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SFN Launch Schedule, updated December 5:
December 13 ~21:20 UTC = ~4:20 pm EST
General Discussion / Re: Predictions 2023
« Last post by Vahe231991 on Today at 09:34 pm »
Spaceflight Predictions for 2023:

 - Starship/SuperHeavy vehicles lift off the pad (under their own power) 3, 4, or 5 times.
 - At least one Starship reaches a trajectory with orbital-equivalent energy.
 - Number of Falcon launches (F9 + FH) less than 115% of the Falcon launches in 2022.

 - Artemis 2 date slips to NET 4Q 2024.

Crew to ISS:
 - Boeing flies a successful crewed flight test of CST-100.
 - All other crewed flights to ISS are on Dragon and Soyuz; no mishaps.

Cargo to ISS:
 - Both Dragon and Cygnus fly successful cargo missions.

Crew to CSS:
 - China maintains uninterrupted occupancy of its space station.

Robotic Lunar:
 - Highly mixed success
    + a few missions fail spectacularly
    + at least one mission succeeds with notable results
    + most missions fade into unsuccessful obscurity

Launch Systems:
 - Vulcan flies at least once; likely twice, likely both successful
- Japan's H3 flies at least once
- Ariane 6 flies successfully in both 2 and 4 booster configurations
- Angara-A5 flies as least once
- More than one NewSpace US launch system reaches orbit for the first time
- New Glenn's first flight slips to 2024
I agree with you that one or two Angara launches could take place in 2023, given that the Angara 1.2 recently made its first orbital launches (the Angara A5 was the first Angara variant to conduct an orbital flight because the first Angara 1.2 launch was suborbital) and the Angara 1.2 is taking over launch roles once occupied by the Zenit, Dnepr, and Tsyklon.

I strongly doubt that NASA would delay Artemis 2 by several more months because back in March 2015 a tentative launch time frame for Artemis 2 (originally called EM-2 before 2019) could take place in either 2021 or 2026, and NASA reviews published in 2017-2019 had estimated that Artemis 2 might be launched sometime in the 2022-2023 timeframe, in which case the 2024 launch window for this mission floated last year could work out.

Boeing's first manned Starliner mission taking place in 2023 is a foregone conclusion, but with the caveat that the window of opportunity for Starliner-1 to be launched next year has been quashed by a busy schedule of Dragon 2 manned and cargo flights scheduled for 2023. Assuming that the first Vulcan launch meets expectations and the next batches of flight-ready BE-4 engines are test run and delivered to ULA on time, there would be good reason to believe that the target time frame for the first orbital flight of the Dream Chaser with the Vulcan will remain set in stone.
Something unusual happening in the company? All the recent hit pieces in mass media about them going silent seems oddly timed...
Other US Launchers / Re: US Launch Schedule
« Last post by zubenelgenubi on Today at 09:28 pm »
HAKUTO-R delayed:
NGA cancellation notice.  HAKUTO-R is now TBD.

Quote from: NGA
052235Z DEC 22
NAVAREA IV 1308/22.

Oneweb Flight 15 launch delayed to December 7:
SFN Launch Schedule, updated December 5, differs re: launch time:
December 7 22:32 UTC = 5:32 pm EST

latest NOTMAR has one day slip
Quote from: Emre Kelly tweet
SpaceX now targeting Wednesday evening for launch of OneWeb (shift from 1737 EST Tuesday). Latest request shows window opening at the same time. [Dec 5]

Launch ~14.5 hours after HAKUTO-R.

Also, nothing the ABL RS1 first orbital launch is currently scheduled from Kodiak NET December 7 22:00 UTC.

O3b mPower 1 and 2 approximate launch time:
SFN Launch Schedule, updated December 5:
December 13 ~21:20 UTC = ~4:20 pm EST

Starlink 4-37:
SFN Launch Schedule, updated December 5:
Launch date TBD.  (No change to the Starlink 2-2 listing.)

SDA Tracking Layer Tranche 0 Flight 1:
SFN Launch Schedule update, December 5:
Launch January 2023

Ben Cooper's Launch Photography Viewing Guide, updated December 5:
The next SpaceX Falcon 9 rocket will launch a batch of OneWeb satellites from pad 39A on December 7 at 5:32 p.m. EST. Sunset is 5:25 p.m. The first stage will land back at the Cape about eight minutes after launch. A Falcon 9 from pad 40 will launch the first HAKUTO-R lunar lander for iSpace on December TBD at 2-3 a.m. EST. The first stage will land back at the Cape about eight minutes after launch. A Falcon 9 will launch a pair of internet satellites for SES on December TBD, around 4 p.m. EDT. A Falcon 9 will launch the Transporter-6 smallsat rideshare mission on December TBD, in the daytime EST. Upcoming launches include more Starlink batches. A Falcon 9 will launch a batch of OneWeb internet satellites on January TBD. And a Falcon Heavy from pad 39A will launch the USSF-67 mission for the U.S. Space Force on January TBD.
Advanced Concepts / Re: Medusa concept using chemical explosives
« Last post by Beratnyi on Today at 09:27 pm »

For example, we have a substance with an energy density of 10 MJ per kg. We can release this energy in a second and get a temperature of 3000 degrees, or we can release this energy in an hour and not even get warm. And hypothetically, we can release this energy in a nanosecond and get millions of degrees. In all three cases, the energy density is the same, but the rate of its release is different. Speed is what matters, which is why the temperature in the center of a nuclear explosion is so high, because the detonation velocity is thousands of times higher than that of any chemical explosive, and not at all because of the energy density.

This is wrong on so many levels.

First, say you have a kg of fuel with 10 MJ of energy. Burn it in any device you wish to produce a jet of gas. The kinetic energy of that gas cannot exceed 10 MJ otherwise you have violated conservation of energy and can make a perpetual motion device. One kg of gas traveling at 4472.13 m/s has just about exactly 10 MJ of energy. It is simple math. Nothing you do can get a faster exhaust velocity.

Second, lets look at the temperature. A hot gas contains more energy than a cold gas. If you burn a kg of fuel producing 10 MJ of energy then the hot gas has exactly 10 MJ of heat more than the fuel you started with. That exactly defines the maximum temperature that gas can reach.  If you exceed that temperature then you have violated conservation of energy and can make a perpetual motion device.

Now lets look at chemicals. Say you have a kilogram of hydrogen/oxygen mix. You say that if we burn that fast enough then we could have temperatures in the millions of degrees. But a kg of water heated to millions of degrees has far more energy than you can ever get from the kg of hydrogen/oxygen. Again a perpetual motion device exactly as stated above. But worse than that at any temperature above 2182 C the water will start to disassociate back into hydrogen and oxygen absorbing heat from the gas and so cooling it. That gives us the maximum temperature we can ever get from burning hydrogen. Millions of degrees would dissociate all of the water and reduce the gas to a plasma.
Why did you decide that 1 kg of water is subject to heating to millions of degrees?
Water is the combustion product of Hydrogen and Oxygen.
The greater the specific impulse, the lower the mass of exhaust gases for a given amount of energy spent on heating.
No. Exhaust mass will not vary (if you throw 1kg of propellant out the back 1kg of propellant goes out the back as exhaust, no matter how its combusted.
In other words, using a limited energy source of 10 MJ/kg for fast heat transfer to the reaction mass, we will increase the specific impulse, but reduce the ejected mass. There is no violation of the laws of physics here.
No, magically losing mass is indeed an egregious violation of conservation of mass. You burn 1kg of propellant, you get 1kg of reaction products.
Fuel and reaction mass are two different things! In chemical rocket engines, this is almost the same thing, which is misleading people. But for example in ion and nuclear thermal engine these things are clearly separated.
Irrelevant for an 'explosive driven' engine: either the explosive reaction products are the remass (in which case the situation is identical to monoprop or biprop chemical rockets) or you're trying to heat some other remass (which which case you have a catastrophically inefficient thermal rocket).
Ask why engineers are so proud of the amount of pressure in the combustion chamber? This does not have a significant effect on the TWR (the Merlin has a better indicator than the RD-180), and the smaller effect of backpressure in atmosphere harms the rocket as a whole rather than helps (since it increases gravitational losses).
False. Chamber pressure is proportional to TWR, for a given engine.
The only reason to increase this parameter is to accelerate the processes of heat transfer in the combustion chamber from the fuel (for example, Methalox) to the reaction mass (water plus CO2), which leads to a higher temperature and, accordingly, to a higher exhaust gas velocity (specific impulse improves).
False. Chamber temperature is what is most strongly coupled to exhaust temperature (and this ISP), which is why the Raptor with it's stupendous 300 Bar combustion chamber pressure has a vacuum ISP of ~363s, whereas the RL-10's puny 24 bar chamber pressure still beats it up and down the street with an ISP of 465s.
There is no magic here, the faster the transfer of heat from the energy source to the reaction mass, the faster the speed of the outflow of gases from the engines and the lower the mass flow.
False. 'Speed of heating' has nothing whatsoever to do with either thrust or ISP. About the only thing it affects is physical length of the combustion chamber.
I explain point by point:
1) The fact that in chemical fuel the energy source and the reaction mass are combined only means that the mass of the energy source is discarded along with the reaction mass, and does not remain a constant load like solar panels for spacecraft with ion engines
2) The pressure in the combustion chamber is not proportional to the TWR, because with a decrease in the volume of the chamber, it is necessary to thicken its walls. That is why the NK-33 has a better TWR than the RD-180 (specially took engines with the same cycle as an example)
3) RL-10 has a higher specific impulse due to a different fuel pair, despite the fact that the temperature in the combustion chamber is lower than that of the Raptor. This is because the reaction mass for hydrolox engines is only water, while for methalox engines it is water plus heavier CO2.
4) The heating rate is of key importance, because the gas is not in a closed volume, it constantly leaves the combustion chamber and the faster we supply heat, the greater the exit gas velocity will be
Always double-check and question your knowledge, and only then can you come up with something new.

The YouTube link to the press conference started very late into the press conference but the Twitter one started on time:
Do you think the fairing would be able to fly down to the ocean like Falcon 9 does?
SpaceX General Section / Re: SpaceX EVA suit
« Last post by Dalhousie on Today at 09:08 pm »
Jarad mentioned the suit as having 'John-117 vibes' in a Thanksgiving tweet. For the non-gamers, it's a Halo reference. It suggests that they've gone with a mix of rigid 'armour' and soft bits.

What does "market does not value performance" mean?

Briefers this afternoon are:

Mike Sarafin, Artemis mission manager, NASA Headquarters
Judd Frieling, flight director, NASA Johnson
Debbie Korth, Orion Program deputy manager, NASA Johnson
Melissa Jones, landing and recovery director, NASA Kennedy Space Center

Sarafin said the mission management team committed today to deploy the recovery forces from San Diego on Dec. 7. This is ahead of a planned Dec. 11 splashdown by Orion in the Pacific Ocean.
Missions To The Moon (HSF) / Re: Gateway Updates Thread
« Last post by yg1968 on Today at 09:07 pm »
Quote from: NASA Gateway
Our international partners @nasa, @csa_asc, @esa, @mextjapan and @JAXA_en met for the 2nd Gateway Multilateral Coordination Board to review status of Gateway’s development and schedule.
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