WI: Apollo 13 becomes the most expensive suborbital flight in history?

Crunch Buttsteak

Crunch Buttsteak

Pretty much what it says on the tin, 5 minutes 40 seconds into the flight, the pogo oscillations on the center engine cause the thrust frame of the S-II to crack, forcing a Mode II abort. Apollo 13 splashes down in the Atlantic minutes later.

How does this affect the space program to have the third lunar landing mission being an embarrassing failure?
 

GeographyDude

Gone Fishin'
Crunch Buttsteak said:
. . . the pogo oscillations on the center engine cause the thrust frame of the S-II to crack, forcing a Mode II abort. . .
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Just as planned for, right?

I mean, a potential problem which we anticipated and planned for. And a response pretty much by the book.

And this is very different from the unlikely series of events which occurred before and during the actual Apollo 13.

——————-

In OTL, we only took a modest 8-and-a-half months between Apollo 13 and 14.

So, we might have a six month gap instead, and with that seemingly small difference, we get Apollo 18, before budgetary constraints hit home.
 
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Dathi THorfinnsson

Crunch Buttsteak said:
Pretty much what it says on the tin, 5 minutes 40 seconds into the flight, the pogo oscillations on the center engine cause the thrust frame of the S-II to crack, forcing a Mode II abort. Apollo 13 splashes down in the Atlantic minutes later.

How does this affect the space program to have the third lunar landing mission being an embarrassing failure?
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Hunh. I never knew that problem happened on Apollo 13!
 

acgoldis

Crunch Buttsteak said:
IOTL, the pogo oscillations on that engine caused the center engine to shut down early, which allowed the mission to the moon to proceed.

Here, I’m proposing that the center engine doesn’t shut down, but breaks apart the S-II stage.
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Had it been any other engine it would have been much worse: asymmetric thrust so the rocket would have started spinning out of control.
 
Workable Goblin

Workable Goblin

acgoldis said:
Had it been any other engine it would have been much worse: asymmetric thrust so the rocket would have started spinning out of control.
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Not really. An asymmetric thrust situation can be addressed by shutting down the opposing engine. Leads to a mission abort, of course, but depending on the timing you weren't going to the Moon anyway.
 
TimothyC

TimothyC

The abort system successfully saving the crew is played up as a triumph of American engineering, and the response is more muted. On one hand it means that any interest in the lunar missions that was stirred up by Apollo 13's OTL events is less, but the push-back against the flights is also lower. As said earlier, this means there might be a chance at an Apollo 18. The hardware for that flight was mostly built, and the marginal cost to actually fly it is less than 50 million then-year USD.

On the other hand, there won't be the same sense of victory in bringing the crew home. In the end, I think this would be a wash.
 
Crunch Buttsteak

Crunch Buttsteak

I do think that there would be an inquest into the POGO oscillation issue and why it wasn’t fixed earlier.

I’m not 100% sure what the Apollo launch windows were, but it might have been possible for 14 to be pushed to an earlier window?
 
marathag

marathag

Banned
acgoldis said:
Had it been any other engine it would have been much worse: asymmetric thrust so the rocket would have started spinning out of control.
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The outboards were gimballed, and engine out could be compensated out. Losing the center engine is the easiest to correct for, just a longer burn from the remaining runners. They had to be gimaballed for normal directional control. Engine out means more movement.
 
TimothyC

TimothyC

Crunch Buttsteak said:
I do think that there would be an inquest into the POGO oscillation issue and why it wasn’t fixed earlier.

I’m not 100% sure what the Apollo launch windows were, but it might have been possible for 14 to be pushed to an earlier window?
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The Saturn S-II stage was already the stage with the narrowest margins, and yes, there would be an investigation, partly as to why the the computer didn't shut-down the center engine.

Launch windows are mostly dictated by the lighting at the landing site. Using parking orbits as Apollo did, there are launch windows every day. As for limiting landing windows, The mission plans call for there to be relatively low sun angles so that shadows of terrain features would be highly visible, which puts missions to a particular launch site on 29.5 day centers.

Depending on when in the burn the failure happens, the RTG on the LM might also be recovered.
 
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