  Asteroid mining offers the possibility to revolutionize supply of resources
vital for human civilization. Preliminary analysis suggests that Near-Earth
Asteroids (NEA) contain enough volatile and high value minerals to make the
mining process economically feasible. Considering possible applications,
specifically the mining of water in space has become a major focus for
near-term options. Most proposed projects for asteroid mining involve
spacecraft based on traditional designs resulting in large, monolithic and
expensive systems.
  An alternative approach is presented in this paper, basing the asteroid
mining process on multiple small spacecraft. To the best knowledge of the
authors, only limited analysis of the asteroid mining capability of small
spacecraft has been conducted. This paper explores the possibility to perform
asteroid mining operations with spacecraft that have a mass under 500 kg and
deliver 100 kg of water per trip. The mining process considers water extraction
through microwave heating with an efficiency of 2 Wh/g.The proposed, small
spacecraft can reach NEAs within a range of $\sim 0.03$ AU relative to earth's
orbit, offering a delta V of 437 m/s per one-way trip.
  A high-level systems engineering and economic analysis provides a closed
spacecraft design as a baseline and puts the cost of the proposed spacecraft at
$ 113.6 million/unit. The results indicate that more than one hundred
spacecraft and their successful operation for over five years are required to
achieve a financial break-even point. Pros and cons of using small spacecraft
swarms are highlighted and the uncertainties associated with cost and profit of
space related business ventures are analyzed.
