请教2道语法题

1。It may be another fifteen years before spacecraft from Earth again venture to Mars, a planet now known to be cold, dry, and probably lifeless.

A.  again venture to Mars, a planet now known to be

B.  venture to Mars again, a planet now known for being

C.  will venture to Mars again, a planet now known as being

D.  venture again to Mars, a planet that is known now to be

E.  will again venture to Mars, a planet known now as being

答案是A，我也觉得A最好，但就是想不通 spacecraft 作为第三人称单数，后面的谓语动词 venture 用原形吗？

2.  Physics professors, the Arnmore Laboratories and Arnmore Research Facilities were founded by Leo and Fontove Arnmore in 1989 after ten years of fundraising.

A.  the Arnmore Laboratories and Arnmore Research Facilities were founded by Leo and Fontove Arnmore in 1989 after ten years of fundraising.

B.  Leo and Fontove Arnmore founded the Arnmore Laboratories and Arnmore Research Facilities by in 1989, after ten years of fundraising

答案是B，我看不懂B里
        by in 1989  这个 by 加在里面是怎么回事？

第一题:
spacecraft:n.（名词）
【复数】 spacecraft
A vehicle intended to be launched into space.Also called  spaceship
航天器：即将被发射入太空的工具也作  spaceship

第２题抄错了吧？