Exhibit 99.1 For Immediate Release Aspen Aerogels, Inc. Receives Conditional Commitment for Proposed DOE Loan and Provides Q3 2024 Preliminary Financial Results Proposed loan of up to 670.6millionwouldfundtheremainingCAPEXneededtocompleteCompany′ssecondaerogelplantInterestrateatapplicableU.S.TreasuryRateatthetimeofeachcashdrawPlantisexpectedtoprovide 1.2B - $1.6B of incremental PyroThin® thermal barrier revenue capacity Project financing structure, with Aspen Aerogels, Inc ...