VOA慢速英语:Space Tourism and Business Looking Up

commercial – adj. related to or used in the buying and selling of goods and services

federation – n. an organization that is made by of joining together smaller organizations

bold – adj. not afraid of danger or difficult situations

remote sensing –n. the use of satellites to collect information about and take photographs of the Earth

microsats – n. very small satellites

constellation – n. a group of people or things that are similar in some way

viable – adj. capable of being done or used