on the real, precious moondust needs to happen. but sd printing on the moon could go beyond putting a roof over astronauts' heads. we can print polymers, metals, ceramic materials. and you could print food. you can print stem cells for medical applications. there's almost no limit of what you could not print. and even more important, what you can do is you can recycle. so you could actually then have a very sustainable operation by reusing stuff we have used for other purposes before. so a robotic version of this sd printer could make use not only of substances found on the lunar surface, but also raw materials transported there in as low a volume as possible. exploration in the past has always been about taking everything you can with you wherever you go.