It's impossible to definitively name the "4 most known" spacecrafts because "known" can be subjective and depend on who you ask! However, based on popularity and cultural impact, here are 4 spacecraft that are very well-known:

1. Apollo 11: This is arguably the most famous spacecraft due to its role in landing the first humans on the Moon.

2. Space Shuttle: This reusable spacecraft was a staple of NASA missions from 1981 to 2011, famous for its iconic design and ability to deliver payloads into orbit and return astronauts to Earth.

3. Voyager 1 & 2: These twin probes, launched in 1977, are the furthest human-made objects from Earth. Their incredible journeys and scientific discoveries make them incredibly well-known.

4. International Space Station (ISS): This giant orbiting laboratory, a collaborative effort of multiple countries, is constantly in the news for its scientific research, and serves as a symbol of international cooperation in space.

These are just a few examples, and there are many other notable spacecraft such as the Hubble Space Telescope, the Mars rovers, and the upcoming James Webb Space Telescope, that could also be considered "famous."