{"id":"https://openalex.org/keywords/specific-impulse","display_name":"specific impulse","description":"A measure of rocket or other reaction-engine efficiency, defined as thrust produced per unit weight flow of propellant.","display_name_alternatives":["I_sp","Isp"],"ids":{"openalex":"https://openalex.org/keywords/specific-impulse","wikidata":"https://www.wikidata.org/wiki/Q51504"},"primary_topic":{"id":"https://openalex.org/T12513","display_name":"Rocket and propulsion systems research","score":0.3585,"subfield":{"id":"https://openalex.org/subfields/2202","display_name":"Aerospace Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T12513","display_name":"Rocket and propulsion systems research","score":0.3585,"subfield":{"id":"https://openalex.org/subfields/2202","display_name":"Aerospace Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10781","display_name":"Plasma Diagnostics and Applications","score":0.2487,"subfield":{"id":"https://openalex.org/subfields/2208","display_name":"Electrical and Electronic Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10806","display_name":"Energetic Materials and Combustion","score":0.0799,"subfield":{"id":"https://openalex.org/subfields/2211","display_name":"Mechanics of Materials"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"works_count":8730,"cited_by_count":71769,"works_api_url":"https://api.openalex.org/works?filter=keywords.id:keywords/specific-impulse","updated_date":"2026-10-22T04:07:25","created_date":"2022-04-12T19:38:12"}