public List<int> FindBurnedResources()
{
//return new List<int>();
var activeEngines = vessel.parts.Where(PartIsEngine);
var engineModules = activeEngines.Select(EnabledEngine);
var burnedPropellants = engineModules.SelectMany(eng => eng.propellants);
List<int> propellantIDs = burnedPropellants.Select(prop => prop.id).ToList();
return propellantIDs;
}