Really Couldn't Reach Moon by 1970 with Orbital Re-fueling?

Proponent

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Most, although by no means all, pre-Apollo concepts for manned lunar flights depended on assembly or at least refueling in LEO. It's my understanding that a reason for dropping this approach was that it could not be done in time to satisfy Apollo's before-this-decade-is-out deadline.

Probably the most carefully-researched LEO-assembly proposal was the Army's Project Horizon (http://www.astronautix.com/project/horizon.htm), completed by the von Braun crew shortly before its was transfer to NASA. Horizon envisioned the first moon landings by the mid-60s. Even allowing for the usual over-optimism, it seems at first glance as though Horizon could have satisfied the timetable easily, while requiring neither the Saturn V or the even bigger Nova. Is it really clear that the large-booster architectures (EOR, LOR and direct) were needed to get to the moon quickly? Were there other factors dictating the abandonment of LEO assembly or refueling?
 

DarkLord

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I agree that if Project Horizon had proceeded it would have probably led to a landing and base by 1970. But it became apparent during the Gemini program and in fact during weightless training for Project Mercury, that working in zero G is far harder than originally envisaged. A von Braun/ Colliers expedition would have been impossible! Assembly in orbit could have been accomlished by docking modules but actual hands on assembly would have been difficult. Even today the shuttle crews find small tasks very difficult to accomplish, hence the modular space station.

If they had listened to Wherner, things would be very different now! Instead of sitting on their backsides in LEO for 40 years the US would probably have reached Mars; and the world would have had a Lunar Colony or a least a Base.

I think the projected costs of Horizon frightened the goverment, it would have been cheaper though in the long run. We would not have a rehashed Apollo system that we appear to be heading for. I am sure von Braun would have developed recoverable Saturns if he had been given the go ahead.
 

starviking

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Proponent said:
Most, although by no means all, pre-Apollo concepts for manned lunar flights depended on assembly or at least refueling in LEO. It's my understanding that a reason for dropping this approach was that it could not be done in time to satisfy Apollo's before-this-decade-is-out deadline.

Probably the most carefully-researched LEO-assembly proposal was the Army's Project Horizon (http://www.astronautix.com/project/horizon.htm), completed by the von Braun crew shortly before its was transfer to NASA. Horizon envisioned the first moon landings by the mid-60s. Even allowing for the usual over-optimism, it seems at first glance as though Horizon could have satisfied the timetable easily, while requiring neither the Saturn V or the even bigger Nova. Is it really clear that the large-booster architectures (EOR, LOR and direct) were needed to get to the moon quickly? Were there other factors dictating the abandonment of LEO assembly or refueling?

Well, the final frontier was the great unknown. To be assured of success refuelling would have to be demonstrated to be low risk. That would have entailed refuelling demonstrations in addition to the rendezvous and docking experiments of Gemini. Considering the time schedule, resources, and the unknowns of refuelling - LOR was the way to go.

Refuelling isn't even a part of today's Project Constellation for reasons of propellant boil-off and the necessity of meeting tight launch windows to ensure the Lunar Craft is fully fuelled before atmospheric drag does its job - in the 60's that would have been near-impossible given the resources applied to Project Apollo.

IMHO.
 

Just call me Ray

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maybe I'll put up a more detailed reply later, but orbital refueling has been something I've looked at heavily, both while studying aerospace in college and as part of what I do now professionally. In both cases I've argued heavily for it since we do not simply have the lift capability to launch pre-fueled transit vehicles.
 

Grey Havoc

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Apollo Design Concepts From 1961 - Original Drawings Revealed

Thanks to Ben for sharing these drawings he found in his Grandfather's files. These are drawings from the original proposal by North American Aviation for the Apollo Command Module. These were made in September 1961 before the Apollo program had decided to use Lunar Orbit Rendezvous to reduce mass requirements. As such the designs are built around landing the command module on the moon using a big lander.

Ben has shared the high resolution scans of the designs at https://apollopreliminarydrawings.com/
Source:
Link; https://apollopreliminarydrawings.com/
Feel free to post this link in a much more suitable topic. :)
 

edwest2

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Just a side note: Mars is smaller than earth, has lower gravity and is very cold. Even if the hardware is built and launched, survival will be difficult. Only by tapping into the water about a mile below the surface can humans and plants survive. I just don't think a restock of food and other things is possible with current technology.
 

RanulfC

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Most, although by no means all, pre-Apollo concepts for manned lunar flights depended on assembly or at least refueling in LEO. It's my understanding that a reason for dropping this approach was that it could not be done in time to satisfy Apollo's before-this-decade-is-out deadline.

Probably the most carefully-researched LEO-assembly proposal was the Army's Project Horizon (http://www.astronautix.com/project/horizon.htm), completed by the von Braun crew shortly before its was transfer to NASA. Horizon envisioned the first moon landings by the mid-60s. Even allowing for the usual over-optimism, it seems at first glance as though Horizon could have satisfied the timetable easily, while requiring neither the Saturn V or the even bigger Nova. Is it really clear that the large-booster architectures (EOR, LOR and direct) were needed to get to the moon quickly? Were there other factors dictating the abandonment of LEO assembly or refueling?

As noted there were a LOT of assumptions made for how working in space would go and most were in fact wrong. Now on top of that we've never had a space suit designed for actually 'working' for long periods of time either in space or no a surface and that needs to change before we can really open up space.

Further, (and because of really those 'assumptions' and their relationship with reality :) ) Project Horizon was pretty damn optimistic and likely VASTLY low-balled both in time and budget. One of the main reasons that EOR (Earth Orbital Rendezvous and assumed assembly and/or refueling) was rejected even though Von Braun and the majority of Marshell engineers preferred the method was simply because they understood it would take longer than LOR. Had there been continuting issues with the Saturn V then EOR would likely have been required to actually do the mission but more than likely it would have been automated docking of Saturn 1B launched, fully fueled parts rather than something like Project Horizion.

I'd always wondered why the Soviet's didn't follow up Apollo with such an architecture but it's clear now, (in hindsight) that the technical and PR risk was simply too high to consider without more years of development.

Randy
 

Archibald

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Dry docking (no prop tranfer) of a pack of Centaurs or slightly larger stages - how hard would it have been ?
 

RanulfC

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Dry docking (no prop tranfer) of a pack of Centaurs or slightly larger stages - how hard would it have been ?

Docking might not be so hard, (but keep in mind the US specifically avoided such in favor of 'controlled' or man-flown docking whenever possible) but the modifications and hardware to do things like keep the HydroLox propellant liquid and keep the various stages in proximity before docking was a bit harder. And due to the way the US was going, (avoiding EVA and on-orbit work due to the inadequate space suits and/or manuever and manipulation capability) there's going to be a lot of push-back over putting stages together in orbit simply because of the higher risk of accident or trouble.

Randy
 

Archibald

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It is interesting to review the S-IVB basic numbers, after all it was Apollo TLI stage. Wikipedia has these numbers on their S-IVB page. What is mind boggling is the mass of LOX compared to LH2. 87 mt over 115 mt of S-IVB was LOX alone. So maybe launch the stage empty on a Saturn IB, then fill it with LOX. Then launch the piloted lunar stack, dock it. Only when everything is ready for TLI, launch the tiny amount of LH2 needed and dock that to the moonship - so that LH2 has no time to boil itself away. Taming LOX boiloff (and perhaps transfer) should be possible with 60's technology, but LH2 would be a real PITA. So leave it alone.
 

DWG

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Just a side note: Mars is smaller than earth, has lower gravity and is very cold. Even if the hardware is built and launched, survival will be difficult. Only by tapping into the water about a mile below the surface can humans and plants survive. I just don't think a restock of food and other things is possible with current technology.

Water is much more accessible than the deep subsurface, the North Polar Cap is 1.5 times the size of Texas and up to 600m thick, while the upper metre of soil above 60 degrees is believed to be around 25% water ice. Phoenix confirmed surface ice in 2008. The South Polar cap has even more water, but capped by CO2.
 

Grey Havoc

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Also, a supply cycler, automated or otherwise, between Earth and Mars should be easily within available resources, even given the current overall trend of scientific and technological backsliding.
 

edwest2

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I think the problem associated with astronaut radiation exposure has not been addressed. At least I've seen no possible solutions. The other issue is gravity. All active time will have to involve weights being worn to counteract the low gravity and prevent muscle atrophy. Water ice being available at the poles does not help unless some means of transport is put in place. NASA is making plans but as in 2010, I am not optimistic regarding manned missions.

 

Michel Van

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There were allot NASA study before Apollo LOR about orbital refueling

Most of them figure out that LOX tankers had to be launch first follow by Apollo spaceship and departure stage with LH2 tank and empty Lox tank
but the Concept had some issue

launching multiple tanker in rapid succession from Cape there the tankers gathering until LH2 and Spaceship is launch
once the arrive at destination the tankers have to dock fast and pump there oxidizer into departure stage then dock the Apollo on it and then Translunar injection

interresting is that Soviet had that in mind for early Soyuz moon landing, but using kerosine and Lox as Propellants
That concept used several N1 with Tankers and one departure stage with lander and follow with Soyuz on R7 rocket
21k_info_1.jpg

Artwork Anatoly Zak
19k_components_1.jpg

Artwork Anatoly Zak
although the landing that Soyuz and lander
19k_lunar_surface_cosmonauts_1.jpg

Artwork Anatoly Zak

Source
 

DWG

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I think the problem associated with astronaut radiation exposure has not been addressed. At least I've seen no possible solutions. The other issue is gravity. All active time will have to involve weights being worn to counteract the low gravity and prevent muscle atrophy. Water ice being available at the poles does not help unless some means of transport is put in place.

Radiation exposure is probably a valid concern, but mostly during flight, and there's a whole bunch of things that can be done, such as water-jacketing the crew areas. Once you're on the ground you can dig in and relegate unnecessary external work to robotics.

At 0.4G Mars gravity is notably less than Earth's, but notably greater than on the ISS, so unlikely to be a showstopper.

WRT water, you go where the water is, you don't transport it, and we know there's significant water in the Martian soil to a considerable distance beyond the poles. A nice equatorial icefield would be simplest, but you can land anywhere the soil contains a significant percentage of water and process it out.
 

edwest2

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I think the problem associated with astronaut radiation exposure has not been addressed. At least I've seen no possible solutions. The other issue is gravity. All active time will have to involve weights being worn to counteract the low gravity and prevent muscle atrophy. Water ice being available at the poles does not help unless some means of transport is put in place.

Radiation exposure is probably a valid concern, but mostly during flight, and there's a whole bunch of things that can be done, such as water-jacketing the crew areas. Once you're on the ground you can dig in and relegate unnecessary external work to robotics.

At 0.4G Mars gravity is notably less than Earth's, but notably greater than on the ISS, so unlikely to be a showstopper.

WRT water, you go where the water is, you don't transport it, and we know there's significant water in the Martian soil to a considerable distance beyond the poles. A nice equatorial icefield would be simplest, but you can land anywhere the soil contains a significant percentage of water and process it out.



Thank you for your reply. The water would have to be tested for bacteria and viruses, plus any chemicals. It will likely need to be filtered. Water ice will have to be heated.

As far as radiation shielding, water is not a good idea.

On the way to Mars.


While on Mars.

 
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RanulfC

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It is interesting to review the S-IVB basic numbers, after all it was Apollo TLI stage. Wikipedia has these numbers on their S-IVB page. What is mind boggling is the mass of LOX compared to LH2. 87 mt over 115 mt of S-IVB was LOX alone. So maybe launch the stage empty on a Saturn IB, then fill it with LOX. Then launch the piloted lunar stack, dock it. Only when everything is ready for TLI, launch the tiny amount of LH2 needed and dock that to the moonship - so that LH2 has no time to boil itself away. Taming LOX boiloff (and perhaps transfer) should be possible with 60's technology, but LH2 would be a real PITA. So leave it alone.

From the stuff I've read, (and while the histories talk about various "other" means to get to the Moon I'm not noting a lot of details in most of the on-line stuff) it really depended on what propellants were planned to be used. For sure the LH2 was a driver for anything where it was used. LOX wasn't seen as that much of an issue though there were some good questions on transfering on-orbit and in microgravity it wasn't seen as a major issue. Hypergols were 'easier' as was stuff like kerosene and peroxide.

But once LH2 was flying it didn't make a lot of sense to look at anything 'less' in performance and transfering LH2 was never going to be 'easy' in any sense. (Short of moving tanks full of the stuff around which was a slightly different concept) So the main ideas centered around "super-insulated" versions of the S-IVB and SII (called the S-IIB) as storage and/or tanker stages:
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So by the late 60s they were confident enough to assume that LH2 and LOX transfer could be done. Late 50s and early 60s not so much.

I'm sure you recall the number of 'dry-docking' Centaur concepts there were for the Lunar Gemini proposals :)

Randy
 

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