Does anyone know a reliable source to find the mass of solar panels on satellites (in particular GEO satellites)? I know they will vary but I am struggling to even find one data point let alone a variety...
Spectrolab's Space Solar Panels (without the substrate) are specified as:
- 1.76 kg/m² for 3 mil thickness of coverglass
- 2.06 kg/m² for 6 mil thickness of coverglass
Spectrolab is the company that made the panels for the Iridium NEXT satellites' solar arrays, so this should be pretty representative of the current state.
Iridium NEXT is a Low Earth Orbit constellation, but the specification says the panels are used in GEO as well.
Solar array designs vary a lot and need to be tailored to the mission they will power, so the specific power ratings (power per mass of the array—higher is better!) vary a lot as well.
In addition to Boeing/Spectrolab mentioned by @called2voyage there are several other manufacturers of space-qualified solar arrays, such as Northrup-Grumman, Lockheed-Martin/ATK, and SpaceQuest.
Boeing/Spectrolab produces thin-film arrays @called2voyage quotes, but they also make rigid arrays, such as those on the Juno spacecraft at Jupiter. Juno is spin-stabilized and carries a camera, so they need structural strength and the rigidity to prevent excessive blurring of images due to solar array vibrational modes. The specific power of such systems is less than those of the thin-film or blanket types of arrays. Arrays on the Boeing 702 spacecraft, designed as a GEO communications satellite bus, are also rigid.
Northrup-Grumman is in the game with such systems as the Ultraflex and Megaflex flexible arrays that deploy into a circular geometry. (Unlike the Ultraflex info sheet, the Megaflex sheet is rather sparse on numbers) They get impressively high specific power specs, but for a few applications they aren't sufficiently rigid.
Last year Lockheed-Martin unveiled their large thin-film arrays for their LM 2100 satellites, and I'm sure they'd sell them to anyone coming to their door with money!
SpaceQuest makes somewhat smaller arrays, many for Cubesats, but they say they have powered spacecraft up to 1000 kg. From their web site you can download data sheets and even CAD models.
The bottom line is that indeed solar array specific power varies a lot, mostly depending on the mission's requirements. If the mission needs strong, rigid arrays, you'll have to throw more mass per Watt at them. Data from the sources above should give you a feel for how the different technologies compare.