He earned his Ph.D. at Princeton University, MSCE at Rice University, preceptorship at what is now the NIST Engineering Laboratory, and BSCE at Rice. Before earning his PhD, Dr. Mullen worked 5 years at Mobil R&D Corp. in their Offshore Engineering Division including 2 years at Mobil E&P Southeast. He then joined the consulting firm ADAPCO Inc. as an FE analyst and later WAI in their Transportation Division.