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STK has been around since the 80's and is a major player in the industry with a substantial market share. Might be overkill but most companies get this if they're not worried about costs and have years until launch.
Having experienced the drawbacks of the tools that currently exist, our team built the tool we wished we had when we were designing and flying spacecraft. ModelSpace is designed to save you time, money, and effort.
Another leading COTS software for space mission analysis and design. Available at a slightly lower cost than STK, but has a steeper learning curve with learning their custom scripting language and added UX complexity.