The Delta IV Heavy has a bigger fairing because it's able to lift heavier/bigger payloads, as we saw in this question. But if a payload is small and still needs a Delta IV Heavy because of its high density or large delta v requirements, can the much smaller fairing from the basic Delta IV Medium on the left be used for an additional performance boost?

In this diagram it looks like it would fit nicely... but I know that's not a valid argument.

Delta IV family diagram


1 Answer 1


tl;dr the company did not offer that configuration

The Delta IV User's Guide did offer two different fairings for the Heavy vehicle, one of which was 0.7 meters shorter than the other. However, neither was as short as the fairings offered for the Medium vehicle.

enter image description here

The longer Heavy fairing was

the baseline 5-m fairing for heritage government payloads flying on Delta IV Heavy launch vehicles.

In the image it's labeled "modified Titan IV fairing".

The image in the question appears to show the 19.1 meter composite fairing.

An older version of the guide listed an even larger 22.4 meter fairing for the Heavy but this was dropped in the later version.

  • 1
    $\begingroup$ at a guess for why, offering a fairing option seems like it'd mean another vibration / acoustic environment characterisation, i.e. extra engineering work $\endgroup$
    – Erin Anne
    Commented Feb 25, 2023 at 21:08
  • $\begingroup$ @ErinAnne absolutely, and the market for this launcher never really materialized except for national security payloads, etc. $\endgroup$ Commented Feb 25, 2023 at 23:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.