Izack
Non sequitur
:lol:
Okay, that's an interesting idea. The crew wouldn't last very long in even solar radiation, but interesting nonetheless...
Space Combat Techniques Discussion
- Thread starter Ghostrider
- Start date
Okay, that's an interesting idea. The crew wouldn't last very long in even solar radiation, but interesting nonetheless...
SolarStorm
New member
I don't know about that. I've been thinking about this a bit, and looking at the graph, 10km might still be close enough. It's just over 6 miles which puts the radiation intensity at about 2000 Roentgen, (or 200 Gray in SI units). I think this might actually be about twice a lethal dose with death resulting somewhere within 0-48 hours, assuming minimal sheilding on the ship. Remember that the graph is showing a tiny warhead, only 20 kilotons and that a viable nuclear weapon in space would be a multi-megaton weapon. I reckon 10km would be within lethal radius.
Also, I'm wondering if the radiation in general would knock the ship around. Orbiter already supports solar sails and radiation pressure, so I wonder if an orbiting ship, even heavily sheilded, could be knocked out of orbit by successive nuclear detonations and the subsequent radiation pressure. Would the OBSP support it? We live in interesting times...
jedidia
shoemaker without legs
That's the TOTAL radiation the bomb releases (at least the figure sounds like it). It spreads out spherically, only a very small percentage of that radiation actually hits the target. The further away, the less. At 10 kilometers these 6000 Rs will have distributed themselfes over a surface area equal to a sphere with 10 km radius, there's really not much left of it calculated on the surface area of the ship.
Unless you detonate the bomb right under your behind, no chance. the surface area of a ship is way too small, and the radiation pressure of a bomb isn't that high. What you're talking about is basically an Orion drive without pusher plate and distant detonations.
There is no stealth in space.I would go with hide-n-seek strategy, relying on spam fire. Passive IR and radar scanning, fire-and-forget missiles deployed out-of-sight, flak fire followed by a change of orbit. Also, lack of drag would offer great stealth possibilities; for an example it may be possible to construct a cloaking umbrella system. Unused, it would reside folded around long rod along the long axis of ship. When you wanna deploy it, pull the rod out, open up umbrella wide to cover larger part of ship and pull the rod back. Umbrella surface would consist of radar radiation absorbing material, with 3 or 4 surfaces (tetrahedron without base or half of octahedral). With possible cooling system throughout the umbrella with LHe or LN2, this system would essentially vanish your radar cross-section, rendering you invisible head-on, for radar, IR scanning and visual. And probably blind
http://www.projectrho.com/rocket/rocket3w.html#nostealth
Interesting ... I'll do the numbers to check this out. Will be back!
Wishbone
Clueless developer
Mneh, what about minisats?
What about minisats? Decoys? They won't be able to simulate the proper thing correctly.
Miniature satellites simply can't do as much as a larger spacecraft.
It might be possible to camoflage yourself as an asteroid or something like that in the inner system, but no, you can't make yourself invisible.
Miniature satellites simply can't do as much as a larger spacecraft.
It might be possible to camoflage yourself as an asteroid or something like that in the inner system, but no, you can't make yourself invisible.
SolarStorm
New member
Actually, scientists have managed to make a material (I forget what it's called but I'll google it later) that makes itself invisible to microwave radiation by bending it around the object. They're now working on bending IR radiation before attempting to bend visible light. Assuming that they get there, stealth in terms of the visible light spectrum may finally be possible.
You didn't read the link I gave. It has nothing to do with materials being invisible to certain spectrums of radiation, and everything to do with the fact that if your ship is doing anything it will be warmer than the background of space and thus detectable.
SolarStorm
New member
Yes, but combine it with orbiting at low altitude around a planet, making the background radiation not from space, but from the planet (or maybe even a large moon.) My thinking is that planets and moons would perform a similar function to what the ground does in terms of aerial combat and terrain masking, (or submarine warfare and underwater terrain masking). Stealth aircraft today can still be detected (in theory) but there is so much background radiation that they get cut out of the picture by the same sofware in radars that filter out things like birds. If you combine as many stealthy traits as possible (the visible spectrum being a big one in space) and then put the spacecraft really close to a massive radiation source like a star/planet/moon, whatever radiation the ship does emit will be at least partially covered and at most, completely drowned out.
Wishbone
Clueless developer
And as soon as you're talking about normal-sized ships (metamaterials are nowhere near being ready for sending them to space), must agree with other posters - no stealth in space (albeit not as categorically). Oh wait, there used to be some black projects in the US for lower-observability spacecraft, yet there's lingering doubt they could have been successful - precisely because of their size and rapidly improving optical detection capabilities.
- precisely because of their size and rapidly improving optical detection capabilities.That might work, if your vessel never uses any kind of thrusters.
As soon as it does, it'll be very, very visible to anyone looking.
jedidia
shoemaker without legs
Radar also consumes an awfull lot of power if you want any reasonable resolution at larger distances. In space, a thousand miles won't really help you much. But the more you increase the distance, the power you have to put into it for maintaining resolution rises exponentially. Might work for a tracking cone, but for a 360 degree arc in both axis it should be terribly inefficient. Plus, you got light-speed lag twice. Radar would play an important role in short range missile defense, but I don't think it's a good solution for engagements at over 10,000 miles (which should be most of them).
Something like a heat imaging camera that makes a complete panorama of the sky that gets analised by some highly specialised algorithm every minute or so might be a good general detecor, while having telescopes that can be trained on a target once it has been identified for target tracking. It's passive (doesn't need power and and cannot be abused to home a missile in on it), and it has the light speed lag only once. combined with a precise gyroscope, good algorithms and smart rounds it should make one hell of a "sniper rifle".
Wishbone
Clueless developer
Just a small correction (yes, I understand the words "poetic license"... sometimes :tiphat: ) the power received by radar follows the inverse fourth power law relative to the distance. For autonomous defense against incoming ASATs or whatever you indeed have to cover all the angles... (they don't have to be in the same plane to hit you - look at this - http://www.orbiter-forum.com/showthread.php?goto=newpost&t=18186)
SolarStorm
New member
Even with the background radiation? I agree that against a background of nothing but space a ship would stand out, but with a a big radiation source, (or something that reflects a lot of radiation) behind it, wouldn't that be like trying to pick out a conversation between two people standing next to a jet engine?:idk:
And thanks Wishbone, metamaterials was what I was thinking of
Wishbone
Clueless developer
How often do you have the pleasure to be between the sensor and the Sun? The detectors can sense 0.1K difference and better, with cooling of course (if there's liquid helium, it can be much better). Most of the time you're against the background of cold space.
A ship's engine ends up giving off quite a big signal if it has any decent power to it.Even with the background radiation? I agree that against a background of nothing but space a ship would stand out, but with a a big radiation source, (or something that reflects a lot of radiation) behind it, wouldn't that be like trying to pick out a conversation between two people standing next to a jet engine?:idk:
And thanks Wishbone, metamaterials was what I was thinking of
jedidia
shoemaker without legs
We had a demonstration of spy drones when I was doing service. Equiped with a heat imaging camera, you could detect any metalic object a man was carrying on himself from a kilometer distance without trouble. They could even tell in which pocket people were wearing their purse (I think that particular camera cost something like 300,000 bucks a piece, tough). So yeah, you might use some cold gas thrusters for rcs (terribly inefficient) without being detected, but if you need to actually do a maneuver, there's no hiding the main engine exhaust, because it will allmost always be severly hotter than any background radiation. Yes, even hotter than the suns background radiation, unles you're really close. But then you'll have other troubles. Hiding in front of the sun might work for chemical engines, but stuff like a VASIMR or fusion engines would be too hot. Let's not talk abut a fictional anti-matter drive like e.g. the venture star's, that one would be comfortably visible at alpha centauri...
SolarStorm
New member
Of course, there's always that option.
But as for my theory, I guess I underestimated the sheer sensitivity of modern sensors, so thanks for taking the time to set me straight guys.:tiphat:
But back to what Polaris said. Now I'm wondering, if you were to fire the main thrusters behind a planet like Mars (relative to Earth), escape the orbit and then coast towards Earth, would sensors still pick up the approaching ship against the background of space, or would this constitute a 'stealthy' approach. Obviously the ship starts off in an east to west orbit around Mars in order to be behind it relative to the Earth. I'm thinking that it wouldn't be possible, but I've been wrong before
lol so I'll just check.Also, RisingFury, is OBSP in the hanger yet or is it still being tested/developed?
