Enlarge / A Blue Moon lander, built by Blue Origin, with an ascent vehicle (built by another company) on top. (credit: Blue Origin) In the nearly two months since Vice President Mike Pence directed NASA to return to the Moon by 2024, space agency engineers have been working to put together a plan that leverages existing technology, large projects nearing completion, and commercial rockets to bring this about. Last week, an updated plan that demonstrated a human landing in 2024, annual sorties to the lunar surface thereafter, and the beginning of a Moon base by 2028, began circulating within the agency.