SR01 ISRU Flashcards
ISRU
What is SRU? Give an example
Space Resource Utilisation
Capturing an asteroid and bringing it back to Earth for terrestrial utilisation
What is ISRU?
„In-Situ Resource Utilization is the collection, processing, storing and use of materials encountered in the
course of human or robotic space exploration that replace materials that would otherwise be brought from
Earth to accomplish a mission critical need at reduced overall cost and risk.“
“In-Situ Resource Utilization will enable the affordable establishment of extraterrestrial exploration and
operations by minimizing the materials carried from Earth and by developing advanced, autonomous
devices to optimize the benefits of available in-situ resources.”
ISCP
In-situ Consumable Production
ISPP
In-situ Propellant Production
ISFR
In-Situ Fabrication and Repair
Fundamental Questions of ISRU
In-situ –>What is locally available?–> Availability
Resource –>What is needed? or Who needs it?–>Demand
Utilisation –>How can it be used?–>Product
Human demands
- Oxygen: max. 3 min without
- Water: max. 3 days without (in mild climate)
- Nutrition: max. 3 weeks without (only if water is available)
- Sunlight: probably a normal lifespan (but not healthy)
Rocket demands
Propellant (liquid bi-propellant most relevant for ISRU)
LOX and LH2 (hydrolox)
LOX and LCH4 (methalox)
LOX and LH2 (hydrolox)
- higher Isp
- problem of boiloff and H2 embrittlement
- can be supplied on Moon
- cleaner
- RS-25 (SLS 2nd stage)
- BE-3 (New Glenn 2nd/3rd stage)
- RL-10 (SLS 3rd stage, Centaur upper stage)
LOX and LCH4 (methalox)
lower Isp
* Higher boiling temperature
* can be supplied on Mars
* Raptor (Starship)
* BE-4 (New Glenn 1st stage, Vulcan 1st stage)
Machine demands
Spare parts and tools
* Mainly metal alloys and polymers
* Material and tools for repairs also need to be considered
* NASA sends up about 7,000 pounds of spare parts to the ISS every year
* 29,000 pounds of hardware spares / replacement units on ISS
(3% of total mass; 445 tons)
* Important for overall mission flexibility
Buildings/Settlement demands
Construction material
* Semi-finished parts
* Structures (foundations, reinforcements)
* Shielding (temperature, radiation, impacts)
* Logistical infrastructure (pads, berms, roads)
Availability on lunar/planetary surface
-Atmosphere
-Sunlight
-Regolith
-Vacuum
-Temperature gradients?
Products derived from ISRU
Propellants, consumables, spare parts, etc.
From regolith: construction, life support (oxygen, water etc), power from solar arrays (sillicon), construction
Benefits of ISRU
- Mass and Cost Reduction
- Reduced Emissions
- Space Commercialisation
- Risk Reduction & Flexibility
- Human Presence
How does ISRU contribute to mass and cost reduction in space missions?
-Reduces the need to transport resources from Earth
-Allows smaller and fewer launch vehicles
-Savings across space missions by refueling with lunar propellant
What are the relations of ∆v, mass, and cost?
∆v depends on effective exhaust velocity (ve) and mass ratio (m0/mf), affecting both propellant mass and cost.
What is the Rocket Equation?
∆v = ve ln(m0/mf)
m0: Initial mass
mf: Final mass
ve: Effective exhaust velocity
What are the effective exhaust velocities (ve) for hydrolox and methalox thrusters?
Hydrolox: Up to 4.5 km/s
Methalox: Up to 3.6 km/s
What cost reductions have been achieved for space missions?
Cost to LEO used to be >5,000 €/kg
Future cost to Moon/TLI could be 2,000–20,000 €/kg
How does ISRU enable further cost reduction?
-Lunar surface refueling for return missions
-Refueling at EML1 for Mars departures
-Refueling in LEO for missions beyond GEO
What are the emission differences between hydrolox and methalox fuels?
Hydrolox: H2O and NOx
Methalox: CO2, H2O, and NOx
What processes are used for hydrogen production on Earth?
Steam Methane Reformation (SMR)
Electrolysis of water
What is the goal for low-emission hydrogen production by 2030?
To reach 49 Mtpa H2 production
