Simplify the following text for a Grade 15 native English-speaking person.
Original: As Voyager 1 heads for interstellar space , its instruments continue to study the solar system ; Jet Propulsion Laboratory scientists are using the plasma wave experiments aboard Voyager 1 and 2 to look for the heliopause , the boundary at which the solar wind transitions into the interstellar medium .
Simplified: As the Voyager 1 space probe heads for interstellar space , its instruments continue to study the solar system ; Jet Propulsion Laboratory scientists are using the plasma wave experiments aboard Voyager 1 and 2 to look for the heliopause .