STL export issues

Afternoon,

Having some issues with a model i made in shapr3d. I can export it properly as a STEP or SHAPR, but when exporting a STL only part of the file is actually showing up. photos are provided, and I would love some help understanding how this is happening. The image of the LCAC is the standard file and the model, The following picture is what results when exporting as a STL.