A summary
In humanity's last years on Earth, supplies dwindled. The International Space Station, however, was chock full of resources. Resources for humanity's first journey to Mars. As the barrier encroached, Kourou spaceport remained. All of Earth's remaining resources were shipped there. The barrier was just 2 years away when the first launch happened. This part was the food module, with enough food for 50 years. The second launch sent up a hydroponics module. The main habitation module was sent up next. The barrier was getting closer. The ships were incomplete. The ponies put all their magic into getting the barrier to cover Kourou Spaceport. One of the last launches was the colonists and a repair module. After that came the transfer stages for the modules.
After they left, one last launch was sent up: A huge heatshield along with the last fuel and an engine. Slowly, the ISS was moved through space. Its inclination was changed to match a certain spot in the Pacific Ocean. Then, it burned retrograde. The station fell through the atmosphere, its new heatshield melting quickly. And then... it was within view. It was going far too fast for anypony to stop it. As it roared through the atmosphere, ponies screamed, ducked for cover, or hid in their homes. That could never help them. The princesses and any pony with enough magical talent attempted to slow it down, but it was either too fast or too large for many ponies to help. Just a few seconds later, it slammed into Equestria with the force of 54 "Fat Man" atomic bombs, or 1.08 Megatons of TNT. Equestria was obliterated and irradiated.
About 2 days later, Kourou was swept over by the barrier. The last human on Earth, living in mission control, which was surrounded by ponies, pushed the button. His last thought was, "God save them." Then, the bomb beneath the launchpad exploded with about half the force of the ISS. Kourou was obliterated and the remaining ponies on Earth did not have anything to refer to for building space vehicles.
As the colonists approached Mars, they took ingenuity in one hand and hope in the other. They aerocaptured in Mars' atmosphere. First, the Habitation Module landed. Then Hydroponics descended to the surface. Something was wrong. It hit the ground and was dashed into pieces. However, the plant storage lockers were intact. Next, the repair module landed. Then the food module touched down succesfully. As the food in the colony ship began to run out, it burned retrograde and touched down less than 20 metres from the main module. The colonists suited up and walked over. They climbed into the Habitation module. Later, they stocked it with food. About a day later, they set to the task of fixing hydroponics. The plant lockers were set up and the dome was fixed. Then, they put the remaining dirt in and planted. Humanity's last hope had survived.
