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New Oryol service module will use for core+dock modules.
Signed. Sealed. DELIVERED!

Over the weekend, we delivered the first two #O3bmPOWER spacecraft to

SES' CTO, Ruy Pinto, says it will "transform the way people think about connectivity."

Read more, here:
Blue Origin / Re: Blue Origin's BE-4 Engine
« Last post by Robert_the_Doll on 12/05/2022 04:48 pm »
The Tory comments are a bit vague and cryptic as usual, but still interesting. Bruno uses a plural here "hot firings every week",

No, a single firing a week would be legitimately described as "hot firings every week"

If he had meant that, then"A hot firing every week" is what I would expect to have seen him write. It is possible he made a typo and accidentally put in the "s". It has happened before. However, we know from other sources that XEEx has done up to three test firings in a week.
New opinion piece from Scientific American on the propriety data period debate. I still think the eighteenth month period on the upper limit is too long.

NASA, as a federal agency that funds and conducts research, is onboard with the idea of freely accessible data. But it has a plan that goes much further than the White House’s and that is highly problematic. The agency currently gives a proprietary period to some scientists who use particular facilities, such as a 12-month period for the powerful James Webb Space Telescope (JWST), so that those scientists can gather and analyze data carefully without fear of their work being poached. NASA is looking to end this policy in its effort to make science more open-access.

Losing this exclusivity would be really bad for astronomy and planetary science. Without a proprietary period, an astronomer with a brilliant insight might spend years developing it, months crafting a successful proposal to execute it, and precious hours of highly competitive JWST time to actually perform the observations—only to have someone else scoop up the data from a public archive and publish the result. This is a reasonable concern—such scooping has happened before.
Advanced Concepts / Re: Using shaped charges as a rocket engine
« Last post by Beratnyi on 12/05/2022 04:43 pm »
TNT has an energy density of 4.184 MJ / kg. Explosives apparently exist with up to 2.38 times greater energy density than TNT (, but those explosives have not been synthesized in any quantity, probably for good reasons, so I'll use 1.90, the highest value for an explosive that seems like someone actually seriously considered using. With perfect efficiency the best possible exhaust velocity is sqrt(2 * 1.90 * 4.184 MJ / kg) = 3,987 m/s. That's not bad, but that assumes 100% efficiency, i.e. that the products all leave the rocket in the desired direction at the same speed. I don't know how efficient shaped charges can be but my hunch is you'd get less than half of this, probably much less, which makes this idea not competitive with traditional rocket propellants. Two things are hurting this idea: the energy density of explosives isn't as good as for bipropellants, and the efficiency of shaped charges is probably much worse than a nozzle's efficiency.

Something similar has been suggested using nuclear bombs: .
Shaped charges typically use explosives with an energy density of 9 MJ/kg, which is comparable to methalox. But the most important thing is the gigantic pressure of hundreds of thousands of bars during the formation of a cumulative jet, which allows it to be accelerated to a speed of 10 km/s or more. For comparison, in the combustion chamber of the Raptor engine, the pressure is "only" 300 bar, and the jet velocity is 3.5 km / s, and this is an incredible achievement - it is not possible to significantly increase this value in a classic rocket engine.
A nozzle in a rocket is needed for only one task - the formation of a directed high-speed jet. In a shaped charge, this jet is formed by the charge itself, so no nozzle is needed.
To form a jet, a shaped charge is accelerating a tamper, not the charge itself*. That tamper is not part of the combustion process, so is pure dead reaction mass that reduces your effective MJ/kg (e.g. if you have 1kg of explosive accelerating a 1kg tamper into a EFP, then your energy density if halved).

Then you have the problem of harvesting that energy for propulsion. A single shaped charge floating in space may be able to fling a het of hot copper to a few km/s. but there's no vehicle that accelerates in the opposite direction in that scenario. You'd need to contain the explosion somehow and capture the gasses that are produces as a result of the explosion in order to use them to push a vehicle forwards. The problem there is that whilst a shaped charge is good at accelerating a tamper in one direction, it's no so good at accelerating the combustion products in one direction: instead, they expand mostly radially: you do not get the equivalent of a lump of gas travelling at the opposite speed to the tamper jet.
We don't need a metal liner! We are not going to penetrate the armor of the tank, all we need is a high-speed jet directed in the direction we need. In a conventional rocket engine, this jet is formed and accelerated by the Laval nozzle, in our case, this jet is formed and accelerated by the charge itself due to the conical recess.
You can compare this with an ion engine where the Laval nozzle is also missing due to the fact that the flow of ionized gas is already accelerated and directed in the right direction.
Even if the gas flow velocity is uneven (which is not a fact in the absence of a liner), then the average velocity value (and hence the specific impulse value) will still be higher than that of any chemical rocket engine.


Day 4 - "green smiley powered rocket"

It burns your standard green slime as a main fuel source with 2 SRBs (Smile Rocket Boosters) for a bit of extra thrust.

Thanks to @AviseMike and Daniel age 8 for the submission.
Chinese Launchers / Re: China's space program
« Last post by Rondaz on 12/05/2022 04:40 pm »
Not that. It's a test ship for a new spaceship.

The new-generation manned spacecraft is a manned space-to-earth round-trip transport spacecraft that is demonstrated for China’s manned lunar exploration and space station operations. The spaceship adopts a modular design, can be multi-tasked and reused, can carry up to 7 people, and has a cabin volume of 13 m³. It adopts the single-component non-toxic engine with the largest thrust in the world at present, and the multi-junction gallium arsenide solar cell with 34% photoelectric conversion efficiency.
Just another day in Mission Control.
Space Science Coverage / Re: Astronomy & Planetary Science Thread
« Last post by Star One on 12/05/2022 04:31 pm »
Long-term multi-wavelength study of 1ES 0647+250

The BL Lac object 1ES 0647+250 is one of the few distant γ-ray emitting blazars detected at very high energies (VHE, ≳100 GeV) during a non-flaring state. It was detected with the MAGIC telescopes during its low activity in the years 2009-2011, as well as during three flaring activities in the years 2014, 2019 and 2020, with the highest VHE flux in the latter epoch. An extensive multi-instrument data set was collected within several coordinated observing campaigns throughout these years. We aim to characterise the long-term multi-band flux variability of 1ES 0647+250, as well as its broadband spectral energy distribution (SED) during four distinct activity states selected in four different epochs, in order to constrain the physical parameters of the blazar emission region under certain assumptions. We evaluate the variability and correlation of the emission in the different energy bands with the fractional variability and the Z-transformed Discrete Correlation Function, as well as its spectral evolution in X-rays and γ rays. Owing to the controversy in the redshift measurements of 1ES 0647+250 reported in the literature, we also estimate its distance in an indirect manner through the comparison of the GeV and TeV spectra from simultaneous observations with Fermi-LAT and MAGIC during the strongest flaring activity detected to date. Moreover, we interpret the SEDs from the four distinct activity states within the framework of one-component and two-component leptonic models, proposing specific scenarios that are able to reproduce the available multi-instrument data.
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