If the Martians were able to arrange to survive the interplanetary launch to velocities more than 3 times that of the ICBM velocity, they should be able to do it on shorter ranges.
Destroying the launch site was precisely what happened in WW-2 by the Allies. The V-1 launch sites were very characteristic and an aerial bombing campaign was launched against them as soon as they were identified. The "V-3" supergun (aka Busy Lizzie) got similar treatment once it was identified. Only the V-2 rocket was immune due to its small footprint on the ground and short prep for launch.
The problem with trying to shoot down the cylinders is the same that faced the Cold War antimissile systems. Radar target acquisition and control of the intercept for two objects closing at high speed was challenging. The Safeguard system of the 1970's could barely do it, even using nuclear warheads to blow a big hole in the sky when it got close. Newer systems using hit-to-kill or conventional warheads are getting there for medium range missiles. Attributing this technology to humans in AQMF time line is quite a stretch.
Plus, we note that the Martians intentionally avoided major urban centers in this second invasion. Defenders could muster too quickly and assault the cylinder as soon as it cracked the hatch. Probably moreso now that we know whazzup with those guys.
Disabling a launch gun would be one of the ideal missions for the thermite that seems to keep coming up. Burn a big hole in the bore or carve a big notch in the side would probably require a total rebuild. The Martians could probably not afford a joint in the gun bore and even filling a hole could create a stress riser weak spot.
Mars' gravity is lower than Earth. You can find the formula at several websites. The value for Mars escape velocity is about 5 km/sec or about 3 miles/sec. For Earth, it is about 11 km/sec or about 6.9 mi/sec. The definition of escape velocity is that speed which would take the object to infinite range arriving there at zero velocity. Interplanetary distances approximate infinity for most calculations to first order.
So, when lofted from Mars, you go into a partial orbit around the Sun as you move toward Earth. Your intuition is correct in that past some point where the grav pull of both planets are equal (the libration point), you will begin to fall toward Earth. The return velocity to Earth is about equal to the escape velocity because you are falling from nearly infinite height. So you will arrive at Earth at about 6.9 miles/sec.
You are going to need burn off a bunch of that velocity or you will make a really big smoking hole after a vertical descent. Wells described the final descent as long shallow flight. He had the correct vision of re-entry.
To escape, what matters is the final velocity. You can attain that short, sharp high acceleration (milliseconds with a gun) or a longer lower acceleration (like months with an ion engine). For orbit calculation, though, a rocket boost is so short compared to the coasting time that it approximates a gun acceleration, but with more reasonable acceleration levels.
Calculation of the acceleration G-force is not difficult, but you must make a number of assumptions or specifications to define the desired performance.
Nice, ty boxholder. Always nice to have IRL science to back our AQ fantasy - bravo! So I believe that the 'protos' can be made with a reasonable success if the Martian passengers are properly protected. In fact, it occurs to me that a radical design change might work better. Instead of trying to fire a cyclinder, perhaps a radical idea, a ball would work better. Once there, it opens releasing the Martians already in their tripods with their drones and construction engines. The construction engines start converting the remains of the ball into new machines, etc., and the Martians begin their assault of Europe. Would require a bit more tech (the ball & its openning system), but as a 2ndGen concept, it certainly would get the job done. The targets in Europe would probably be marshes, allowing softer impact and some cover from many human eyes. The tripods & drones would definately be on the move quickly and European geography ,being the second smallest continent, would probably lead to conquest. This is even more so if you exclude the usual amount of Russia in that description, being classical antiquity of the non-oceanic boaders given the "continent".
Yes, a sphere could be considered. The tradeoff is in the caliber of the gun to deliver a given volume of payload. A cylinder can have more volume for a given diameter than a sphere due to the extra length behind the frontal area. That said, the sphere has more drag, so it would tend to shed velocity faster and might ease the landing. The comparison to bullets is hard to avoid. Round balls, even fired from a rifle, did not have the range of "conical" bullets (which had conical noses and cylindrical bodies) fired from the same gun.
However, range is predominantly determined by the velocity, so there is no free lunch during the launching.
Packaging all those &^%#^%$#!! legs would be a real trick. Also, getting everybody deployed without entangling everything would be a hoot to watch!! Especially if they have no way to make sure that the sphere lands right side up.
Hmmm, good point on the legs - so maybe the 2ndGen Martians having come up with 'folding legs' aka like ww2 folding wings on naval aircraft on carriers? My vision is that there is no 'right side up'- the design is for the sphere to completely fall apart signal. Yes - it would be fun to watch lol.
A sphere can be very unsteady in flight, especially if it is unbalanced even a little. Consider the way a baseball can curve or sink, and the reason a "spitball" is illegal. A little spit does not weigh much, but it really makes a ball dance. If you want to make a good cat toy, put a metal jingle bell in a plastic golf ball. It will hop about in random ways and keep the cat occupied for hours. Spitballs are great for baseball (well, if you're a pitcher, anyway) but for ballistics, not so much. I'd go with a cone or a cigar shape with pop-out tail fins for stability. On the other hand, the sphere might work really well because of the "cool" factor. I could see a Martian "long range" sphere surrounded by a mound of earth amid the wreckage of a town on my tabletop.
I think Tripod legs should quickly attach and detach, so they can be easily changed out in the field. The prey that stings seems to love attacking the legs of Tripods. (Mwah ha ha ha!)
Good points all. Whatever form it takes, I'm sure the Martians have a long range plan to get to Europe, if only from Russia if nothing else. They just didn't realize that America will oppose them on all fronts and become 'the prey-that-stings'.
Well, nothing says the unscrewing the base of a cylindrical projectile is the only way to open it up. It is entirely possible to make the body as a set of petals that would open up like a flower. You could really disembark quickly from that.
Following the flower analogy a bit further, the tripods with folded legs could be arranged radially around a central column, like seeds. Multiple tiers would let you have a bunch of them in there. When the petals open, they extend the legs and walk away from the column. Structurally, the central column would transfer the accelerating force from the base of the projectile to the contents and nose.
Damned inventive, those Martians.
There was no backdoor at the Alamo. Planet Earth doesn't have one either. Fight and win or DIE!
In regard to the sub-orbital cylinder launch, here is my attempt to calculate the g forces on Martian launches. I assume the launch tubes are build up the sides of Mons Olympus. Mons Olympus is about 13 miles high, but with an average slope of only 5%. So if the tube was built from the base to near the summit it would be 185 miles long. Martian escape velocity is 16,493 feet/second. To achieve that velocity the tube must be transited in 118 seconds. This translates to an acceleration of 4.3 earth gravities. Which would be over 12 Martian gravities. Human astronauts usually experience about 3 Gs during launch and humans pass out at around 9 gs. So that suggests the Martians are pretty tough.
Theoretically the Martians could handle the G-forces. So the real issue becomes how would the Martians construct launchers on earth? The 3 Gs for human space flight is based on rocket launchers and suborbital flight would either use fewer Gs or the same Gs for shorter time. If the Martians understood rocket technology why did they not use it on Mars? Or perhaps they did and the launch tubes were just guides. According to AQ they do have missiles for the dominator tripod, but perhaps they cannot build large rockets.
Building a 100 mile tall gun to launch the cylinders seems improbable. I'll do some more noodling and see what I can come up with for a launch tube with, say, a 5 G-force launch. If nothing else, remembering how to do the calculations will be interesting.
Finally, it has been 40 years since I took physics and I am not now nor have I ever been an astrophysicist. So I may have made errors. And of course the starting assumptions are all vaporware which means the whole thing is suspect.
OK, assuming a max acceleration of 5 Gs (earth Gs), and velocity needed to achieve a 60 mile high suborbital arch of 3190 feet per second (according to the internet). At 5 Gs a projectile would reach this velocity in 20 seconds. That means the gun must be 6 miles long. The most likely configuration would be a launch tube rising slightly until near the end when it bends sharply to expel the projectile at a 30 to 45 degree angle to the planet surface.
Biggest problem I see would be the landing. Without some breaking the cylinder is going to hit the ground at nearly the velocity it left the launcher. So some sort of terminal guidance and breaking will be needed.
Terrance: Your calculation is spot on for the acceleration pulse of the Olympus Mons gun. The equation you want is: acceleration = [(velocity change)^2] / 2 acceleration distance. Use consistent units. For your example: acceleration = [(16493 ft/sec)^2] / 2(185mi*5280ft/mi) = (272019049 / 2(976800) =139.2 ft/sec^2 = 4.32g
The equation shows that accel needed is inverse to length of acceleration. Double the barrel length halves the accel needed for a given velocity change. Halving the length doubles the accel needed. This assumes that the acceleration is continuous over the whole barrel length. This is difficult to attain, but that is another thread.
However, your 9G tolerance level is for a human pilot wearing a G-suit and experiencing downward g-force (into the seat). Lateral g-force tolerance is much greater. For NO g-suit:
chart from Aviation Medicine.
Acceleration for the Saturn V moon rocket peaked about 4g's ("eyeballs-in" or transverse accel) briefly. Humans are pretty durable in some ways.
Let's remember that missiles are part of the AQMF timeline, not HG Wells'. His book noted explosions or eruptions on Mars that appeared to be hydrogen. Sounds like a gun blast, not a rocket booster.
A flash of light can be the result of many things. The flashes seen on Mars may be what we see at the very end of a long acceleration. Whatever the Martians are working on, Humanity is also working on a way to strike back at Mars.
Now that the principal of the coil gun has been worked out, think of what kind of payload humanity could send to Mars from an accelerator that stretched from the Gulf of Mexico to Cape Canaveral, across Florida. A few tons of compressed air full of Microbes?
Think also of what we puny humans can do to sabotage one of those Martian Super-Cannons?
I love real science. Was into chemistry in high school & college. Surely, our gamers can come up with 'fake science' to explain the suborbital launches. But, game balance wise, this really should be an end to this thread. If the Martians can 'fire' even small forces over short (100 miles or less) distances, the human lines will be breached. And despite some fierce rear guard actions and heroics, the east is compromised. Maybe even the west if the Rocky Mountains can also be bypassed. The primitive airborne forces of the humans can cause major problems for the Martians; but, the Martians don't depend on 'lines' for resistance as do the humans. I still entertain the notions put forth here - but, as a game element this debate really would destroy the game itself. Giving the Martians the equal of airborne forces puts end to game balance too greatly. So, my proto-projector goes on the shelf of fun ideas with game balance destruction. Its all good