Rocketry General Thread


SpaceX Dragon capsule docks with space station - bbc article with inside crew area video

Scott Manley discusses the Dragon 2 Spacecraft Docking At Space Station


Here’s the video.


SpaceX Dragon demo capsule returns to Earth - bbc

SpaceX Crew Dragon Splashes Down in Atlantic to Cap Historic Test Flight - space dot com

SpaceX’s Crew Dragon was a pristine white when it left the International Space Station on March 8, 2019. Now it’s a “toasted marshmallow.”(Image: © NASA TV)


Just watched the Apollo 11 movie. It was totally mindblowing. Recommend it to everyone here to go see it on the best screen you can.

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I had the thought today that space will become the next arena of warfare - but for a good reason. Air superiority is what one establishes to develop air supremacy.

It’s pretty hard to establish air supremacy if you can launch a deorbiting missile from space moving so quickly and at such an odd angle that it’s impossible to avoid. It’s not like a fighter jet will take out a large military spacecraft with missles onboard.

Say that Russia decides to establish space supremacy. No, scratch that. Suppose that the Pentagon decides that because Russia could be developing its own cheap rocket program (and because China is), it becomes an automatic decision to prepare for foreign attempts at space supremacy.

It’s a game theory problem. Establishing space supremacy ensures air supremacy - something the United States is required to establish.

This should be a massive cash grab for SpaceX next decade - a flourishing of space R&D funding.

Brace yourselves, shit’s about to get wild.


De-cluttering Earth orbit would be my first priority, something at our present rate is going to take decades.


Scott Manley asks can Orion Fly Around The Moon Without SLS?


Militarization would, in fact, require the decluttering of LEO.

I’m not a hawkish person, but I do think that the military being convinced that space is necessary for defense is more useful than dangerous. We already have nukes.


Indeed. It’s impossible to hide anything in space, and de-orbiting weapons would be difficult compared to simply launching them on a non-orbital trajectory in the first place.

It’s far more likely that space based systems would be more anti-weapon systems than anything else.


When I read this yesterday I thought that application was outlawed. Then I checked and saw that in fact it is “only” Weapons of Mass destruction that are not allowed.

Also. Didn’t see much mention of low earth orbit in there but I think no “permanent” WMDs there either.

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not to belittle the spirit of pioneering, but i foresee a lot of unnecessary deaths in the wake of privatized space flight because sometimes eagerness and optimism(especially when investment money is involved) will overcome common sense and caution


I would tend to agree, we’ll likely see some tragic incidents at some point in the future. However, the current players have placed a high priority on safety, and working closely with their respective government agencies (upon which they depend) to ensure new systems are thoroughly tested / proven prior to loading precious “human cargo” :wink:

As more players enter the game it’s likely that as with other developing industries, people will cut corners and learn from tragedy caused by poor design, overconfidence, rushed development etc.

I have to admit, the current Starship development that SpaceX is pushing is moving at a high rate, which gives me some concern they could be moving too quickly. As exciting as their progress is…


It’s on-brand


My biggest fear about Starship is indeed its speed of development. I worry that there is some hubris in their schedule.

A big mistake that people make is that after a victory, they take it to another level too fast. Maybe a weightlifter pulls a muscle, or a pianist gets an overuse injury and misses a performance.

Or a business overexpands and goes bankrupt.

It’s quite unnerving, and if it was anyone other than Elon Musk I’d say it would be about to fall apart.


This video is awesome! Though it’s taken awhile, it shows a lot of progress that RE has made over the years. That pre-cooler is insane.

The weapons/tech race for it is already here. The tech demo’s by various nations have been ongoing throughout the last decade and has everyone scrambling to figure out what’s next.

Kessler Syndrome is a serious issue for spaceflight, however in space warfare I don’t think it will become a problem unless everything goes to shit. It’s just like terrestrial nuclear weapons. If you remove space based assets with kinetic weapons it’s mutually assured destruction of that orbit(and potentially those below it) and nobody gets to use the high ground. I feel like traditional ASAT missiles are a last resort option in today’s modern world that views space based assets as a necessity for communication and navigation.

There has been a lot of research into space based ASAT weapons that can disable a satellite without causing debris and that’s where the race is at currently. This is just my opinion but that’s way I see space warfare playing out in the future. If you want to think about where space warfare is headed that’s the direction to look in.

For those interested read about Kosmo 2504 or SJ-12. The Space Review has a couple of good articles on the topic in the Dancing In The Dark series if you want to get a feel for it.


Scott Manley tells us about the Raptor Rocket Engine Analysis and Starship Testing Update


There has been a lot of research into space based ASAT weapons that can disable a satellite without causing debris and that’s where the race is at currently.

I already had the thought.

I was wondering about your thoughts on a gas-based debris capture. So, you launch a vehicle, release a bunch of the optimal gases at the right altitude to slow many items down enough to start reentering, i.e. making a 100 mile wide plume of gas which is traveling initially at an orbital velocity, but renters due to the large number of velocities of gas particles causing collisions.

So, you might have a bunch of space junk which hits the plume and then you integrate dv(x)/dx over 100 miles of several objects possible traveling in the opposite direction of the plume.

EDIT: Boeing already has a patent.

So far that’s my favorite idea, seems like you could capture a lot more debris at once.


Interesting idea. I wanted to run some back of the envelope maths on it to see if it could significantly slow down anything but I haven’t had the time. Best I can do with near-zero work is say that within a few orbits your gas will be dispersed along a huge portion of the orbit(potentially the entire thing) and probably won’t create any significant drag force at that point. It’s hugely dependent on the amount of pressurized gas you bring up but I can see issues arising there.

As an example, here’s a graph I made a couple of weeks ago showing an initial random distribution of a single particle using 1000 points and ± 10km position and ± 1cm/s velocity. The location is plotted initially and every quarter portion of it’s orbit for 1 orbit.

Ignore the blue dots, we were looking at the difference between individually integrated points vs a linear approximation. The red is essentially truth.

One would need to do the math to see what equivalent mass of gas would need to bring up to increase the ambient pressure in some volume and see if it’s any appreciable number. My initial guess says it might not but if you brought enough it could be? This would only really work in ~400-600km orbits to speed up decay by lowering their orbits to where the natural decay can act in a relatively quick fashion.

This integration didn’t have any atmospheric drag in it and the apogee is huge(origin of planet is at (0,0) for reference) rather than a circular orbit.