The carbon sequestration target is blocking forward progress. When it became available, I was below 50% of the goal. Now, after researching several levels of the endless technologies and blowing up hundreds of chests full of grey landfill to consume carbon, I'm still only at 94%. Is there an easier way to reach the target?

It's a hard thing to calibrate. Some people are already past that checkpoint by the time they launch a rocket. Not sure what makes some factories able to do so much research without as much production as others. I'd be curious if there is anything unusual about your factory.

The checkpoint is a bit simpler than the oxygen mission goal. The checkpoint only counts oxygen produced, with no penalty for other gases vented. So any method that produces oxygen will work, assuming that oxygen is the problem. That checkpoint has 2 parts, so progress could be blocked on the oxygen half or the carbon dioxide half. You can verify which by checking your production statistics window. Under the fluid tab. Look for carbon dioxide in the consumption panel and oxygen in the production panel. Compressed oxygen or compressed carbon dioxide count for 4x the uncompressed version, so tally up both forms. You can see whether it's your oxygen or carbon dioxide that aren't at the checkpoint target yet.

Assuming oxygen is the problem, and not carbon dioxide, the checkpoint has 2 prereqs, either one of which could help. One method, which from your comment it sounds like you're using, is to use the new carbon sequestration recipe to make oxygen directly from carbon dioxide. This recipe was improved in a recent update, by the way, to produce oxygen faster and more cheaply, if you aren't up to date.

The other method is to use the algae recipe. Algae growth produces a ton of oxygen, and unlike electrolysis you can speed it up with modules. So you can just grow a bunch of algae solely to vent the oxygen byproduct, and it may be a bit easier to scale up than electrolysis if you use beacons. A recent update also improved this method by adding a recipe to void unwanted algae.

Thanks for the advice. I was short of the oxygen target and I had been using the carbon sequestration recipe. I started using algae disposal to produce more oxygen.

I don't know what I do differently from other players. Perhaps maximizing productivity. 20% productivity gains compounding over 4 steps means 50% less input per output, and the production chain from electrolysis to science is quite deep, so productivity makes a big difference in oxygen per science.

This checkpoint blocked me for a long time too. It made me feel “I didn’t build my factory the way the designer intended” but without knowing what I should have done differently. In the end I just brute forced it by blueprinting some beaconed sub factories whose only job was to turn electricity into vented oxygen. It still took a very long time. FWIW I am now at 66% completion of the overall mission goal and can see the end in sight! Really enjoying the mod, thanks anachrony.