Beside the age 16+ designation for the Shuttle Adventurer vs the 14+ age designation on the Shuttle Expedition and some different photography they look identical except they don't sell the Shuttle Adventurer anymore on shop.lego.com. Is there any practical difference?
The LEGO Direct team's answer to this question is on brickset:
Since its release in 2010, 10213 Shuttle Adventure has proven to be very popular! Although the model was designed for a 16+ target audience, our consumer call center has brought to our intention that many younger children have been building and playing with the model. As a result, the Direct team has decided to look at the model once more to see what changes could be made in order to provide a better build and play experience for a slightly younger target audience. 10231 Shuttle Expedition may look similar to Shuttle Adventure in many ways, however its build is very different and offers several advantages.
- The fuel tank has been reinforced with supports to strengthen the assembly
- The landing gear is strengthened to function better across many different floor types
- The Cargo doors can now be more rigorously opened and closed
- The entire build has been reworked to limit opportunities for misplacing elements
- Astronauts now have wigs in addition to their helmets (1 male, 1 female). Face prints are also different.
- The new set now has 1,230 elements
- New Satellite can be securely positioned on the new mechanical arm 10231 Shuttle