## Approaching the ISS

Next step is to approach the ISS. The Approach processor will bring the vessel within 1000 meters to the ISS, so that the docking phase can be initiated.

### Process definition

    <Step>
      <Label>Approach to ISS</Label>
      <Processor type="Approach">
        <Var name="Reference"> ISS </Var>
        <Var name="NAV"> 136.90 </Var>
        <Var name="CompleteAt"> D(ISS) = 1000 </Var>
      </Processor>
    </Step>

Reference defines the target we will approach.

NAV specifies the navigation frequency for the target. REDSHIFT automatically sets the NAV1 frequency to this value.

CompleteAt defines the condition, when approach is considered complete; in our case if the distance to the ISS is 1000 meter.