling as the molten ablative sloughs off the projectile, but that might be alright.
> a “space penetrator” project, offered as a lower-cost alternative to sending rovers to our planetary neighbours
To mangle the already mis-quoted report from the Vietnam War. Firing a devastating projectile into an exploration target doesn't really work if the thing you wanted to learn about is either blown into little pieces, or so disrupted that what survives the "attack" is unrecognisable. Imagine the yay! behind: "We discovered new forms of life on Comet ZZ9 Plural Z-Alpha, but unfortunately we destroyed it in the process."
Though on reflection, I suppose this is exactly how nuclear research is done (with "colliders" 'n' all), so maybe there is a future in it after all.
"...but unfortunately we destroyed it in the process."
Not going to happen in the case of Europa, with kilometers of ice between the vacuum and the oceans beneath.
But, it can read temperatures, listen for sounds of Europaquakes, listen for vulcanism, listen to icequakes, measure chemicals, etc.
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