548
a range of products. While carbon dioxide has become problematic on Earth, it
offers potential as a resource in other planetary systems. This is enhanced by the
availability of methane in addition. The prospect for establishing a sustainable
human settlement in planets such as Mars requires opportunities for the utilization
of extra-planetary resources by the development and deployment of technologies.
This is also referred to as in situ resource utilization (ISRU) which is defined as the
as the conversion of local resources at a space destination to provide useful infrastructure and commodities [93]. In situ resource utilization was first proposed in
1978 to produce rocket fuel on Mars for refuelling of an empty ascent vehicle for
the return flight [94]. Utilization of Martian resources for life support and exploration will significantly reduce the costs of human missions and support for human
settlements in Mars by reducing launch mass and cost of storage of consumables
(O 2 , food, fuel, H 2 O). A recent study shows that ISRU for propellant and oxygen
production results in about a 95% reduction in mass of the Mars ascent vehicle
(MAV) [95]. Also, the availability of Mars-generated consumables could significantly extend the duration and range of crew operations and greatly enhance the
science returns of missions to Mars.
The atmosphere of Mars is the most significant natural resource on the planet. It
consists about 96% CO 2 , 1.9% Ar, 1.9% N 2 , 0.014% O 2 and 30 ppm H 2 O with an
atmospheric pressure of 700 Pa and average temperature of 220 K [93]. The Martian
atmosphere will be the principal source of carbon and oxygen. Also, the highest
potential sources of water include Martian regolith (hydrated minerals and clays)
[96] within the top surface of Mars and ice [97] at the subsurface. Several minerals
including oxides, chlorides, perchlorates, sulphates, sulphides, carbonates and silicates of Fe, Mg. Al, Ca, Na, K have been detected in Mars [98].
Oxygen and water are essential for life in Mars. Methane has been identified as
an optimal rocket fuel which can be produced in Mars because of its relative ease of
production using Martian resources, high specific impulse, low refrigeration power
requirement with boiling point similar to oxygen and reduced risk of metal embrittlement in storage [94, 99]. The Sabatier/water electrolysis process has been demonstrated to produce oxygen and methane. In 2011, the Sabatier reactor was
integrated into the international space station water recovery system [99].
In the Sabatier/electrolysis process, hydrogen is reacted with compressed CO 2 in
a heated chemical reactor to yield methane and water. Ruthenium and Nickel on
alumina catalysts have been found very effective for the Sabatier reaction with CO 2
conversion and yield greater than 99% at temperatures between 300 and 400 °C and
pressure of 1 atm [100]:
CO
H CH
H O
2
2
4
2
4
2
+
=
+
(10)
The methane water mixture is separated in a condenser. While methane is dried and
stored for use as a propellant, water is collected, deionized, and electrolyzed in a
standard electrolysis cell;
2
2
2
2
2
H O
H O
=
+
(11)
O. Okonkwo and P. Biswas
a range of products. While carbon dioxide has become problematic on Earth, it
offers potential as a resource in other planetary systems. This is enhanced by the
availability of methane in addition. The prospect for establishing a sustainable
human settlement in planets such as Mars requires opportunities for the utilization
of extra-planetary resources by the development and deployment of technologies.
This is also referred to as in situ resource utilization (ISRU) which is defined as the
as the conversion of local resources at a space destination to provide useful infrastructure and commodities [93]. In situ resource utilization was first proposed in
1978 to produce rocket fuel on Mars for refuelling of an empty ascent vehicle for
the return flight [94]. Utilization of Martian resources for life support and exploration will significantly reduce the costs of human missions and support for human
settlements in Mars by reducing launch mass and cost of storage of consumables
(O 2 , food, fuel, H 2 O). A recent study shows that ISRU for propellant and oxygen
production results in about a 95% reduction in mass of the Mars ascent vehicle
(MAV) [95]. Also, the availability of Mars-generated consumables could significantly extend the duration and range of crew operations and greatly enhance the
science returns of missions to Mars.
The atmosphere of Mars is the most significant natural resource on the planet. It
consists about 96% CO 2 , 1.9% Ar, 1.9% N 2 , 0.014% O 2 and 30 ppm H 2 O with an
atmospheric pressure of 700 Pa and average temperature of 220 K [93]. The Martian
atmosphere will be the principal source of carbon and oxygen. Also, the highest
potential sources of water include Martian regolith (hydrated minerals and clays)
[96] within the top surface of Mars and ice [97] at the subsurface. Several minerals
including oxides, chlorides, perchlorates, sulphates, sulphides, carbonates and silicates of Fe, Mg. Al, Ca, Na, K have been detected in Mars [98].
Oxygen and water are essential for life in Mars. Methane has been identified as
an optimal rocket fuel which can be produced in Mars because of its relative ease of
production using Martian resources, high specific impulse, low refrigeration power
requirement with boiling point similar to oxygen and reduced risk of metal embrittlement in storage [94, 99]. The Sabatier/water electrolysis process has been demonstrated to produce oxygen and methane. In 2011, the Sabatier reactor was
integrated into the international space station water recovery system [99].
In the Sabatier/electrolysis process, hydrogen is reacted with compressed CO 2 in
a heated chemical reactor to yield methane and water. Ruthenium and Nickel on
alumina catalysts have been found very effective for the Sabatier reaction with CO 2
conversion and yield greater than 99% at temperatures between 300 and 400 °C and
pressure of 1 atm [100]:
CO
H CH
H O
2
2
4
2
4
2
+
=
+
(10)
The methane water mixture is separated in a condenser. While methane is dried and
stored for use as a propellant, water is collected, deionized, and electrolyzed in a
standard electrolysis cell;
2
2
2
2
2
H O
H O
=
+
(11)
O. Okonkwo and P. Biswas