user: Question: If the arrival date is January 2059, what is the total amount of signal power?
Columns: ['HD designation', 'Constellation', 'Distance ( ly )', 'Spectral type', 'Signal power ( kW )', 'Date sent', 'Arrival date']
Types: ['text', 'text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['HD197076', 'Delphinus', '68.5', 'G5V', 126.0, 'August 29, 2001', 'February 2070']
SQL:

assistant: SELECT SUM("Signal power ( kW )") FROM "Table" WHERE "Arrival date" = 'January 2059';