You have been directed to decide on propulsion system alternatives for a vertically launched sounding rocket with a payload of 150 kg and an empty weight of 1500 kg (excluding the payload). the rocket employs twin liquid engines with a storable propellant combination that provides an average isp of 280 s. the payload contains sensitive instruments, which cannot withstand acceleration levels in excess of 4g. assuming negligible drag and that the engines are not throttreable, determine the propellant load.