Sequence Diagram Lifelines

[michael.j.driver4.ctr@army.mil]

Can component lifelines be added to a sub-system lifeline on a sequence diagram (SD). This would be similar to the swim lanes under a sub-system on a Activity Diagram (AD)?

[beccared09@gmail.com]

Not in a single sequence diagram. To decompose per SysML 1.6 (https://www.omg.org/spec/SysML/1.6/PDF) use the reference block as seen in D.4.3.3 Sequence Diagram – Start Vehicle Black Box & White Box.