Venusian Space Program

[RanulfC]

Jared wrote:

I haven't firmly settled on which Saturn-II variant gets adopted, but my first thought was some construction of the INT-18 version with 2 solid boosters that gets ~40 tonnes to LEO. This is very much designed as a workhorse version, with 12+ launches per year, so the SRBs at least will probably be made to be reused; the core of the rocket, not so much.

And

ITTL, I had the Soviets abandon the UR-700 in 1972, but work out a kerlox replacement by 1981. That seems to fit the general timeframe outlined above. What they've come up with isn't the Energia of OTL, of course, but a sort of hybrid cross between the hypergolic UR-700 reworked for Kerlox, and the descendants of the planned N-1. But I figure a name like Energia is still likely, and the lift capacity is in approximately the same range (about 100 tonnes), so for the purposes of trying to plan TTL, a convenient shorthand for is "this is Energia 6 years early".

And previously:

It's also important to keep a manned presence in orbit (mostly low-earth orbit).

So there's a conundrum. The Saturn V is ghastly expensive, but any space shuttle or equivalent reusable, 1-stage, 1.5 stage or 2-stage to orbit, or air breather, is still at least 1980 before it's useable - and that's if everything goes right. There needs to be a heavy, or at least medium-heavy lift vehicle to use in the meantime. A manned orbital mission may be built in a modular fashion - and quite possibly using NERVA in orbit - but it will need something. So, from the US point of view, either an Saturn 1+ or a Saturn V-, or maybe a souped up Titan III.5 or IV, or a wild-card Delta Clipper if that will be faster than the shuttle-analogue.

So the U.S. space program will start to diverge wildly, but in one way or another they're trying to get the manned orbital mission to Venus ASAP, with the possibility of a manned landing speculated about but still tantalizingly out of reach.

The Soviets will have their own problems (and some successes), but it's harder to gauge what that will look like.

In general, Earth-to-Orbit space launch is going to drive a lot of things and provide factors on what everyone can and can't do. I'm not sure it can be finagled at this point but rather than "abandoning" the UR-700 the Soviets would 'transition' the design to kerolox boosters and then the core vehicle to possibly hydrolox propulsion. Overall that's more than enough to get 'renamed' as "Energia" (though to be "technical" here that design was actually called "Vulkan 1" {http://www.astronautix.com/v/vulkan1.html} as it was 'in-line' rather than side-mount) and within the abilities of the USSR to come to by the mid-70s early 80s. They'd try to incorporate recovery in the boosters early on as was planned for OTL "Energia" but the problem is they are going to quickly run into funding problems and require another solution despite the loss of payload. The American's with the "Saturn-II" despite having a little less than half the payload-to-orbit of the UR-700/"Energia" are actually going to be able to aim for cheaper access. Unless the USSR want's to really push some buttons and throw public/world PR in the trash and use the 'nuclear' option (http://www.russianspaceweb.com/ur700a.html) they are going to have to come up with a more economical LV pretty quickly (If it wasn't already too late I'd suggest that Yangel had gotten a green light on organizing and running the Soviet space effort shortly after the 'minor' POD of 1962. His R56 was actually a more logical and less over-the-top concept than the UR-700 which would quickly bankrupt the Soviets in operation even if it works right)

Under the circumstances, I'd see the "Energia" version being somewhere between 20 to 80 tonnes payload but it's still going to be terribly expensive and they'll need alternatives. I'll also point out there were 'lighter' variaents of the OTL "Energia" such as the "Energia-M" (http://www.astronautix.com/e/energiam.html) which given TTL's more modular nature might be the more logical way to proceed. Only using the "full" "Energia" for specific missions and using the smaller, more economical designs more often.

As I noted earlier the Saturn SII stage can be made recoverable with some effort along with the SRBs at the S-IVB can be made 'cheaper' and improved J2S and then T (toroidal) engines which is going to preclude reusability but will allow a 'mass production' type savings. This gives the US a little over half the Soviet up-mass but the ability to launch more often at an overall less cost. If they decide to go with the "Clipper" program the S-IVB gives them a good basis for starting the program and if they can accept a significant payload loss early on they can use it as a replacement 'upper-stage' for the Saturn-II for full reusability. (Off-the-cuff figures are something like 20 tonnes for the Saturn-II version and maybe somewhere around a third of that if it can actually do SSTO)

Similarly if the US feels a 'need' to keep-up with the Soviets they have an option which while expensive will probably be less so than the UR-700/"Energia" and keep some semblance of the Apollo Saturn-V going on life support as it were. The proposed Saturn S-1D 1.5 stage design and variants, (http://www.astronautix.com/s/saturnv-c.html, http://www.astronautix.com/s/saturnv-b.html) would allow occasional payload launches from 50 to over 100 tonnes if SRBs are used. Expensive, but the US can afford it occasionally. Especially if the Saturn-II designs use the 'milk-stool' launch and the majority of the Saturn-V infrastructure is retained.

In both cases I suspect both sides will look towards reusable 'upper-stages' or return vehicles for orbital use as soon as they get booster recovery down pat. One thing to keep in mind is that once you have thrown off the "Shuttle" shackles and not forced a certain set of assumptions on the design there were in fact numerous variants that COULD have been used that have been advance over time.

Take for example the McDonnell-Douglas TAV study: http://pmview.com/spaceodysseytwo/spacelvs/sld057.htm
While it says 1984 in reality this is based on earlier studies of the FDL5 lifting body that dated as far back as 1968 and the "Integral Launch & Reentry Vehicle" (ILRV) studies (http://pmview.com/spaceodysseytwo/spacelvs/sld018.htm) The main difference, (as you may note) is that the earlier study focused on something closer to OTL Shuttle in the use of expendable tanks and fully recoverable Orbiter which would have large issues due to how bad hydrolox is as a booster propellant whereas the later study avoided this by using a more 'conventional' TSTO design. MD had gone as far as fabricating prototype hull and reentry system test modules from titanium but NASA was reluctant due to the requirement of an active, (transpiration cooling) TPS system and the need for deployable wings to reduce the landing speed to a reasonable level.

Note the booster on this one; It was developed from Bono's concepts as a boost-back, VTVL vehicle capable of being used to loft other payloads other than an "orbiter" (which is always nice) and (hoped for) eventually being upgraded to a possible SSTO configuration. This is pretty much what you want for a Venus lander btw, short, squat and capable of landing in any open space preferably

Changing the standard J-2 engines to J-2S' is a start following up with either the J-2T (toroidal) in 200K to 250K versions and later upgrading to something like the high-pressure HG-3 315K to 350K thrust engines as they continue to refine the plug nozzle program for both launch and recovery. I went over this a bit on the 'issues' with an LH2 lifting body but you have issues with the shorter, squatter booster/SSTO concepts as well due to the same problems with shaping the LH2 tank which is why most designs use a spherical LH2 tank and toroid or multiple sphere LOX tanks to compensate for the required shaping. The other 'downside' of such short, squat, conical designs is you have major issues adding 'booster' capability, (such as attaching SRBs) if you really need to since their line of thrust is now canted and if they are jettisoned before they burn-out for any reason they WILL run into the vehicle with predicable results. Conversely adding drop/external tanks is not as hard but getting them to jettison when nearly full is problematical without explosive or very high power pushers. Not insolvable but a definite engineering challenge.

Many of these overall 'issues' are addressed in the cited paper above on the Gomersall SSTO/High Performance Booster, (https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680025115.pdf, https://ntrs.nasa.gov/search.jsp?R=19680025115) which does address booster augmentation as well as upper stages design and use but for a vehicle designed to deliver a million pounds of payload to Earth orbit per flight. Given the right 'incentive' the booster at least might have replaced the S-1C/S-II if anyone had been willing to build the SRBs and upper stages as suggested.

Couple of things to note in the cited paper, (as I'm not having luck finding the actual reports themselves which may have different information take this with a grain of salt) one thing people seem to miss with Gomersall's concept is it is specifically an EXPENDABLE SSTO design NOT a reusable one and specifically reusability would significantly cut into the vehicle margins. On the other hand it can be scaled as I noted to something based on the S-II and while very far short of a 'million' lbs to LEO it would have a respectable payload and CAN lead to a recoverable/reusable booster design. (Arguably the Saturn-INT and Saturn-II designs were headed in this direction anyway and an expanded space program pretty much requires this to be workable) The main 'problem' with recovering a cylindrical shape is entry heating loads as they will impinge the sides of the vehicle enough to require some SERIOUS TPS on par with the main TPS system. This will mass a lot and as always cut into your payload though the booster ratio is actually better than that of the upper stage by a lot. As with all designs based on the concept of "performance is more important than cost" the former will always be indicative that the latter will be a LOT higher no matter the 'fig-leaf' of "cost-reduction" applied in operation

Going back to the MD TAV design cited above, if you look at the Booster I'll point out it resembles a design I BOTE'ed for a version of the F9 where height was an issue. (Yes I know width is determined by the ability to get the stage from the point of manufacture to the point of use so railway, road and canal width is the defining issue for width whereas height is determined by the maximum height of underpass', bridges and other infrastructure, I was assuming direct shipment by barge at sea to a port, or on-site manufacture actually and wasn't bothered by any such restrictions, sue me. I'm probably lucky SpaceX didn't, as I noted that a 'better' version could be built using H2O2/Kerosene and only three (3) BA-810 rocket engines and it would probably be cheaper all around ) While land recovery is nice you can actually avoid having to use landing gear if you land in the water and both kerolox and keroxide motors have proven to be very effective at ignoring water/salt-water issues versus more 'high-powered' engines. The biggest 'sticking' point is everyone has "assumed" for decades that any 'highly reusable' rocket engine has to use LH2 or Methane to avoid 'coking' issues as a refurbishment complication. Strangely enough even SpaceX has subscribed to this belief despite pretty much proving the exact opposite with the Merlin engine from the start.

So anyway to get an idea of a high-use, medium-to-low mass LV take the MD TAV "booster" and put a Millennium Express of DC-X like upper stage on it and there you have it. The 'problem' OTL was convincing the people 'in-charge' that VTVL was not only possible but could be practical as they had been convinced that the only 'safe' way was to rely on lift and a runway landing since we "knew" that airplanes were both. A habitable Venus will probably provide some extra incentive but your main point is you'd still need a medium-to-heavy LV as well and the main interest would be turning THAT into a fully reusable vehicle first which makes your initial booster that much bigger AND probably starting off as per the Saturn-II designs being an SRB boosted, LH2 main stage type vehicle which will resist changing due to sunk costs and special interests.

Still this actually leave an opening for "Musk/Beal/Whomever" to aim at the "market" that most of the mainstream companies and agencies are overlooking.

Randy

 

[Dathi THorfinnsson]

It seems to me that the only conceivable option to orbit is SSTO (at least once you've got the project well underway).

The limiting factor is Venus.
If you have multistage craft on Venus, you have to lift the heavy first stage out of Earth's gravity well (hard), then get it to Venus (relatively easy), then get it landed ON Venus (which requires special landing provisions).

If the Venerian launcher uses any expendable stages, they ALL have to be carried into Earth orbit, and then landed on Venus before they can be used. This would be hellaciously expensive for more than a couple of expeditions.

You really need an SSTO with in situ fuel generation. And if you've got an SSTO for Venus, you (essentially) have one for Earth.

----
I'm surprised no one has mentioned SM Stirling's 'Lords of Creation' duology, 'The Sky People' and 'In the Courts of the Crimson Kings'.
Of course, those have, not only life bearing worlds, but humans there.

 

[1965 Timelord]

Project Nova, almost-ran Apollo launcher alternative, comparison table of Saturn V and Nova configurations & http://www.astronautix.com/n/nova.html. This version seen to be more suitable for Venusian manned mission because it's looks much bigger than the Saturn V but not to the other proposed Saturn models. If the ASB earth habitable Venus appeared in the 1940s, would you think the Nova launcher would have chosen instead over Saturn(more Lunar than large planetary/Martian) if Venus is more prestigious propaganda space goal than the moon?

 

[Shevek23]

Project Nova, almost-ran Apollo launcher alternative, comparison table of Saturn V and Nova configurations & http://www.astronautix.com/n/nova.html. This version seen to be more suitable for Venusian manned mission because it's looks much bigger than the Saturn V but not to the other proposed Saturn models. If the ASB earth habitable Venus appeared in the 1940s, would you think the Nova launcher would have chosen instead over Saturn(more Lunar than large planetary/Martian) if Venus is more prestigious propaganda space goal than the moon?

It's just incremental though; even the biggest Nova on that table is "only" twice the capability of a Saturn V, 90 tons to escape (same ballpark as TLI or TVI) versus 45+ for Saturn V as ultimately developed. Many Nova iterations, including that double-sized biggest ones, required development of a third rocket engine beyond the essential F and J engines, including some nuclear options. The M type engine might have been an asset and attainable, perhaps--it was IIRC a gigantic hydrogen engine in a similar thrust class to the F ker-lox engine family. Presumably it too would have suffered combustion instabilities that would put a shadow of risk on the whole program; as things were the J-2 engines were working pretty well long before the F proved out. The fundamental common difference between "Saturn" and "Nova" was the number of F-1 engines to be used by the first stage, and that means going with Nova meant a near doubling of thrust at liftoff--which means yet more heroic efforts at containing the various kinds of blasts including sheer sonic noise.

Surely it would be doable, though perhaps raising the risk of failure due to multiplying the number of engines involved in a launch might lead to spectacular failures the OTL Saturn program avoided. And any major failures would be a spectacle indeed!

If we want a wildcat mission sending some human explorers on a one-way trip to Venus with any prospect of return something that would happen years or decades later, Saturn V is good enough to send over 40 tons there. Doubling that to 80 or so would probably be desirable of course. Either is good enough for a flyby mission also, again the largest Nova's greater size would be an asset--but not essential!

For a mission wherein human explorers pull a big enough ship to return to Earth into Venus orbit, and land with the ability to return to orbit within days, weeks, or months, we need at least an order of magnitude more mass. 10 Saturn V launches, 5 Novas--I'm just wildly guessing but you do the math if you think that's not an optimistic underestimate! Using nuclear thermal rockets can help but the order of magnitude remains much higher than 100 tons, clearly.

In the 1960s, optimistic designers were presenting designs for "a million pounds to orbit," which is about 440 tons, or 4 Saturn V--or two of the biggest Novas. I don't think 440 tons in LEO is big enough to enable a round trip Venus mission. One way or another, by means of multiple separate launches of equipment to land separately on Venus or orbit it, or assembling a great big ship or two similar to von Braun's latest proposal for a Mars mission, a mission to Venus that enables astronauts to land and then return to Earth would require at least a dozen, maybe many dozens, of launches of the biggest designs seriously proposed.

The only alternatives to Venus programs that amount to hundreds of Saturn V class launches becoming routine would be to develop something radical like Orion as a launch vehicle--an option I think I am a moderate on, for I neither dismiss it as impossible or far too polluting to contemplate, nor take the gung-ho position it was a sure thing and the pollution with fallout is either not a problem at all or not one worthy of worrying about. Or, my preferred approach, develop a non-rocket (mostly anyway) launch system such as a Loftstrom Loop, which ought to be favored in an ATL where some second habitable world orbits the Sun.

So, honestly, whether Nova gets the nod over Saturn is a coin flip; as OTL, it is a tradeoff between capability and risk. Saturn V is halfway to the most extreme Nova anyway.

 

[RanulfC]

Dathi THorfinnsson wrote:
{quote] It seems to me that the only conceivable option to orbit is SSTO (at least once you've got the project well underway).[/quote]

Mostly yes, but it's going to be almost as hard to do with a usable payload as on Earth which pretty much means you have to figure out how to do it there first

Significantly though, an expendable-SSTO is a very good possibility though a 1.5 is more likely. As I noted in my 'proposal' and response getting a TSTO is going to be a real bear.

The limiting factor is Venus.
If you have multistage craft on Venus, you have to lift the heavy first stage out of Earth's gravity well (hard), then get it to Venus (relatively easy), then get it landed ON Venus (which requires special landing provisions).

Yes, and no really. Depends a lot on how you do it, (which I'm still playing with for a second proposal, probably third actually as current number two is bit of a doozy and shout-out to a classic SciFi movie ) but keep in mind that there are different types of 'staging' possible. A good example is a "two-stage" return vehicle landed without propellant which would be pretty light. Another is a 'multi-stage' vehicle which stages the tanks rather than what we consider as normal "stages" during ascent. Most of these would require ISRU propellant production but you can also land multiple propellant storage/tankers and use light weight collapsible tanks.

Any lander/ascent vehicle can use part of its propellant load to help with the landing and if you can fill the tanks on Venus then so much the better.

If the Venerian launcher uses any expendable stages, they ALL have to be carried into Earth orbit, and then landed on Venus before they can be used. This would be hellaciously expensive for more than a couple of expeditions.

Well, yes but you work with what you have and it will really depend on there being a significant economic case for the exploitation of Venus in the long run. You can do something like an "Antarctic" science base using expandable parts if you make the expendable parts cheap and easy to make. Getting them 'down' on TTL Venus is actually easier and cheaper than OTL Mars. Once you have some sort of surface infrastructure you begin to have more ways to access the surface and space.

You really need an SSTO with in situ fuel generation. And if you've got an SSTO for Venus, you (essentially) have one for Earth.

Pretty much what I said above but you do NOT in fact NEED SSTO for early return to space and once you have any surface infrastructure and support, (including ISRU) your options open up a bit. Collapsible or un-assembled 'drop-tanks' can be landed cheaply and be assembled and filled on-site. Depending on the design they could be attached to a core vehicle with hand or low-powered systems and supported by a man-portable ground support system.

I'd fully expect there to be more than just SSTO vehicle in TTL due to the need for larger payloads than a reasonable SSTO can handle. They will probably be regulated to passenger and light cargo duty with fully reusable TSTOs for most payload/cargo use on Earth and Venus as soon as applicable.

I'm surprised no one has mentioned SM Stirling's 'Lords of Creation' duology, 'The Sky People' and 'In the Courts of the Crimson Kings'.
Of course, those have, not only life bearing worlds, but humans there.

Actually I'd thought it was brought up, might be in the main thread though. Mostly about comparisons as THE reason this isn't ASB is this Venus has an obvious and clearly differently evolved biosphere

1965 Timelord wrote:

Project Nova, almost-ran Apollo launcher alternative, comparison table of Saturn V and Nova configurations & http://www.astronautix.com/n/nova.html. This version seen to be more suitable for Venusian manned mission because it's looks much bigger than the Saturn V but not to the other proposed Saturn models. If the ASB earth habitable Venus appeared in the 1940s, would you think the Nova launcher would have chosen instead over Saturn(more Lunar than large planetary/Martian) if Venus is more prestigious propaganda space goal than the moon?

Much as Shevek23 says though I tend to call this the "Waste-anything-but-Time" fallacy, (or more currently the "We have a Saturn-V so we need to justify a Saturn-V/SLS" fallacy ) in which you end up 'requiring' large launch vehicle because you specify large payloads because you have large launch vehicles so bigger is always better.

Truth is what you need for an actual exploration and exploitation scenario is ECONOMIC transportation which will determine the best amount of payload per flight and that pretty much requires a high flight rate and reusable vehicles. It also means you try and separate the various aspects of the voyage instead of trying to "do" everything with a single launch.

This doesn't mean you don't have Saturn-V size payloads as you obviously do, and here I differ from Shevek23, but they are few and far between while the majority of flights are smaller more economical vehicles flying much more often. You MIGHT need "1 million tons a year on-orbit" but you will get them there in smaller increments over multiple launches NOT one launch a year

Significantly different from OTL our post-Apollo planning will require us to establish and maintain a space station and some on-orbit infrastructure from the start since we will have to build a dedicated orbit-to-orbit ship to transport crews to Venus on anything like an affordable basis. We can't afford to throw away massive portions of our spaceship every flight so we'll have to have a way to support and 'turn' such a ship after every flight.

It seems to a lot of people that most of the post-Apollo interplanetary planning seemed excessively wasteful what with throwing away partially used NERVA rockets after every 'burn' but that wasn't the actual reason for doing so. The primary reason was once they have run they are highly radioactive and to approach them from anywhere but a narrow aspect covered the shadow and reactor shield is fatal so you want to keep 'used' reactors away from LEO and populated areas. Since part of the post-Apollo planning was HAVING LEO infrastructure and people you wanted to avoid bringing those "hot" reactors back, or at least back into LEO as HEO or a Lunar orbit is safer.
http://www.projectrho.com/public_html/rocket/atomicfuel.php
http://www.projectrho.com/public_html/rocket/realdesigns.php#austin

Of course we actually worked a lot of the needed operations even before we got to the moon;
(see "Basic Solid Core NTR entries: http://www.projectrho.com/public_html/rocket/realdesigns.php)

You need to park the ship in a spot where it can be accessed and serviced and the reactor removed and replaced when needed and that's probably NOT going to be in LEO so you will need not only regular access to LEO, but also a place for transfer of supplies and buildup of materials between flights and to support other space operations. From there you will require a system to move all this outward on a regular basis, (and someday hopefully inward) all of which is going to be done more efficiently and economically with dedicated transportation on regular basis. Not occasional large shipments directly to and from the destination.

Instead of "100 tonnes" per launch once or twice a year you want dozens of 10-to40-tonne launches a year. And that first step of surface to orbit is going to be the most expensive and hardest for the longest time and the one that needs to be addressed at the earliest possible time. Unlike OTL NASA, the US and Russia all have an opportunity to avoid OTL mistakes on following certain assumptions

(Yes I'm pointing out to Jared that the Soviets are going to need to seriously re-think that monster rocket he's planning

Randy

 

[Shevek23]

Um, since the monstrous 440 tonne "million pound" launchers were also supposed to be reusable, or at least largely so, the intent was not to launch a million pounds once a year. No, they were thinking they'd go full on 2001: A Space Odyssey, and have Moon bases with populations of hundreds and a whole series of big space stations and possibly loads of orbital WMD, and missions to Mars on von Braun scales, and so on. They'd be launching the million pound launchers many many times a year! Try keeping up with that with a 40 ton limit per launch!

But of course the point is OTL, there was never any budget even for 200 tons a year, just a couple small space stations, no return to moon, no deep space expeditions. Obvious in these conditions, even aiming for a 40 ton single launch capability is aiming much too high!

The question here is, with the lure of a habitable Venus out there, will we invest far more? Because if we insist on staying within OTL budgets obviously we'll be moving pretty slowly, even if we are smarter about what we buy with those budgets. Will funding authorities have patience with a Venus expedition ship that takes 15 years to assemble in orbit? Heck, by the time it is finished per design the components will be half a generation out of date--a human generation, don't ask me about microchip generations. A dozen or so of those I guess.

Even if a Venus ship is sold to Congress at the price of taking a decade to build it, I bet somewhere in that decade someone gets impatient and gets Congress to pony up the money to accelerate the construction and go for an earlier launch window. Or alternatively they shut it down half-built. Maybe when it was sold to Congress before, they had to emphasize that it could be mothballed and moved to a higher parking orbit if need be, and some budget cutter session mandates that be done, "we'll get around to finishing it later."

 

[Anarch King of Dipsodes]

In the ASB subforum, I've recently started a timeline (thread here) about a potentially habitable Venus. Setting aside the ASB aspects - which are outside the scope of the post-1900 subforum - I'm interested in people's thoughts about how the space race would have turned out if there was a realistic option of sending a manned mission to Venus.

It seems to me that while getting a manned mission to Venus may be a problem (though it's much closer than Mars) ...

Not really much closer. Any mission to Mars or Venus will involve a long tangent orbit, with duration mainly dependent on the relative positions of the planets on their orbits. Mariner 2, the first Venus mission, took 109 days. Mariner 4, the first Mars mission took 228 days. Mariner 5, to Venus, 160 days. Mariner 6, to Mars, 156 days. Mariner 7, to Mars, 131 days. Mariner 9, to Mars, 168 days. Mariner 5, to Venus en route to Mercury, 94 days. Pioneer 12, to Venus, 198 days. Pioneer 13, to Venus, 123 days. Viking 1, to Mars, 304 days.
Viking 2, to Mars, 333 days.

In general, the Venus probes had shorter voyages, but the really big difference is between fly-bys and landing/orbiting probes. The latter need to arrive with minimum relative velocity, which means a longer, slower voyage.

 

[Michel Van]

A remark from me on some Discussion topic

Venus is easier to reach as Mars,
do Mars complex orbit, you can only launch every 779.421 days a probe to Mars and if it Heavy it need more time to get there !
for Venus you have every 583.92 days and launch window with around 107 to 142 days transit.

Venus Gravity is only 90% of Earth, so a SSTO would work better as on Earth.
also a mulit stage rocket would be smaller as Earth version

On Launch Vehicle, try the General Dynamics proposed Saturn V-Reusable model
It would be perfect, reusable first stage, allow launching large payload and using already build Saturn V hardware and infrastructure.

 

[robertsconley]

Just to be clear my SSTO proposal is focus solely on Phase I of getting people down and back. It also an engineering proposal in that it is about flying test vehicles until we get a design to work. Not developing new technology. It meant to work with zero support on the surface of Venus. It also designed to throw as little of the vehicle away as possible. The only thing that thrown away is the deorbit motor even there a mini tug could be develop that would de-orbit the lander and immediately boost itself back into higher orbit.

Once the Clipper gets people down and back for two, or three expeditions, enough should be known about surface conditions to pick a place for a base. There the focus will be to use the clipper to get people down and up until the base is good enough shape to use something reusable that has multiple stages so more people and mass can go up and down.

The follow up for clipper would be to look at spaceplanes and reusable multi-stage rockets like the falcon. Maybe adapting the Clipper as a second stage to a a first that does a return to base. The mission profile with a operational base would look like this.

The Clipper deorbit via Venus Orbit Tug
Venus Orbit Tag boost back into orbit.
The Clipper re-enters the atmosphere.
The Clipper performs a powered landing for precision.
The crew disembarks and the cargo is unloaded.
The Clipper is mated with the flyback booster.
The Clipper and booster are refueled using the base's fuel processor.
Crew and passengers board. Cargo is loaded.
The Clipper+booster is launched.
Staging occurs and the Clipper continues to orbit.
The booster does a powered landing back at the bade.
The Clipper returns to orbit and docks with the station orbiting Venus.

I would call the booster the Eagle.
I would also try to see if I can make the Eagle as a SSTO and launch it back to orbit with nothing but fuel. That way a Venus Expedition can generate all the fuel it need local resources.
Also have an emergency package to allow people to strap themselves on top of the Eagle and use it as an alternate form method of returning to orbit.

 

[RanulfC]

Um, since the monstrous 440 tonne "million pound" launchers were also supposed to be reusable, or at least largely so, the intent was not to launch a million pounds once a year.

Actually the 'intended' flight rate was to be that but projected to be less than that under anything but the most optimistic scenario. It was the same problem with the Sea Dragon really, it required a much larger space based operation than was realistic let alone feasible. And they all were "reusable" for a certain value of the word, but depended on a high flight rate per year which wasn't going to happen.

No, they were thinking they'd go full on 2001: A Space Odyssey, and have Moon bases with populations of hundreds and a whole series of big space stations and possibly loads of orbital WMD, and missions to Mars on von Braun scales, and so on. They'd be launching the million pound launchers many, many times a year! Try keeping up with that with a 40 ton limit per launch!

No they actually were not thinking that, which is the reason the Super-NOVA's never went further than paper studies and why work moved to smaller more economical 'workhorse' vehicles. The simple fact is that putting up monolithic payloads of that size really are NOT sustainable or economical on a regular basis until AFTER you have a huge on-orbit transportation and infrastructure in place. They DID foresee multiple launches per year, someday, maybe. And in fact NASA later went back to those same companies with a possible use for such capability: SPS

However, as we should all know by now it became quickly clear that launching the materials to build and support SPS from Earth was never going to be economical even at the high flight rates envisioned. And that was squarely the 'problem' with the big launch vehicles; They are unable to economically carry LESS than their fully capacity and require to do so frequently which means that they can only be used when such payloads are already in demand on a regular basis. And in no transportation system has that happened at the start but only once it is well established with a set network and market.

In the end they found that at best an early market, space infrastructure and interplanetary transportation system would require a couple Saturn-V/Improved Saturn-V/N1 class launches per year, while a smaller, more economical and flexible launch system would be used for the majority of the workload for decades to come. Early "Shuttle" studies specifically looked at ways to use both a dedicated orbiter and an expendable 'high-payload' stage for that very reason.

While there was a lot of support for large monolithic space stations, it gradually changed to modular stations not just because they were adjusting to loss of the Saturn-V OTL but because it was quickly realized that the monolithic stations have very limited lives and are hard to maintain/modify to extend it. And since you need a smaller vehicle to service and maintain such a station...

Under the given scenario there is an obvious and compelling reason to keep the Saturn-V in some capacity because you WILL need occasional heavy lift capability but it will have to be modified to become more economical even at a the lower flight rate, (but higher than OTL actually ) and streamlined operations. It could also be a basis for the lower-payload, higher flight rate workhorse vehicle with a fly-back S-1C. But there's very little reason to expect a new larger launch vehicle as "Advanced" Saturn's could be configured to carry varying loads more efficiently.

But of course the point is OTL, there was never any budget even for 200 tons a year, just a couple small space stations, no return to moon, no deep space expeditions. Obvious in these conditions, even aiming for a 40 ton single launch capability is aiming much too high!

Thing was there actually WAS the budget for keeping some, or most of the Apollo hardware though it would have been close and getting to the more 'economical' model of operation would have taken some serious work. It was more the political environment which drove the "need" for a new agency consuming "mission" on par with Apollo, that and the fact NASA really didn't/doesn't know how to operate any other way.

But...

The question here is, with the lure of a habitable Venus out there, will we invest far more? Because if we insist on staying within OTL budgets obviously we'll be moving pretty slowly, even if we are smarter about what we buy with those budgets. Will funding authorities have patience with a Venus expedition ship that takes 15 years to assemble in orbit? Heck, by the time it is finished per design the components will be half a generation out of date--a human generation, don't ask me about microchip generations. A dozen or so of those I guess.

Well, "MY" opinion is it might actually NOT be that great of a driver given the rather obvious fact "Earth" and what happens here will always be the major point of interest and driver for human activity for the foreseeable future even WITH a habitable Venus. While it very well could become a new frontier of science and possible other benefits the simple fact that we could never place enough colonists there to effect Earth's population at a reasonable price it will remain similar to our Mars, (or the Moon for that matter) since we CAN "live" on either if we so desired or even near-Earth space but we don't have any incentives to do so. At the 'time' if we find the Soviets are seriously planning on going we will of course make plans to go as well but it very much will not be a "major" effort for either side. It WILL be expensive and require a large effort but it won't be an actual "Apollo" like effort with an unlimited budget and set timetable.

However the TL itself assumes a much higher interest than that and though I need to catch up again if the 1969 OST was 'different' than OTL's version it could in fact require a 'race' with an Apollo like effort but IIRC it was at least very close to OTL's version.

Even if a Venus ship is sold to Congress at the price of taking a decade to build it, I bet somewhere in that decade someone gets impatient and gets Congress to pony up the money to accelerate the construction and go for an earlier launch window. Or alternatively they shut it down half-built. Maybe when it was sold to Congress before, they had to emphasize that it could be mothballed and moved to a higher parking orbit if need be, and some budget cutter session mandates that be done, "we'll get around to finishing it later."

Someone will always be impatient, however there's no reason expect they would get any traction for the idea. Further if they get Congress behind building it in the first place it will be easier to keep the support up, especially if you can directly point to the Russians 'doing' something along the way.

Looking over the various Mars mission proposals, (https://history.nasa.gov/monograph21.pdf) assembling the ship would not take anywhere near a decade, but a lot depends on how 'smart' things are done TTL. (And how much of a hurry everyone is in, again I suspect fiscal reality will have set in and everyone's pace will slow until they can get an infrastructure set up)

One thing that's going to be very clear is while they can do flyby's, maybe even some basic orbital missions using pretty much growth versions of Proton-Soyuz/Salyut, Saturn-Apollo/Skylab architecture but anything else is going to take a dedicated interplanetary ship (ITV/Interplanetary Transfer Vehicle, as we all know how much "the government" hates the idea of just calling it a damn Spaceship ) and support infrastructure for the same.

Now what's interesting here is that under the circumstances is the US has an opportunity since we still did the Apollo program ITTL and its possible over those mission we might have actually found the water on the Moon which significantly changes the available options for a Venus (Solar System actually) Exploration/Exploitation program. With Lunar sourced water, (LOX/Hydrogen) LOX, (lunar regolith) and materials it would make sense to move a lot of the assembly and support for the ITV to one of the L-points, (and even at the time the merits of operating from L2 were well known) which solves most of the issue with using Nuclear propulsion. And I'd be surprised that with an ongoing NERVA development problem the don't stumble across the idea of LOX thrust augmentation and bi/tri-modal operation much sooner, meaning it's even less likely they consider throwing NERVA's away on each mission.

And as a 'bonus' NASA can reasonably argue including Mars in most of the missions both as part of the flyby's and also the orbital missions. There's a conjunction class series for Earth>Venus>Mars>Earth where if you're willing to spring for a couple of weeks in Venus orbit and spend the propellant you can then visit Mars for around 2 months and still gets back to Earth in under two years total mission time, (see: http://moonsociety.org/publications/mmm_papers/venus_rehabpaper.htm, "Visits to Venus En Route to Mars" article) and that assumes no advanced propulsion like an Ion drive, which was being considered in conjunction with a NERVA for Mars missions as early as 1966. (Unfortunately NERVA was only used as a booster out of LEO in this plan instead of being used to both boost the vehicle and then power it during flight but like I noted we can hope for some clearer thinking) Even a 1970s Ion drive can cut transfer times significantly, especially if coupled with NERVA for high-thrust operations.

It would take getting out of the "Apollo" mindset where everything but time can be wasted and into a more sustainable, long-term thinking and planning mindset but it's pretty clear the thinking existed at the time but was greatly hampered by the falling budget, loss of support and lack of focus about the post-Apollo space program that will obviously be less of an issue in TTL.

Randy