EVA (Extra-Vehicular Activity)

👨‍🚀 What Is EVA?

EVA stands for Extra-Vehicular Activity, commonly known as a spacewalk.

It’s any activity where astronauts leave the pressurized environment of the ISS to work outside in space. 

EVA Crew Identification

Inside the Quest airlock, two astronauts prepare using different markings on their suits:

Pre-EVA Leak Check

Before depressurizing the airlock, the crew performs a leak check hold — holding pressure at 5 psi for 5 minutes to confirm no leaks before opening the EVA hatch.

🇷🇺 RS EVA: Pirs (or Poisk) Airlock – Russian Segment

• Airlock Name: Pirs DC-1 (previously) or Poisk (MRM-2) (currently used).

• Spacesuit Used: Orlan suit (Russian-built).

• Purpose: Maintenance, antenna installation, and servicing of Russian-built modules.

🧩 Diagram (Right Side)

The image shows the ISS layout divided into:

• ROS – Russian Operating Segment (highlighted with the Russian flag).

• USOS – U.S. Operating Segment (highlighted with the U.S. flag).

Key modules labeled:

• FGB (Zarya) — first module launched.

• SM (Service Module / Zvezda) — Russian living quarters and control.

• MRM-2 (Poisk) — current Russian EVA hatch.

• Quest Airlock — U.S. EVA module with:
  
  

  • Crew Lock → where astronauts suit up and depressurize.

  • Equipment Lock → where suits and tools are stored.

  • EVA Hatch → the door to space.

📊 EVA Statistics (Bottom Section)

(Values will update dynamically in the simulator or telemetry feed.)

🧠 In Simple Terms

This screen summarizes:

• Where and how spacewalks happen (U.S. vs. Russian airlocks).

• Which suits are used (EMU vs. Orlan).

• How astronauts are identified (EV1 = no stripes, EV2 = red stripes).

• The ISS modules involved and total EVA history.

It’s essentially a mission operations dashboard for monitoring and recording spacewalk activity across both station segments.

EVA (Extra-Vehicular Activity) Status Monitor for the U.S. Airlock “Quest” aboard the International Space Station

It’s a real-time operations display showing airlock pressure, crew member status, and leak check procedures before or during a spacewalk.

 🧩 Left Section

🇺🇸 “US Airlock: Quest”

• Indicates that this display monitors the U.S. Quest Airlock — the main EVA module used for spacewalks with EMU suits (Extravehicular Mobility Units).

• The blank box is typically used to display a live camera feed from inside the airlock or suit monitoring system.

⚙️ Center Panel — Current EVA Status

🕐 “Currently No EVA” / Timer

• The large digital timer (0:00:51) shows elapsed EVA time once a spacewalk begins.

• “Currently No EVA” means no active spacewalk is taking place at this moment — the timer is idle.

🔽 Airlock Pressure Gauge (Right Side)

• Displays current airlock internal pressure, measured in psi (pounds per square inch).

• The gauge shows 14.53 psi, which is normal cabin pressure (same as inside the ISS).

• When an EVA begins, this value gradually decreases to near 0 psi as the airlock is depressurized before hatch opening.

Color Zones:

🔧 Airlock Pump Status

🧑‍🚀 Crew Information Section

When an EVA is active, this section displays the astronauts’ names, suit telemetry data (oxygen, CO₂, temperature, power).

🧪 EMU Leak Check

• “EMU” = Extravehicular Mobility Unit (spacesuit).

• Before depressurization, the suits undergo a leak check — ensuring each suit holds pressure independently.

• The Leak Check Hold typically lasts 5 minutes at 5 psi, confirming airtight integrity before proceeding with depressurization of the airlock.

🧭 Indicators (Top Arrows)

🧠 In Simple Terms

This display is the EVA control and monitoring panel for the Quest Airlock.

It lets flight controllers and crew:

• Track airlock pressure (for depressurization and repressurization).

• Monitor EVA start and duration.

• Verify EMU suit leak checks.

• Display crew names and suit data for EV1 and EV2.

At this moment:

• The airlock is fully pressurized (14.53 psi).

• No EVA is happening.

• Airlock pumps are inactive.

• Both astronaut slots are empty

Russian Segment (RS) Airlock EVA Monitor

Russian Segment (RS) Airlock EVA Monitor, specifically for MRM-2 (Mini Research Module-2, also known as “Poisk”), which is currently used for Russian spacewalks (EVAs) aboard the International Space Station (ISS).

 🇷🇺 RS Airlock: MRM-2 (Poisk)

• The Mini Research Module-2 (MRM-2) is attached to the Service Module Zvezda on the Russian Orbital Segment (ROS).

• It serves as both:

  • A docking port for Soyuz and Progress vehicles.

  • The main airlock for Russian EVAs using Orlan suits (since the Pirs DC-1 module was deorbited in 2021).

This airlock supports up to two cosmonauts at a time for maintenance, external payload installation, or science experiments.

⚙️ Right Side — Airlock Pressure Gauge

• The analog-style gauge shows airlock pressure in psi (pounds per square inch).

• The indicator needle is near 14–15 psi, meaning the airlock is fully pressurized, equal to cabin atmosphere.

Pressure Zones

🧪 EMU Leak Check Indicator

Although labeled “EMU Leak Check” (same graphic used in the ISS Mimic display), in the Russian context this refers to the pre-EVA integrity test performed on the Orlan suits and the airlock compartment.

During a real EVA:

1. The crew closes the inner hatch to isolate MRM-2.

2. The airlock is gradually depressurized.

3. A 5-minute hold at 5 psi confirms no leaks before continuing to vacuum.

When repressurizing after a spacewalk, this gauge climbs back toward the green zone.

🧑‍🚀 EV1 / EV2 Fields

• These represent the two Orlan suit operators:

  • EV1 (EVA Leader): Typically the most experienced cosmonaut.

  • EV2 (Assistant / second cosmonaut).

• The black rectangles are placeholders for suit telemetry or helmet camera feed (in the ISS Mimic software).

• In a real system, these would display parameters like oxygen, battery voltage, pressure, and CO₂ levels for each suit.

📺 Left Side

• “RS Airlock: MRM-2” label (with Russian flag) identifies the monitored module.

• The empty box is used for live video or telemetry overlays.

• During EVA operations, this might show hatch camera views or telemetry graphics.

🧠 In Simple Terms

This display shows the status of a Russian EVA operation from the MRM-2 Poisk airlock:

• The airlock is pressurized (no EVA in progress).

• Leak check system is ready but inactive.

• EV1 and EV2 placeholders await crew identification when a spacewalk starts.

It’s essentially the “mission control dashboard” for Russian spacewalks, tracking airlock pressure, suit status, and timing in the same way the U.S. Quest airlock monitor does for NASA astronauts.

Extravehicular Mobility Unit (EMU)

🧑‍🚀 Extravehicular Mobility Unit (EMU) Overview

The EMU is not just a suit — it’s a self-contained spacecraft designed to:

• Provide oxygen, temperature control, communication, and mobility for astronauts outside the ISS.

• Protect astronauts from vacuum, radiation, and micrometeoroids.

• Support missions for up to 6.5–8.5 hours outside the station.

🔧 Left Side – EMU Components (Labeled Diagram)

Each part labeled in red corresponds to a major subsystem:

💧 Water Recharge System (In-Flight Refill Unit – IRU)

• The EMU has two water tanks: one for cooling, one for drinking.

• The IRU pumps water from ISS storage to refill the EMU between EVAs.

• The system also removes air bubbles and maintains suit pressure integrity.

Displayed text explains this:

“The In-Flight Refill Unit (IRU) pumps water from the ISS to the EMU for recharging the EMU water tanks.”

⚡ Right Side – Electrical and Recharge Telemetry

The EMU is powered by battery packs that can be recharged from the ISS before a spacewalk.

The small green text values (e.g., -0.03 V, -0.00 A) show live electrical telemetry — right now, both suits are not charging (values near zero)

🔋 EVA Battery & Power Flow Summary

1. Before EVA: EMUs are connected to the EVA Battery Operations Terminal (EBOT) in the Quest airlock for charging.

2. During EVA: Power switches to the suit’s internal battery for independent operation.

3. After EVA: The battery is reconnected for recharge and data logging.

Each EMU battery can typically last 8 hours, with 30 minutes of reserve.

🧠 In Simple Terms

This screen explains:

• How the EMU suit works and what each part does.

• How the suit’s electrical and water systems are monitored and recharged from the ISS.

• That currently, no suits are being charged or in use (voltage/current near zero).

Essentially, it’s a status dashboard + learning reference showing how a NASA spacesuit operates as a mini spacecraft.