Need some help with my grammar

[mcknme]

Greetings!

I would really appreciate some feedback regarding my sentence analysis in terms of clauses and phrases (along with their functions):

The STS Utilization and Operations Office at NASA’s Johnson Space Center (JSC) in Houston had prepared the document(1), which was meant to be revised quarterly(2) as new customers chose the Space Shuttle as their cheap and reliable ride to space(3).

(1) - main, finite clause
(2) - subordinate, finite relative clause
(3) - subordinate, finite adverbial (of reason or time?) clause

The STS Utilization and Operations Office - NP, functioning as the subject
at NASA’s Johnson Space Center (JSC) in Houston - AdverbP, functioning as adverb of place
had prepared - VP
the document - NP, functioning as an object

which - NP, functioning as subject
was meant - VP
to be revised - VP
quarterly - AdjectiveP

new customers - NP, functioning as subject
chose -VP
the Space Shuttle - NP, functioning as object
their cheap and reliable ride to space - NP, functioning as object complement

Please correct me where I am wrong. Thanks a million,

Luke