Friday, October 20, 2017

About the EVA Procedures by Prabhu Victor


The day before each EVA, mission control gives the crew members a pre-brief on what to expect during the EVA. This includes explaining about the tasks, the equipment available and results that are expected. The crew then decides which crew members will perform the EVA’s and who remains in the habitat to act as Capsule Communication (CAPCOM). The CAPMCOM in this instance acts as a relay for information between mission control and the EVA team. The crew then prepare all the necessary tools they need for the EVA and set them aside.



The Pre-EVA is an extensive process that takes about 30 mins to complete.

Figure 1: This is the usual attire of someone about to wear the NDX-2AT space suits. 1. The headset is connected to a radio used to communicate with mission control and CAPCOM. The headset provides voice activated communication which provides the crew member the ability to use both of their hands for other EVA related activities. 2. The upper body clothing is tight fitted and covers most of the skin to mitigate bacteria contamination with the bladder of the NDX-2AT suits. The tight fit allows the crew member to slide into the suit easier without having any cloth bunch up while entering the suit. 3. The pack holds both the batteries for the suit as well as the radio used for hands free communication. 4. The white gloves prevents the crews hand from sticking to the inside bladder of the suit due to perspiration. The gloves also mitigate bacterial contamination of the suits. 5. Tight fitted pants allow the crew member to slide into the suit easier without having any of the pants bunch up from the inside bladder. 6. Long socks are worn over the pants in order to prevent the hem of the pants getting caught in the inner bladder. Shoes are not worn when entering the suits.

Fig. 2

Fig. 3
Figure 2, 3: Here, the crew members can be seen fitting the suits with the suit cameras. The cameras give CAPCOM a video transmission of each suit which allows for better coordination and communication between the EVA crew and CAPCOM.


Getting in the suits:

4a                                                         4b
Figure 4: a) The suits are docked on the suit ports in the EVA module. b) The inside of the suits. The yellow cloth is the inner bladder of the suit. The crew members have to put their feet in first and then once their feet is secure and on the ground, they can insert their hands into the suits. c) Here is crewmember Stefan entering the rear entry NDX-2AT suits. The bar above helps the crew support themselves as they lower themselves into the suit. It helps to have upper body strength to go on an EVA because sometimes it can take a little longer to get into the suits and your arms can get very tired.

During EVA

Figure 5: After donning the suits the EVA team exit the EVA module and begin completing their objectives. In this example, the crew had to use UND’s Roborover, built by Space Studies graduate student Chris Follette, to retrieve samples places around the ILMAH in specific GPS coordinates. The crew used a handheld GPS to locate the samples, retrieve them and place them in the sample return box located in the Pressurized Electric Rover.


Figure 6: After crewmembers complete their task's they conclude their EVA with checking the status of the Hab. Throughout the EVA, the crew members in the suits are in constant communication with CAPCOM and Mission Control to ensure proper completion of tasks.


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