That's a good theory, but it can't be her only goal. Remember on Venus, the Stranger says "Hold position, kill the engines and don't let them find you.", if she was only with Maya, that wouldn't make much sense and she entered the machine alone, not with backup. So who is she talking to? Unless she's been through many events in order to reach Maya, then that would make sense. I'm thinking she might be related to Praedyth. Since his dead corpse is found in a hidden area near a chest, she could have been in the Vault of Glass and helped Praedyth, which would explain the "Hold position, kill the engines and don't let them find you" quote. Also the fact that VOG lore plays with the past and the Vex populate it. Now, i'm not 100% sure she was related to him, as there are no 'engines' in VOG, unless they she means oracles or Vex plates. However, i think the No Time To Explain might have been his gun. He might have given it to her or the Stranger took it with the remains of his death. Because The Stranger's Rifle is really similar to No Time To Explain. And you can't find it in VOG loots, so it was either taken or given to her. Also the fact that she says "I don't even have time to explain why I don't have time to explain." Clearly exposing No Time To Explain and the fact that she time travels. Also, not all Exos were once humans. Exos were war machines created back in the day for the wars. Within time, Exos were considered complex enough to hold a human's life, memory, intel, etc. But there are many unknown reasons why some humans were transferred into an exo body. Some were to be saved and forget, some were because they had the possibility such as perhaps Chioma here and Cayde was to pay his debt to Clovis Bray. Also, Exos get rebooted instantly after the process from human to Exo. The reboots are just so they forget their past and focus on the present and future. Since they're machines after all, too much memory leads to a reboot. The numbers next to an Exo's name are the number of reboots they received. Like Cayde-6, six reboots. Banshee-44, forty four reboots. Reboots occur to all Exo, guardian or not. Now, since we don't know the Stranger's amounts of reboots, we can be sure she has at least 1 from being turned into an Exo. So going back to what the Stranger's goals are, can't just be to save Maya. I'd only assume so for the lines she says, like "Too late, returning. How many?" and "I will. I will. I know." Also because we know she could have been a scientist as you say, so wanting to discover about the Guardian, the Light, the enemy races out of curiosity makes sense. So she must have someone with her also aware that they're in the past. So it could be Maya but most probably be someone else. As the person the Stranger's talking to, knows about the Guardian and his/her's goals. In conclusion, it's just one big clusterphuck that leads to more possibilities xD