1

Historical Spaceflight / Re: Satellite signals intelligence in the 1960s

« Last post by Blackstar on Today at 12:54 pm »

Still some ridiculous deletions. P-11 and P-989 have been declassified for years (P-11 was never classified), and NRO released info on the types of targets. Of course it is possible that this was being declassified many years ago, before the NRO declassified their stuff, and so it reflects the older security redactions. But I suspect it is really just one hand of the bureaucracy unaware of what the other hand is doing.

That said, even if it was perfectly intact, it would not tell us anything that we don't already know. There's not enough text there to contain useful details.

2

SpaceX Starship Program / Re: SpaceX Starship IFT-2 : Starbase TX : 18 Nov 2023 DISCUSSION

« Last post by dabomb6608 on Today at 12:48 pm »

Does anyone know why SpaceX did not show any images or videos taken from the Starship during the launch?

I believe I haven’t seen any launch where they didn’t do it since the Falcon 1.

I think it's safe to say that, for one reason or another (experimental Starlink feed?) they didn't get any onboard video, either.

I can't imagine they would risk getting zero onboard video data on an experimental test run of data transfer technology without some form of traditional backup datalink. It isn't like they couldn't afford the extra weight of additional hardware being installed. Or lacked the time needed to install said hardware.

However I do find it odd they haven't released any footage to this far post launch...we have all been surprised by their methods before.

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Other Launchers (Korean, Brazilian etc.) / Re: December 4, 2023 05:00 UTC South Korean military orbital LV launch

« Last post by Galactic Penguin SST on Today at 12:46 pm »

USSF 18SDS has confirmed objects reached orbit:
2023-188A/58500 (S-STEP): 636 x 653 km x 46.98°
2023-188B/58501 (rocket final stage): 424 x 653 km x 46.92°

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Chinese Launchers / Re: Aiji-2 & Xingchi-1 02A/B - CZ-2C - Jiuquan - December 4, 2023 (04:10 UTC)

« Last post by Galactic Penguin SST on Today at 12:44 pm »

4 objects found from this launch:
2023-187A-C/58496-58498 (the 3 payloads) found in 627 x 642 km x 98.01° SSO
2023-187D/58499 is the CZ-2C 2nd stage and is in 582 x 637 km x 98.14° orbit.

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Chinese Launchers / Xingshidai-18/19/20 - ? - ? - 2023/2024

« Last post by mikezang on Today at 12:21 pm »

国星宇航举行“一箭三型卫星”出征仪式

Nationstar Aerospace held the "One Arrow Three Satellite" departure ceremony

On November 30, the 2023 Chengdu Satellite Internet and Satellite Application Industry Development Conference was successfully held. This conference invited a number of national research institutions and institutions such as the Institute of Aerospace Information Innovation of the Chinese Academy of Sciences, the International Research Center for Big Data for Sustainable Development, the China Satellite Application Industry Association, the China Satellite Navigation and Positioning Association, and the Zhongguancun Public Trust Satellite Application Technology Industry Alliance. Industry organizations attended the meeting.

As the "chain master" company of Chengdu Satellite Internet, Dr. Lu Chuan, the founder of Nationstar Aerospace, was selected into the first batch of "Star" expert think tanks. Other members include Wang Jiayao, academician of the Chinese Academy of Engineering, Gu Xingfa, academician of the International Academy of Astronautics, and China's second-generation satellite navigation system. Nine academicians, experts, and entrepreneurs, including Cao Chong, a member of the Major Expert Committee, form the "most powerful brain" of Chengdu's satellite Internet and satellite application industry.

During the conference, Nationstar Aerospace held a three-star expedition ceremony for Star Age-18, Star Age-19, and Star Age-20. Yin Jun, Technical Director of Beijing Xingyi Lianxin Technology Development Co., Ltd., and Sichuan Satellite TV Channel Vice President of Sichuan Radio and Television Station Director Zhou Tianshu, senior vice president of Nationstar Aerospace Guo Tao, deputy director of Chengdu High-tech Zone Future Science and Technology City Development Service Bureau Huang Zhu, executive vice president of Nationstar Aerospace Dr. Zhao Hongjie, and Helium Star Optical Link Technology (Shenzhen) Co., Ltd. COO Wang Xue all pressed the button to set off. button, more than a hundred representatives of upstream and downstream enterprises and scientific research institutions in satellite Internet and satellite applications witnessed the launch of Nationstar Aerospace’s “Made in Chengdu” satellite.

Guo Tao, senior vice president of NationStar Aerospace, said that the Star Times-18/19/20 three-type satellite has been developed and will be launched in the near future. The One-Arrow III satellite will become a major breakthrough for NationStar Aerospace, which not only reflects the Aerospace's ability to respond quickly and deliver in batches also marks that NationStar Aerospace has entered a new stage of concurrent development of multiple satellites from single-satellite development.

In the future, NationStar Aerospace will always adhere to the core value of "together with the motherland", continue to work on the construction of "aerospace integration", continuously improve the core technology level, and contribute Nationstar's strength to the construction of Chengdu into a benchmark city for satellite Internet and satellite applications. .

The Xingshidai-18/19/20 (星时代-18/19/20) will be launched recently.

6

SpaceX Starship Program / Re: Starship hot staging

« Last post by Slarty1080 on Today at 12:15 pm »

This means the SH fuselage will experience a brief slam of negative acceleration relative to its own prop.

I was disabused of this notion back about 2,000 pages.
Without more telemetry data, or a much more serious analysis, all we can say is that the acceleration of SH was REDUCED from the pre-hot staging acceleration.  We really don't have enough information to say that it we reduced far enough to go negative.  As long as the acceleration remains at least slightly positive (say, went from +3G to +0.01G), the propellants will remain settled at the bottom of the tank.  This is the simplified view; one would also need to take into account the rotational acceleration to truly model the behavior of the propellants, but that kind of work makes my head hurt.

It's not a certisnty, but there's certainly supporting evidence, both in the vented gasses and in the slosh simulation, and also force analysis supports the idea.

And opposing the idea is that the centre engines remained lit throughout hot-staging, and all but one of the centre 13 relit after hot-staging had completed and the flip started. And that the entire reason hot-staging was implemented was to keep booster prop settled through the staging sequence without needing to re-pressurise the tanks or resettle prop.

Whatever happened that caused the last engine in the boostback reignition sequence not the light, and the lit engines to start shutting down, occurred well into the post-staging flip.

I've been noodling the issue of the three engines staying lit while purportedly experiencing negative acceleration. You know a lot more about this than I do. Could you (and everybody else for that matter) critique an idea?


For the sake of argument assume there really was a negative acceleration and let's only look at the earliest moments before the flip starts. And let's further assume the methane header holds enough that, at least initially, methane starvation is not an issue. We'll concentrate on the LOX.


The simplest of model has the LOX moving towards the common dome as a simple cylinder of fluid. But there is a force moving a portion of the lox towards the engine inlets. Inertia. It wouldn't be applied to the entire fluid cylinder. It would mostly be in the center around the downcomer and above the three center engine inlets. It would also probably be in the form of three vortexes which (I think) would help keep the inertia effects strongly localized.


The simple cylinder of fluid would most likely transform into a rough cone, apex to the inlet area with a fluid cylinder above that. This would be a strictly transient effect with a full detatch inevitable if the negative acceleration continues. Once the flip starts the LOX would go chaotic.


If I've noodled this correctly, the three center engines could keep running for a short time while the LOX was otherwise reacting to the negative acceleration. As long as we saw them running? I do not know.


If my surmise is realistic we can't rule out negative acceleration.

Can't rule out negative acceleration by accident, but I suspect it would be deadly. As soon as LOX is in motion in the head space there will be ullage collapse to some degree in the main tank. Reapplication of acceleration would slam the bulk of the LOX back against the bulk head with resulting splash back especially if any turning moment was applied. Any significant ullage collapse would lead to pressure reduction and cavitation. And even if the header tank somehow avoided this fate the pressure loss in the main tank would have robbed all of the advantages of hot staging as vast quantities of cold compressed (heavy) gas would be required to repressurise it.

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Historical Spaceflight / Re: Satellite signals intelligence in the 1960s

« Last post by hoku on Today at 12:09 pm »

Yet another partially un-redacted iteration of "UNITED STATES CRIPTOLOGIC HISTORY/American Criptology during the Cold War, 1945-1989"  is out. This one has been FOIAed by John Greenewald. "Book II: Centralization Wins, 1960-1972" includes a brief section on "The P-11 Payloads".

Attached is the TOC and the relevant section. Have fun with filling in the blanks ;-)
(for comparison, the previously released version is attached as well)

https://documents2.theblackvault.com/documents/nsa/MDR-113301.pdf

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Other Launchers (Korean, Brazilian etc.) / Re: December 4, 2023 05:00 UTC South Korean military orbital LV launch

« Last post by Galactic Penguin SST on Today at 12:07 pm »

Per machine translation: The satellite launched was not in South Korea MoD’s original plans for this test flight, but rocket co-developer Hanhwa Aerospace approached them with their own SAR prototype satellite (apparently named S-STEP) waiting for a ride, and both agreed to replace the planned dummy payload with it. The MoD calls it a “win-win” situation.

https://m.yna.co.kr/view/AKR20231204088651504?input=tw

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ESA Launchers - Ariane, Soyuz at CSG, Vega / Re: Vega VV24 - Biomass - Q2 2024

« Last post by HVM on Today at 12:04 pm »

So how soon we see it top of a Falcon, do you take bets?

10

SpaceX Reusability / Re: Progress on rapid booster reuse

« Last post by FLHerne on Today at 11:51 am »

As these boosters creep up on the 20 flight mark, does anyone think they will add more flights beyond 20?

Yes -- from Ars Technica article here: https://arstechnica.com/space/2023/10/next-year-spacex-aims-to-average-one-launch-every-2-5-days/

With so many launches planned next year, 20 flights is probably not a stopping point. "We might go a little higher," the SpaceX official said.

----

Unrelated from another thread:

Some reusability stats for this launch (Starlink Group 6-31):

Booster B1078.6 turnaround time: 78 days 0 hours 21 minutes
(its previous mission was Starlink Group 6-16 on Sep 16, 2023 UTC).

That's kind of slow turnaround time for a relatively new Falcon 9 booster

I think this overlooks that booster availability isn't a constraint at the moment (except possibly the small West Coast fleet) so turnarounds aren't the minimum possible.

They could be deliberately reducing the use of low-flight-count boosters on Starlink to keep them available for pickier customers.