# Thread: Did I work this problem correctly...Aggregate RDF problem--series combination

1. ## Did I work this problem correctly...Aggregate RDF problem--series combination

Using the information from table 1 below, what is the aggregate RDF for a vehicle configuration using 3 strap-on boosters?
Assume a 'series' combination of the launch elements shown for your calculation.

TABLE 1:
Vehicle subsystem subsystem reliability Replacement cost
1st stage liq engine 0.991 $25.4M 2nd Stage liq engine 0.995$17.1M
payload section/fairing 0.993 $12.7M Strap-on Booster 0.997$4.2M

I assumed that an aggregate RDF would mean to work this is as a simple series combination. I was not sure if I needed to include all the components in the series or just the 3 strap-on booster rockets. I included all components and worked it this way:
Reliability = 1st stage x 2nd stage x payload section x booster 1 x booster 2 x booster 3
= .991 x .995 x .993 x .997 x .997 x .997 = 0.97035 = 0.970
RDF = 1-reliability = 1 - .97035 = 0.02965 = 0.0230

Is this correct? Please let me know. I have to have this right in order to work the other problems.

Thanks,
coolmom

2. ## Re: Did I work this problem correctly...Aggregate RDF problem--series combination

Hello, did you get the correct answer for this? I have a similar problem I am trying to solve

3. ## Re: Did I work this problem correctly...Aggregate RDF problem--series combination

Did you ever get a resonse for this question? I assume you are taking MG 415 at Athens?