Simplify the following text for a Grade 4 native English-speaking person.
Original: It was discovered on 18 July 1999 by John J. Kavelaars et al . and provisionally designated S\/1999 U 1 .
Simplified: It was found on 1999-07-18 by John J. Kavelaars et al . and designated S\/1999 U 1 .