ðə ɹᵻdˈʌkʃən ɔːɹ aʊtɹˈaɪt ɹᵻmˈuːvəl ʌv sˈʌlfɜː slˈoʊd ðə bˈɜːn ɹˈeɪt, wˌaɪl ɹᵻplˈeɪsmənt ʌv hˈaɪɚ məlˈɛkjʊlɚ wˈeɪt sˈʌlfɜː daɪˈɑːksaɪd baɪ kˈɑːɹbən daɪˈɑːksaɪd ɔːɹ mʌnˈɑːksaɪd ɪnðə pɹəpˈɛlənt ɡˈæs mˈɪkstʃɚ ɡˈeɪv ɐ hˈaɪɚ spəsˈɪfɪk ˈɪmpʌls.
The reduction or outright removal of sulfur slowed the burn rate, while replacement of higher molecular weight sulfur dioxide by carbon dioxide or monoxide in the propellant gas mixture gave a higher specific impulse.