How to apply for an Employment Authorization Document (EAD) to legally work while in the country.
Travel requirements and the necessity of valid DS-2019 forms. j2.pdf
If your document is about orbital mechanics, it likely focuses on the —the effect caused by Earth's "bulge" at the equator on satellite orbits. How to apply for an Employment Authorization Document
Strategies for minimizing secular J2 effects in satellite formations. j2.pdf