Mars Ascent Propellants and Life Support Resources – Take it or Make it?

Engineering Optimization – Evaluating “Take It or Make It” Approaches for Mars Missions

Engineering Optimization is at the core of space exploration, enabling mission planners to balance costs, risks, and logistics. Human missions to Mars have introduced the concept of “take it or make it,” referring to whether to bring resources from Earth or produce them in situ. This blog explores a comprehensive study on optimizing ascent propellant and life support strategies for Mars missions.

For more details, read the HTML article or explore the PDF version.

Introduction

Mars missions require a careful evaluation of Initial Mass in Low Earth Orbit (IMLEO), which significantly impacts costs and risks. Historically, high launch costs drove investments in mass-reduction technologies. However, with modern advancements like SpaceX’s Starship, launch costs are projected to drop below $1,000/kg, challenging traditional approaches. This study reexamines whether to “take” ascent propellants and life support resources from Earth or “make” them on Mars using in situ production.

Challenges and Considerations in Mars Missions

1. Ascent Propellants

• “Take It” Approach: Bringing methane (CH₄) and oxygen (O₂) from Earth ensures reliability but increases IMLEO, requiring super-heavy launch vehicles.
• “Make It” Approach: In situ propellant production (ISPP) reduces IMLEO but involves autonomous operations on Mars, which introduces high costs and risks.

2. Life Support

• Air and Water Requirements: Daily water needs for a crew vary from 7 kg (survivable) to 16.7 kg (comfortable Earth-like conditions).
• Recycling Systems: Air and water recycling reduce IMLEO but rely on complex systems that must function flawlessly for 900 days.

Key Findings

1. ISPP Challenges

1. • ISPP systems are power-intensive and require long-term autonomous operation.
   • Producing both CH₄ and O₂ involves mining regolith, increasing risks and costs.
   • Atmosphere-only ISPP (producing O₂) is less risky but still costly, with development estimates exceeding $5 billion.

2. Life Support Options

1. • Bringing survival resources from Earth minimizes risks but requires substantial launch logistics.
   • Hybrid approaches, combining Earth-brought resources with recycling systems, balance costs, reliability, and comfort.

3. Cost Analysis

1. • Launch costs for “take it” approaches are lower than ISPP validation costs.
   • ISPP with regolith processing may exceed $10 billion in development and operational costs.

Engineering Optimization Strategies

1. Hybrid Systems for Life Support

1. • Combining Earth-brought air and water with recycling systems optimizes reliability and comfort.
   • This approach reduces IMLEO while maintaining robustness.

2. Super-Heavy Launch Vehicles

1. • Vehicles like Starship can accommodate the high IMLEO associated with bringing ascent propellants and life support from Earth.

3. Risk Mitigation in ISPP

1. • Atmosphere-only ISPP offers a safer, cost-effective alternative to regolith-based ISPP for producing O₂.

Future Directions in Engineering Optimization

1. Advanced Recycling Technologies

Developing robust, fault-tolerant recycling systems will enable sustainable long-duration missions.

2. Enhanced Validation Processes

Cost-effective and reliable validation methods for ISPP and life support systems are essential to reduce mission risks.

3. Dynamic Cost Modeling

Using real-time launch cost trends and advancements in autonomous systems will refine “take it or make it” decisions.

Conclusion

This study underscores the importance of Engineering Optimization in Mars mission planning. By leveraging hybrid approaches, advanced technologies, and cost-effective solutions, space agencies can ensure mission success while addressing logistical and financial constraints.

To delve deeper, explore the HTML article or the PDF version.

FAQs

• What is the “take it or make it” approach in Mars missions?
  The “take it or make it” approach evaluates whether to bring resources like ascent propellants and life support materials from Earth (“take it”) or produce them on Mars using in situ production technologies (“make it”). Each approach has implications for cost, risk, and mission logistics.
• Why is reducing Initial Mass in Low Earth Orbit (IMLEO) important for Mars missions?
  Lowering IMLEO reduces launch costs and logistics complexity. Historically, high launch costs made mass reduction a primary goal. However, with modern advancements in launch technology, this focus has shifted, especially for human missions to Mars.
• What are the main challenges of in situ propellant production (ISPP) on Mars?
  ISPP is highly power-intensive and involves autonomous operations in harsh environments, such as mining regolith for methane production. It also requires extensive validation and demonstration on Mars, making it expensive and risky compared to bringing propellants from Earth.
• How do life support requirements vary for Mars missions?
  Life support systems must provide air and water for the crew. Daily water needs range from 7 kg (minimum survivable) to 16.7 kg (comfortable Earth-like conditions) per crew member. Recycling systems can reduce the need to bring large water supplies from Earth but introduce reliability challenges.
• What are the recommended strategies for balancing cost and risk in Mars missions?
  The study suggests hybrid approaches, such as combining Earth-supplied resources with recycling systems, and prioritizing low-risk technologies like atmosphere-only ISPP for oxygen production. Leveraging super-heavy launch vehicles can also manage high IMLEO requirements efficiently.