Simplify the following text for a Grade 10 native English-speaking person.
Original: In the close approach that led to its initial discovery , not enough observations could be made to calculate an orbit , and Adonis was a lost asteroid until 1977 when it was rediscovered by Charles T. Kowal .
Simplified: In the close approach that led to the first time it was found , not enough sightings could be made to find out it 's orbit , and Adonis was lost until 1977 when it was found once again by Charles T. Kowal .