A radius of 224 meters is 1 g acceleration at 2 revolutions per minute. It is directly proportional, so half the acceleration is half the radius. 0.5g or less might be good enough.

Now this is a pretty huge space craft, but compare that with the ISS which is already 108 meters wide by 73 meters long. It's a huge undertaking but in the realm of possible. Of course, there's still the issue with mass and thrust required to propel a huge craft to an interplanetary trajectory.

The question is whether artificial gravity is a requirement for interplanetary human expeditions.