My progress so far:
I decided to go along with Null's plan to speak with cartographers. I met a Vykeen cartographer at the Konaka Stellar Observer station, who told me to prove my worthiness by visiting a Vykeen reliquary on planet Jodice G20. I got an ancient tablet from the reliquary and showed it to the cartographer. In return I was told of Vykeen's history. Before finding the next(Korvax) cartographer to talk, I warped out of Konaka system and reached Rakino X system to check out something called "Atlas Station". It looks like a kind of space station where you can contact Atlas. Atlas gave me the blueprint of "Captured Nanode". I'll visit more Atlas Stations to find out what it's all about. (log #21)
I discovered a settlement on planet Erheg II in Rakino X system. I defended the settlement from Sentinel invasion and became Overseer there. On the way to the 2nd Atlas Station in Gagasera system, I received a distress call from my settlement. So I teleported back and took out another wave of Sentinels. Shortly after that, Tethys from the Space Anomaly station contacted me and told me to check if there is anything left of the Sentinels. I found a damaged Sentinel drone. (log #22)
I visited the Space Anomaly station with the damaged Sentinel drone I previously obtained. Tethys on the station repaired the drone with a few components offered by other Travelers. I got back to my settlement and summoned the drone. It gave me a coordinate for a Sentinel Pillar. After taking out guardian Sentinels and control nodes, I could access the Archive Terminal and download blueprints for Minotaur mech and Sentinel Hardframe right arm. It's time to build a mech. (log #23)
I went back to my second base and built a Minotaur Geobay which comes with the Minotaur mech. Now that I had a mech, I used the previously obtained Sentinel Hardframe right arm blueprint to upgrade the mech's arm.
Upgraded right arm looked cool, but it didn't make any difference other than that.
Also, there was a citizen enquiry in my settlement because their "overseer" which is me had been seen walking with a mysterious Sentinel drone. I teleported to my settlement to address the issue.
They wanted to go on an expedition to find answers about this new situation. Maybe they could find something interesting.
As for myself, the drone gave me another coordinate data to check out.
The location was in another star system nearby, so I dropped by the Space Anomaly station to get some tech blueprints for my new mech. I purchased Minotaur Laser for mining and Minotaur Cannon for defense.
I warped to Rozawanu V system. The coordinate data I got from the drone directed me to an abandoned factory on planet Icianu IV.
I downloaded another Sentinel Hardframe blueprint via the factory terminal. It was for left arm. I came back to my base and installed the upgrade.
Meanwhile, the citizen expedition was complete. They found another Sentinel Hardframe blueprint, for legs. I installed this upgrade too.
The Minotaur mech was changing into a Sentinel mech with blue color, instead of typical Sentinel red.
The drone wanted to have designation because it was separated from Sentinel Hive. It asked me why it didn't have a name, and I said I didn't know. It decided to give itself a name, Laylaps. Hello, Laylaps.
Laylaps gave me another coordinate data, saying it wanted to help the mech to have "mind". I went along with Laylaps's guidance and went to planet Aputon Sigma.
Aputon Sigma was a frozen planet, so I installed Exocraft Summoning Station to summon the mech. The mech's cockpit provided protection from harsh environment.
At the location where Laylaps directed me to check out, there was a gigantic Sentinel Walker. I took out the Walker with Minotaur Cannon and obtained a pristine Sentinel brain.
I went back to the Space Anomaly to visit Tethys who repaired Laylaps before. As expected, Tethys rewired the brain so that it could be installed into the mech. Additionally I was given blueprint of Sentinel Hardframe body.
The rewired brain had to be activated by "crimson". Tethys said it would draw attention once I went out to the space. Sentinels maybe?
I went out of Space Anomaly, and fortunately what I encountered was not a Sentinel, but a communication relay of Atlas. I opened comm channel with it, and the brain was transformed to "radiant brain", ready for mech body upgrade.
Back to my base, I installed body upgrade to Minotaur mech, making it into fully upgraded Sentinel Hardframe. The mech became autonomous, moving without a pilot. Of course I could jump in and control the mech any time if I wanted to. Cool.
With an autonomous mech companion, or "friend", Laylaps wanted to be completely disconnected from Sentinel Hive. Disconnection had to be done via a Sentinel terminal. Thus, I would need to attack another Sentinel Pillar.