One major goal of the mercury program was to send a manned spacecraft into orbit and to

the answer is: bring it home safely

The project was initiated during the period of space race, when united states compete with the soviet union to explore the space and hopefully bring home new resources that can benefit the nations.

The biggest challenge faced by the mercury program is that the pressure that a vehicles might face as pass through the atmosphere into the earth could make the vehicles explode and kill all the passengers in it.

other sources of text

explanation:

this can be magazines, news reports, scholarly articles, textbooks, research papers etc.