The common description of the map box states that it takes "Two orbital sweeps to create a map chip". Does anyone want to hazard a guess as to how long this would take based on planet size?
Orbital mapping
- Thread starter Spartan159
- Start date
Well, Low Earth Orbit around Earth takes around 90 minutes to complete one orbit.
There are probably two ways to do this. The active orbital approach and the passive one.
The passive one is obvious. Put the ship into an orbital pattern around the planet. If the planet rotates, use a polar orbit. If not, or not quickly, you can use something with high angle to cover more territory.
The active one uses the ships engines to fly around the planet in the most efficient pattern. In a universe where engines take fuel, this would be really expensive. For Traveller, it becomes an question of how much time you want to spend.
So, how big are your engines? Distance should be twice the circumference of the world, times the number of orbits. Use the standard D = a * T2 form, solving for T you get sqrt (D/a).
A:0 Imperial Fringe states you can determine the hydrographic portion of a planet's UWP by orbit in three hours.
If you're looking for where water is, you're also looking for where water isn't.
As for the three hours, figure that's for a size code of 8 then adjust up and down accordingly.
A:0 Imperial Fringe states you can determine the hydrographic portion of a planet's UWP by orbit in three hours.
If you're looking for where water is, you're also looking for where water isn't.
As for the three hours, figure that's for a size code of 8 then adjust up and down accordingly.
Note that 3 hours (180 minutes) is 2 orbits of earth at roughly 400km AGL. A comparable altitude around a smaller body is also a smaller orbit but also (due to reduced gravity) a lower orbital speed, and thus not a huge change in time.
So, that one shouldn't vary by size much; if anything, smaller is longer, as the orbital velocity is a function of mass/distance² ... and mass is a function of diameter³, so orbital velocity is roughly a function of size³/distance²...
Keep in mind... rosetta's 25-50 mile orbit of comet 67P was 14 days...
Even better!
Looks like you once again achieved for exceptional success on that Navigation roll...
Even better!
Looks like you once again achieved for exceptional success on that Navigation roll...
Nope... just remembered to check for 3 data points.
The third: 400 m MSL lunar is 2:27:46 or so
Smaller is longer.
Forgot to document third (now have) and ISS is 1:32:42
Thanks all, much appreciated.
I would imagine the TL and type of sensor used would come into play here.
My reference card for the Landsat series says 16 days for a complete cycle. That is one satellite and one set of instruments in a polar orbit.
Depends if your ship has an EMS Active Array.
"A starship will have starcharts of subsectors and sectors,
and its sensors can provide a map of any system it enters
within a few days at most. Any populated world usually has
for sale detailed maps of its surface. A starship’s sensors can
provide at least a continental outline map of a world it is orbiting."
_Referee's Companion_, p 85.
"Map, Electronic: The “map box” is a compact
(250 x 250 x lOmm, which expand to 1000 x 1000 x 1Omm
when opened) display system for computerized maps of a
world. Scale may be adjusted. Most inhabited planets have
mapclips (diskettes until Tech Level 13, holocrystals at higher
levels) available for Cr150. When not available, two orbital
sweeps of the world are required to obtain the necessary
photographs to construct a map chip. Blank mapclips are
available for Cr30."
_Imperial Encyclopedia_, p 61.
Just need someone to tell me how long it takes to do two orbital sweeps...
