The rocket will be used to power the Bloodhound car in the hope it'll break the world landspeed record, travelling at more than 1000 miles an hour.
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Pupils at Hayle Community School launched the pasty as part of a project they are undertaking.
After a dry end to the day, it will grow colder overnight with a light breeze.
It will turn chilly tonight with largely clear skies and light winds.