Valhalla data graphic (IMAGE) DOE/Sandia National Laboratories Caption Examples of plots produced by the Valhalla framework, developed at Sandia National Laboratories, to assist in space system design analysis. Credit Graphic by Johanna Hartenberger. Usage Restrictions For use with coverage about this research. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.