About Us

Nimbis Services is the technology-transition engine for U.S excellence. We support the full trusted and assured technology-transition lifecycle, from research and development to acquisition, maintenance, and sustainment.

The Nimbis Trusted Stratus is a dual-use Modeling, Simulation, and Analysis (MS&A) platform accelerating the transition of microelectronics, manufacturing, and aerospace technologies. Our platform's unique digital-twin capabilities supports radiation effects analysis, thermal analysis, and hardware-software co-verification, and more.

Over the past 15 years, Nimbis has launched and implemented numerous projects and prototypes for the DoD and supported over 300 projects and 150 organizations. We are deeply experienced in the underlying cloud and on-prem high-performance computing, data, and networking infrastructures that support MS&A and digital engineering.


Our team of world-class technologists fully understands the unique modeling, simulation, and & analysis and digital twin needs of the DoD and the Defense industrial base.

  • Headshot of Robert Graybill

    Robert Graybill

    Chief Executive Officer

    Robert Graybill, Chief Executive Officer of Nimbis Services, is responsible for leading the company, strategic development and executing its mission to serve our DoD and commercial cloud user communities. To this role, Robert brings four decades of experience as a business leader, defense contractor weapon system developer, DARPA program manager, Inventor, member of various Defense Science Boards, innovation policy leader and technology researcher.

    Before co-founding Nimbis Services in 2008 and growing Nimbis Services to become an industry leader in secure collaborative cloud hosted microelectronics ecosystems, Robert held key positions as:

    • Information Processing Technology Office High Performance Computing (HPC) Program Manager at DARPA , developed and implemented six new transformational programs in high-end computing architectures and responsive embedded computing hardware, software and network systems.

    • Director of Innovation at Southern California Information Science Institute (USC-ISI), advanced the development of forward national high performance computing (HPC) collaborative environments that would help companies, universities and national laboratories share high performance computing systems and computational science expertise. While also representing USC-ISI at Council on Competitiveness to improve the competitive position of U.S. companies in world markets.

    • Other Notable engineering management positions at Lockheed Martin Government Electronic Systems, Martin Marietta Naval Systems/Corporate Laboratories, Westinghouse, Sanders, and Motorola.

    Mr. Graybill was the key inventor and developer of Arbitron’s Portable People Meter (PPM) that revolutionized radio rating business. Robert holds an M.S. in Computer Science from Johns Hopkins University and B.S. in Electrical Engineering from Pennsylvania State University.

  • Headshot of Brian Schott

    Brian Schott

    Co-Founder and Chief Technology Officer

    Brian F. Schott, Chief Technology Officer and Co-Founder of Nimbis Services, is responsible for leading the strategy for technical architectures, platforms, and systems used to serve our DoD and commercial customers.

    Brian has over 30 years of agile software development and R&D project management experience in the areas of cloud, high performance computing, embedded systems, network security, and distributed systems. Prior to cofounding Nimbis Services in 2008, Brian held positions at the University of Southern California Information Sciences Institute, BDM Federal, and the IDA Supercomputing Research Center. Brian holds an M.S. in Computer Science at the George Washington University, and B.S. in Computer Science at the University of Maryland.

  • Headshot of Schoeller Porter

    Schoeller Porter


    Schoeller Porter, President, is responsible for managing the tactical operation and strategic execution for Nimbis Services' vision of providing cloud-first state-of-the-art platforms for solving complex digital engineering problems for DoD and commercial customers. In his role, Schoeller oversees Business Development, Product, and Engineering.

    Schoeller has more than 25 years of experience in corporate and product management, sales and business development, engineering and product development, and customer support in the high-performance and technical computing, data analysis, cloud, and artificial intelligence industries. Schoeller holds a Master of Business Administration and a B.S. in Aeronautical and Astronautical Engineering from the University of Illinois at Urbana-Champaign.

  • Headshot of Kimberly Lineberg

    Kimberly Lineberg

    Vice President, Finance and Administration

    Kimberly Lineberg, Vice President of Finance and Administration, oversees all financial and contract management responsibilities, including budgeting, financial reporting, and compliance. Her contributions play a crucial role in maintaining the company's financial health and stability.

    As a certified public accountant (CPA), Ms. Lineberg boasts extensive experience as a senior accounting leader across various environments, including state government, public companies, and private corporations. She has over 20 years of collaborating with exceptional accounting and cross-functional teams, achieving successful outcomes. Kimberly's passion for technology and finance aligns perfectly with Nimbis Services' mission, and she continues to drive the company forward.

  • Headshot of Stacie Valencia

    Stacie Valencia

    Chief of Staff

    Stacie Valencia, Chief of Staff, is a strategic partner and leader who drives communication, coordination, and strategic alignment of business functions while supporting C-Level Executives and the entire team at large within Nimbis. In her role, she is responsible for streamlining high importance projects and conducting leadership level internal and external initiatives that have significant impact on Nimbis business objectives. Ms. Valencia provides guidance and direction to all levels of the organization based on C-Level Executive Vision and Guiding Principles.

    She collaborates with technical product managers and external customer stakeholders, to develop and track detailed business requirements for multiple projects with sometimes conflicting timelines and priorities; from concept to launch leveraging Nimbis common collaborative cloud platform.

    Ms. Valencia has over 33 years' experience in the executive administrative function and manages a broad variety of special projects, key team member in business development activities, builds crucial relationships and is a direct liaison with government and commercial customers and partners, oversees and supports program and project commitments while also serving as acting Contracts Administrator.

  • Headshot of Tanya Stephens

    Tanya Stephens

    Tanya Stephens, Human Resource Director, is responsible for managing the human capital strategy for Nimbis Services, Inc. With over 15 years of professional Human Resources experience, Ms. Stephens is passionate about building strong working relationships and initiatives focused on solving business and people challenges. She is a results focused leader whose prior experience was focused on talent acquisition before joining Nimbis as an HR Department of One. Since joining Nimbis she has expanded her knowledge in talent acquisition, employee relations, compensation, benefits; training and development; and compliance.

    Ms. Stephens holds a B.S. in Business Administration with a minor in Management from Gardner-Webb University and is SHRM-SCP certified.

At Nimbis Services, our mission is to help the U.S. government keep pace with commercial technological developments while ensuring that it can maintain and make use of a wide range of technologies from legacy microelectronics to state-of-the-art.

We have been a trusted partner of the defense community for the past 15 years, and we are poised to help meet this ongoing challenge.

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