This is how I found the sentinel freighter for combat in space in the new Interceptor update, hope this helps you!
How to Get Sentinel Freighter
This probably has more than one approach, but here goes what worked for me.
First I already have found the dissonant system (even more than one) and dissonant planets, where I fought many new sentinels and collected the resonator for the harmonic base (found 2 in total, many battles). So at this stage I had collected 3 new sentinel ships, a new gun and the new Aeron Turbojet backpack.
Not sure if you need go through all the the above but that was the order that worked for me.
Once I was in my new sentinel ship I follow the steps:
- Warp into another dissonant system (Calypso galaxy have plenty);
- Find another dissonant planet;
- Fly into this planet and start shooting a new group of sentinels;
- Once they are engage in attack, jump back into your ship and navigate back into space;
- This will make many groups of singles, doubles and trios of sentinels to attack you, be prepared!
- Once many waves of attacks happen, the new sentinel freighter will spawn!
- Be ready for them, it will take many, many more waves of sentinel ships attacking you while you try to shoot the sentinel freighter.
It will make a countdown from 100% until 0% to be considered defeated and this will take a while.
During this time you will be hammered with attacks, be sure to have plenty of resources with you to fix your ship. Good Luck!