Explanation:

- Apophis: This is not a spacecraft. Apophis is an asteroid that had the potential for a very close pass to Earth, causing some concern in the past about a possible impact.

- Cassini: This is indeed a spacecraft. The Cassini mission was a collaboration between NASA, ESA, and ASI to study Saturn and its system, including its rings and moons.

- Spitzer: This is a spacecraft. The Spitzer Space Telescope is one of NASA's Great Observatories, designed to observe the universe in infrared light.

- Tech Sar: This is not a spacecraft in the traditional sense within the context of exploring other celestial bodies. It is an Israeli reconnaissance satellite equipped with advanced radar imaging capabilities.