Space Launch System - Orion

Space Launch System - Orion

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Discussion

Eric Mc

Original Poster:

123,878 posts

280 months

Monday 12th December 2022
quotequote all
I think there is far too much talk about perceived "risk aversion". The reason why Apollo was willing to take risks was because it was a programme run on a war footing. In this case, the war was The Cold War but as far as time pressures and budgets were concerned, it was very similar to the crash programmes insitigated in World War 2.

What is interesting is that one of the main reasons why the moon landings ended with Apollo 17 (and not Apollo 20 as originally intended) was that President Nixon did not want any Apollo astronauts killed on his watch. "Risk Aversion" was already built into Apollo - it just needed a couple of years to raise its head. Once the stated programme goal (landing a man on the moon and returning him safely to the earth) had been achieved, the President was not terribly enthusiastic for NASA to keep pushing their luck. Apollo 13 showed how risky the whole project was.

Artemis/Orion has not been funded nor has it been placed under time pressures the way Apollo was. In fact, it has been a very low priority as far as Federal funding is concerned so has been hampered by lack of interest from those in charge of the funding coupled with vaccilation over what the programme aims are. Those are the real reasons why Artemis/Orion has moved so slowly.

If China anounced tomorrow that they were planning to land a human on the moon within 5 to 10 years - and demonstrated the mission architecture (i.e. they weren't just expressing a wish but showing how they intended to do it), I am sure the US would respond and funding for Artemis would become more of a priority.

Eric Mc

Original Poster:

123,878 posts

280 months

Monday 12th December 2022
quotequote all
Perhaps. The underlying difference between then and now was that the Cold War was in full swing and there was genuine concern about Communism becoming even more dominant than it appeared to be at that time. That view was held by most of the Western world but most acutely in the US. Apollo has always to be seen in that context.

We may not be close to where we were Cold War wise (epecially compared to the late 1950s early 1960s) but the geo-political landscape has changed quite a bit since the original Constellation programme was announced almost twenty years ago.

I think we are far more wary of China and its technological and global ambitions than we were even ten years ago.

Eric Mc

Original Poster:

123,878 posts

280 months

Friday 6th December 2024
quotequote all
Apollo used skip entry. It reduces the peak heat load on the heat shield and the G loads on the astronauts. Whether you use skip entry or direct entry is irrelevant regarding the popping of the parachutes as by that stage in the re-entry, whatever type of re-entry has been used, aerodynamic drag will have slowed the spacecraft down to a safe speed for (initially) drogue deployment followed by the parachutes.

Eric Mc

Original Poster:

123,878 posts

280 months

Saturday 28th June
quotequote all
These new generation SRBs are quite different to the current ones. Try something new with rockets - they often blow up - at first.

Eric Mc

Original Poster:

123,878 posts

280 months

Saturday 28th June
quotequote all
The SRBs used on the Space Shuttle were capable of being gimballed too. They were actuated hydraulically. These new era SRBs have the gimballing powered by electric motors. The SRB casing is also made of carbon fibre rather than steel.

Carbon fibre is great for lightness but a couple of recent incidents seem to be highlighting its weaknesses.

Eric Mc

Original Poster:

123,878 posts

280 months

Sunday 29th June
quotequote all
Flooble said:
What was the other incident?
I was thinking of the Oceangate disaster.

Carbon fibre is great for certain applications but as various organisations have found out, there are times when metal is still best e.g. Rolls Royce RB211 fan blades, deep diving submersibles and (maybe) solid rocket boosters.

Eric Mc

Original Poster:

123,878 posts

280 months

Sunday 29th June
quotequote all
I was also thinking of the explosion that made a mess of the recent Starship test. That seems to have been caused by a carbon filament gas bottle rupturing.

Eric Mc

Original Poster:

123,878 posts

280 months

Sunday 29th June
quotequote all
I wonder if long term use of carbon fibre as primary material for aircraft structures has been properly thought through. I'm thinking of the 787 here.

Does carbon fibre fatigue over the long term?

Eric Mc

Original Poster:

123,878 posts

280 months

Saturday 5th July
quotequote all
MartG said:
Oceangate are a good example of designers who did not fully understand the material
Or who wilfully ignored all those who pointed out why it was the wrong material for a submersible.

Eric Mc

Original Poster:

123,878 posts

280 months

Sunday 6th July
quotequote all
Somewaht reassuring and it certainly looks like there is a shift away from Starship. Ignoring the obvious problems that now exist with the Trump/Musk relationship - from a technical point of view this seems like a right move - at the moment.

Meanwhile, over in China.......

Eric Mc

Original Poster:

123,878 posts

280 months

Sunday 6th July
quotequote all
Yep - the science side of things looks faiirly shafted.

But MAGA means "knowledge and science is irrelevant", sadly.