Saturn V for Skylab - Second Stage

[MalzM]

Hey guys,

I'm currently reading a lot about the less famous NASA missions, and I've come to a very specific question, that I could not find any precise information on. My question is regarding the second stage of the modified Saturn V rocket, used to launch Skylab into space in 1973. As far as I know, the modified Saturn V actually consisted of the normal first and second stage, with the third stage being replaced by Skylab itself.

In case of the "normal" Saturn V, the first and the second stage would usually crash down into the ocean, while the third stage - which carried the instrument unit - could be steered into another directory after the CSM/LM where separated from it.

On Skylab however, I can't see, how the second stage would be removed from orbit, after placing Skylab in its orbit and being separated. It does not seem, like the second stage featured the necessary instrumental equipment or the means of RCS necessary. Does this mean, that the second stage was just moved away from Skylab a bit at separation with solid boosters, but left in an orbit slightly different than Skylabs orbit?

I hope someone here can provide an answer... Thanks!

Regards, Malz

[Bill Phil]

Yep. The S-II that inserted Skylab into orbit stayed in orbit until, due to atmospheric drag, it reentered the atmosphere.

Edited July 21, 2017 by Bill Phil

[MalzM]

Alright, but didn't it pose a threat for spacecraft on trajectories close to Skylab, like those coming in for rendezvous?

[Bill Phil]

Not really. The S-II was huge. That makes it easy to track. Which makes it easy to avoid.

[MalzM]

Alright, that was simple , thanks for your help!

[regex]

1 hour ago, MalzM said:

Does this mean, that the second stage was just moved away from Skylab a bit at separation with solid boosters, but left in an orbit slightly different than Skylabs orbit?

Yes, by definition separation by means of retro motors would place it in a different, slightly lower orbit. That would mean it would experience more drag than Skylab as well, further lowering its orbit over time. With Skylab being launched on the 14th and crew being launched on the 25th, the S-II would have been in a very different orbit and probably posing no danger to the crewed mission.

[Ultimate Steve]

One of the original proposals (iirc) was to use a Saturn 1 to launch a stage into orbit (with engines and tanks and everything) that later would have been broken into by a crew and converted into a station, wet workshop style.

They canceled it in favor of Skylab, the "dry workshop."

 

But I think it would be really, REALLY cool if they had kept the second and third stages connected on the Skylab mission, and used the second stage as a wet workshop. Then, you have both dry and wet workshops! It would certainly have been interesting!

[StrandedonEarth]

16 hours ago, Ultimate Steve said:

But I think it would be really, REALLY cool if they had kept the second and third stages connected on the Skylab mission, and used the second stage as a wet workshop. Then, you have both dry and wet workshops! It would certainly have been interesting!

Now THAT is an excellent concept. It gives a ready-to-use base to do the converting work from. Maybe the ITS could use the wet-workshop approach when it has arrived at a permanent location.

The key to wet workshop is to design and build the future WW to be easily reconfigurable, with all the hatches and fittings and lugs and conduit paths all built in. There are also the anti-slosh baffles to move and re-purpose and otherwise play with. The payload can consist of all the equipment to move inside.

[kerbiloid]

23 hours ago, Bill Phil said:

That makes it easy to track. Which makes it easy to avoid.

If there were engines on Skylab...

[DerekL1963]

On 7/22/2017 at 8:33 AM, StrandedonEarth said:

The key to wet workshop is to design and build the future WW to be easily reconfigurable, with all the hatches and fittings and lugs and conduit paths all built in. There are also the anti-slosh baffles to move and re-purpose and otherwise play with. The payload can consist of all the equipment to move inside.

And that's not easy...  Anything inside the tank (in the case of an S-II or S-IVB) needs to be able to survive a bath in deep cryogens while also posing no threat to the engines nor introducing dangerous slosh modes.  (Oh, and not retaining pockets of helium when the tank is filled, nor pockets of cryogens when the tank is emptied.)   All the equipment outside the tank needs to be broken down into components sized to fit through a tiny hatch, and shouldn't require a hundred times more man hours to be assembled than the programs provides across all occupancy periods.

That's a *very* tall order.

There's a reason why the 'wet' workshop was abandoned when a 'spare' Saturn V became available.

[tater]

Oddly enough, the concept is being revived by NanoRacks, though.

https://arstechnica.com/science/2017/06/after-50-years-a-private-company-will-revive-nasas-wet-workshop/

Berger adds a great quote:

Quote

A few years ago the NASA engineer who managed the Apollo Applications Program from Johnson Space Center in the 1960s, Robert Thompson, told Ars that the wet workshop "was just about the dumbest idea I've ever heard. And I've heard a lot of dumb ideas." 

Maybe they're in it for the grant, lol. Doesn't seem like a great idea (still).

 

[rocketman6000]

Hey guys i just have one question and maybe you guys could help me with this but I'm having trouble assembling the actual rocket. I've been able to assemble the Skylab module itself but I couldn't build the entire rocket itself. Please help me with this so I could launch it and send more rockets to it!