David Scott took this photograph from the open hatch of the CM Gumdrop docked with the LM Spider as he had clambered partially outside for a stand-up EVA, still hooked to the spacecraft through a life support umbilical system.

Russell Schweickart is wearing an Extravehicular Mobility Unit (EMU) including a Portable Life Support System (PLSS) and an Oxygen Purge System (OPS) on his back. The EMU provided communications and oxygen as well as circulating water through the suit to keep the astronaut cool, eliminating the need for an umbilical connection to the spacecraft. A 25-foot-long nylon rope was the only connection that kept the astronaut from drifting away.

Schweickart has his feet placed into specialized gold-painted foot restraints affixed to the front LM porch dubbed the “golden slippers.” His visor reflects the docked CSM/LM spacecraft and the Earth. He holds, in his right hand, a thermal sample which he is retrieving from the LM exterior. Extravehicular transfer handrails on the LM are in the foreground. The LM ladder and footpad are visible at the bottom of the picture.

Russell Schweickart was originally to transfer to the CSM Gumdrop for a rescue simulation to verify a way of getting from one spacecraft to the other if the tunnel were not available. However he stayed with Spider in part to avoid stress after his previous space sickness and this step was not completed beyond evaluating the specific extravehicular transfer handholds which Schweickart found to be easy for maneuvering. Mission Control considered this first, and the only one before the Moon landing, test of the spacesuits and PLSS a complete success. During the EVA, Schweickart used the call sign “Red Rover,” a nod to the color of his hair.

From the mission transcript during the EVA:

073:34:42 Schweickart (PLSS):

Oh, that Sun is really bright! Houston, this is Red Rover. If you read me, I’m just going to call you in the blind here. The suit is very comfortable. I’m on MIN cooling, and I haven’t had any problem at all. The only thing that is warm at all are my hands, and they are just barely warm; they are not very hot at all.

073:35:07 Mission Control:

Roger. Red Rover, this is Houston. We are reading you loud and clear. We are copying all transmissions. [...]

073:37:50 McDivitt (Spider):

Rusty, why don’t you exercise the handrails just a little bit just to see how they work, and don’t go very far up. [...]

073:38:40 McDivitt (Spider):

Why don’t you come over and get the thermal sample and get it in so we won’t have to mess around with it.

073:38:44 Schweickart (PLSS):

That’s a good idea; coming up. [...]

073:39:25 Schweickart (PLSS):

Okay, hook it on down there and lock it. Dave, have you taken any pictures yet?