Butch will be M1 for this capture, meaning that he will have the hands on the controllers of the robotic arm in the final stages. At that point, Dragon will be holding position at the capture point, at a distance of about 10 meters from Station and with its grapple fixture roughly aligned with arm end effector (that’s the “end” of the robotic arm, which has snares that can capture Dragon’s grapple fixture).
After receiving a “GO for capture” from Houston, Butch will fly the arm towards Dragon, compensating any relative movement the vehicle will have to keep the end effector aligned with the grapple fixture and, once on the grapple pin and at the right distance, he will pull the trigger to close the snares and capture Dragon.
While Butch will focus on this, as M2 I will support by “running the procedure” (making sure we don’t miss any step) and by having recovery/response steps ready for any malfunction we might encounter in the different stages, from Dragon misbehaving to issues with our robotic arm.
I will also take care of com with Houston and I will support in the final stages by giving Butch information on remaining distance to cover and closure rates, since he will be fully focused on alignment with the target. I will also send Dragon the “free drift” command, probably around 2 meters: at that point Dragon will stop controlling its own attitude and will keep whatever translation and rotation rates it has. We don’t want to send the command too early, but we’re also not allowed to get closer than 1.5 meters without confirmation that Dragon is in free drift. As you can imagine, we don’t want to make a rigid mechanical connection to a vehicle that is firing thrusters to orient itself: the Station is also actively controlling its attitude all the time and we don’t want Dragon and Station to be fighting each other!
Fortunately, we have a great simulator onboard to practice all this: it’s called ROBOT and it includes hand controllers just like the ones of the real robotic workstation and a big monitor with virtual control panels for cameras, robotic arm and Dragon.
Butch and I had our first scheduled session yesterday: our robotics instructors were running the simulator setup remotely from the ground, observe our work real-time and give us feedback over a privatized space-to-ground channel. Like having them onboard with us! And of course, since you never know what happens, I also get to practice the capture.
Hey, I got so carried away talking to you about Dragon capture that I forgot to mention the science I did yesterday: with the help of Terry and our remote guider Dave on the ground, I took ultrasound images of brachial artery, carotid artery and heart (challenging!) for the experiment CardioOx. I will have several more sessions in the next months, so we’ll have more chances to talk about it.
Have a great weekend!
Futura mission website (Italian): Avamposto42
avamposto42.esa.int
(Trad IT) Traduzione in italiano a cura di +AstronautiCAST qui:
https://www.astronautinews.it/tag/logbook
(Trad FR) Traduction en français par +Anne Cpamoa ici:
https://spacetux.org/cpamoa/category/traductions/logbook-samantha
(Trad ES – Currently not updated) Tradducción en español aquí:
https://www.intervidia.com/category/bitacora
13/12/2014