UPDATE 1-Northrop revenue beats; sees lower taxes boost 2018 profit

(Adds details on the quarter)

Jan 25 (Reuters) - U.S. weapons maker Northrop Grumman Corp reported a better-than-expected quarterly revenue helped by higher sales in its aerospace and mission systems businesses that make parts for the F-35 fighter jets, and said it expects a lower tax rate to boost earnings in 2018.

The maker of Global Hawk surveillance planes said it expects 2018 profit in the range of $15.00-$15.25 per share, and revenue of about $27 billion.

Analysts on average were expecting 2018 earnings of $14.23 per share, and revenue of $26.91 billion, according to Thomson Reuters I/B/E/S.

Northrop, like its peers in the United States, is benefiting from higher demand for weapons, fighter jets and tanks amid heightened security concerns around the world.

Sales at Northrop's aerospace unit, which makes the center fuselage for the F-35 jets, rose 4.6 percent to $3.01 billion, in the fourth quarter ended Dec. 31.

Overall net sales rose to $6.63 billion in the quarter, from $6.40 billion a year earlier, topping Wall Street expectation of $6.35 billion. (http://bit.ly/2DBxzFn)

However, net income for the maker of Global Hawk surveillance planes fell to $178 million, or $1.01 per share, from $525 million, or $2.96 per share, a year earlier.

Net earnings were hurt by a higher tax expense and $500 million discretionary pre-tax pension contribution. (Reporting by Ankit Ajmera in Bengaluru; Editing by Anil D'Silva and Supriya Kurane)