Depends on what the goals are.<p>Among other things Apollo was also really expensive propaganda with a lasting impact.  In that context it worked well.  50 years later and the US is still the country that put a man on the moon where probes are generally forgotten outside of Voyager.<p>Energy research similarly has a lot of indirect value outside of simply changing local emissions.  By reducing costs you can push world wide adoption through economics not just politics.  And create economic incentives to keep improving things over the long term. That&#x27;s a lot of leverage and well past what direct spending on &#x27;clean&#x27; energy could have achieved in the 1980-2000 timespan.