Back in March someone asked a very similar question. One comment that I found very clever was advising to work on Open Source Projects. They may not be directly

Back in March someone asked a very similar question. One comment that I found very clever was advising to work on Open Source Projects. They may not be directly related to 'public health and equitable growth and space travel' but it will indirectly help. The impact on the world of, say, a Rails contributor is massive. Another stuff I would recommend is to add something the public domain. Anything that someone else can reuse for free. That makes everyone richer.