Editing Specific impulse (section)

===Density specific impulse===

A related measure, the '''density specific impulse''', sometimes also referred to as '''Density Impulse''' and usually abbreviated as {{math|''I''<sub>s</sub>''d''}} is the product of the average specific gravity of a given propellant mixture and the specific impulse.<ref>{{cite encyclopedia |url=https://encyclopedia2.thefreedictionary.com/density+specific+impulse |encyclopedia=The Free Dictionary |title=Density specific impulse |access-date=20 September 2022}}</ref> While less important than the specific impulse, it is an important measure in launch vehicle design, as a low specific impulse implies that bigger tanks will be required to store the propellant, which in turn will have a detrimental effect on the launch vehicle's [[mass ratio]].<ref>{{cite web |title=Rocket Propellants |url=http://www.braeunig.us/space/propel.htm |website=braeunig.us |access-date=20 September 2022}}</ref>