Radha had toruble understanding the notion of aging and death but then she saw it right before her eyes. As the earth seemed dead people around her continued to age. Pretty and strong Suzie became weak and fragile, Fransico had troubled moving around and First officer Yakub died of heart attack. Yakub's death was the first death Radha got to see first hand. With teary eyes the entire crew gave him proverbial burial at space. His lifeless body was put in a space capsul and fired towards sun. 

Radha found it weird that now everyone suddenly got busy with their own life. No one ran tests on her sometimes she even felt that people on the ship disliked her. As time passed more people on the spaceship died. Radha was expected to do more work as she was younger and strong and less likely to die. Chief Pilot Thorat taught her to steer the plane and Fransico taught her repair work. As per the protocol the most senior officer was supposed to assume the command to ship if the captain dies. By that rule the number of captains changed rapidly. Some died natural deaths and some might have killed themselves. 

Within 20 years or so the ship had run out of all its exotic food such as alcohol, fish, cola and meat. All the food that was available was now basically recycled food which was synthetically generated by recycling the human waste, water and large quantities of hydrocarbon storage. It tasted exactle same everyday. 

Radha by now was proficient in all aspects of the ship. She could steer it, repair it, nurse other people and also quickly dispose off dead bodies. She was also proficient in communicating with remote space ships. Out of the 4 ships that went to marse only 1 had made it while others got destroyed on their way. The only ship that survived the journey however not only landed on surface but also actively setup the camp on the existing marse base. There were around 75 people in total on mars now. 

One of the ideas that the remaining crew on IBSS had to do was to ask whether they would continue to live on the ship or wehther they should move to mars as well. Over the course of 30 years only 9 people were remaining on IBSS. Over 500 people had died. 

The captain of the ship by this time was the junior doctor Silvia. She obvsiously had no experience running the ship but she decided to step down and instead make Radha, the youngest person on ship the captain as they all agreed that Radha is essentially the future of humaniy. Silvia was around 62 years old. Journey to Mars would have taken at least 2 month for the spaceship and the IBSS was not designed to land on a planet, it instead has small transport modules which could land on earth. 

Radha decided not to go to Mars. She had done the math. There was plenty of food for everyone on the ship. The fish in the tanks were now plenty, since population was only 9 people, it was also possible to grow enough vegetables in the vertical farm and the algae based alcohol could also be consumed. Taking such large ship to Mars was tough and putting it into the orbit was harder too. In last 40 years or so there was no communication from earth. 4 people had gone to earth in transport module to do recon but had not returned. All hope for earth was lost. 

And as expected more years passed by and Radha was the only remaining surviver of IBSS. There was no successful human reproduction on Mars either so the mars colony was dead too. 

Radha was the only human alive outside of earth. Her life on the ship because routine. She shut down all the non essential parts of the ship. Lowered energy usage to maximise the life of the ship. Like a clockwork every single day she would work thoroughly on one small section of the ship, creating an inventory of all available items and parts. Every day she would spend 4 hours exploring possible ways to land on earth. Every week she would pick one person and go through their personal recors trying to understand their life. Their diaries, their last thoughts, what they worked on and so on. 

She would then go to the theater and watch movies and documentaries about earth. Everything worked like a computer program as years passed by. Her physical body was in great shape. Her knowledge had vastly increased and as around 300 years had passed, the ship to managed to somehow survive. Some parts would occasionally go off, especially the battery operated devices but she had figured out a way to bypass the batteries and connect them directly to carbon cells. 

She constantly monitored the planet earth using all the equipment. Most of the sattelites around earth had now collapsed. The north american continent was mostly covered by ash and the Yellowstone volcano was cooling down. Japan was not there on map anymore where as Arabian ocean seems to have disappered completely. She could occassionally spot tree cover in some areas but mostly it was snow. The snow at some palces was melting though.