guest blogger john hare
I noticed an objection to reusing tanks in orbit again that struck me as minor. Insulation popcorning off the tank creates an orbital debris problem that is increasingly unacceptable. It would seem to me that an Echo type balloon much larger than the stage could be used to contain the problem even if it didn’t keep the insulation in place.
A very light balloon structure would seem to be quite sufficient to contain any popcorning problems until permanent solutions could be incorporated. Inflation in vacuum can be done with tiny fractions of an atmosphere of pressure. A drop of water has been used for the purpose for smaller balloons. Think of it as an inflatable hanger.
Using it as a hanger for converting the previous upper stage to living quarters of a propellant depot has other advantages. Lost gloves and tools don’t leave the vicinity, you can get them back without endangering crew or other spacecraft. The balloon can be slightly opaque to cut down on suit heating during the daylight portions of the EVA. The balloon could also re-radiate a bit of heat back to the EVA personnel during time in shade or night portions of the EVA. Tethers would still be needed, but drifting away from the ships would be less dangerous. Over time, the fractional ton balloon hanger could become a major assembly station as it accumulated tools and supplies from multiple contracts.
On the downside, drag will cause it to require substantially more station keeping propellant than the tanks it contains would have on their own.