MarcusIII
Cosmic Mongoose
Yes, we can.
No, it isn't. It is physics. Deep space is about 3 degrees kelvin. A ship is dumping heat from a fusion reactor. Lets say MINIMUM 366 kelvin. Your ship is a fcking bonfire in the solar system.
Inbound System Comms
- Thread starter OriginalCaruso
- Start date
OriginalCaruso
Cosmic Mongoose
I’m fascinated by your assertion @MarcusIII and I’d like to understand the physics behind your calculations
For simplicity sake, let’s limit the star system to Sol, limit the whole sky scan to the minimum orbit of Pluto and further assume we are observing only.
How long would the full sky scan take, and what resolution would we expect at Pluto?
For simplicity sake, let’s limit the star system to Sol, limit the whole sky scan to the minimum orbit of Pluto and further assume we are observing only.
How long would the full sky scan take, and what resolution would we expect at Pluto?
MarcusIII
Cosmic Mongoose
Atomic Rockets has everything you need. There are pages on the subject of stealth in space being impossible because of simple heat.
You completely ignored the rest of the statement. If you are doing nothing but radiating the heat (which, by the way, is a lot harder than most people realize) your argument would be valid. But that's not at all what I said. And you also ignore how passive sensors work. Both of these two things are also physics. The 3 degrees kelvin issue is VASTLY overstating the actual complexity of this. There are multiple factors that have to be taken into account.
Also I'd like to see some backup to your argument that we can scan the entire system in 30min with passive sensors and detect anything of significance other than the largest emitters of heat. That's not really how it works. The James Webb telescope is the most advanced device we have in orbit. It takes between a day and a week scanning ONE object to get its very detailed analysis. The WISE telescope launched in 2009 took nearly 10 months to do a full sky analysis. These devices (and you can only do it from space) have relatively small apertures. JWST has an image view of about 2.4 arc minutes (or about .05 degrees).
All of that says you can't do it in 30min. Where is this magic coming from?
OriginalCaruso
Cosmic Mongoose
Ah but you haven’t answered the question asked with the reasonable constraints proposed.
What conclusion should I draw?
MarcusIII
Cosmic Mongoose
Because the rest was irrelevant to the subject.
MarcusIII
Cosmic Mongoose
That you need to back fill your high school science education.
The following is if one were using only a 3 centimeter detection lens. Star ports would be using IR detectors several meters in diameter and much higher than 1999 tech.
Rd = 13.4 * sqrt(A) * T2
where:
- Rd = detection range (km)
- A = spacecraft projected area (m2 )
- T = surface temperature (Kelvin, room temperature is about 285-290 K)
Example
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OriginalCaruso
Cosmic Mongoose
Facile answer and you should do better than be rude and ignorant
To passively scan out to the minimum orbit of Pluto assuming a beam width of 0.1 degrees results in an angular distance of ~7.5M km at Pluto. Meaning an object can be anywhere within the 7.5M km arc, the calculation does not consider elevation for this simple example.
Detecting a heat source at distance accurately is problematic as the physics show. Scanning takes time, a reasonable estimate to scan the whole sky using a 0.1 degree beam width and 1 second scan time is around 61 days. Parallel scans are possible assuming the antennas are correctly aligned.
For me, the physics win and illustrate the difficulties involved
MarcusIII
Cosmic Mongoose
I did better. Read the rest of the post. As far as ignorance goes...
OriginalCaruso
Cosmic Mongoose
Nice edit after your original rude and ignorant original response, which neatly illustrates how difficult detection at range is, as opposed to your earlier posts within this thread.
This is definitely passive, so yes. More like a geiger counter, or eyes. Or a radio telescope, not active radar.
Triangulation is still possible, by comparing data from different observation points. Which, like eyes, might consist of many small sensors in an array.
Quite likely, you'd have dozens of high tech gravity detection modules arranged in a spherical array, as widely separated as was practical. An incoming wave triggers the nearest ones, then passes through the array, giving you a bearing.
Now, we don't really know the limits of gravitic science; there may be other tricks to establish bearing, but the above applies in general to all forms of signal. Geiger counters are like light meters... put them in an array or use other techniques and you can also get a bearing from them.
Triangulation is still possible, by comparing data from different observation points. Which, like eyes, might consist of many small sensors in an array.
Quite likely, you'd have dozens of high tech gravity detection modules arranged in a spherical array, as widely separated as was practical. An incoming wave triggers the nearest ones, then passes through the array, giving you a bearing.
Now, we don't really know the limits of gravitic science; there may be other tricks to establish bearing, but the above applies in general to all forms of signal. Geiger counters are like light meters... put them in an array or use other techniques and you can also get a bearing from them.
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MonsterX
Emperor Mongoose
Well, you better go work for NASA then, because obviously they aren't doing it right. You go tell them how it's done.
Blimey, I actually do have this one. Buried admittedly but there it was. Never opened it to be honest and now I'll probably be using the extended system generation rules (they seem a bit more accessible than the WBH).
Fluffy Bunny Feet
Emperor Mongoose
A 1 Terabyte NAS OFF THE SHELF (you specified off the shelf) with a single 1 terrabyte file system in 2000? Nope.
Fluffy Bunny Feet
Emperor Mongoose
How do you see BEHIND things like the moon, planets and SUN from one location? Not to mention behind the EARTH from your earth based (or orbiting) detector. If you can't you would be seeing far less than the WHOLE solar system.
MarcusIII
Cosmic Mongoose
No it crashed during the post. Had to redo the entire thing. So, hopefully the simple but adequate data I posted will help you understand why you can't hide a fusion reactor from IR sensors within interplanetary range.
MarcusIII
Cosmic Mongoose
you obviously didn't read my replies.
MarcusIII
Cosmic Mongoose
Oh, DO try to think. From one location one can scan the ENTIRE SPHERICAL space in that time. Of COURSE hiding behind a planet masks you. OMFG, THINK! Try to move away from that f'ing planet aand you are NAILED.
Fluffy Bunny Feet
Emperor Mongoose
Really
YOU specified storage. Your own words. Then you changed it to.
Then you changed the goal posts again.
You set just a distance no mention that you were going to EXCLUDE entire volumes of space. You move away from the planet and STILL it blocks a large volume as does the Sun and maybe the moon. Besides which you were saying it could be done in 2000. How far OFF PLANET was an off the shelf PC being sent? Just a few hundred kilometers to the ISS. Even then I think it was only laptops which could not take a terrabyte. A off the shelf NAS would likely be wrecked if shipped up.
You said:
YOU specified storage. Your own words. Then you changed it to.
Moving the goal posts with that statement. Also you still need to explain what OFF THE SHELF file system could handle a terrabyte in a PC so Windows or Mac file system. NAS with a terrabyte were NOT off the shelf items in 2000.
Then you changed the goal posts again.
You set just a distance no mention that you were going to EXCLUDE entire volumes of space. You move away from the planet and STILL it blocks a large volume as does the Sun and maybe the moon. Besides which you were saying it could be done in 2000. How far OFF PLANET was an off the shelf PC being sent? Just a few hundred kilometers to the ISS. Even then I think it was only laptops which could not take a terrabyte. A off the shelf NAS would likely be wrecked if shipped up.
