Idea for a short story
On a commercially run colony on Mars, energy is rationed to keep costs down. Colonists are given extra energy quotas as a reward for overtime, community efforts and so on. One group of school children undertake a programme of good deeds, pooling the energy quotas they earn as a result. Eventually they have enough to trade for a launch of a vehicle into Mars orbit. They reveal that what they have been working on in craft lessons is a satellite that is little more than a giant mirror. Once in orbit it reflects and focusses sunlight back to the surface, providing free energy to the colony. The children become heroes and the gold foil mirror becomes the flag of a new Mars independence movement.