5
$\begingroup$

Inspired by comments under this answer to this question Just how pointy does a rocket's nosecone need to be? (see also Why are the nose cones of current spacecraft less pointy?)

Why was the External Tank's nose cone pointy?

enter image description here

(Image source: https://steemitimages.com/DQmXscrjPZRpFwkAdvTvUHkL1Bb9csesUpqzBz2JA8Q8JZk/image.png)

$\endgroup$
7
$\begingroup$

The original External Tank nose cone design was indeed blunt - almost like a fireplug, as seen in this 1975 concept art.

enter image description here

[Image source - lost in the mists of time to me, but NASA somewhere]

However, wind tunnel testing at the Arnold Engineering Development Center revealed that this configuration caused unsteady aerodynamic buffeting at some conditions. A bi-conic spike design was conceived and further wind tunnel testing showed that it eliminated the problem.

The nose cone served several functions besides its aerodynamic one.

enter image description here

[Cropped from https://www.nasa.gov/centers/marshallimages/content/149235main_IMG_2558_3072x2048.jpg ]

  • It also covered the LO2 vent/relief valve and provided vent exits for gases boiled off from the LO2 tank, which were subsequently carried off by the "beanie cap" umbilical arm.

enter image description here

[Image Source https://contactsam.files.wordpress.com/2014/11/vent_arm_141113_2.jpg ]

$\endgroup$
  • 1
    $\begingroup$ The concept art is interesting. No hatches for the ejection seats. $\endgroup$ – DrSheldon Oct 3 at 20:38
  • 1
    $\begingroup$ @DrSheldon it was the least wonky one I could find. The others had OMS pods extending onto the payload bay doors, antennas sticking out of the nose cone, etc. etc. ...Artistic license.... The first link in the answer shows a (sadly blurry) picture of the wind tunnel model with the fireplug on the front. $\endgroup$ – Organic Marble Oct 3 at 20:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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