One of first pieces of media with actual use of Time dilation and it was done extremely well, the best friend of the mc grew and had a daughter when she first came back and the latter asked her to take her daughter to the space station with her should earth be destroyed to which she declined, the MC's senpai had to deal with the death of her love interest. The mc for some time thought her father who had disappeared years ago might still be alive because his ship was travelling near light speed but he was not. The series also had the first use of gifs I've ever seen