We’re passionate about impact.

Who We Are

The Solarium Group is a boutique strategic advisory firm built for moments of consequence. We are not career consultants; we are former senior diplomats, military officers, foreign affairs specialists, and leadership practitioners whose careers were spent leading at the nexus of diplomacy, defense, and development.

Collectively, our advisors and affiliates have worked in more than 100 countries, guiding governments and institutions through complexity, crisis, and transformation. Our team is not composed of observers who analyze complexity from afar. We are practitioners who have spent the past several decades on the ground, implementing policy, leading missions, and navigating uncertainty where decisions carry real consequences. That experience—forged in embassies, field commands, multilateral institutions, and fragile states—is what sets us apart.

We have advised presidents and cabinet officials, counseled four-star generals, and stood alongside ambassadors, governors, and ministers when choices mattered most. Our personnel have led through some of the world’s defining challenges of the past three decades: from rebuilding institutions in post-conflict Balkans, to shaping stabilization efforts in Afghanistan and Iraq, to mounting crisis responses during the Ebola outbreak in West Africa. We have worked on the front lines of drought-driven humanitarian emergencies in the Horn of Africa, advised military commanders at CENTCOM during pivotal transitions, and led efforts to open doors to the future—advancing trade, investment, and energy initiatives across the world, forging partnerships that drive growth, resilience, and prosperity.

That perspective—practical, global, and hard-earned—is what we bring to every engagement. Through our two core practices—Strategic Advisory and Leadership & Organizational Development—we translate lived experience into clarity, resilience, and results that endure

Our Mission

The Solarium Group exists to bring clarity where it is most needed. We equip leaders, teams, and institutions to navigate complexity, make high-stakes decisions, and deliver results under pressure. Our mission is to ensure strategies succeed not just on paper, but in the real world.

Our Vision

Our vision is to redefine how institutions endure in a world defined by complexity — building strategies, leaders, and systems that thrive under pressure and shape outcomes that last. We aspire to be the firm that global decision-makers trust when navigating uncertainty, making bold choices, and building resilient futures.

Our Values

    • Positioning The Solarium Group as an industry thought leader requires unrivaled vision, persistence, and execution. We never settle — in everything we do, we challenge our ideas of what’s possible in order to be the best versions of ourselves.

    • We set and achieve ambitious goals, work constantly to improve, and are dedicated to helping our team (and our clients) realize success.

    • We believe in helping others, and take satisfaction in providing effective solutions that address your greatest challenges. 

    • Our drive and energy are contagious, inspiring our clients and those around us.

    • We meet our challenges with creativity and optimism, pushing ourselves beyond our limits. 

    • We step into the spaces others avoid — the uncertain, the volatile, the high-stakes — because that is where clarity is needed most.

    • We carry the weight of decisions that matter, standing firm when the cost of hesitation is too high.

    • We maintain high standards of quality and ethics, are confidential in discussions and decisions, and are honest about our own biases.

    • We preserve client confidences.

    • We keep our commitments, act consistently and fairly, and do what we say we will.

The Birth of Solarium

Project Solarium, launched by President Dwight D. Eisenhower in 1953, was a bold yet clinical exercise in strategic planning. Faced with the complexities of the Cold War, Eisenhower convened three teams of top thinkers—military leaders, diplomats, and scholars—to rigorously debate and develop competing strategies for countering Soviet expansion. The process was not just an academic exercise; it was a masterclass in structured decision-making, forcing participants to challenge assumptions, pressure-test ideas, and align national policy with long-term strategic imperatives. The result? A pragmatic, sustainable doctrine—known as the New Look—that shaped U.S. foreign policy for decades.

Which brings us to the origins of our name – The Solarium Group – a nod to one of the most sophisticated strategic exercises in U.S. history. This branding isn’t just symbolic. It reflects our approach to solving complex challenges: rigorous scenario planning, structured debate, deep thinking, pragmatic execution, and the same spirit of intellectual rigor and strategic foresight born by President Eisenhower’s Project Solarium. But beyond the name, we built The Solarium Group because we believe in the power of ideas, the discipline of strategy, and the impact of clear-eyed leadership. We believe that the toughest problems demand discipline, creativity, and courage. And our team—a purpose-driven coalition of big thinkers, doers, and strategic misfits who are drawn to complexity and motivated by mission—exists to turn challenge into clarity, and vision into momentum.

Solving wicked problems is in our DNA. It’s more than what we do; it’s who we are

Meet the Team

  • Troy Tillis is the Founder and CEO of The Solarium Group, where he sets the firm’s strategic vision, leads its global advisory practice, and oversees a network of senior practitioners serving clients across government, industry, and international institutions.

    With nearly two decades of global experience, Troy has led high-stakes missions and managed multi-country operations in 19 countries across Southern Africa, Latin America, Central Asia, and South Asia. A former senior executive in the U.S. Foreign Service, he directed multi-disciplinary embassy teams, advised on foreign policy and national security, and delivered results in some of the world’s most dynamic and fragile environments.

    As CEO, Troy drives The Solarium Group’s mission to help leaders and institutions navigate complexity with clarity, strengthen organizational resilience, and deliver lasting impact when the stakes are highest.

Troy Tillis, CEO

  • Jeff Cohen is a retired career member of the U.S. Senior Foreign Service (nominated to the rank of Minister Counselor) bringing over 25 years of distinguished leadership in foreign policy, international development, and operational excellence.

    Most recently serving as USAID Mission Director in Indonesia, Jeff oversaw a six-year, $800 million strategy while managing 150 staff and more than 2,500 contractors. His leadership included spearheading a $45 million sustainable fisheries initiative that expanded marine protected areas by 8.6 million hectares and secured partnerships with global companies like Walmart and Bumble Bee Tuna. He also directed Indonesia’s $65 million COVID-19 response, training more than 840,000 frontline workers and reaching over 260 million people.

    Jeff’s senior assignments have spanned Afghanistan, Washington D.C., Peru, and the Dominican Republic, where he managed portfolios exceeding $5 billion and built groundbreaking partnerships ranging from countering illegal mining in the Amazon to youth development with Major League Baseball. He began his career in public service with the Peace Corps in Bolivia and Honduras, following early entrepreneurial and private sector experience in Spain and Detroit.

Jeff Cohen, Senior Affiliate

  • Greg Howell brings more than 20 years of senior leadership in foreign affairs, directing high-impact programs across Latin America, Africa, and the Middle East.

    Most recently serving as Senior Deputy Assistant Administrator (SDAA) in USAID’s Bureau for Latin America and the Caribbean, he oversaw $1.2 billion in foreign assistance and soft power strategy across 16 Western Hemisphere countries. Greg has also held senior leadership posts in West Africa and Guatemala, and has advanced U.S. foreign policy through assignments in Iraq, Afghanistan, El Salvador, and beyond.

    At The Solarium Group, Greg will help clients shape policy, foster economic growth, and strengthen international partnerships—bringing strategic insight to organizations navigating complex global environments and new market frontiers.

Greg Howell, Senior Affiliate

  • A member of the U.S. Senior Foreign Service with the rank of Minister Counselor and recipient of the Presidential Rank Award for Distinguished Service, Maura brings more than 30 years of experience at the intersection of diplomacy, military, development, and global policy. She has directed multi-billion-dollar portfolios, advised cabinet-level leaders, and engaged in multilateral processes through the United Nations, COP climate discussions, and U.S. interagency dialogues connected to G7 and G20 priorities. 

    Most recently, Maura served as Senior Development Advisor to the four-star Commander of U.S. Africa Command (AFRICOM), where she led civilian-military strategy and interagency coordination across 53 nations. Previously, she was USAID’s Senior Deputy Assistant Administrator for the Bureau of Resilience and Food Security, overseeing a $2 billion portfolio  across 45+ countries. She led deployment of $760 million in Ukraine supplemental funding, and drove bureau-wide reforms to strengthen organizational effectiveness and accountability. As USAID Global Water Coordinator, she drove the NSC interagency process behind the White House Global Water Action Plan and the U.S. Global Water Strategy, and led USAID’s 2023 UN Water Conference delegation. 

    Earlier in her career, she held senior leadership roles in Jamaica, Afghanistan, Kenya, Sri Lanka, Somalia, Thailand, and Djibouti, building a reputation as a trusted advisor in advancing resilience, institutional reform, and international partnerships.

Maura Barry Boyle, Senior Affiliate

  • Peter Natiello is a career member of the Senior Foreign Service with the rank of Career Minister, bringing more than 35 years of distinguished leadership in foreign policy, international development, peace building, and organizational transformation.

    Most recently serving as USAID’s Senior Humanitarian and Development Counselor to the U.S. Mission to UN Agencies in Rome, Peter has also held some of the U.S. government’s most critical leadership posts—including Mission Director roles in Afghanistan, El Salvador, Colombia, and Bolivia, advancing civilian-military affairs as Senior Development Advisor to the U.S. Special Operations Command (USSOCOM), and senior assignments across Latin America, Africa, and multilateral institutions.

    A recipient of the Presidential Rank Award, Peter will bring unmatched expertise in strategy, leadership, and international partnerships—helping corporate and government clients navigate the complexities of geopolitics, organizational change, and leadership development.

Peter Natiello, Senior Affiliate

  • Andrew is a former U.S. diplomat and senior advisor with more than 20 years of experience shaping foreign policy, strategy, and partnerships in some of the world’s most complex geopolitical environments, with a particular focus on Central Asia and Eastern Europe.

    He has advanced economic reform, regional connectivity, and institutional resilience initiatives across Eurasia, serving in senior roles in Kazakhstan, Turkmenistan, and Kyrgyzstan—where he guided U.S. stabilization efforts during the 2010 Kyrgyz revolution and helped design and execute regional strategies under the New Silk Road and C5+1 platforms. Most recently, as Senior Advisor at the U.S. Embassy in Moldova, Andrew played a central role in reshaping U.S. engagement in response to Russia’s war in Ukraine, securing more than $400 million to strengthen Moldova’s energy independence and long-term stability.

    Beyond his diplomatic service, Andrew has held leadership roles in the private sector, including as Chief Innovation Officer and Chief of Staff for a global digital health company during the COVID-19 pandemic. He has also built leadership pipelines across Eurasia through flagship graduate fellowship programs, including the Edmund Muskie Graduate Fellowship. A professional Russian speaker with working knowledge of Turkic languages, Andrew is recognized for bridging foreign policy and practice across cultures and institutions.

Andrew Segars, Senior Affiliate

  • Keisha is a retired executive of the U.S. Foreign Service, bringing more than 18 years of senior leadership in diplomacy, international development, and organizational transformation. She has directed U.S. foreign assistance portfolios exceeding $2 billion across Sub-Saharan Africa, combining operational excellence with international statecraft to advance U.S. foreign policy priorities across the African continent.

    Most recently serving as Mission Director for USAID/Rwanda and Burundi, Keisha informed and led U.S. priorities at the intersection of U.S., East African, and Central African affairs, leading a team of over 100 to advance health and education diplomacy, regional security and stability, and humanitarian assistance efforts. Earlier in her career, she held senior acquisition and assistance leadership roles across Ghana, Nigeria, Liberia, and Tanzania—managing some of USAID’s largest platforms, negotiating landmark partnerships including a $780 million PEPFAR agreement in Nigeria. A long-time champion of small business, she was recognized three times throughout her career for the prestigious “Small Business Contracting Officer of the Year Award”.

    With her ability to lead large multicultural teams and deliver operational excellence under pressure, Keisha will bring unmatched expertise in strategic leadership, organizational transformation, and international partnerships—helping clients achieve impact across diverse and challenging operating environments.

Keisha Effiom, Senior Affiliate

  • Lacy is a senior executive with nearly 20 years of experience creating measurable and adaptable strategies, leading cross-sectoral programs, and driving streamlined operations across government, multilateral, and crisis-affected environments.

    Most recently serving as Deputy Director for Legislative Affairs at USAID, she oversaw engagement with Congress on a $40 billion foreign assistance budget and advised senior leadership on strategy and communications. Earlier, as the first Chief of Performance at the United Nations Development Programme (UNDP), she led more than ten strategic transformation initiatives across the organization—driving reform, improving effectiveness, and strengthening accountability. Her previous roles include Managing Director for Strategy and Performance at the U.S. Department of State, Director of Strategy, Budget, and Performance for USAID’s Afghanistan and Pakistan programs, and Senior Liaison on the U.S. House of Representative’s Appropriations Committee.

    Across her career, Ms. Kilraine has advanced U.S. foreign policy and priorities in more than 15 overseas locations in Latin America and the Caribbean, Central and South Asia, and Africa. Recognized for her ability to bridge strategy with execution, she has driven organizational change and fostered cross-sector partnerships in the most complex environments.

Lacy Kilraine, Senior Affiliate

  • Helen is a senior executive and strategic advisor with more than two decades of leadership across Africa, the Middle East, and Asia. An attorney and member of the U.S. Senior Foreign Service at the rank of Minister Counselor, she has directed multi-billion-dollar portfolios, negotiated high-level legal agreements, and led organizations through political transitions, conflict environments, and complex crises.

    Most recently, Helen served as Mission Director in Mozambique—one of the largest U.S. development portfolios globally—overseeing $2 billion in investments and a staff of 227. She co-chaired Mozambique’s Development Cooperation Platform with the United Nations, aligning more than 30 donor governments and multilateral banks, and partnered with the finance ministry, International Monetary Fund, and African Development Bank to shape national economic reform priorities. In Sudan, she guided U.S. Government engagement during a fragile democratic transition, managed $700 million in new supplemental funding, and led crisis response during the COVID-19 pandemic.

    Helen has advanced governance and localization reforms across multiple countries, shifting more than $100 million in awards to local organizations and forging innovative agreements with ministries, courts, and civil society to strengthen service delivery, accountability and resilience. Drawing on her dual background as lawyer and diplomat, she now advises governments, corporations, foundations, and multilateral institutions on governance, strategic engagement, institutional reform, and complex donor coordination.

Helen Pataki, Senior Affiliate

  • Nancy is an economist and strategic advisor with more than two decades of experience at the intersection of national security, economic policy, and organizational transformation—helping governments and institutions align strategy, resources, and partnerships for lasting impact.

    A retired U.S. diplomat, Nancy has served in senior roles across Africa, Eastern Europe, and the Middle East, including as Country Representative to the Republic of Djibouti and as Development Advisor in the Pentagon, US Department of Defense, Office of the Secretary of Defense for Policy. Her career has spanned the design of interagency strategies on economic resilience, governance, and global health, as well as leadership of complex regional growth and partnership initiatives. Nancy is a Distinguished Graduate of the National Defense University's Dwight D. Eisenhower School for National Security and Resource Strategy, and holds an MA in Business Economics from the University of South Florida. She speaks Italian, Spanish, French, and Romanian, and is the author of two published works on purpose, balance, and leadership.

    At The Solarium Group, Nancy will help clients navigate the nexus of security, economics, and institutional performance—bringing the rigor of an economist and the perspective of a seasoned diplomat to strengthen leadership, alignment, and execution in dynamic environments.

Nancy Ostrowski, Senior Affiliate

  • Jason brings more than 25 years of senior leadership across international development, law, and renewable energy—bridging the worlds of diplomacy, policy, and private investment to drive sustainable growth and resilience across Africa, Latin America, and the Caribbean.

    A former U.S. Senior Foreign Service Officer and USAID Mission Director, Jason has led transformative country programs in Angola, Ethiopia, Jamaica, and Rwanda. His leadership has spanned billion-dollar portfolios and high-impact partnerships with global companies such as ExxonMobil, Microsoft, GE, Angola LNG, and Bayer—strengthening governance, expanding access to energy, and advancing economic opportunity.

    Beyond public service, Jason has distinguished himself as a lawyer, author, investor, and entrepreneur—dedicated to catalyzing private capital and expanding business opportunities that deliver both commercial and social returns. He currently serves on the Board of the Guyana Infrastructure Consortium, is a Principal with Mowana Capital Group , LLC, a member of the Society for International Development (SID-US) and is Board certified with the Massachusetts and New York State Bar Associations.

Jason Fraser, Senior Affiliate

  • Betty Chung is a senior executive and international development attorney with more than two decades of leadership spanning law, diplomacy, and development across Asia and the Pacific. She has guided major U.S. assistance portfolios in fragile, post-conflict, and climate-vulnerable contexts, helping governments strengthen governance, resilience, and rule of law.

    Most recently, Ms. Chung served as Deputy Mission Director for the Pacific Islands and Mongolia, overseeing USAID programs spanning 12 Pacific Island nations and Mongolia. In this role, she guided initiatives to enhance climate resilience, natural resource management, and economic opportunity—while advancing the Pacific Island Forum’s 2050 Strategy for the Blue Pacific Continent. Previously, she served as a senior Resident Legal Officer in Pakistan, Indonesia, and Afghanistan, where she provided legal and policy counsel on governance, fiscal, and regulatory matters, and helped negotiate complex bilateral and donor agreements in dynamic political environments.

    Earlier in her career, Ms. Chung served as Deputy Assistant General Counsel for Legislation and Policy in USAID’s Office of the General Counsel, advising senior leaders on legislative and policy frameworks for U.S. foreign assistance. She began her career as an attorney with Arnold & Porter and later with the U.S. Small Business Administration, developing expertise in regulatory reform, contracts, and government operations.

    At The Solarium Group, Ms. Chung advises clients across Asia and the Pacific on navigating the legal, political, and economic complexities of emerging markets. As part of Solarium’s Strategic Advisory practice, she provides counsel to public and private partners on market entry, risk mitigation, and partnership strategy—helping organizations operate confidently in some of the region’s most dynamic and rapidly evolving environments.

    Ms. Chung holds a Juris Doctor from the George Washington University Law School and a Bachelor of Arts in History and International Relations from Brown University. An avid golfer and scuba diver, she also speaks Mandarin Chinese and Korean.


Betty Chung, Senior Affiliate

  • Nina is a strategist and communicator with more than 20 years of experience helping institutions translate ambition into action—building the teams, partnerships, and narratives that drive measurable impact across global markets.

    From the U.S. International Development Finance Corporation (DFC) to USAID and the White House’s Prosper Africa initiative, Nina has led some of the most dynamic communications and partnership portfolios that advance U.S. economic diplomacy. She helped position DFC’s $50 billion investment portfolio across 110 countries, guided strategy for USAID’s $2.5 billion Southern Africa regional program, and built Prosper Africa’s engagement platform from the ground up—catalyzing $15.7 billion in new commercial commitments between the U.S. and African private sectors.

    Across each role, the throughline is clear: Nina exemplifies what we value most in a Solarium affiliate—an advisor who brings clarity to complexity, an architect who builds strategies that endure, and a convener who connects ideas, people, and institutions to move systems forward.

    At The Solarium Group LLC, Nina advises clients on strategic positioning, partnerships, and stakeholder engagement—helping them craft influence strategies that build trust and drive action across sectors and geographies. We’re honored to have her join The Solarium Group’s growing bench of world-class experts, bringing her insight, creativity, and deep experience building bridges between government, business, and global institutions.

Nina Prieur, Senior Affiliate