With no explanation, label each line with "product-other", "O", "organization-government/governmentagency", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
NASA
's
Viking
1
and
Viking
2
space
probes
arrive
at
Mars
.
NASA:organization-government/governmentagency
's:organization-government/governmentagency
Viking:product-other
1:product-other
and:O
Viking:product-other
2:product-other
space:O
probes:O
arrive:O
at:O
Mars:O
.:O