Orbital Mechanics and Spacewalk Safety: Would a Detached Astronaut Continue Orbiting with the ISS?

When astronauts work outside the International Space Station (ISS), their safety and the integrity of the station are paramount. In cases of unexpected events, such as a space walker detaching from the ISS, the astronaut's motion can be both fascinating and concerning.

Understanding Orbital Mechanics

The key to understanding the motion of a detached astronaut is orbital mechanics. While astronauts are attached to the ISS, their speed and trajectory are determined by their orbital velocity. This velocity is such that the astronaut and the station continuously fall towards Earth, but due to their horizontal velocity, they miss the planet and continue in a stable orbit.

When a space walker lets go of the station, the astronaut retains the velocity imparted by the ISS, thanks to the principle of inertia. However, any change in this velocity would result in a change in the astronaut's orbit. According to the laws of orbital mechanics, if the astronaut detaches above the station, their orbit will be slightly larger, causing them to fall behind the station. Conversely, if they detach below the station, they will drift in front of it.

What Happens if an Astronaut Deteriorates?

Without external forces or corrections, these objects typically drift and eventually re-enter the atmosphere, burning up upon re-entry. This phenomenon is similar to objects that astronauts lose during spacewalks, such as bolts or gloves. These items eventually decay and re-enter the atmosphere, posing no significant threat beyond the space station's orbit.

Robust Safety Protocols and Tools

However, safety measures are always in place. If an astronaut does detach, the space station crew can attempt to use the robotic arm to re-grapple the astronaut. Alternatively, the SAFER (Suit Arenas For EVA Replications) system, which includes small rocket thrusters on the space suit, can be used to course correct and return the astronaut to the station. SAFER is a life-saving tool that allows astronauts to gently maneuver their position relative to the station, even in the event of a sudden acceleration.

Additional Considerations

While the primary concern is the safety of the astronaut, considerations for other objects in orbit, such as fragments of debris or other space vehicles, should not be overlooked. Orbital mechanics dictate that any small mass in orbit will follow a specific trajectory, influenced by the gravitational pull of Earth. This means that any object detached from the ISS will follow a predictable path, though it may decay and re-enter the atmosphere after a period of time.

Conclusion

In conclusion, if an astronaut were to detach from the ISS, they would continue to orbit the Earth with the station, provided they retain the same trajectory. However, safety measures such as the robotic arm and the SAFER system ensure that in the event of an accident, the astronaut can be safely returned to the station. Orbital mechanics play a critical role in understanding and addressing these situations, ensuring the safety of all astronauts in space.