Source: APCL, Aerospace Engineering, SNU, Seoul, The
Republic of Korea(Al – Aluminum, Cu - Copper, Ge – Germanium, Si – Silicon) An amount of 273.33 W electric energy is required for melting 1 kg of
aluminum in the ISS at a temperature of 750o C and
pressure of 96.52 kPa. Additionally, 750-1000° C range heating system is
required to retain aluminum in the liquid state at a pressure of 1.03
MPa in the atomization process of 12 liters of water, obtained from the
alkaline fuel cell, at an electric energy consumption of 3-5 kW. The
potassium hydroxide is used as an electrolyte in the alkaline fuel cells
at a temperature of 90o C at a pressure of 101.35 kPa.
During this process 9 liters of water and 33.33 kW of electricity are
acquired as derivatives for 1 kg of hydrogen. The required amount of
water is generated from the Bacon fuel cell for the atomization
process. The estimated electric power needed for atomization, dewatering
and filtering processes is 1.5 kW. Note that a temperature of 55° C for
dewatering [39] and 24° C for filtering must be maintained in the
system. The water is segregated into hydrogen and oxygen with the aid of
the potassium hydroxide as an electrolyte at an energy consumption of 50
kW for 1 kg of hydrogen at a temperature range of
60-80o C, and at a pressure of 3 MPa. The generated
hydrogen and oxygen are permitted to recycle in the onboard system to
produce the water continuously for the water atomization process. The
required powder, as an end product with desirable size, is obtained
through appropriate sieving. Note that, if necessary, hydrogen gas could
be either transported from the earth or obtained from space by utilizing
the Bussard’s ramjet [40].
The solar energy conversion system is invoked for an efficient power
generation, as the ISS has 2,500 m2 solar panel, which
could produce up to 84–120 kW [41]. Additionally, the fuel cell
could contribute 33.33 kW of electricity, which mainly utilized for the
recycling process. In the proposed technique, a total amount of 40 kW is
required for processing 1 kg of aluminum. It is estimated that up to 1
kW power can be generated using a solar panel with one square meter
area.
The satellite, named SNUSAT-2, a 3 U CubeSat designed and developed by
the Seoul National University (SNU), South Korea for remote sensing is
selected for our analytical case study. The main elements and the
connected materials employed in the SNUSAT are given inTable-2 . It is evident from the component details that once
this SNUSAT becomes non-operational, it gives 1350 g of
aluminum powder. In the case of a non-operational Vanguard-1 [42] we
could collect an amount of 1420 g of aluminum through recycling, which
could be converted into fuels for spacecraft propulsion.