https://www.thespacereview.com/article/3440/1
Might also be interesting to figure out how the "precursors"(?) SDS-A (Jumpseat 1) and SDS-B (Jumpseat 3) fit into the story.
The SDS’s primary payload was always the communications relay for the KENNEN reconnaissance satellites. The two secondary payloads were just that—secondary. In August 1974 the Secretary of the Air Force approved adding a third secondary payload to the satellites, the Atomic Energy Detection System. This was introduced starting with the third satellite. Similar nuclear detection payloads—also known as “bhangmeters”—were already carried on Defense Support Program satellites. They could detect nuclear detonations in the atmosphere and space.
Quote from: hoku on 07/07/2023 06:34 amMight also be interesting to figure out how the "precursors"(?) SDS-A (Jumpseat 1) and SDS-B (Jumpseat 3) fit into the story.As far as I can see they are precursors only in same way that the Gyrostat-based TACSAT was a precursor to Intelsat IV and JUMPSEAT. It's now clear that the first SDS was launched in 1976, close to the first KH-11. This was a source of confusion, possibly deliberate, for decades, but the Vance Mitchell history makes it clear that SDS hadn't fully firmed up by the time that the first JUMPSEAT flew.
Well, then you need this stuff.The Vance Mitchell article is a bit frustrating. You'll see why.My article here is from 2006. I am 99% sure that I updated it in some way and have re-published it since then (maybe the title of my revised article was "Shadow Dancing" but I cannot find that). If I did revise it, I don't have it on hand. So use this for now.
One of the secondary missions initially proposed for SDS was relaying data collected by Air Force DSP missile warning satellites then in development. But in summer 1970 members of the DSP program office—then operating under the deliberately obscure designation of Project 647—began to have reservations about using SDS relays for DSP satellites. Later in the year the Project 647 office withdrew from participation in the SDS in favor of relaying DSP data directly to the ground. That decision required DSP to develop its own ground stations, including a politically sensitive ground station in Australia. It also meant that SDS again became a single payload satellite.This change annoyed Grant Hansen, the Assistant Secretary of the Air Force for Research and Development. Hansen wanted dual or multiple users on SDS. In a January 1971 meeting with several reconnaissance officials he discussed the options. Hansen had justified SDS in front of Congress on the basis of it having more than one payload and did not want to go back to members of Congress and explain why that was no longer the case. In an effort to force both SAMSO and the NRO to develop other payloads for SDS, Hansen suspended funding to SDS and placed the program on temporary hold.
I believe that I was told that the Vance Mitchell history article was actually a summary version of an SDS history that he wrote. I may have filed a FOIA for that history and was told by NRO that it was denied in full, although I'm not sure of that. Seems like I could try again for that history.
<snip>As far as I can see the first two secondary payloads are i) the (deleted and then reinstated) SIOP helix antenna and associated kit, and ii) the AFSCF link.Both are described in your 2018 TSR article. [Edit: and, impressively, I see that Jeff R had the missions already by 1984 in his JBIS article as summarised at ADS abstracts: "SDS is a system of pole-orbiting satellites that have three functions: to maintain polar communications with the Strategic Air Command (SAC) aircraft, to provide a link in the control of USAF satellites, and to act as a relay for information transmitted from the Keyhole-11 photoreconnaissance satellite to a US ground station"] <snip>
Quote from: LittleBird on 07/08/2023 09:16 am<snip>As far as I can see the first two secondary payloads are i) the (deleted and then reinstated) SIOP helix antenna and associated kit, and ii) the AFSCF link.Both are described in your 2018 TSR article. [Edit: and, impressively, I see that Jeff R had the missions already by 1984 in his JBIS article as summarised at ADS abstracts: "SDS is a system of pole-orbiting satellites that have three functions: to maintain polar communications with the Strategic Air Command (SAC) aircraft, to provide a link in the control of USAF satellites, and to act as a relay for information transmitted from the Keyhole-11 photoreconnaissance satellite to a US ground station"] <snip>The Feb 1972 budget hearing by the House Armed Services subcommittee gives the impression that the SIOP capability (coverage at high latitudes/polar regions) was the Air Force's primary talking point for getting SDS approval in the 1973 budget.
The capability of using "communication satellites" to transmit "electronic signals" of EOI satellites is only mentioned in Michael Getler's WaPo article from Feb 8, 1972, on Air Force Project 1010 (aka ZAMAN/KENNEN), which they added to the congressional record. The discussion of the article naturally evolves around the question on why the subcommittee members have to learn about this project from reading WaPo. On the hot seat is Assistant Secretary of the Air Force Grant L. Hansen, who tries to deflect any questioning. My favourite quote is "I don't know there isn't such a thing."
A few more details from the FY78 budget hearings:SDS FY77 approved budget was US$59.4M, and the requests/projections were $83.2M for FY78, and $26.1M for FY79. The 4th SDS, which was purchased in FY77, was the refurbished qualification model ($30.1M). The FY78 request lists $49.1M for the 5th SDS satellite (USA-4, which was launched in 1984?). Launch vehicle costs for FY78 include "sustained launch capability" for the Titan IIIB booster ($4.1M) and the Agena upper stage ($3.5M). The purchasing costs for the Agena were $10.4M. The purchasing costs for the booster ($29.3M) were part of the FY77 budget.Thus total purchasing costs for the hardware for the launch of one 1st generation, new (not-refurbished) SDS satellite were about $90M in 1977 US$ (inflation adjusted US$450M in 2023).Edit: FY72 ($17.8M), FY73 ($23.0M), FY74 ($40M), F75 ($36.5M), F76+F7T ($23M) budget estimates added.
I should continue this over in the SDS thread (I guess I should cross-post my earlier post), but wanted to mention this image.I almost certainly saw this before, but it did not completely register. This may in fact depict the second block of SDS satellites, which I learned were based on the Leasat series. This looks like Leasat with a deployable skirt--something that was done for other Hughes satellites, but was not done for Leasat.I will hold a certain amount of skepticism, because usually these graphics are not based on reality but are notional. But this one is intriguing.
Re Blackstar's recent post in the KH-11 thread about an image of SDS in an NRO YouTube video that I had posted (first grab below) Quote from: Blackstar on 11/16/2024 05:12 pmI should continue this over in the SDS thread (I guess I should cross-post my earlier post), but wanted to mention this image.I almost certainly saw this before, but it did not completely register. This may in fact depict the second block of SDS satellites, which I learned were based on the Leasat series. This looks like Leasat with a deployable skirt--something that was done for other Hughes satellites, but was not done for Leasat.I will hold a certain amount of skepticism, because usually these graphics are not based on reality but are notional. But this one is intriguing.I am wondering if this also confirms what Aviation Week had reported in 1980 about the second generation SDS being based on , and thus "short and fat" (see grabs 2 and 3 below) ?
The Dirks blue book is dated May 68 so indeed Intelsat III is the known quantity, see first grab. Interestingly, at that time, GEO seems to be favoured over HEO, see other grabs, I haven't dug into when HEO first made an appearance in the SDS story. As you'll recall you (and others) uploaded some of the key docs in the SDS thread: https://forum.nasaspaceflight.com/index.php?topic=59168.0 thanks all.
