Becoming detached from the International Space Station (ISS) during an EVA (spacewalk) is a low probability occurrence. While not likely to happen, since it is possible, astronauts prepare for it.

For each and every spacewalk, one of the first --and most critical-- steps occurs before ever departing the station's airlock. With hatches still closed and locked, astronauts verify their individual safety tethers (85 foot braided steel cable w/retractable reel) are appropriately "closed and locked" on their spacesuits. In addition, while inside the station's "porch," the two spacewalkers hook their safety tethers together, in a move we call the "daisy chain." Now, both astronauts are connected to each other, and one of them is also anchored firmly inside the station.

When the hatch finally opens, another critical procedure is executed. The lead spacewalker --EV1-- will exit the airlock headfirst and attach the other (free) end of their safety tether to an anchor point

outside

. Now, the two still-daisy-chained astronauts are anchored inside and out. At this point, EV1 will break the daisy-chain and hook partner EV2's safety tether to the external anchor point. Now both crewmembers are safely, and separately, anchored externally.

Exiting the ISS airlock, for my first EVA July 23, 2007.

It is now time for the still-inside EV2 astronaut, to disconnect his/her internal anchor point and exit the hatch. Voila! Two spacewalkers, each safely anchored outside the ISS, ready to go to work.

All of that effort may still not be enough if proper "tether protocol" is not exhibited by our brave spacefarers throughout the spacewalk. As they both move away from the airlock --anchor points still firmly attached-- each must endeavor to keep their individual 85' lines separate and untangled, a task that seems simple, but isn't always so, during a 6.5 hour excursion outside in a micro-gravity environment. In addition, if the worksite is more than 85' away from the starting point, additional safety tethers must be carried with them, and "tether swaps" must be appropriately/safely executed as needed.

Yet I haven't really answered your question have I? If all of our "tether protocol" efforts still fail us (remember, this is an extremely low probability), and one of us totally detaches from the ISS structure, we will be ready, albeit a tad bit embarrassed.

While unlikely to fall all the way to earth as your question suggests, it is possible the rates imparted to a spacewalker who has lost physical contact with the station could be high. The resulting drift away from "home" and deeper into outer space would not be good. Rescue by another spacecraft would be futile, taking too long to undock, rendezvous, and capture the wayward astronaut. Another option was required.

The solution? It's pretty amazing. Like Buck Rogers, we have a jetpack attached to our suits and

unlike

Mr. Rogers, we have virtual reality (VR) to train for this exact scenario.

With Rick Mast...