4. EXAMPLE 2 : SPACE STATIONS 4.1 Meeting a Recurring Operational Need The type of communications satellites launched today are clearly not suitable niche market candidates for the first Powersat system because the power requirements and savings per user are very small. Obviously, potential Powersat developers need to look for a niche market that involves users who consume large quantities of power. However, more fundamentally, the most suitable market will be one where the annual recurring cost to support a particular user’s power system is large. For a comsat that uses a Powersat, the cost savings occur only once per spacecraft purely as a result of not having to launch a large solar array, battery, or other components. Like most spacecraft, comsats are launched as fully self-contained units. If comsats fail in GEO there is currently no real possibility for retrieval, repair and re-launch. For the same reasons, comsats must work without the possibility of a continuous supply of propellant and other consumables to keep them functioning. This is not the same for large low Earth orbit platforms and space stations. Here, the one-off cost savings from not having to build and launch a large power subsystem are of less importance than the annual recurring cost savings from not having to support this large power subsystem. Again, as discussed in Section 2.1, it is important to emphasise that even in the '‘Powersat era." all spacecraft will need a power subsystem of some description in the event of extended outage periods. In some cases, this integral power subsystem will need to be very substantial to maintain the health status of large space platforms. These arguments will become clearer in later examples. Analogies with the terrestrial supply of power are appropriate here. Potentially, every home or business could have its own electrical power generator systems. However, the recurring costs of having to purchase and
RkJQdWJsaXNoZXIy MTU5NjU0Mg==