With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: International Space Station is unsuited for the testing of spacecraft systems.
text_B: Self Portrait is a work by graffiti artist Banksy .. Banksy. Banksy. In 2007 , it sold for 198,000 pounds , nearly five times its estimated pre-sale value .
not_related.