4 ms·

The wings were dictated by DoD requirements, and the size of the Shuttle almost doubled. But the idea of putting it on the side of the fuel tank, where insulat

The wings were dictated by DoD requirements, and the size of the Shuttle almost doubled. But the idea of putting it on the side of the fuel tank, where insulation could fall down and damage it -- that configuration predated the DoD-driven doubling in size. See: http://www.nss.org/resources/library/shuttledecision/p219.gif http://www.nss.org/resources/library/shuttledecision/p219.gi... It was already a bad design, it just got worse when the DoD got involved. It needed to be a lot smaller -- small enough to fit on top of the stack. And there was no need to risk astronauts' lives to launch payload -- use an unmanned launcher for that.

rbanffy 13y ago
Putting it on the top of the stack would prevent the first stage engines from being reused.
- tanzam75 13y ago
  > Putting it on the top of the stack would prevent the first stage engines from being reused. That's true, but reusability was the wrong goal. It forced a bad design to be adopted. It also led directly to the wishful thinking (50 flights per year!) that caused the schedule pressure on the Challenger. The actual goal should've been low cost. Instead of designing the most awesome closed-cycle engine that we could, we should've mass-produced a low-tech and low-cost engine. That's what the Russians did, and that's what SpaceX is doing today.
  - rbanffy 13y ago
    > Instead of designing the most awesome closed-cycle engine that we could, we should've mass-produced a low-tech and low-cost engine Exactly. Unfortunately, it's often not possible to find out something is impossible before you fail repeatedly trying. We now know mass-produced engines is the way to go, but building the SSMEs was what taught us that.
- gus_massa 13y ago
  I can’t find the exact quote, but the engines needed a lot of maintenance between launches. It was more a total refurbishment that a simple reuse. The engines had a lot of problems and it was necessary to replace a lot of pieces to keep them working. For example, reed the section “Liquid Fuel Engine (SSME)” in the Feynman’s apendix report about the Challenger disaster.
  - rbanffy 13y ago
    I am not saying reusability of the SSMEs was an attainable goal. I am just saying they went for the side-mounted vehicle because they were trying.

rbanffy 13y ago

Putting it on the top of the stack would prevent the first stage engines from being reused.

tanzam75 13y ago
> Putting it on the top of the stack would prevent the first stage engines from being reused. That's true, but reusability was the wrong goal. It forced a bad design to be adopted. It also led directly to the wishful thinking (50 flights per year!) that caused the schedule pressure on the Challenger. The actual goal should've been low cost. Instead of designing the most awesome closed-cycle engine that we could, we should've mass-produced a low-tech and low-cost engine. That's what the Russians did, and that's what SpaceX is doing today.
- rbanffy 13y ago
  > Instead of designing the most awesome closed-cycle engine that we could, we should've mass-produced a low-tech and low-cost engine Exactly. Unfortunately, it's often not possible to find out something is impossible before you fail repeatedly trying. We now know mass-produced engines is the way to go, but building the SSMEs was what taught us that.
gus_massa 13y ago
I can’t find the exact quote, but the engines needed a lot of maintenance between launches. It was more a total refurbishment that a simple reuse. The engines had a lot of problems and it was necessary to replace a lot of pieces to keep them working. For example, reed the section “Liquid Fuel Engine (SSME)” in the Feynman’s apendix report about the Challenger disaster.
- rbanffy 13y ago
  I am not saying reusability of the SSMEs was an attainable goal. I am just saying they went for the side-mounted vehicle because they were trying.