What Speed is Needed to Launch a 1500 kg Cargo Container to 160 km Altitude?

[ElfredaCyania]

Now I started to wonder if it's possible, at least in theory, to fire something directly from the ground into Earth-Moon L4 or L5, it's probably the simplest solution for single-shot-to-orbit.

 

[Drakkith]

Now I started to wonder if it's possible, at least in theory, to fire something directly from the ground into Earth-Moon L4 or L5, it's probably the simplest solution for single-shot-to-orbit.

Good luck getting through the atmosphere at 10+ km/s...

 

[Tom.G]

Good luck getting through the atmosphere at 10+ km/s...

Yup, Mach 30 would be a, uhmm, uhh, shall we say, a definite challenge?

[EDIT] See thread https://www.physicsforums.com/posts/7091509
The USA military will be trying to hit Mach 7 in early 2025, just to see what happens. Kind of a slow start for your Mach 30.

 

[Flyboy]

Now I started to wonder if it's possible, at least in theory, to fire something directly from the ground into Earth-Moon L4 or L5, it's probably the simplest solution for single-shot-to-orbit.

From the surface of the Earth, not recommended. As others have mentioned, the drag and compressive heating loads are, frankly, absurd.

Now, from the surface of the Moon? Now that’s a whole different critter, and has been proposed several times over the years for mid to late colonization periods.

 

[sophiecentaur]

The direction of the velocity is perpendicular to Earth's surface. And by initial speed I mean a sudden thrust, after which there's no thrust at all.

SpinLaunch is just another scam project that exists only because investors and sponsors have no idea about physics. Just like Mars One, SpinLaunch will cease to exist pretty soon without launching a single satellite, and sponsors will just lose all invested capital.

From what you write in the first quote (nonsense) , I can't see how you can possibly feel qualified to make the comments in the second quote. If you want to be taken seriously, you should at least have some reference to justify your dismissal of Spin launch.
But I wouldn't invest my money in spinlaunch.

 

[Zybex]

From what you write in the first quote (nonsense) , I can't see how you can possibly feel qualified to make the comments in the second quote. If you want to be taken seriously, you should at least have some reference to justify your dismissal of Spin launch.
But I wouldn't invest my money in spinlaunch.

Okay, even if I can't think about a formula to apply, do I need to be qualified to understand that a Boeing 747 will fall to the ground while trying to make a turn at 1000 ft while the speed is only 250 mph? It's called common sense, isn't it? On the contrary, I've seen many instances in my life where people with degrees in their fields make basic mistakes on a daily basis.

SpinLaunch seems very fishy to me. You can disagree and bring some facts to educate people like me, which I hope to get here and that's why I'm here. When I see projects that don't make sense to me personally, I have questions and doubts.

I'm not a scientist, but I am aware of basic things like air resistance, gravitational force, vacuum, etc. Everyone can experience the air resistance even at any indoor skydiving. I watched space launches, documentaries about SR-71 and scramjet, and I grasped the concept of the amount of energy required to go beyond Mach 5. When Mars One was the thing and people were signing up for it, I knew it's not gong to happen on the spot. I didn't have to do calculations, etc. It all happened in my head in a second.

I knew that humanity never had such a long space travel, I knew that the space is very dangerous to our DNA and cells, I read about Van Allen Belts and that solar radiation will affect equipment and living organisms, I was thinking about what would be needed on that ship, where they are going to get air to breath, water to take showers, food to eat, medics, equipment, tools, materials to solve any medical issues on another planet, what protection will they get with such a thin atmosphere with 98% of CO2, no nitrogen and barely any oxygen, how they going to be able to work and exist in such environment, how the crew would take such a trip mentally (7 months to get to Mars in a totally different environment where a human can't do many things the way they used to on Earth), what they are going to do when accidents happen, and many other things.

Then I listened to the interviews with Mars One founder and got even more convinced that it's just a scam. Do I need to know exact formulas to remotely understand the amount of challenges that scientists and engineers have to think about before even suggesting to go to another planet? Should I remind how many times Elon Musk promised different things to his investors and those never happened? He promised full self-driving since 2014 and it is still on Level 2. When I saw him ditching LIDAR, I knew that he's not going to get even to Level 4 just using camera vision in a long time. But people still happily pay $10k for, what I call it, "fool" self-driving.

So, when I first time saw SpinLaunch trying to do their thing, that made me very skeptical about the whole concept of launching anything to the orbit without any thrust. Other issues would be the reliability of the motor spinning the arm, a sudden release of the payload on one side of the arm while spinning at 450 rpm, going from vacuum to air pressure, etc.

Now, do you feel qualified to judge whether I'm qualified to talk about SpinLaunch without knowing what I know? :D

 

[berkeman]

Thread is closed temporarily for, well, you know, review...