Episode 5

Episode 5 ("My Big Sister is dead!?") is the fifth episode of the Null & Peta anime series.

Summary
After forcing her way into an old space station, Null tries to recharge Peta. While the majority of the space station still works, and Null manages to connect to Peta, backing up her memories turns out impossible, leaving Null no choice but to delete Peta's program when plugging her in.

This seems like no big deal to Null at first, but after recalling some memories with human and robot Peta (including an original version of Peta bringing Null her gym shorts), she becomes increasingly reluctant to go through with it.

The space station is then damaged by a stray solar panel floating around, causing Peta to be flung through the room and somehow recharge by herself. Together with an overjoyed Null, she flies back to Earth, leaving behind the exploding station.

The last scene has Peta combine the previously presented noodles and chocolate to a horrifying Ramen mix.

Trivia

 * A quick look at the relevant Wikipedia article suggests the closest match for the depicted space station being the Soviet station "MIR", abandoned in 2001.