The special volume called the Archive is stored back at mission control on Kerbin. To be allowed to copy files between it and a vessel that's far away the vessel will need antennae to reach the archive.
To access the archive back at base, a vessel needs a number of antennae on it according to the range from home it is.
(Please be aware that this part of how the KOS plugin works is a bit controversial among its users and it may be subject to change in the future. There is talk of interacting with the RemoteTech mod (if it's installed) and using it to decide the antenna range instead of using this system, and only using this system as a fallback if RemoteTech isn't installed. The information in this page could become incorrect at a moment's notice.)
The range calculation works like this:
- Let = number of deployed* Long Antennae on the vessel.
- Let = number of deployed* Dish Antennae on the vessel.
* An antenna is only deployed if it's been extended. A closed dish antenna does not count. A retracted long antenna doesn't count. (This requirement to have the antennae extended seems to have been removed in KOS 0.9 and they now work even when retracted. Perhaps this is because the Science system in KSP 0.22 has a tendency to keep retracting the antennae after they are used to transmit data.)
This works out to:
|Max range||Context for comparison|
|0||1||20,000 km||Mun-to-Kerbin = 12,000 km|
|0||2||4,000,000 km||Almost the closest distance Moho gets to the Sun.|
|1||2||44,000,000 km||A bit bigger than the 'diameter' of Duna's orbit of the Sun.|
|2||2||84,000,000 km||A bit bigger than the biggest distance between Jool and the Sun.|
|3||2||124,000,000 km||A bit bigger than the biggest distance between Eeloo and the Sun.|
|1||3||8,800,000,000 km||Larger than any distance in the Kerbal system.|