Maria Celeste was Galileo's daughter and helped his work tremendously. Even though she was held up in a convent for most of her life, she still managed to help Galileo. She did many things for him. She helped him financially and paid his taxers and bills. She helped edit and get his book published before the time of his death. She gave him medicine in order to fend off the black plague. She created many medicinal potions that helped Galileo through his daily activities and helped him stay alive. She also would look after her father. She obviously cared for him a great deal and showed it by helping him with everyday activities and helping him get his ideas in a book and helped spread his ideas to the rest of the Western European world.
If it were not for Maria Celeste, then Galileo would have probably perished from the black plague or from the church when he was being accused of treason and going against the church. As we can see, Maria Celeste helped greatly with Galileo's life and without her, the rise and spread of astronomy and his philosophical ideas would have been impossible.