Artemis II Wet Dress Rehearsal Update: Countdown Progressing

NASA ^

[SunkenCiv]

NASA continues to press ahead through the Artemis II wet dress rehearsal countdown – a fueling test of the SLS (Space Launch System) rocket.

Early this morning, at approximately 3 a.m. EST, teams powered up the rocket’s core stage, which will be loaded with more than 700,000 gallons of liquid oxygen and liquid hydrogen during the tanking phase of the countdown. This will occur over a series of different propellant loading milestones to fill, top off, and replenish the tanks. The interim cryogenic propulsion stage also was powered up overnight.

Around 11 a.m., or L-33 hours, 30 minutes in the countdown, operators began charging Orion’s flight batteries. Core stage battery charging is scheduled to begin this afternoon. Later today, engineers will conduct final preparations of the umbilical arms and perform a walkdown at the launch pad.

A 24/7 live stream of the rocket at the pad continues online. NASA will provide a separate feed during tanking activities, as well as real-time blog post updates regarding the test during the fueling day.

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TOPICS: Travel
KEYWORDS: artemisii; nasa; orion; sls

[SunkenCiv]

Engineers at NASA's Kennedy Space Center are conducting a prelaunch test to fuel the Artemis II Space Launch System—a vital step in ensuring this rocket is ready for its upcoming trip around the Moon.

During the rehearsal, teams will demonstrate the ability to load more than 700,000 gallons of cryogenic propellants into the rocket, conduct a launch countdown, and practice safely removing propellant from the rocket without astronauts inside the spacecraft. This is the second "wet dress rehearsal" test, following a previous rehearsal on Feb. 2.

Teams are counting down to the opening of a simulated launch window at 8:30 p.m. EST on Feb. 19 (0130 Feb. 20 UTC), which could extend to up to four hours

NASA's Artemis II Fueling Test (Official Feed) | NASA
12.7M subscribers | 2,791 watching now | Started streaming 2 hours ago

[al baby]

I got a bad feeling about this one

[SunkenCiv]

Something like eight hours to go. The other feeds of this have live comments (audio and texts from participants). The NSF feed has about 1000 more viewing it than are viewing this NASA feed.

[SunkenCiv]

😁

[SunkenCiv]

The NSF feed link:

https://www.youtube.com/watch?v=pOAOV9I6zEA

[MarlonRando]

back in the day, they used to use your IQ and had rigorous testing to pick the best.Today, you always have to have the lady, the black guy, the chinaman etc. So I worry. Neil Armstrong landed on the moon because he was a fu&$ing genius. He was able to do 100 things at once. He was an actual hero. They were going to run out of fuel and crash, and he turned it into a raging success. Do these guys on Artemis have the right stuff? I hope they do.

[Jan_Sobieski]

Hopefully THIS is the voyage that they figure out how to get living bodies through the Van Allen belts without radiation poisoning!

NASA: Technology not invented yet…

[SunkenCiv]

Spaceflight Now
https://www.youtube.com/watch?v=aiy5YLuza_w

The Launch Pad
https://www.youtube.com/watch?v=l_55N9Un2uI

Getting Ready for Artemis II: WDR #2 Pre-Game Show | Philip Sloss
https://www.youtube.com/watch?v=-glHUIicm5s

Interstellar News Hub
https://www.youtube.com/watch?v=l8yfzvhKy4s

[SunkenCiv]

The same way Apollo did it — a little shielding and a propulsion system.

[ProtectOurFreedom]

I was just wondering why NASA is using the difficult liquid hydrogen / liquid oxygen combination. Turns out Congress mandated in the 2010 NASA Authorization Act that Shuttle-era technology be incorporated to reduce development costs and risks by leveraging decades of flight-proven hardware (the Shuttle flew 135 missions successfully, with no failures attributed to hydrogen issues).

Newer rockets (e.g., SpaceX’s Starship) favor liquid methane / liquid oxygen (”methalox”) for easier handling and long-term storability, SLS prioritized reliability from heritage systems for the demanding lunar missions.

[PIF]

I got a bad feeling about this one

—
Nothing is getting launched today - relax.

[PIF]

The Chinese are using kerosene which is a great fuel and is nowhere near as explosive as US fuels

[SunkenCiv]

They’re not going to be landing, assuming that the launch happens in March, or April.

And yeah, Neil was not picked for that job by accident, or chromosomes.

The story of Neil Armstrong’s X-15 Test Flight that Bounced Off the Atmosphere
By Dario Leone
April 29 2021
https://theaviationgeekclub.com/the-story-of-neil-armstrongs-x-15-test-flight-that-bounced-off-the-atmosphere/

and as Dave Scott said, years later, “that’s why you put Armstrong in charge.”

Mission Monday: Gemini 8 and Agena, the first docking with an uncrewed spacecraft
https://spacecenter.org/mission-monday-gemini-8-and-agena-the-first-docking-with-an-uncrewed-spacecraft/

[MarlonRando]

he was a legend. People will still be talking about Neil 1000 years from now.

[Larry Lucido]

[ProtectOurFreedom]

I remember reading a good article some years back on the SpaceX decision making process regarding fuel trade-offs. Here's a simple summary.

Propellant Type	Vacuum ISP*	Propellant Density	Handling Difficulty	Key Advantages	Examples
Hydrolox (LH2/LOX)	450–460 s	Very low (requires massive tanks)	High (extreme cold, leaks, boil-off)	Highest efficiency for deep space/heavy lift	SLS core/upper, Space Shuttle, Centaur upper stage
Kerolox (RP-1/LOX)	300–350 s	High	Moderate (dense, room-temperature fuel)	Better thrust-to-weight, easier storage	Falcon 9, Saturn V first stage, Atlas V
Methalox (CH4/LOX)	350–380 s	Medium	Lower (less cryogenic than hydrolox)	Cleaner burn, potential for in-situ production (e.g., Mars)	Starship, Blue Origin New Glenn (upper)

*Specific Impulse, thrust per unit of propellant mass

[rktman]

Ah yes. The old WTDC procedure. I remember them well. 🚀😊👍

[ClearCase_guy]

[SunkenCiv]

The SLS is a Shuttle-derived vehicle, and that’s the fuel combination the Shuttle used — and is why de facto staging is performed on both by solid rocket boosters. The biggest risk in the system is, alas, the SRBs.

The Soviets reverse-engineered captured V2 engine(s), but the original vehicles used alcohol with LOX as the oxidizer. A third fuel, a monopropellant, drove the turbopumps used to feed the main engine.

RP-1 (chemically consistent kerosene) was settled on by Von Braun, and widely copied as a result.

By VB’s time, Germany had been the capital of the chemical sciences for over a century. Most of the rocket propellants which have been tried (including those of the USSR) were developed and tested historically (not necessarily in flight, or even for rocketry) in prewar Germany.

In the US, VB switched to RP-1, and in 1946 launched a modified V2 to an altitude record. While up there the first photos were taken from space. Sez here leftover modified V2s continued to be fired as research through 1950.

https://spacecenter.org/first-photo-taken-from-space/

Using subcooled kerosene (Falcon 9) or liquid methane will probably wind up preferred to liquid hydrogen as things go forward. Hydrogen’s main drawback is, under high pressures needed, it will leak out of whatever it’s in, becasuse it’s the smallest atom.

[PIF]

That's the famous China man, Wan Hu, reportedly attached 47 gunpowder rockets to his chair, lit the fuses and took off, and was never seen again.