Why can't we build the Saturn V again?

[Rusty_Barton]

I like this size comparison diagram of space stations.

http://forum.nasaspaceflight.com/forums/get-attachment-big.asp?action=view&attachmentid=10351

[vt_hokie]

Rusty_Barton - 26/3/2008  5:26 PM

I like this size comparison diagram of space stations.

Cool!  What's on the far right, the proposed Chinese station?

[davcbow]

cneth - 23/3/2008  8:07 PM

To me, the analogy is to think about recreating a car like the 65 mustang again.  Sure, you could re-create it, but do you really want a 'new' 65 mustang?  Without airbags, seatbelts, crush resistant bumpers, fuel injection, etc, etc, etc?   After all, that 65 mustang would take you to the grocery, just like today's car, right?

The reality is that today's vehicles are many times safer, handle better, get better fuel mileage, etc.    And that's what you want.   Yes, they do the same 'mission', but today's car does it better and safer.

Just look at that Apollo landing computer - your cell phone has more capability.  And that's just one system.  By the time you 'upgrade' all the parts, well, you may as well start over.

The 65 Mustang was a simple car to work on, any shade tree mechanic could repair it. Do that with todays designs....

[Oersted]

Rusty_Barton - 26/3/2008  10:26 PM

I like this size comparison diagram of space stations.

http://forum.nasaspaceflight.com/forums/get-attachment-big.asp?action=view&attachmentid=10351

Great diagram!

Internal volume of Skylab (+ Apollo command module): 368 cubic meters.

Internal volume of the ISS when completed: 1200 cubic meters.

- Most importantly, the ISS will have taken 46 launches to reach that figure!

[iamlucky13]

vt_hokie - 26/3/2008  2:35 PM

Rusty_Barton - 26/3/2008  5:26 PM

I like this size comparison diagram of space stations.

Cool!  What's on the far right, the proposed Chinese station?

I'm actually curious what's on the far left. I'm pretty sure it's bigger than a Salyut.

And I assume to the left of Mir is Mir in an earlier stage.

An interesting thing to note is that the internal volume of the ISS may only be 3-4 times more than Skylab, but it looks way more impressive because of the huge solar wings and truss structure (and that image shows at least one cancelled module on the ISS).

[William Barton]

davcbow - 26/3/2008  5:56 PM

cneth - 23/3/2008  8:07 PM

To me, the analogy is to think about recreating a car like the 65 mustang again.  Sure, you could re-create it, but do you really want a 'new' 65 mustang?  Without airbags, seatbelts, crush resistant bumpers, fuel injection, etc, etc, etc?   After all, that 65 mustang would take you to the grocery, just like today's car, right?

The reality is that today's vehicles are many times safer, handle better, get better fuel mileage, etc.    And that's what you want.   Yes, they do the same 'mission', but today's car does it better and safer.

Just look at that Apollo landing computer - your cell phone has more capability.  And that's just one system.  By the time you 'upgrade' all the parts, well, you may as well start over.

The 65 Mustang was a simple car to work on, any shade tree mechanic could repair it. Do that with todays designs....

What you'd end up with is a contemporary car with the '65 Mustang Outer Mold Line. Me, I prefer the 1960 Corvette OML...  :laugh:

[vt_hokie]

iamlucky13 - 27/3/2008  1:56 PM

(and that image shows at least one cancelled module on the ISS).

Not to mention the "power tower"

[Takalok]

cneth - 23/3/2008  8:07 PM

To me, the analogy is to think about recreating a car like the 65 mustang again.  Sure, you could re-create it, but do you really want a 'new' 65 mustang?  Without airbags, seatbelts, crush resistant bumpers, fuel injection, etc, etc, etc?   After all, that 65 mustang would take you to the grocery, just like today's car, right?

The reality is that today's vehicles are many times safer, handle better, get better fuel mileage, etc.    And that's what you want.   Yes, they do the same 'mission', but today's car does it better and safer.

Just look at that Apollo landing computer - your cell phone has more capability.  And that's just one system.  By the time you 'upgrade' all the parts, well, you may as well start over.

I'd have to disagree with the analogy, which assumes that materials and fluid engineering have kept pace with IC technology.  Really, nothing could be less true.  While it is true that electronics have advanced tremendously, rocket engines really haven't advanced much at all.  The actual comparison would be between a '65 Mustang and a '68 Mustang.

As for safety, I would submit the Apollo rocket is still the safest rocket ever built - far more so than STS.  Given that Ares is a copy / restart of Saturn in many respects, I expect it has a chance to be comparably safe.  But the use of the solid booster would probably make the Ares less safe than Saturn.  

[edkyle99]

Takalok - 28/3/2008  11:06 PM

As for safety, I would submit the Apollo rocket is still the safest rocket ever built - far more so than STS.  Given that Ares is a copy / restart of Saturn in many respects, I expect it has a chance to be comparably safe.  But the use of the solid booster would probably make the Ares less safe than Saturn.  

I'm not so sure about "less safe".  Solid rocket motors have a lower failure rate than liquid rocket engines.  

Saturn had some close calls - three Saturn V flights (502, 508, 513) came very close to total failure (502 actually did suffer a launch vehicle failure) and one Saturn IB just barely avoided a catastrophic total engine shut-down just after it lifted off.   There were only 13 Saturn V launches and 19 by Saturn I/IB.  If NASA had flown Saturn as much as Shuttle, it would most likely have suffered at least as many failures - and there were non-survivable Saturn failure modes.

 - Ed Kyle

[hop]

Takalok - 28/3/2008  9:06 PM
As for safety, I would submit the Apollo rocket is still the safest rocket ever built - far more so than STS.

I don't see any justification for that. The sample size is far too small. Remember, if STS had only flown as many times as Saturn V, it would have a perfect safety record too. In fact, it had a perfect record for many more flights.

Furthermore, if you look at LV failure rates, they don't seem to correlate particularly well to the underlying design (i.e. number of engines, type of propellant, number of stages) at all. If you can find any pattern at all, experience of the organization and maturity of the vehicle look like far better candidates.

I personally find the Saturn V aesthetically pleasing. It looks more like the right way to do it to me than Ares, but I don't think the reliability argument is at all convincing.

[8900]

besides, Saturn V can be used to assemble a really huge space station
100 tonnes modules connected together can produce a really big interior space for all research purposes
And then scale up the Apollo (similar to Orion) to accommodate more people(6-7people)

[clongton]

8900 - 29/3/2008  1:21 AM

besides, Saturn V can be used to assemble a really huge space station
100 tonnes modules connected together can produce a really big interior space for all research purposes. And then scale up the Apollo (similar to Orion) to accommodate more people(6-7people)

I recently had the opportunity to revisit the Smithsonian Air and Space museum again, and I couldn’t wait to revisit the Skylab station, one of my favorite exhibits. While there, we had a good discussion with a subject matter expert, and one of the topics was about station design. It turns out that one of the lessons learned from Skylab was that the open space can actually be “too big” in a zero-g environment. The compartments are quite large and there was more than one occasion when a member of the crew found themself floating in the middle of the “room”, completely unable to get to anything, because they couldn’t reach any wall, piece of equipment or protrusion of any kind. They ended up flaying around until one of the other crew members arrived to quite literally “pull them in”. Imagine being in this situation during an emergency when you must accomplish some task in order to stay alive, but are literally unable to move your body to the location required.

I relate all that to say that the lesson learned from Skylab in this regard is that in a zero-g environment, the open space inside must not be large enough for that scenario to happen. So what you see on ISS, for example, is about the size of available open space in any compartment that you will likely ever see in a zero-g station. Now of course, a large station made up of half a dozed 100mT modules could have lots and lots of compartments, including very large ones that occupy an entire "deck" stretching across the station, but you can be sure that a bulkhead, wall, ceiling or deck will never be further away than the length of a human body with an outstretched arm.

[grakenverb]

clongton - 29/3/2008  8:55 AM

 It turns out that one of the lessons learned from Skylab was that the open space can actually be “too big” in a zero-g environment. The compartments are quite large and there was more than one occasion when a member of the crew found themself floating in the middle of the “room”, completely unable to get to anything, because they couldn’t reach any wall, piece of equipment or protrusion of any kind. They ended up flaying around until one of the other crew members arrived to quite literally “pull them in”. Imagine being in this situation during an emergency when you must accomplish some task in order to stay alive, but are literally unable to move your body to the location required.

Perhaps if such a large space is constructed on a space station again, station occupants could wear a "utility belt" that has a can of compressed air ($2.99) that can be used as a method of propulsion in an emergency.

[Takalok]

8900 - 29/3/2008  1:21 AM

The compartments are quite large and there was more than one occasion when a member of the crew found themself floating in the middle of the “room”, completely unable to get to anything, because they couldn’t reach any wall, piece of equipment or protrusion of any kind. They ended up flaying around until one of the other crew members arrived to quite literally “pull them in”.

LOL, what an image.  

I was only around 10 years old at the time of SkyLab, but I don't recall NASA mentioning "marooned" astronauts.  Heh, I can imagine why.

I suppose a configuration like an airliner, where the top and bottoms of the tube are used for storage and support systems would solve the problem.

[clongton]

I actually like the look and feel of decks, like floors in a high rise building. If the basic structure were 10m diameter, then each “deck” would be a 10m diameter deck, with different sized compartments located on it, like different sized “offices” on a high rise floor. Each deck would not exceed the floor to ceiling length of a human body with an outstretch arm, which would provide the necessary “grabbing” room, but would allow for virtually any size compartment on the deck, from a tiny water closet to a huge conference room occupying the entire deck, and everything in between. To me it seems like a more efficient use of space, no pun intended.

[Takalok]

hop - 29/3/2008  1:11 AM

Takalok - 28/3/2008  9:06 PM
As for safety, I would submit the Apollo rocket is still the safest rocket ever built - far more so than STS.

I don't see any justification for that. The sample size is far too small. Remember, if STS had only flown as many times as Saturn V, it would have a perfect safety record too. In fact, it had a perfect record for many more flights.

Furthermore, if you look at LV failure rates, they don't seem to correlate particularly well to the underlying design (i.e. number of engines, type of propellant, number of stages) at all. If you can find any pattern at all, experience of the organization and maturity of the vehicle look like far better candidates.

I agree the sample size is too small for a very persuasive statistical argument, but there's other ways to crack this nut.

I think it's reasonable to say that Saturn as a system is safer than STS as a system simply because of the Launch Escape System (LES), which STS doesn't have.  The launch of Soyuz T-10-1 in 1983 is a pretty good demonstration of that.  Constellation is going back to a capsule with a LES like Saturn had for good reason.

After LES jettison, the astronauts could still abort and (hopefully) parachute down safely.  No such option exists for STS (as with Challenger)

Also, in Apollo, the service module protected the heat shield, and the boost protective cover (BPC) protected the top of the capsule.  STS has it all hanging out there during launch which (as with Columbia) is a bit of a risk.

As for the comparison between solid and liquid motors, there are a couple of well known arguments, most of which were put forward in the original design of the Saturn:

     Once a solid booster is lit, you can't shut it off.  That makes it more dangerous than a liquid.

     Small clustered liquid engines provide a redundancy not available with large solids (aka STS)

     Solids have oscillation problems.  It might be a mistake to compare that to "pogo" problems with liquid motors, but at this time pogo is resolved, and solid oscillation is not.  For Ares I, this is a problem.

Unfortunately, there are are very few systems to ever have put a human into space, and they basically boil down to (excluding the early ICBMs) Soyuz, Saturn and STS.  Hey, shoot me, but of the three, I'll give the nod to Saturn for safety.

However, lighting off several million pounds of fuel under your butt is never "safe."  It is all somewhat relative after all.

[hop]

Takalok - 29/3/2008  8:10 AM
I think it's reasonable to say that Saturn as a system is safer than STS as a system simply because of the Launch Escape System (LES), which STS doesn't have.  The launch of Soyuz T-10-1 in 1983 is a pretty good demonstration of that.  Constellation is going back to a capsule with a LES like Saturn had for good reason.

From a crew survival point of view, I completely agree. I assumed (perhaps mistakenly) the discussion was about the launcher, not the LV/Spacecraft combination.

[khallow]

hop - 29/3/2008  3:14 PM

Takalok - 29/3/2008  8:10 AM
I think it's reasonable to say that Saturn as a system is safer than STS as a system simply because of the Launch Escape System (LES), which STS doesn't have.  The launch of Soyuz T-10-1 in 1983 is a pretty good demonstration of that.  Constellation is going back to a capsule with a LES like Saturn had for good reason.

From a crew survival point of view, I completely agree. I assumed (perhaps mistakenly) the discussion was about the launcher, not the LV/Spacecraft combination.

Doesn't mean it's safer. The  Shuttle went 122 missions with only one time when the LES might have been useful (during the Challenger disaster). It's possible for the Saturn V to have a much higher launch failure rate and a higher crew loss rate during launch (that is LES improves the odds but not enough) than the Shuttle, despite the presence of the LES. That's just during launch. We also have to consider the safety of the system during the rest of the mission over which the LES isn't used. There's no clean comparison there because most of Apollo missions were high risk missions to the Moon while the Shuttle hasn't done anything nearly that high-risk.

[Patchouli]

The Lox kerosene first stage on the Saturn is in theory safer then an SRB though the RSRM is now well understood now and is safe so long as you follow safety procedures .

Of course all this so called safety is with the 4 segment RSRM and with side mount I feel on Ares I none of the shuttle's past performance can be applied since the booster will experience new forces not seen in it's past service.

The Jupiter 120 for example might actually be safe enough you may never need to use the LAS so long as the same safety procedures as the shuttle are followed.

Yes I know it's a different vehicle but all segmented SRBs have issues with cold even the Titian III and IV did.

On safety Soyuz isn't lot better then the shuttle it too had two LOC events one can actually be blamed on there not being enough room for the crew to ware pressure suits.

Soyuz was completely redesigned after Soyuz 11 and the descent vehicle that flies today has little in common with the old Soyuz 7KT-OK internally.

Challenger falls under a soyuz 11 type failure since the RSRM was redesigned and new safety policies introduced.


Apollo I'd say over all had a worse safety record then the shuttle one LOC in training ,one LOM and one near LOC but only 16 missions.

Though Apollo 1 can be partly blamed on Russian secrecy covering up and early accident with pure O2 and the US space program being unusually lucky dealing with pure O2 at 1 ATM.

If the US knew of the early Russian accident Apollo might not even have flown with a Pure O2 atmosphere.

But the Apollo likely would have survived the challenger type failure because of it's LAS and the fact it rides on top of the launch vehicle.

Also it's LAS was better then what Soyuz had until I think Soyuz TM in that it had a better thrust profile not as high g as an early Soyuz only 10g vs 15 to 20g.

The US just had much more experience with SRBs and it took a while for the Russians to catch up.

Of course these are not capsule specific features just things you get to have because the vehicle rides on top of the stack.

Though the lunar Apollo's were very high risk missions while the shuttle and Soyuz typically didn't perform high risk missions.

Well docking with a space station and staying in it for nearly 24 days was high risk back in 1971.

Also in defense of Soyuz in someways it was a much larger leap from Voskhod then Apollo was from Gemini.

[Patchouli]

8900 - 29/3/2008  12:21 AM

besides, Saturn V can be used to assemble a really huge space station
100 tonnes modules connected together can produce a really big interior space for all research purposes
And then scale up the Apollo (similar to Orion) to accommodate more people(6-7people)

I wonder if a modern Saturn like vehicle well a Saturn in spirit could be cost effective.

Such as using ET tooling to make the first stage and using the RS 84 or TR-107.

It could save on operating costs if the stage is able to fly back for reuse since this doesn't impact payload too much since the first stage needs little thermo protection and any wings can also hold more kerosene.

They actually studied this back in the 60s before the shuttle was set in stone and it didn't impact the payload too badly but the F1 engines were only good for one use.

Not sure if it would be practical to reuse the second stage as TPS and recovery systems for it will eat up about one half to 70% of it's payload or it did in the 1960's study.

Also a 70% scale shuttle type orbiter that rides on top of a Saturn V class rocket likely would be a very safe vehicle.

Just about every failure with the shuttle can be attributed to the side mounting of the orbiter exposing it to debris and making it too difficult to separate it from the rest of the launch vehicle in flight.