The delta 2 is an American space launch system and was made by McDonnell Douglas. Thirteen seconds after the Delta rocket lunched it exploded in the air.

There have been 5 rovers sent to Mars:

Mars 2 Prop-M rover was launched by a Proton K Rocket and carried by the orbiter.

Mars 3 Prop-M rover was launched by a Tyazheliy Sputnik Rocket and carried by the orbiter.

Sojourner rover was launched by a Delta II rocket and carried by the Pathfinder Orbiter

Spirit Rover was launched by a Delta II rocket and carried by its orbiter.

Opportunity was launched by a Delta II rocket and carried by its orbiter.

The rocket that launched Near on 17 February 1997 was a Boeing Delta II.

Thor-Delta continue to launch satellites and space probes. By 1969 the Thor core was being used regularly both in Delta vehicles and in the USAF.

Yes, except south of Saigon, the former MR4 (IV Corps) was mostly swamps (the Mekong Delta).