stˈiːm ɹˈɑːkɪts ɑːɹ jˈuːʒuːəli pɹˈɛʃɚ fˈɛd, bˌʌt mˈoːɹ kˈɑːmplɛks dɪzˈaɪnz jˈuːzɪŋ sˈoʊlɚɹ ˈɛnɚdʒi ɔːɹ nˈuːklɪɹ ˈɛnɚdʒi hɐvbɪn pɹəpˈoʊzd.
Steam rockets are usually pressure fed, but more complex designs using solar energy or nuclear energy have been proposed.