Which sentence uses the word "mission" as an indirect object? 1. Sally Ride's mission to retrieve a test satellite was successful. 2. During what mission did the astronauts ride in the shuttle Challenger? 3. Which mission did Sally Ride fly for NASA? 4. On her mission, Sally Ride launched two satellites.

An indirect object:

A word or group of words representing the person or thing with reference to which the action of a verb is performed, in English generally coming between the verb and the direct object and paraphrasable as the object of a preposition, usually to or for, following the direct object, as the boy in -  He gave the boy a book.

You should be able to take it from here.

I expected this to be a no-brainer, but it would appear there are have more categories in the objective case than I remember.

The objective case is the form of a noun or pronoun used in the direct object, indirect object, object of preposition, object complement, and subject of an infinitive.

There are direct links for the words I've italicized at: http://englishplus.com/grammar/00000352.htm )

And, "Subjective case is sometimes called the nominative case. A noun or pronoun is in the subjective when it is used as the subject of the sentence or as a predicate noun. A predicate noun follows a form of the "be" verb, and it renames the subject of the sentence."

http://www.english-grammar-revolution.com/list-of-prepositions.html contains "the preposition song."

Random thoughts:

Sentence 1)---mission is the subject of the sentence.

Sentence 2)---during is a preposition and mission is an object of the preposition.

Sentence 3)---mission is the object.

Sentence 4)---on is a preposition and mission is its object.

That is all I know for sure. (I think?)