Re-enable NASA as one of the "ASNS_AT_TOP"

[ssawchenko]

During #593 the resulting data set for 2018 did not include NASA's ASN number, causing the app to crash on load. As a work around we have removed NASA as one of the ASNS_AT_TOP, but we should look back into why the node was not present in the year file as the ASN number is still valid.