Friday, 22 April 2016

3d unprinting

3d printing, or as NASA calls it, additive manufacturing is destined to play a big part in future space work, test work has already been done building complex metal parts on earth and plastic parts have been manufactured in space. The next big launcher the SLS will use 3d manufactured parts to allow it to be lighter, complex geometries can be created in a single piece, removing the need for joining. See here.
Plans have been made and experiments have taken place, about using lunar or martian regolith+
 to construct habitats. I would expect experiments to take place on the moon with the next 5 to 10 years. See here. In 2015, NASA ran a habitat design challenge see here.
The return to the moon is a staging post and practice for going to mars, there is little point simply repeating the Apollo mission, with the advance in robotics in the intervening 50 years the work of Apollo could be added to with a single human going. The only real justification for sending people is the practice for Mars, to see how bodies cope with long-term low gravity and high radiation.
If I was going to Mars, I would want a lot of infrastructure in pace both in mars orbit and on the surface. Enough to extend a mission almost indefinitely, in the event of a great discovery or failure of one part of the  return system, some have even planned one way missions, which there would be no lack of volunteers for. While with the SLS it should be possible to launch a lot of equipment and with Bigelow's inflatable system get a lot of space out of it, it would be costly. So 3D construction of some of the habitats, even if it is only unpressurised shelters for equipment is almost a requirement. You have to launch the 3d printer and any the equipment to fit out the structure but that is all.
Or is it.
A large part of what lands on either the moon or mars will stop being useful the minute it hits the ground, other bits like heat shields etc will stop being useful before even then and will have been ejected along with other parts. Some of the parts like tankage might be useful but unless it is for spares the majority of the mass, engines, control system etc will be waste.
Unless of course in addition to the 3d printer, a 3d dismantle is taken along, capable of disassembling the redundant decent stage into materials suitable for 3d printing, not perhaps by the construction robot, but doors, wiring etc. Large chunks of a metal descent stage would be recyclable but a little extra care could increase the reprocessed percentage. Plastics could be recycled via Thermal depolymerization, metals by simply sorting, as the recycler is grinding them with a very low energy budget and of course as little mass as possible.
Using similar equipment on earth the could allow the removal of complex equipment from confined spaces or the energy efficient recycling of used aircraft or cars without a complex separation process.


  1. I think you're right in that recycling on the Moon/Mars is the way forward, if for no other reason than the fact that otherwise we'd need to implement some sort of weekly bin collection and work out how to build landfill sites.

    And if you think about it, if you did that, you wouldn't need to take all that much with you in raw materials. In fact, if you were weren't planning on doing a return trip, the spacecraft that took you there would probably be all the raw materials you'd need.

    1. The real problem is were to get the multicoloured bins.