Ultra‐Low Intensity Continuous Wave Laser Ablation Propulsion With Graphene‐Engineered Wood

ABSTRACT Conventional propellant materials, including polymers, metals, and doped polymers, have long been investigated for laser ablation propulsion, though achieving desired specific impulse values with low‐intensity continuous wave laser irradiation remains a challenge. This study presents low‐density graphene‐delignified wood composites as novel, sustainable propellants for continuous‐wave laser ablation propulsion. Experimental results show that natural wood achieves a density‐specific specific impulse of 5043.0 ± 188 s g −1 cm 3 , surpassing the performance of all previously reported conventional propellants. Graphene delignified wood improves the absorption of laser energy of natural wood by 98.61%, thereby achieving an ultra‐low ablation threshold intensity of 0.54 MW m −2 ; the lowest intensity attained so far, and an exceptional density‐specific specific impulse of 1569.60 ± 57.40 s g −1 cm 3 . The absolute specific impulse values of NW and GDW are 907.74 and 800.49 s, respectively, whereas no other material has achieved a value >100 s under CW laser irradiation. Additionally, graphene delignified wood has a tensile strength of 273.1 MPa, ∼10 times greater than NW, and a specific tensile strength of 533 MPa g −1 cm 3 , exceeding common aerospace structural materials in strength‐to‐weight ratio. The findings unlock the potential of lightweight and sustainable graphene delignified wood for use in various light and space applications.