Session: 

Paper Number: 150166

150166 - The Orbital Shepherds: A Vision for a Sustainable Space Ecosystem 

Our skies are becoming crowded. Myriad satellites, each a marvel of engineering, whiz around Earth fulfilling vital roles in communication, navigation, and scientific observation. But like any bustling metropolis, this space traffic creates challenges. Satellites can malfunction, drift from their designated paths, or simply run out of fuel. Here, the concept of a "space tug" emerges as a potential solution, akin to orbital shepherds ensuring the smooth operation of our celestial infrastructure.

This paper delves into the design and deployment of a versatile space tug system, moving away from the limitations of specialized, single-use tugs. We envision a fleet of reusable, adaptable vehicles capable of addressing a range of satellite needs. Unlike a tow truck on a highway, space tugs operate in the unforgiving vacuum, demanding innovative solutions.

Our approach begins with a thorough understanding of the current on-orbit population. Just like a city planner analyzes traffic patterns, we identify "target orbital zones" – the most densely populated areas in space. These zones, like bustling geosynchronous (GEO) orbits or the dynamic low Earth orbit (LEO) region, present unique challenges for satellite maintenance.

Next, we employ a mission-driven engineering methodology. Imagine a team of architects and engineers collaborating in real-time to design the most suitable building for a specific location. Similarly, our methodology harnesses computer simulations to analyze various tug configurations tailored for each target zone. Factors like propellant type, operational base (parking location), and the tug's onboard hardware and software complexity are all factored in.

By analyzing the "cost-versus-utility" tradeoff, the study reveals a sweet spot for tug design. Just as building a skyscraper in a quiet suburb wouldn't be practical, an overly complex tug wouldn't be cost-effective for all missions. The "knee" in this tradeoff curve represents the optimal balance between a tug's capabilities (delta-v, response time) and its development and operational costs.

The research unveils fascinating possibilities. For instance, the study suggests that a single, conventionally powered "bipropellant" tug could effectively handle most LEO missions. Conversely, the unique demands of the GEO region, where satellites maintain a constant position relative to Earth, might necessitate an electric-powered tug for greater efficiency.

The concept extends beyond individual tugs. The paper explores the potential for a modular family of tugs, where components like grappling arms, central "bus" modules, and propulsion units can be interchanged. Imagine a fleet of space vehicles, each customized for specific tasks yet built upon a common platform. This modularity not only enhances cost-effectiveness but also allows for rapid response and adaptation to unforeseen situations.

In conclusion, this research paves the way for a more sustainable space ecosystem. By employing versatile space tugs, we can ensure the continued functionality of existing satellites, potentially extending their operational lifespans. This not only reduces the need for costly replacements but also minimizes the ever-growing debris field in Earth's orbit. The orbital shepherds envisioned in this paper represent a crucial step towards a future where space exploration and utilization are conducted responsibly and efficiently.

Presenting Author: Mahantesh Hiremath Aadi Space Inc.

Presenting Author Biography: Dr. Mahantesh Hiremath has over 30 years of wide range of industry experience – space, energy, transportation, and infrastructure. He is among handful in the world to have designed and analyzed complex systems in four environments – deep underground strategic petroleum reserves, off-shore oil platforms, high-rise buildings, and high-flying geosynchronous satellites.

His areas of expertise include – Structural Analysis and Dynamics, Mechanical Environments and Testing, Systems Engineering, Failure Analysis and Risk Management.

Dr. Hiremath served as 140th President of American Society of Mechanical Engineers (ASME) for term 2021-22. He is the first Asian and Indian to be selected for this honor. He is a recipient of the 2023 College of Engineering Distinguished Alumni Award from The Ohio State University, Columbus, Ohio.

He is currently the Vice President at SC Solutions, a premier engineering consulting firm in the San Francisco Bay Area. Earlier, he was Senior Technical Director at Spinlaunch. He held several important positions at Space Systems Loral (SSL), ARES Corporation, Northrop Grumman, and Stellar Solutions.

Dr. Hiremath is a Fellow of the American Society of Mechanical Engineers (ASME). He was also selected as ASME’s Congressional Fellow and served on the Capitol Hill as Technical Advisor to the Science, Space and Technology Committee of the US House of Representatives.

He is an Adjunct Faculty in Civil and Mechanical Engineering at the Santa Clara University. Dr. Hiremath received his M.S. and Ph.D. in Civil Engineering from The Ohio State University, Columbus, Ohio. Later, Dr. Hiremath earned the Certificate in Systems Engineering from Stanford University.

Authors:

Mahantesh Hiremath Aadi Space Inc.
Jayram Deshpande Aadi Space Inc.