Earth is the third planet from the Sun and the only known astronomical object to harbour life. Its liquid water, oxygen-rich atmosphere, and magnetic field create the perfect conditions for life. About 71% of its surface is covered by water — giving it the nickname "the Blue Marble".
| Mission | Year | Notes |
|---|---|---|
| Sputnik 1 | 1957 | First artificial satellite to orbit Earth |
| Apollo 8 | 1968 | First crewed mission to leave Earth orbit |
| Landsat 1 | 1972–present | Continuous Earth observation from orbit |
| ISS | 1998–present | Permanent human presence in low Earth orbit |
| Sentinel | 2014–present | ESA Copernicus Earth observation constellation |
Images courtesy of NASA Image & Video Library. All images are public domain.
Images courtesy of NASA Image & Video Library. All images are public domain.