Hire engineers with documented GMAT experience. Software is a structured field on every profile and every service — so filtering by it returns people who actually use the tool, not people who listed it once.
When GMAT is the tool your output has to open in, that is a hard requirement rather than a preference — a model delivered in the wrong package is not a deliverable. Every profile and service here records software as structured data, so a search for GMAT returns engineers who have actually produced work in it.
Ask for native source files explicitly in your brief. Many engineers include them at the premium package tier or as an add-on, and it is far cheaper to agree that up front than to discover afterwards that you only have a PDF of something you need to edit.
Naval Defense Engineering specialist — aerodynamic analysis & certification compliance
Propulsion Engineering specialist — thermal control & aerodynamic analysis
Radar Engineering specialist — stress & sizing & composite structures
Aircraft Structural Engineering specialist — composite structures & aerodynamic analysis
4DaysRemoteNaval Defense Engineering
3DaysRemotePropulsion Engineering
6DaysRemotePropulsion Engineering
4DaysRemoteRadar Engineering
2DaysRemoteRadar Engineering
3DaysRemoteAircraft Structural Engineering
5DaysRemoteAircraft Structural Engineering