A new influx of private investment should create a bright new future for manned space exploration, making the possibility of commercial space tourism a much more viable than it was 10 years ago.
When a modifying phrase modifies an action and not a noun, the first verb in the modifier changes to the <ing> form and 'which' is removed.
BOOK, page 78)
The police found the murder weapon, which made the prosecutor's job much easier.
As in above sentence, when a modifier beings with 'which', it modifies the noun it touches; in this case 'murder weapon'.
To correct this problem, just change the verb starting the modifier to its <ing> form as done above; 'which made' changed to 'making'.
The police found the murder weapon, making the prosecutor's job much easier.
This makes it clear that the modifier is modifying the action of finding the murder weapon.
Does this clear it up for you?