Tuesday, July 26, 2005

Cross format debate

in Thread
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Derek Lyons wrote:
> Luke7351@aol.com wrote:
>
> >Well, yes. But I think we'd have to be rather further back than that.
> >Hauling up the various bits and peices to build an O'Neill habitat
> >would be really, really pricey via OTL's rocket tech.
>
> That's mostly because OTL has never spent any real attention to
> decreasing costs. The current (high) costs are an artifact of
> history, not a certainty.
>
> >Hence, the appeal of Orion.
>
> An Orion isn't really much cheaper than an ordinary rocket in OTL.
> Nuclear weapons (excuse me, "plasma pulse units") are expensive little
> beasties.
>
> D.

Response

Care to elaborate? Expensive per what energy unit?

"Hydrogen bombs are the only way to burn the cheapest fuel we have, deuterium."
"...fuel cost for deuterium is about .0003 (1968) cent per kilowatt
hour."
Freeman Dyson - Interstellar Transport - Physics Today October 1968

http://groups-beta.google.com/group/soc.history.what-if/msg/72384bc6fedf5014?hl=en&

http://groups-beta.google.com/group/soc.history.what-if/msg/6d8a71293183ff9b?hl=en&
--------------------------------
Calculations
http://www.projectrho.com/rocket/rocket3c2.html#orion plus new column

Gross Mass 4,000 tons 10,000 tons 380,000 tons
Propulsion System Mass 1,700 tons 3,250 tons 123,500 tons
Exhaust Velocity 39,000 m/s 120,000 m/s 120,000 m/s optimize for L5
Diameter 41 m 56 m 345 m
Height 61 m 85 m
Average acc up to 2 g up to 4 g up to 4 g
Thrust 8e7 N 4e8 N 1.52e10 N
Propellant Mass Flow 2000 kg/s 3000 kg/s 114,000 kg/s
Atm. charge size 0.15 kt 0.35 kt 13.3 kt
Space charge size 5 kt 15 kt 570 kt
Num charges to 38,000 m 200 200 200
Total yield to 38,000 m 100 kt 250 kt 9.5 mt
Num ch. for 480km orbit 800 800 800- add Luna and L5 legs
Tot yield 480 km orbit 3 mt 9 mt 342 mt
Payload 1,600 t 6,100 t 231,800 t
Tons of Pulse units used 700 t 650 t 24,700 t
Average size 1,750 lb 1,625 lb 30 t


--------------------------------
Another response

John Schilling wrote:
> In article <1122388443.059460.212670@g47g2000cwa.googlegroups.com>,
> bombardmentforce says...
>
> >>He was talking about interstellar Orion (enormous vehicle)
>
> >>an Orion intended...launch vehicle. ... would use rather low yield
> >fission bombs.
>
> >The Soviet L5 lifter would have to be huge and should use medium size
> >fusion dominated pulse units.
>
> Yes, but the Soviets would have had more urgent need of those "fusion
> dominated pulse units", to wage the global thermonuclear war that would
> ensue from the rest of the world's realization that the Russians were
> actually going ahead with such a scheme.
>
> You're talking about tens of thousands of megatons worth of nuclear
> airbursts, and hundreds to low thousands of megatons of groundbursts.
> Even with "fusion dominated pulse units", that's a global catastrophe
> in the megadeath range, and the portions of the globe that are not the
> Soviet Union are going to react poorly to that sort of thing.
http://www.thebulletin.org/article_nn.php?art_ofn=mj98norris
"The total energy release for all 715 (Soviet) tests is estimated to be 285.4
megatons, with 1961 and 1962 alone accounting for 220 megatons or 77
percent of the total. The amount after 1963 is 38 megatons, all
underground....The U.S. total yield was about 179 megatons; 38 megatons underground."

So that's 247 and 141 for a total of 386 megatons aboveground.

The proposed 380,000 ton Soviet orion uses 342 megatons launch of the core structure of a Dumbbell shaped colony to 480km orbit. So your megatonnage estimates are high and should not include groundburts, the intial burst is only 13.3 kt and would not contact the ground.


----------------------------------------


References
Mass of dumbbell design 380 kiltotons
Plus 33.5 megatons of shield, lunar material prefered.

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