Сделать вопрос косвенным, на англ. Начинать так: "They ask..."
1. Has anybody landed on Mars ?
2. Is there life on Venus ?
3. Will people live on the Moon some day ?
4. Do astronauts often visit Space Flight Control center ?
5. Are there any aliens out there ?

if anybody has landed on marsif there is life.....if people will live......if astronauts often.....if there are any.....