ESA ATL Plausibility Checks and Development

[Bahamut-255]

Originally Posted by Michel Van

I see no Problem in uprating the Delta in this TL

There is need by NASA, USAF, USNavy and NRO to launch medium satellite or space probes to Mars, Moon, Venus
in OTL the Transformation from Delta 7000 series to Delta 8000 aka Delta 3 was so a step
the RP-1 tank was replace by new one but instead 2.44 meters ø it is now 4 meters ø what reduce the stage length to 20 meters
this Hammerhead configuration is not new, the Titan III-IV and Ariane 1-4 used it years before.

the use of new LOX/LH2 upper stage with RI-10 is only question of financing by NASA or Pentagon.
Alternative MDC could buy Ariane 4 third stage H-10 III who is similar to second Stage of Delta 8000 series.

And I do see one problem. Everything else that's happening here. This is why I'm certain that TTL Delta II will be like OTL Delta II for at least the initial couple of years. Further evolution later on is possible, but not at first IMHO.

As for a new upper stage, LOX/LH2 does come across as being the most likely option for me, primarily on account that LOX/LH2 is the only Liquid-Propellant mixture that has received serious investment over the years in the US AFAIK.

For that, there are two options. The OTL Delta III, or a different, smaller LOX/LH2 upper stage.

Now I have been doing some sketchwork on such a setup, which utilises a 10ft upper stage, with the 1st stage kerosene tank widened to match. it does provide me with a reasonable payload bay while keeping it no taller than 40 metres - which IIRC, means it would be easier to integrate into their existing launch facilities.

The primary advantage I can see with my design is that the upper stage would be small enough that you wouldn't need a high-thrust LOX/LH2 engine for it, making most of the existing designs they have available usable for it, as opposed to OTL Delta III which required an all-new engine, with associated development costs.

One other note. ITTL, there is no Ariane 1, 2, 3, 4 or 5. It's Europa and Argo. Although insofar as Hammerhead Payload Shrouds are concerned, that's moot.

The use of RL-10A in begin in program and later change to RL-10B or buy H-10III stage

RL-10A could be used. H-10III is politically a Big No-No for what will be used for military payloads.

[Michel Van]

Dam, i forgot this is TL used Blue Streak Hardware
sorry about that Bahamut-255

How about this:
British government makes join venture with Pentagon
and build second Stage with RZ.20 engine for Delta 8000
in exchange to launch British Satellite also spy Sat.

RZ.20 was Roll Royce answer to RL-10 engine for ELDO-B/C later Europa III, back in 1960s

[e of pi]

Originally Posted by Michel Van

Dam, i forgot this is TL used Blue Streak Hardware
sorry about that Bahamut-255

How about this:
British government makes join venture with Pentagon
and build second Stage with RZ.20 engine for Delta 8000
in exchange to launch British Satellite also spy Sat.

RZ.20 was Roll Royce answer to RL-10 engine for ELDO-B/C later Europa III, back in 1960s

It'd make very little sense for either the Brits or the Americans. The Americans have a lot of hydrolox experience natively, including the equivalent RL-10 engine, so for them I think developing their own stage makes more sense. On the British side, they have access through ESA to the Europa family which already would provide them with a Delta 8000-class capability and then on into Argo for larger payloads up to 36 metric tons and of course crew. Factor in "Not Invented Here Syndrome" on both sides of the Atlantic and I really don't see that deal having much plausibility.

[Michel Van]

Originally Posted by e of pi

It'd make very little sense for either the Brits or the Americans. The Americans have a lot of hydrolox experience natively, including the equivalent RL-10 engine, and the Brits have access through ESA to the Europa family and then on into Argo for larger payloads and eventually crew. Factor in "Not Invented Here Syndrome" and I really don't see that deal having much plausibility.

That also true

[e of pi]

Originally Posted by Bahamut-255

Now I have been doing some sketchwork on such a setup, which utilises a 10ft upper stage, with the 1st stage kerosene tank widened to match. it does provide me with a reasonable payload bay while keeping it no taller than 40 metres - which IIRC, means it would be easier to integrate into their existing launch facilities.

Wouldn't such a 10ft stage essentially be a Centaur variant? If I was designing that, I'd certainly explore the option for such commonality. Might be able to get away with re-using tank domes and thrust structure, at least, even if you need new barrel lengths.

[Bahamut-255]

Well E of Pi has already covered all the points I was going to make Van. So lets move on. The most likely engine I see for a LOX/LH2 upper stage on an upgraded Delta II would be the Pratt and Whitney RL-10A-4. Certainly likely to be in use at the time. Good thrust for the stage. Nice - if not great - Vacuum Isp. And given just how light that upper stage I'm looking at will be - no more than 50% greater than the OTL Delta-K - does appear to be the best option available for them.

Seems to me to be the most likely path they'd take.

[Bahamut-255]

Originally Posted by e of pi

Wouldn't such a 10ft stage essentially be a Centaur variant? If I was designing that, I'd certainly explore the option for such commonality. Might be able to get away with re-using tank domes and thrust structure, at least, even if you need new barrel lengths.

It's an option, yes. But I'm gonna have to look into the specs for a good Centaur stage who's parts I can use. It would certainly help with the development though.

[e of pi]

Originally Posted by Bahamut-255

It's an option, yes. But I'm gonna have to look into the specs for a good Centaur stage who's parts I can use. It would certainly help with the development though.

Well, you're going to have 3.05m tank domes--Centaur offers those. Ditto for a single RL-10 thrust structure, at least as of Centaur-D/E. So the question is if you can get the barrel length you want, and I think it's doable enough.

[Bahamut-255]

Originally Posted by e of pi

Well, you're going to have 3.05m tank domes--Centaur offers those. Ditto for a single RL-10 thrust structure, at least as of Centaur-D/E. So the question is if you can get the barrel length you want, and I think it's doable enough.

Well that simplifies matters a good deal. The only issue I found was that 9.00 metres appears to be the shortest that the stage can be - that being the length of the original Centaur-C - whereas I was looking at about 8.00 metres - 29.5ft vs 26.25ft in imperial figures. In any case, it just means an 8 metre payload fairing instead of 9 for a max height of 40 metres, certainly more than doable. I suppose it's best I go with that to give them what is essentially an uprated Centaur-C upper stage. That is, one engine instead of two, but of better performance in terms of both thrust and efficiency.

[e of pi]

Originally Posted by Bahamut-255

Well that simplifies matters a good deal. The only issue I found was that 9.00 metres appears to be the shortest that the stage can be - that being the length of the original Centaur-C - whereas I was looking at about 8.00 metres - 29.5ft vs 26.25ft in imperial figures. In any case, it just means an 8 metre payload fairing instead of 9 for a max height of 40 metres, certainly more than doable. I suppose it's best I go with that to give them what is essentially an uprated Centaur-C upper stage. That is, one engine instead of two, but of better performance in terms of both thrust and efficiency.

Centaur-C is the shortest because Centaur has always been trasnferred onto larger LVs--it started out being sized as a fourth stage for Saturn V, then it turned out to be really useful in getting the most out of Atlas, and ended up as a second stage for Atlas. As Atlas variants grew, they stretched Centaur to get more fuel into it. You're attempting a smaller stage, yeah? Less that the original ~14 capacity? In that case, you can shrink the stage in length, maybe down to about 2/3 of the original length. See the picture attached.

[Bahamut-255]

Originally Posted by e of pi

Centaur-C is the shortest because Centaur has always been trasnferred onto larger LVs--it started out being sized as a fourth stage for Saturn V, then it turned out to be really useful in getting the most out of Atlas, and ended up as a second stage for Atlas. As Atlas variants grew, they stretched Centaur to get more fuel into it. You're attempting a smaller stage, yeah? Less that the original ~14 capacity? In that case, you can shrink the stage in length, maybe down to about 2/3 of the original length. See the picture attached.

Well in that case, I think that's TTL Delta 8000 series sorted insofar as stages and dimensions are concerned. Now to get some numbers for payloads.

[e of pi]

Originally Posted by Bahamut-255

Well in that case, I think that's TTL Delta 8000 series sorted insofar as stages and dimensions are concerned. Now to get some numbers for payloads.

Always happy to help.

[Bahamut-255]

And now I managed to get some performance figures for the Delta III.

Using the OTL Delta naming/numbering system, this is what I get for the following forms:


Delta-8330 - 4,165 Kg

Delta-8430 - 4,565 Kg

Delta-8930 - 7,460 Kg


All are for a 185x185 Km orbit with an inclination of 29 degrees.

Incidentally, for a C3 of 15Km2/s2 with a declination of 0, I have a payload of 510 Kg for the Delta-8930. About what is needed for Trans-Venus/Mars injections.


Obviously, in the 4-number system, the first number, '8', represents the Thor 1st stage with widened Kerosene tank. The second number states the number of GEM-40 SRBs used. The third number, '3', means it uses the new LOX/LH2 upper stage. While the last number represents a final stage, '0' meaning there isn't one.

[e of pi]

Originally Posted by Bahamut-255

And now I managed to get some performance figures for the Delta III.

Using the OTL Delta naming/numbering system, this is what I get for the following forms:


Delta-8330 - 4,165 Kg

Delta-8430 - 4,565 Kg

Delta-8930 - 7,460 Kg

Glad to hear the numbers worked out, they look fairly impressive. How much did you end up modifying the Centaur?

[Bahamut-255]

Originally Posted by e of pi

Glad to hear the numbers worked out, they look fairly impressive. How much did you end up modifying the Centaur?

A bit. It shrank from 9 to 8 metres, while keeping a diameter of 10ft. Though I was extremely conservative with the propellant mass, so the odds could well be that I've underestimated the payload capability of this particular LV.

Not that that's a bad thing, mind you. Remember that the Saturn V was very conservative when they calculated the initial payload - it went up by 20% - and was over-designed to begin with. Two things that allowed it to succeed in spite of the CSM/LM 50% weight growth over its development.

[e of pi]

Originally Posted by Bahamut-255

A bit. It shrank from 9 to 8 metres, while keeping a diameter of 10ft. Though I was extremely conservative with the propellant mass, so the odds could well be that I've underestimated the payload capability of this particular LV.

Based on a length of 8m (engine inclusive?), I'd estimate a propellent load of roughly 10.5 metric tons, and a dry mass of perhaps 1800 kg. That roughly match what you were thinking?

[Bahamut-255]

Originally Posted by e of pi

Based on a length of 8m (engine inclusive?), I'd estimate a propellent load of roughly 10.5 metric tons, and a dry mass of perhaps 1800 kg. That roughly match what you were thinking?

Boy did I get the propellant load off! I had it at 8,500Kg, with a dry mass of about 1,500Kg. Using a single RL-10A-4 engine with vacuum thrust 92.61KN, and vacuum Isp of 449s. That's gonna change the figures a good deal.

But yes, it does include the engine in the length. As well as the Stage 1/2 interstage.

[e of pi]

Originally Posted by Bahamut-255

Boy did I get the propellant load off! I had it at 8,500Kg, with a dry mass of about 1,500Kg. Using a single RL-10A-4 engine with vacuum thrust 92.61KN, and vacuum Isp of 449s. That's gonna change the figures a good deal.

Well, I'm basically estimating that you're chopping about 1.2 meters off the stage's tanks. With a diameter of 3.05m, this is a volume decrease of 8.76 m^3. Hydrolox fuel averages out to about 360 kg/m^3, though obviously that depends on the mixture ratio--more LOX per LH2 and it gets denser. Anyway, 8.76m^3 at 360 kg/m^3 is about 3,200 kg in lost fuel capacity. You started with 13,600 kg, so the end result is about 10,400 kg.

[Bahamut-255]

And with the recalculated propellant mass (thanks for the help E ). Here's the revised payload figures:


Delta-8330 - 4,310 Kg

Delta-8430 - 4,725 Kg

Delta-8930 - 7,720 Kg


Furthermore, for a C3 of 15Km2/s2 with a declination of 0, I have a payload of 1,380 Kg for the Delta-8930. That is a serious spike in the performance capability in that particular regard! Clearly, something appears to be off with that number, though I suppose there's no reason I can't just grab an upper stage - not dissimilar to OTL Delta II - to get that number.

[Michel Van]

Originally Posted by Bahamut-255

Furthermore, for a C3 of 15Km2/s2 with a declination of 0, I have a payload of 1,380 Kg for the Delta-8930. That is a serious spike in the performance capability in that particular regard! Clearly, something appears to be off with that number, though I suppose there's no reason I can't just grab an upper stage - not dissimilar to OTL Delta II - to get that number.

that's second stage is a centaur, it usual can be adapted for carrying a Solid rocket engine.
like the forth Solid stage from Titan IIIE,
the Star-37S more here, http://en.wikipedia.org/wiki/Star_37

I know it reduce the payload to 669 kg, but that would be a Voyager 1/2 class, very fast fly-by probe to Uranus, Neptune, Pluto and outer asteroid belt


by the way
the Star-37/Burner series were also used on Thor Delta...