Yeah, is cherry picked, but a lot of the early USA stuff on that list is like "first geostationary satellite" which isn't really the same level as "first satellite". USSR got the first living being in space, but the USA got the first chimpanzee in space? Fair but also not really the same milestone.

[–] AntiOutsideAktion@hexbear.net 12 points 3 days ago (1 children)

Getting a satellite back is on the same level as getting a satellite out. There were a lot of firsts to go around. The first rendezvous and docking are as important as reaching space and orbit, to kerbal space program at least. The first planetary flyby...

My take on the space race is that the US unilaterally decided there was one and what the goal would be. If you just put the accomplishments next to each other it's just good stuff.

[–] AntiOutsideAktion@hexbear.net 9 points 3 days ago (1 children)

I just noticed on that list that 'first space launch from another celestial body' was the same mission as 'first manned landing'

shocked-pikachu They didn't test that first??

[–] buckykat@hexbear.net 4 points 3 days ago (1 children)

They did test uncrewed engine restart and takeoff from the moon with Surveyor 6, they just didn't take it back to orbit.

[–] TankieTanuki@hexbear.net 5 points 2 days ago* (last edited 2 days ago) (1 children)

The Surveyor 6 had a different type of engine. The Apollo Lunar Module's used hypergolic fuel, meaning it didn't require an ignition source. It also produced 23 times as much thrust as the Surveyor 6.

Not only was the Apollo 11 mission the first time that that particular engine model had ever been fired on the Moon; it was the very first time that that particular unit had been fired, ever. Because it had to be rebuilt after each use, it was impossible to test it on the ground before the mission as a quality control measure.

Incredibly gutsy.

[–] buckykat@hexbear.net 3 points 2 days ago (1 children)

it was the very first time that that particular unit had been fired, ever.

This is true of pretty much every rocket engine ever fired (including the space shuttle main engines which also had to be almost completely rebuilt after each use) except a few recent reusable first stages.

[–] TankieTanuki@hexbear.net 1 points 2 days ago (2 children)

I'm not sure that's true. You can find videos of NASA's hot fire tests. This article says they test the "flight version" of the RS-25, which sounds like it's the same unit to be used in the mission. Hypergolic propellants are too corrosive to do similar testing.

Slop machine [DeepSeek] output

Prompt: Can rocket engines be test fired before a mission?

Yes, rocket engines are routinely test-fired before a mission. This process, often called a static fire test or hot fire test, involves igniting the engine while the rocket remains secured to a test stand or launch pad.

NASA conducts full-duration static fires for engines like the RS-25 (Space Launch System) and previously for Space Shuttle Main Engines. SpaceX performs static fires of Falcon 9 and Starship engines before nearly every launch. Blue Origin, Rocket Lab, and others follow similar practices.

However, not every individual engine on a production line is test-fired if the design is well-proven and quality control is rigorous. But for crewed missions, new engine designs, or engines that have been refurbished, test firing is standard. Also, some solid rocket motors cannot be test-fired once fully assembled (they are test-fired in segments or via subscale models, because once lit they burn completely).

Prompt: Was this also true of the Apollo Lunar Module's ascent engines?

Yes, but with a critical nuance: while the ascent engine could not be static test-fired on the ground after being installed on a flight-ready Lunar Module (LM), it was certified through an exhaustive program of separate component testing and a single crucial in-flight test.

Ground Test-Firing: Not performed on a completed, flight-configured LM. The hypergolic propellants were too corrosive and would damage the engine if fired more than once.

Reason: The engine used hypergolic propellants (Aerozine 50 fuel / nitrogen tetroxide oxidizer) that ignite on contact, ensuring reliability but causing internal wear.

The ascent engine was unique because it was the only major Apollo system without a physical backup. If it failed on the Moon, the astronauts would be stranded with no rescue option. Because of this, the design prioritized absolute reliability over testability. The use of hypergolic propellants meant the engine had no ignition system to fail, but this same hypergolic chemistry meant the engine would destroy itself if fired more than once on the ground.

[–] buckykat@hexbear.net 1 points 2 days ago

The RS-25 is the space shuttle main engine, and a major reason the space shuttle never achieved its planned flight cadence was that the engines required a significant amount of rebuilding between each flight. The way they were used on the shuttle was to light them with the launch platform holding the shuttle down and make sure they were firing well before lighting off the SRBs (which cannot be shut down once lit) and releasing the launch clamps.

The Falcon (and to some limited degree Starship) are most of what I was referring to with "a few recent reusable first stages"

[–] HexReplyBot@hexbear.net 1 points 2 days ago* (last edited 2 days ago)

I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:

[–] Commiechameleon@hexbear.net 6 points 3 days ago (1 children)

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[–] PolandIsAStateOfMind@lemmygrad.ml 3 points 3 days ago (1 children)

[–] Commiechameleon@hexbear.net 1 points 1 day ago

Yes, but with Tito's face please. That's basically how America 'beat' the USSR. If I'm remembering what I had seen/heard there were Yugoslavian scientists assisting NASA/US during the space race. I'm not certain about the finer details or the vid I watched with my Serbian coworker while picking up some wheed but I'm sure it's out there somewhere.