Possible Clues:

• Starter of avocado eaten by diner? One might put rocket in this
• Who's eating sandwiches at timeless Nasa installation?
• Platform for firing a rocket or missile
• Engineer unclear initially how this provides propulsion
• Meal includes a starter of endive with Roquefort on the side produced by one tossing rocket perhaps?
• Diner eating a source of rocket?
• Diner wolfing last of rucola? Never bolt down rocket here
• First hint of annoyance in diner — one letting off a rocket?
• Part of many a silo
• Someone having a meal eats a starter