PASADENA, Calif. — NASA says two small asteroids discovered just days ago will zip harmlessly past Earth on Wednesday, a double flyby that should be visible through a telescope.

The asteroids were discovered Sunday by the NASA-funded Catalina Sky Survey in Arizona. The Minor Planet Center in Massachusetts, which tracks asteroids and comets, determined there was no chance of an Earth collision.

Asteroid 2010 RX30, thought to be 32 to 65 feet (10 to 20 metres) long, will pass within 154,000 miles (248,000 kilometres) of Earth shortly before 3 a.m. PDT; (1000 GMT) Wednesday.

The second one, dubbed 2010 RF12, will fly by about 11 hours later at a distance of about 49,000 miles (79,000 kilometres). NASA says the second one is 20 to 46 feet (6 to 14 metres) long.