X0306 4 2018-06-20 0 0001145986 ASPEN AEROGELS INC ASPN 0001677366 Blalock Rebecca C/O ASPEN AEROGELS, INC., 30 FORBES ROAD, BLDG B NORTHBOROUGH MA 01532 1 0 0 0 Common Stock 2018-06-20 4 A 0 9677 0.00 A 32702 D Stock Option (right to buy) 5.27 2018-06-20 4 A 0 13517 0.00 A 2028-06-20 Common Stock 13517 13517 D The reporting person was granted restricted shares of common stock representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. These restricted shares will vest on the earlier of (a) June 20, 2019 or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2019. The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) June 20, 2019 or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2019. /s/ Poongunran Muthukumaran, Attorney-in-Fact 2018-06-22