Difference between revisions of "EVA (procedures)"

Latest revision as of 19:22, 26 April 2013

EVA

Definition

EVA

Extra-Vehicular Activity. An astronaut puts on a self-enclosed environment suit, which is able to withstand the near-vacuum of space, the heat of solar wind (resistant to ionizing plasma charges of roughly 13,000V), radiation (reduction factor of the EVA suits is approximately 1:10,000), and most other hostile conditions. Defeating the suit's protection while in a near-vacuum environment can result in skin burns, internal burns, blindness, sterility, leprosy, and/or death.

EVA suit preparation

Astronauts will need assistance in putting on the EVA suits.

1. They should first take off as much unnecessary clothing as possible. Any supplies or equipment on their persons should be transferred to the EVA suits.
2. They should then put on any inner layers the EVA suits may have.
3. Then the full body suit (if present) should go over top.
4. Turn on the main power. Insert any cooling packs and activate any fans.
5. Close the outer suit layer with clips or clamps (if applicable), covering over sealing points with Velcro flaps. Ensure that there are no leaks.
6. Place the boots over the astronauts' feet, and seal them as tightly as possible into the legs, clamping them in place (if applicable.) Use duct tape if necessary. Repeat this with the gloves. Duct tape should be limited to once around, as excessive use can slow de-suiting.
7. Attach any equipment the astronaut will need to the outside of the suit. Standard equipment is as follows:
   • flashlight
   • duct tape
   • sample containment box
   • headset
8. Attach the headset to the EVA suit, and turn it onto voice activation (VOX) mode. If necessary, use hair clips or duct tape to attach the headset firmly onto the astronaut's head.
9. Finally, after receiving the final go-ahead from Mission Control, attach the helmet onto the suit. If the helmet has a ventilation fan, turn it on.
10. Make sure there are no air leaks.

Leaving the Habitat

Once the EVA suits are complete and sealed, the Astronauts are to obtain clearance from Mission Control to enter the airlock. Once inside, they are to close the door behind them, and ask Mission Control to depressurize the airlock. Watch the airlock lights for clearance to leave. Mission Control will give the go-ahead to open the outer door. Leave through the door.

Entering the Habitat

Once finished the EVA, approach the hotlab-airlock and deposit all samples. Then move toward the airlock. Check with the Habitat Commander who will check with Mission Control (if possible) that it is indeed safe to open the airlock if it is now closed. Once informed it is safe, open the airlock and enter. Close the door behind you, and ask the Habitat Commander to ask Mission Control to start pressurizing the airlock. You must wait for confirmation from Habitat or Mission Control to open the inner door. Enter the Habitat where the EVA suit will be removed with all haste possible in a horizontal reflection of all procedures involved in putting it on to said astronaut.

Surface Activities

EVAs have four purposes:

Exploration

While exploring on an EVA, astronauts should describe what they see so that it may be recorded in Mission Control by the INCO, and pick up any samples that are of interest.

Repair

A repair EVA is often a standard EVA to check and do maintenance to the Habitat, which is often hit by small meteorites; potentially threatening dents need to be repaired.

Emergencies

Emergency EVAs usually have a specific purpose. Often this is to go out and survey damage to the habitat. Sometimes they must repair damage or retrieve broken parts of the Habitat. In the worst case, they may be out on the surface to rendezvous with an emergency supply probe. Emergency supply probes must be requested at least a day in advance, since the travel time is significant. Only call on such a request if something extremely critical is required and in a significant quantity. These probes are expensive to send up.

Scientific research

While out on scientific research, the EVA usually will have a mission protocol, so the astronauts should run through whatever this procedure is. It can vary from setting up equipment, to gathering data, to whatever they may be interested in researching for the Mission.

Astronaut Recovery

Once an astronaut has completed his/her EVA, biomeds should be taken (P2.5.3) and transmitted back to Mission Control. Ensure that the astronaut has not suffered from any adverse conditions (heat stroke, exhaustion, suffocation, etc.) Give the astronaut time to rest, as an EVA is very tiring. Also, have a glass of cold liquid ready to give them as soon as they get out of the suit. This may sound trivial, but if you're in an EVA suit, you'll understand.