Tim Dodd is a world treasure when it comes to space education. The material he's produced are timeless. Thanks Tim for the quality and down to earth content you've made and all the behind the scenes interviews with Musk and other rocket companies.
How do you power a rocket engine?
41–50 of 87 posts
Re: How do you power a rocket engine?
#42Earlier quoted context omitted.
Quoted post unavailable.
> All that stuff was financed by people who didn't live to see such applications, and without their consent. How can a collective group of people give consent? Basically everything any state does is without consent. Do you only consider direct democracy where people can directly decide on each choice the government makes as legit? By your definition it seems social security is also without consent. So by that logic n…
> Do you only consider direct democracy where people can directly decide on each choice the government makes as legit?
Humanity is like a plane at some point there is enough lift that unless somethnig traumatic happens the plane is in the air and would still be . The analogy is that people would still get interested in stuff on their own and they'd finance those things even without extorting them.
And it would be a much better distribution of capital and human resources.
This model where we extort people was valid maybe in the 1800s.
Speaking of today's situation NGOs, foundations, endowments are much better than governemnts because they can't use violence, hence they have to convince and only those who they manage to convince end up giving them money.
Re: How do you power a rocket engine?
#43Earlier quoted context omitted.
Integza is one of my favorite channels of all time, his videos are always really informative and fun to watch. The only problem is he’s completely careless about safety—mainly by not wearing any protective gear for the exhaust fumes which include burned plastic.
I’m really torn on Integza. It’s a great channel and I love his spirit, but guys like that (and the teenagers that follow them) end up getting hurt or burning down their houses, which makes the news and gets new restrictions passed on all of us. Just a _little_ more nodding to safety would make him an awesome resource. Maybe safety culture in Portugal is different, but in the US he does tons of stuff that violates th…
I wouldn’t consider the rocketry code itself a good argument. The model rocketry code, frankly, is biased hard against any kind of liquid (especially non-hybrid) rocket engines, so there’s not even really a way he could follow it with a liquid in any reasonable way.
(Which isn’t to say he couldn’t follow better safety common sense.)
Re: How do you power a rocket engine?
#44Very good article, but have few shortcomings.
1. Only first generations of "Soyuz" used H2O2 propellant, because it have very limited time before use (for "Soyuz", guaranteed 6 months), and because it have relatively high melting temperature.
First chose H2O2, because "Soyuz" planned as independent ship, to fly relatively short missions around Moon (it is near impossible to withstand even 6 months in so small volume).
When "Soyuz" primary role become companion ship for space station, it switched to hydrazine type propellant.
2. In pressure fed engines used almost all possible propellants and oxidizers. This is not error just clarification.
3. Exists three-propellant engines. For example, exists soviet engine for "spiral" system, which used kerosene+LOX+LH. First it run on mostly kerosene+LOX, with small percent of LH, than switched to pure LOX+LH (sure, LOX share also other).
4. Exists simpler bipropellant engines than mentioned, unfortunately with worse efficiency. - First Britain satellite flown on H2O2+RP1 Black Arrow rocket.
Re: How do you power a rocket engine?
#45Has anyone ever tried to capture outside air and mix it in the rocket exhaust? The reason would that more mass expelled at lower velocity can produce the same thrust with less energy.
Momentum is MV while kinetic energy is 1/2 MV*2. what a rocket really needs is change in momentum, so high energy exhaust.
Re: How do you power a rocket engine?
#46Has anyone ever tried to capture outside air and mix it in the rocket exhaust? The reason would that more mass expelled at lower velocity can produce the same thrust with less energy. Momentum is MV while kinetic energy is 1/2 MV*2. what a rocket really needs is change in momentum, so high energy exhaust.
Yes. See:
https://en.wikipedia.org/wiki/SABRE_(rocket_engine)
https://en.wikipedia.org/wiki/Skylon_(spacecraft)
But there are lot of problems with this and it adds a huge amount of complexity.
Re: How do you power a rocket engine?
#47Has anyone ever tried to capture outside air and mix it in the rocket exhaust? The reason would that more mass expelled at lower velocity can produce the same thrust with less energy. Momentum is MV while kinetic energy is 1/2 MV*2. what a rocket really needs is change in momentum, so high energy exhaust.
No post body was provided.
Re: How do you power a rocket engine?
#48Earlier quoted context omitted.
I think that you are wrong in many ways, but I will point out just one of them: GPS was developed in the 1970s, and was made available for public use in the early 1990s. Quite a lot of people whose taxes paid for the development of GPS in the 70s were still alive in the 90s to make use of it. In fact, many of them are still alive today, 30 years later. They have benefited greatly from that investment.
The conversation is about GPS for the general public and google maps. Those things emerged for the general public circa 2010. So 1970 to 2010 that's 40 years not 20. Also those who paid the lionshare of that were of course not young but in their 50 or 60, because that's the demographic which pays more taxes. Highly unlikely they got to see it. That's the reason why every person talking about space should know that th…
You're off by a decade.
Garmin introduced their StreetPilot in 1998. I didn't buy the first model, but when the StreetPilot III came out in early 2002 I jumped on it. That GPS served me well for many years.
Sure, GPS wasn't ubiquitous like it is today where everyone has one in their pocket, but it certainly was available to the general public.
Re: How do you power a rocket engine?
#49it’s going to be interesting to see personal rockets one day complete with regulations and all the ins and outs of that industry becoming mainstream
How will we ever afford the colossal amounts of fuel that will use, and think of the pollution!
> think of the pollution!
Hydrolox engines only emit water
Re: How do you power a rocket engine?
#50Earlier quoted context omitted.
The conversation is about GPS for the general public and google maps. Those things emerged for the general public circa 2010. So 1970 to 2010 that's 40 years not 20. Also those who paid the lionshare of that were of course not young but in their 50 or 60, because that's the demographic which pays more taxes. Highly unlikely they got to see it. That's the reason why every person talking about space should know that th…
You're off by a decade. Garmin introduced their StreetPilot in 1998. I didn't buy the first model, but when the StreetPilot III came out in early 2002 I jumped on it. That GPS served me well for many years. Sure, GPS wasn't ubiquitous like it is today where everyone has one in their pocket, but it certainly was available to the general public.
> Garmin introduced their StreetPilot in 1998. I didn't buy the first model, but when the StreetPilot III came out in early 2002 I jumped on it. That GPS served me well for many years.
https://www.cnet.com/roadshow/reviews/garmin-street-pilot-ii...
"the manufacturer lists $1,272"
1,272$ in 2002 = 2120$ in 2022.
This is what people mean when they say techno-utopianists, space fans and SV types are completely detached from reality.
Living in the world of fairy tales and unicorns.
In the end when things are not done with enthusiastic consent from all parties involved, it's only a matter of time before the chicken come home to roost and people will look to get their money back from the organizations that took them
Rockets and Mars helicopters are cool but the vast majority of the population has other priorities. The companies providing actual quality of life to Americans are Walmart, Costco, Google, Microsoft, Exxon, IBM, Shell, McDonalds, Berkshire...not spaceX