Re: [FT] Sensor Range Question

Dealing with space sensors can be tricky. First is where are you using
your
sensors? Deep space use will give you a better range than in-system use.
The
planetary bodies emit and/or reflect enough radiation that they can mask
anything near them. In deep space there is less interference. A
wonderful
example is to look at the stars while in a city, and then to go
somewhere
remote, away from the city lights and look at the stars. Without the
interference from a city lighting system you can see stars that you
could
never see otherwise.

Of course ships operating in deep space (especially on reconissance or
pirate missions) will probably be "Running Silent" or on "Emm.Con.".
This
would entail minimising or controlling all emissions: magnetic, radar,
engines, ect., closing all windows (light emissions) and generally
making
onesself fade into the surrounding blackness. While standard procedure
for
military ships, even civilian ships might use this technique between
jumps
to avoid being raided. So "Running Silent" might in theory negate the
bonuses to sensor operations in deep space.

As far as how well we watch our own solar system: Yes we do have very
good
data about other planets, we even have reliable information about what
some
of them (mostly the gas giants) are composed of. But this kind of data
takes
months to gather. A spectral analysis must be averaged againtst time ,
the
combined orbits of the observer and the observed, rotation speeds,
eclipses,
ect. to compensate for a host of possible errors, the least of which not
being the infamous doppler shift.
If you want to see something the size of a fleet carrier, in time to do
something about it, you are limited to the distance between the earth
and
the moon. This kind of detection is only practical for ground and space
stations, a moving ship causes too much distortion, mostly in parallax,
to
warrant having those kinds of sensors, unless it is a dedicated science
vessel, which usually would end up in geosynchronous orbit anyways.

As far as sensor "Evading": Very few modern astrophysical sensors are
directional. Radar is a commonly used device, then with the radar
detection
the optical, IR, and Thermal cameras can be trained on the target. We
have
the technology now, that would be practical to mount on a starship to
have a
contstantly rotating camera array creating a "Photo Mosaic", updating
each
time the camera passes. Multiple array's of cameras with overlapping
fields
of view may even be able to give a real time 3D view of the surrounding
space (either with the computer alerting the sensor operator to
potential
targets in a specific area on a normal screen, or projecting a
holographic
representation around the bridge with a HUD overlay on it, depending on
your
preferred level of cinematism).

Then there's the manuver itself. I assume that space combat occours at
the 1
inch = 1 kilometer scale. That makes the average table 60 kilometers by
40
kilometers across (30 mile by 20 mile) a respectable distance for space
combat, and more than most space sci-fi shows give themselves. Trying to
"Jink" off even an obsolete directional sensor at these ranges is nearly
impossible. Remember, the father away an object is the less you can see
it's
movement. at initial detection range (60km by my scale) in order to
"Jink"
off of a directional sensor which may have an arc of 45 degrees from
center
(a rotating sensor turret would have your ship in the center of the
field)
you would have to apply 120 points of thrust (60 accel. 60 decel.),
through
port and starboard manuvering thrusters, in one to ten seconds (common
time
intervals for RPGs and wargames). This would be the equivalent of being
hit
by a asteroid traveling at 21,600 kph to 216,000 kph, twice! This
"delta-V"
will quickly reduce your entire crew to a thin paste of the color of
their
insides. Any slower and the detecting ship can calmly track your
position as
normal. Even trying to blur your image with such a jink will involve
sudden
manuvering acclelleration/decelleration in excess of 1,000 kph /sec.
This
will be enough to injure even power armored marines, much less the light
to
medium flexible spacesuits the crew will be wearing. If your ranges are
longer (which I see being discussed on the group), this requires an even
faster delta-V with more traumatic consequences.