https://nsarchive.gwu.edu/document/1934 ... uilder-d-c
C.H. Builder, D. C. Kephart, A. Laupa, "The U.S. ICBM Force: Current Issues and Future Options," RAND Corporation, PR-1754-R, October 1975, Secret, excised copy
Stuart may have seen this as this was a 1975 RAND study and Stu was in the business by 1985 or so.
However, even if you leave the classified portion of the Business, you still need to abide by NDAs, for personal reasons...if you want to be a military analyst, you have to keep your mouth closed; no going off like Polmar -- because USG can pull contracts from your company if you're too leaky and Stu was working right up to his death; so he couldn't really comment on what he had seen until it was officially declassified.
US ICBM Performance Characteristics c. 1975 Declassified
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MKSheppard
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US ICBM Performance Characteristics c. 1975 Declassified
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MKSheppard
- Posts: 461
- Joined: Mon Nov 21, 2022 1:41 am
Re: US ICBM Performance Characteristics c. 1975 Declassified
Some commentary on this from twitter:
"CEPs should only be believed if shown on a Velocity-Reentry Angle-Range Map. They can be highly variable."
"CEPs should only be believed if shown on a Velocity-Reentry Angle-Range Map. They can be highly variable."
Re: US ICBM Performance Characteristics c. 1975 Declassified
The MIRV laydown footprint numbers are very interesting, and given the other data here can tell us a lot about the entire flight profile, particularly where and when each RV would be released.
The usual factors involved here are (I’m converting it all to m/s and km as that’s what I’m most familiar with when it comes to orbital dynamics):
-Delta-v of the RV bus, stated for the Minuteman III as 381 m/s in the tanks at most, while the total velocity peak sub-orbital velocity is likely a bit north of 6,000m/s. For comparison, orbital velocity for a very low (and short-lasting) 200km x 200km orbit is about 7,760m/s or so, and an orbital rocket would expend very roughly 9,100m/s of delta-v to get to that point (fighting gravity and atmospheric resistance).
-It’s VASTLY easier to modify the downrange impact point than make any lateral (inclination) adjustments, which require a tremendous amount of delta-v (the Dynasoar had a very interesting atmospheric-skipping solution as a way to reduce the fuel required for this).
-The earlier in your flight path (but after the bust is released from the second stage) that you can make these adjustments and release the RV, the larger the change you can make.
-Lofting trajectory. The higher you go (i.e. upper stage flight path and burn-out while angled at 45 degrees above the horizon getting you to above 3,000km above the earth, at the likely typical burnout velocities for this missile), the easier it will be to make lateral and downrange impact points. But that increases total flight time *significantly* (interception risk going way up!), hence they take a bit more “orbital-insertion-like” max altitude of 700km (still 3x the normal insertion altitude, but far less than 3,000km). But that in turn does require more total delta-v to achieve the same downrange, which makes the missile that much bigger to carry the extra fuel that will carry the required fuel (damn you, Tsiolkovsky!).
All of this also has a major impact on the possible re-entry angles available to each RV.
The usual factors involved here are (I’m converting it all to m/s and km as that’s what I’m most familiar with when it comes to orbital dynamics):
-Delta-v of the RV bus, stated for the Minuteman III as 381 m/s in the tanks at most, while the total velocity peak sub-orbital velocity is likely a bit north of 6,000m/s. For comparison, orbital velocity for a very low (and short-lasting) 200km x 200km orbit is about 7,760m/s or so, and an orbital rocket would expend very roughly 9,100m/s of delta-v to get to that point (fighting gravity and atmospheric resistance).
-It’s VASTLY easier to modify the downrange impact point than make any lateral (inclination) adjustments, which require a tremendous amount of delta-v (the Dynasoar had a very interesting atmospheric-skipping solution as a way to reduce the fuel required for this).
-The earlier in your flight path (but after the bust is released from the second stage) that you can make these adjustments and release the RV, the larger the change you can make.
-Lofting trajectory. The higher you go (i.e. upper stage flight path and burn-out while angled at 45 degrees above the horizon getting you to above 3,000km above the earth, at the likely typical burnout velocities for this missile), the easier it will be to make lateral and downrange impact points. But that increases total flight time *significantly* (interception risk going way up!), hence they take a bit more “orbital-insertion-like” max altitude of 700km (still 3x the normal insertion altitude, but far less than 3,000km). But that in turn does require more total delta-v to achieve the same downrange, which makes the missile that much bigger to carry the extra fuel that will carry the required fuel (damn you, Tsiolkovsky!).
All of this also has a major impact on the possible re-entry angles available to each RV.
-Luke