I've read that tetramethylethylenediamine is a possible less toxic replacement for hydrazine which also acts as a hypergolic propellant with nitric acid. However, I found little information about research on that topic and conducted experiments. Are there papers on that matter I was not able to find?

I'm playing KSP with the Realism Overhaul mods and I have a question: to the best of my knowledge, engines that run on hypergolic propellant, such as the LR91-5 (the one used in the TITAN II rocket), should be able to restart virtually as many times as I wanted, since hypergolic propellants spontaneously ignite in contact, but the one included in realism overhaul (I don't know which mod exactly adds the real life engines to the game) has only 1 ignition... Is it wrong or am I missing something here?

Mods, if this is too unsafe you can take it down, makes perfect sense and I won't be mad

EDIT: PLEASE take it down if it is, I don't want anyone getting hurt from my post

From what we saw in Tim Dodds interview, there seems to be an earnest hope that regular raptor can be used for moon landings without kicking up too much regolith or boring a hole into the surface leaving the lander partially buried. Given the obvious alternatives I can't say I blame them. Most press material we've seen so far depict a ring of ~12-16 smaller thrusters located higher up the rocket to perform final landing burn deceleration. Are these hypergolic using traditional (super)dracos and HLS has an entire separate fuel storage and and distribution system? Do they adapt dracos to burn methlox propellant? Or design a completely new methlox engine for these landing thruster? The upside for these latter two options is they can utilize a common methlox fuel same as the main engines which much simplifies propellant considerations. The massive headache is that these two options require design certification. Compared to just using regular raptor, the mammoth task of developing testing, and getting NASA approved, human-rated certification for an entirely new engine size would be gargantuan. Massive time, energy and finance costs. If testing does ultimately indicate regular raptor alone is unsuitable for lunar landing, are there plausible ideas to be explored around swapping a regular main engine for a down-scaled landing variant? Or an engine bell with some form of thrust diffuser or deflector be it fixed or deployable.

Third option often discussed is some use of hot ullage gas/ hot thrusters but I'm not sure that 1/6th Earths gravity is a great enough reduction for gas thrusters alone to provide adequate landing and/or takeoff amounts of thrust. Again, many benefits with these two options as it keeps fuel types and plumbing solutions fairly similar. Either way, what we’ve seen in the press release images actually seems to be one of the least appetising options and imo it’s very likely we’ll see SpaceX aggressively exploring all kinds of pathways in an attempt to avoid a complete novel design/certification process. Especially since 2024 is not far away at all.

I was recently reading up on the development of the ICBM programmes of both the US and the USSR and got the impression that as time went on, the US started to lean towards solid-fueled ICBM, with the exception of the TITAN ICBM, while the USSR relied more on liquid-fueled ICBMs.

I also started doing basic research on the advantages vs disadvantages of solid-fuel vs liquid fuel ICBM.

Some online articles pointed out that Liquid-fueled ICBMs often tend to have better "impulse thrust" or "Throw-weight-ratio", which I take to mean that it has more thrust for its mass when ignited, compared to solid-fuel. Another was that solid-fuel ICBM have no choice, but to burn all the way after ignition, while ground-control stations can switch-off, switch-on, and/or adjust the amount of thrust of liquid-fuel ICBMs. Is that correct?

I also read that liquid-fuel ICBMs often have to be fueled right before launch, which makes it vulnerable to decapitation strikes because of the time vulnerability. But given the time disadvantage, why did the USSR stick with liquid-fuel ICBMs for so long? Also, why liquid-fuel ICBMs can't be pre-filled beforehand?

I am currently designing a gas generator-cycle liquid rocket engine and want to use ethanol as a fuel and hydrogen peroxide as an oxidizer. I need to know a few things in order to design parts, increase efficiency, and run said engine in a safe environment.

• What ratio of Ethanol to Hydrogen Peroxide is most efficient for combustion?
• What is the highest temperature combusting Ethanol and Hydrogen Peroxide Achieve?

What is this about?

This post is about viability of a kickstage inside dragon trunk. Belly of the Dragon, or Bowels. Whichever you prefer. Either way, flame comes out.

Prelude

While I was trying to get the "no villager acquired" achievement in AOEIIDE barbarossa campaign third mission, pope and antipope, unsuccessfully I might add. A thought occured to me.

Chapter 1 - Hectonewton

According to SpaceX Website Dragon Trunk has 37 m3 (metercubed) volume. But that is the extended trunk, which never saw use to date as far as I know. The actual trunk in use today should have something like 12.5 m3 volume. Let's say we want to make a propulsion module that fits inside this trunk. Sort of a restartable kickstage. One that is purpose built for crew dragon trunk. Let's omit obvious launch abort issues this would cause.

We want to use %100 pure hydrogen peroxide because why not and RP-1, 1.45 g/cm3 and 1.02 g/cm3 respectively. The engine can be a hydrogen peroxide decomposition turbopump powered vacuum optimized thing but that is just details, right? I looked up the British lipstick rocket which had similar engines, 30% water diluted peroxide at 8:1 ratio. I'm going to go and say we want to have a nice 7:1 ratio. Why? I have no idea to be honest. If we use 30 m3 of volume for our propellant that comes to 38062.5 kg of Hydrogen Peroxide and 3825 kg of RP-1. Combined 41887.5 kg of propellant. As a result our drymass comes out to be 2112.5 kg, for obvious reasons of rounding up. That is 44 metric tons total. That is a lot of mass. Who wouldn't want 44 tons dangling inside the dragon trunk during launch? When you add in the dragon + trunk, then it becomes 55 metric tons. That is a lot of mass.

Requires Falcon Heavy to launch to LEO, which is not human rated so there is no use for launch abort anyway. 420 hN engine on this restartable kickstage engine should produce 3.2G of thrust when propellant is depleted. And should be able to hover when throttling. Why? I haven't decided yet. By the way hectonewton is real, but it won't hurt you, promise. 420 hN = 42 kN.

If you calculate you'll find out the vehicle drymass to be 13.1125 metric tons. Let's say we have a terrible ISP of 300s. I'm sure more can be achieved but let's go with this. Bear with me. And just like that we have all the numbers, so let's calculate some performance.

Whopping 4218 m/s deltaV. A ridiculous 2934 seconds of burn time, that's 49 minutes. We need to do something about that burntime. Oh

Cover || First

Previously

Story Discord (all THR art and related discussion can be found here)

O-O-O

Author's note: I think I've worked through the majority of my grief related writer's block, so now I just have the regular kind to wrestle with. Additionally, this chapter is significantly longer than usual, enjoy.

Also, you’ll probably wanna read the last chapter again on account of how long it’s been…sorry

O-O-O

1745, 5 January 2253, Hollis’ Hangar, Nyx, L5

Moxie barely fit in the packing netting, but she’d be secure for the flight. As the doors swung shut, obscuring her mech, Hollis waved to the crane operator who began lowering the hexagonal container onto the cargo trailer. With a creak of suspension springs, the container holding her life’s work dropped into place.

Hollis walked to the front of the trailer and pulled out her terminal. She needed a substantially bigger vehicle than her little cart to haul this trailer. After posting a job request, she leaned up against the container and waited for a response.

She thought as the noises of the evening surrounded her. I can’t believe I’m doing this. Hollis drummed her hand against the white container as she waited for someone to show up. There’s oxy-nitrogen pressurizing the container and it’ll stay pressurized for 5 years at the current rate, at least. She’ll be fine. Hollis sighed. This was the craziest thing she’d ever done, and that included getting into a fight with the mafia with an unmodified construction vehicle as her sole weapon.

O-O-O

1800, 5 January 2253, Gold Horizon Supercarrier En Route to Nyx

Sam drifted into the common room, Ana’s ears perking up a bit as the lynx entered. Her eyes darted towards Matt and then to Ana herself. She shook her head and said, “You two need to....ugh, this operation is dangerous.”

Ana swallowed and replied. “Obviously. Why are you telling us?”

Sam wrung her hands as she looked around the room. “You two should write...something to go to your family...if the worst happens.” She didn’t make eye contact with either of them.

Ana gritted her teeth. “Well it won’t. I won’t let that happen. Not again.” Her fur began to stand on end as her tail lashed.

Matt sighed and shook his head. “Ana....”

Steel crept its way into Sam’s v

I don't want to step on anybody's toes here, but the amount of non-dad jokes here in this subreddit really annoys me. First of all, dad jokes CAN be NSFW, it clearly says so in the sub rules. Secondly, it doesn't automatically make it a dad joke if it's from a conversation between you and your child. Most importantly, the jokes that your CHILDREN tell YOU are not dad jokes. The point of a dad joke is that it's so cheesy only a dad who's trying to be funny would make such a joke. That's it. They are stupid plays on words, lame puns and so on. There has to be a clever pun or wordplay for it to be considered a dad joke.

Again, to all the fellow dads, I apologise if I'm sounding too harsh. But I just needed to get it off my chest.

I guess the concept didn't work

Alot of great jokes get posted here! However just because you have a joke, doesn't mean it's a dad joke.

THIS IS NOT ABOUT NSFW, THIS IS ABOUT LONG JOKES, BLONDE JOKES, SEXUAL JOKES, KNOCK KNOCK JOKES, POLITICAL JOKES, ETC BEING POSTED IN A DAD JOKE SUB

Try telling these sexual jokes that get posted here, to your kid and see how your spouse likes it.. if that goes well, Try telling one of your friends kid about your sex life being like Coca cola, first it was normal, than light and now zero , and see if the parents are OK with you telling their kid the "dad joke"

I'm not even referencing the NSFW, I'm saying Dad jokes are corny, and sometimes painful, not sexual

So check out r/jokes for all types of jokes

r/unclejokes for dirty jokes

r/3amjokes for real weird and alot of OC

r/cleandadjokes If your really sick of seeing not dad jokes in r/dadjokes

Punchline !

Edit: this is not a post about NSFW , This is about jokes, knock knock jokes, blonde jokes, political jokes etc being posted in a dad joke sub

Edit 2: don't touch the thermostat

Exhibit A: So - holy shit. SpaceX want to develop Starship reliability and cost where they can land a fully-equipped, extremely high-value ship to lunar orbit and then take a crew down to the surface. In about 5 years. On top of all the Mars stuff. With not nearly enough NASA money to do so. How are they going to do that?

Answer: reusing existing hardware.

Exhibit B: new Lunar Starship render from the NASA press release in extremely high resolution and with lots of juicy details. People have already pointed out the lack of pointy nosecone, I'm also very interested in the new landing legs and the probable information we can glean from the windows into the crew cabin. But I'm most interesting in what's missing from this image - the big landing thrusters sitting above the main propellant tanks on all the old renders.

Those were always a massive unanswered question for me - what were they? More variant Raptors? A new engine entirely? Where's the development work on it? What's it called? Many questions and no answers.

But now they are gone. In their place, a ring of small holes around the base of the crew/cargo section. I haven't measured but I'd hazard a good guess that they're almost right above the top of the propellant tanks. What are they?

The ol' reliable technique of holding a ruler up to a monitor reveals they're about 1/38th as wide as Starship (=23cm wide) with an aspect ratio of about 2.5:1. They're arranged in clusters of 6, with either 4 or 6 clusters around the vehicle. That brings us to...

Exhibit C: Crew Dragon, and particularly the SuperDraco thrusters. Repeating the screen-and-ruler trick gives us a width of 25cm and an aspect ratio of about 2.7:1. Coincidence? Maybe, let's dig further.

Exhibit D: The numbers. SuperDraco has a rated thrust of 73kN, which is enormous for this purpose - enough to lift about 45t in lunar gravity. 24 or 36 would be ludicrous. However, one of the under-used features of SuperDraco for the Dragon abort role is the deep throttle. SpaceX claim a deep throttle capability down to 20%, which brings the minimum thrust down to 15kN = 9t under lunar gravity. (The famously deep-throttlelable LMDE could get down to

Do your worst!

How the hell am I suppose to know when it’s raining in Sweden?

Ants don’t even have the concept fathers, let alone a good dad joke. Keep r/ants out of my r/dadjokes.

But no, seriously. I understand rule 7 is great to have intelligent discussion, but sometimes it feels like 1 in 10 posts here is someone getting upset about the jokes on this sub. Let the mods deal with it, they regulate the sub.

Mathematical puns makes me number

They were cooked in Greece.

I'm surprised it hasn't decade.

Now that I listen to albums, I hardly ever leave the house.

He lost May

Two muffins are in an oven, one muffin looks at the other and says "is it just me, or is it hot in here?"

Then the other muffin says "AHH, TALKING MUFFIN!!!"

Don't you know a good pun is its own reword?

For context I'm a Refuse Driver (Garbage man) & today I was on food waste. After I'd tipped I was checking the wagon for any defects when I spotted a lone pea balanced on the lifts.

I said "hey look, an escaPEA"

No one near me but it didn't half make me laugh for a good hour or so!

Edit: I can't believe how much this has blown up. Thank you everyone I've had a blast reading through the replies 😂

It really does, I swear!

Just not sure when to use all of the different fuel types versus just liquid fuel and oxidizer, and why you can use fuel with or without oxidizer. I really appreciate it.

And now I’m cannelloni

Because she wanted to see the task manager.

But that’s comparing apples to oranges

And boy are my arms legs.

Put it on my bill

Heard they've been doing some shady business.

but then I remembered it was ground this morning.

Edit: Thank you guys for the awards, they're much nicer than the cardboard sleeve I've been using and reassures me that my jokes aren't stale

Edit 2: I have already been made aware that Men In Black 3 has told a version of this joke before. If the joke is not new to you, please enjoy any of the single origin puns in the comments