The ATV3 Edoardo Amaldi rendezvous with the ISS has started. We are 248 minutes from contact (if all goes well).

We have several hold points:

  • RGPS initialisation at S1 (not a hold point)
  • the first at 2.5 km from ISS (S2)
  • the second at 250 m fr ISS (S3)
  • the third at 20 m (S4)
  • the fourth at 12 m (S41)

At each point, ATV will stop and will only start if ATV-CC sends a GO. This is a security measure.

if all goes well we will have contact at 22:33 GMT tonight (00:33 local time in Toulouse).

After contact, there follows a mechanical docking sequence where the automatic docking system performs probe retraction (the probe is ca 0.5 m); this sequence includes latching and closing of ISS and ATV hooks. This closes and seales the ATV-to-ISS interface.

From this point on, the interface is sufficiently ‘stiff’ to allow attitude control of the ISS ‘stack’ with ATV attached. The mechanical sequence takes ca 20 min. As soon as this is done we continue with electrical merging, power merging and bus merging.

Once this sequence is finished ATV is attached to the ISS, the electrical power interface is established, allowing ATV to receive power from ISS
Then the data busses are connected, which allows the ISS computers to communicate with the ATV computers (and vice versa).

Hatch opening will take place tomorrow.

Cheers from ATV-CC!

— Charlotte
You can follow it live on www.esa.int and via the blog   https://blogs.esa.int/atv/