Voices of A Distant Star: Mikako Nagamine

The heroine and the pilot of the mecha called an Tracer, she is trained to stop the enemy alien race known as Tarsians, they are named after the Tharsis region of Mars where they were first encountered the UN Space Army. She and her best friend, Noboru Terao, communicate through their text messages on their phones as she move further and further away from Earth to receive Noboru's text messages. This OVA could have the potential to be an TV series since there were manga and light novels of this.