Artemis 1 moon rocket launches

SamR

Joined Mar 19, 2019
4,485
When they launched the first Apollo Mission Atlas rocket it was the largest and most powerful rocket to date. An older friend was a young EE with RCA working at the cape as contractors on the Apollo Mission. He and another young engineer were assigned to collect some "field telemetry" about a mile from the launch pad. They had built a large bunker for launch control and the on-site dignitaries and astronaut's families to watch from but John and his fellow EE were completely out in the open. Walter Cronkite was on-site and had a large Winnebago RV that he had a fishing fighting chair bolted to the roof of for Walter to strap into and watch from. John said they could see Walter in the chair just before launch from where he was stationed. The Atlas launched and the rolling pressure waves from it were extremely strong. John claimed that they were lying prone but were bouncing off of the ground from the enormous roar of the Atlas engines. When it finally eased up enough that he could collect his wits he looked over to Walter's RV to see how he was doing. Walter and his chair were gone. The resonant pressure waves had been so strong that the RV's roof had collapsed landing Walter and his chair inside the RV.
 

Wendy

Joined Mar 24, 2008
23,065
While I do not know, I believe these SRB's are reusable. I wonder how much of the rest of the spacecraft is reusable.
 

Wendy

Joined Mar 24, 2008
23,065
I still wonder how much of this spacecraft is reusable, otherwise I suspect we will be using SpaceX the long term. Wear and tear is one thing, just throwing something away after one use is another. The engines themselves are reusable if they are salvaged properly.
 

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nsaspook

Joined Aug 27, 2009
10,679
I still wonder how much of this spacecraft is reusable, otherwise I suspect we will be using SpaceX the long term. Wear and tear is one thing, just throwing something away after one use is another. The engines themselves are reusable if they are salvaged properly.
The only things likely reusable would be the crew capsule and SRB rockets but the rockets were dumped on this flight. That spcecraft is a kludge of parts that's unlikely to ever be redesigned for reuse IMO.

https://www.cbsnews.com/news/nasa-launches-artemis-rocket-on-mission-to-the-moon/
In stark contrast to SpaceX's commitment to fully reusable rockets, everything but the Orion crew capsule is discarded after a single use. As SpaceX founder Musk likes to point out, that's like flying a 747 jumbo jet from New York to Los Angeles and then throwing the airplane away.

"That is a concern," Paul Martin, the NASA inspector general, said in an interview with CBS News. "This is an expendable, single-use system unlike some of the launch systems that are out there in the commercial side of the house, where there are multiple uses. This is a single-use system. And so the $4.1 billion per flight ... concerns us enough that in our reports, we said we see that as unsustainable."

But the SLS has two near-term advantages: flight-tested "human-rated" components and the ability to launch 30 to 50 tons to the moon in a single flight.
 

Wendy

Joined Mar 24, 2008
23,065
I have to wonder what the Falcon heavy lift vehicle can do. It may be the spacecraft of choice in the future.
 

cmartinez

Joined Jan 17, 2007
7,880
It's the price to pay for the second space race ... get to the moon again before China does ... and China will get there, and soon.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
10,679
I have to wonder what the Falcon heavy lift vehicle can do. It may be the spacecraft of choice in the future.
The Falcon Heavy center section is not 100% reusable depending on the mission type. For a moon or direct to GEO launch (like the latest USSF-44) they need center running to zero fuel and maybe even the side boosters to zero for a max heavy load.

The Falcon Heavy is harder to be a fully-reusable configuration on most flights because of the rocket equation. Payloads which are heavy and payloads to high-energy orbits (speed).
https://www.khanacademy.org/college...top-scorers/v/the-tsiolkovsky-rocket-equation
https://web.mit.edu/16.unified/www/SPRING/propulsion/notes/node103.html

It might be the choice of the future but it's still a dream while the man-rated NASA ship is headed to the moon today.
 
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nsaspook

Joined Aug 27, 2009
10,679
Are they planning to leave it in orbit? Or is it even the actual capsule and not a weighted mockup?
It's the full capsule with instrumented dummies and a normal splash down planned.

https://gizmodo.com/nasa-s-moonikin-will-boldly-go-where-no-test-dummy-ha-1847114263
So yeah, sending a dummy on this first flight is a smart idea, as the exercise could reveal potentially dangerous conditions for astronauts. What’s more, data collected during Artemis I “will be used for Orion crew simulations and to verify crew safety by comparing flight vibration and acceleration against pre-flight predictions, then making model refinements as necessary,” Mark Baldwin, Orion’s occupant protection specialist for Lockheed Martin, explained in a statement. Success in the mission will set the stage for Artemis II, in which the exact mission will repeat, save for the presence of an actual crew.

To be clear, the Artemis manikin is no crash test dummy, which is a separate category of human stand-in, as NASA explains:

Similar to manikins, NASA uses Anthropometric Test Devices, or “crash test dummies,” that are equipped with various instruments for other crew safety evaluations. Dummies are used in tests that drop a test version of Orion from an aircraft, with the final set of tests scheduled for later this year, to verify the Artemis II seat and suit can limit the risk of head and neck injury during the most severe acceleration environments – abort and landing. During water impact drop tests at Langley, dummies also occupied crew capsule prototypes to help engineers better understand what Orion and its crew may experience when landing in the ocean after missions to the Moon.
...
Artemis I will also include a pair of simulated torsos named Helga and Zohar. The pair will be strapped into the lower two seats on Orion, and record radiation exposure during the mission. One torso will be used to test a radiation-shielding vest, called AstroRad, which is designed to reduce exposure.
https://www.dlr.de/content/en/articles/news/2018/4/20181115_helga-zohar-radiation-exposure.html
Helga and Zohar: radiation exposure on the way to the Moon

1668743407524.png1668743526430.png

It's a long trip to the moon. ;)
 

WBahn

Joined Mar 31, 2012
27,868
Are they planning to leave it in orbit? Or is it even the actual capsule and not a weighted mockup?
It's pretty much the full-up Orion capsule. In fact, the delays that Artemis I has undergone have pushed back Artemis II specifically because of the need to reuse items from the Orion module (but apparently not the capsule body itself -- I don't know if that is set to be refurbished and reused or not.

The four engines on the core module are reusable -- they ARE the engines from the Space Shuttle, one of which was flown twelve time -- except that the entire core is being dumped into the ocean, so bye-bye.

The booster segments and nose cones are also from the Shuttle program and you would think recovering and reusing them would be almost automatic, but I haven't been able to find anything that even hints they were going to be recovered (and I did find numerous sites that said that it was a single-shot rocket except for the Orion capsule).

I've read a few things that say that the physics strongly favors single-use rockets for either very heavy lift or very high orbit (and Artemis is, of course, both). I haven't tried to evaluate the basis for the claims.

On a different note, I tend to sigh a bit every time I hear the "most powerful rocket ever" claim (sometimes with the "successfully flown" caveat). While true for the total thrust (8.8 Mlb) of the two SRBs (at about 3.6 Mlb of thrust each) and the four SR-25 Shuttle engines (512 klb) each (yes, that adds up to 9.25 Mlb, but the main engines are not at full power at launch on the current configuration), it is a sleight at the mighty F-1 engines on the Saturn V, which produced 1.5 Mlb of thrust each -- or about three times the thrust of the SR-25 engines. I wonder if they considered making an enhanced F-1 engine to get enough additional thrust so that the core could have had just a single engine. I'm guessing they did consider it and rejected it -- but possibly only because they have a stock of SR-25 engines left over from the Shuttle program. It's also conceivable that the total cost for four of the smaller engines is less than one of the larger engine -- they are operating in a regime where economies of scale don't necessarily win out.
 

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nsaspook

Joined Aug 27, 2009
10,679
Now that we have the reusable technologies perfected, even if it isn't NASA. It is just a matter of time
We have reusable technologies for smaller payloads but they are not perfected (due to hard to engineer physics with current technologies) in the Heavy rockets (the core booster of traveling all the way to orbit) needed for manned planetary travel yet.

SpaceX Starship looks good but is still in development.
 
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