Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
altitude above the Earth's surface of 500 to 39,900 km has what orbital period?

### Inputs:
table_name: table, columns: ['orbit', 'center-to-center distance', "altitude above the Earth's surface", 'Orbital period', 'specific orbital energy']

### Response:
SELECT Orbital period FROM table WHERE altitude above the Earth's surface = 500 to 39,900 km