The thread for space cadets!

[Berzerker]

Just found formal definition of ecliptic plane out of curiosity - it's actually not quite the same as the Solar system plane! Didn't know this. By definition it is the Earth orbit's plane and it's inclined by ~1 degree to the Solar system plane (which can be considered as weighted average of all planets orbits)
Orbits of other planets are within 6 degrees of inclination to it.

I thought the ecliptic (Earth's orbital plane) was actually 7 degrees off the equatorial plane of the Sun. The invariable plane - the planets combined - is 5.6 degrees off the sun's equator. Thats a significant clue to the existence of a large 9th planet with an inclined orbit, something we captured in the distant past, something we haven't found yet but has been dragging the planets - even Jupiter - away from the Solar plane. Its possible anyway.

https://asterisk.apod.com/viewtopic.php?t=19165

 

[red_elk]

I thought the ecliptic (Earth's orbital plane) was actually 7 degrees off the equatorial plane of the Sun. The invariable plane - the planets combined - is 5.6 degrees off the sun's equator. Thats a significant clue to the existence of a large 9th planet with an inclined orbit, something we captured in the distant past, something we haven't found yet but has been dragging the planets - even Jupiter - away from the Solar plane. Its possible anyway.

https://asterisk.apod.com/viewtopic.php?t=19165

By Solar system plane I meant the invariable plane. About the Sun's equator - I think since the orbits of Jupiter and Saturn are inclined to it, most likely that was the result of some irregularities during formation of solar system, and not necessary means the existence of 9-th planet. If you mean the 9-th planet should compensate the inclination of Sun's equator to the invariable plane, then it should be something huge so that we should have detected it long ago. Just my thoughts, as a non-astronomer.

 

[Michkov]

Keep in mind that Uranus and Neptune were only discovered with the advent of telescopes. If something similar sized is lurking much further out it's going to be very faint, especially if the orbit is as elliptic as proposed. The time it spends close to the sun is going to be short.

 

[red_elk]

Right, but IIRC they were first detected by their gravitational effects on other planets. And we are talking about massive object, which should be able to (roughly) compensate the effects of Jupiter and Saturn combined! May be this thing is indeed hard to see through telescope, but its gravity must have very noticeable effect on Solar system.

 

[Michkov]

Exactly, gravitational effects, imagined or really there are the reason people came up with the hypothesis. So we are seeing the effects, the problem is that the periods are so long that we cant really wait it out and see what happens. We get a couple of snapshots to interpolate an orbit from, and those come with big errorbars. Which can mess with accuracy if you are running long time predictions.

 

[hobbsyoyo]

Russia announced yet another new rocket they can't afford and won't actually develop. This is a very small rocket (600kg payload) with a first stage that has deployable wings that will allow it to return to land at a runway. This is like a scaled-down version of the Baikal booster proposal.

https://www.telegraph.co.uk/news/20...nology-fund-says-will-begin-testing-reusable/

 

[Berzerker]

By Solar system plane I meant the invariable plane. About the Sun's equator - I think since the orbits of Jupiter and Saturn are inclined to it, most likely that was the result of some irregularities during formation of solar system, and not necessary means the existence of 9-th planet. If you mean the 9-th planet should compensate the inclination of Sun's equator to the invariable plane, then it should be something huge so that we should have detected it long ago. Just my thoughts, as a non-astronomer.

It would have to be something big, but something that does enter the realm of the planets too. I doubt a planet on the outskirts of the solar system could be responsible for all the planets (minus Mercury) having inclined orbits to the Sun's equatorial plane if it just stayed way out there the whole time. It has to interact with the other planets somehow.

 

[Imaus]

Noted. Keep in mind that a (highly theoretical) 200 megawatt VASIMR could get to Mars in 40 days. Yeah, it isn't feasible right now, and waving around the Fantasy Science wand (antimatter! fusion!) doesn't actually do anything, but this is what I am primarily touting when I refer to it as the future.

That having been said, maybe I shouldn't have hyped anyone up on the premise of a technology that only works with fantasy power sources.



A quick glance tells me I'll definitely need to unpack this in detail later. Woah. O_o

Pardon the necro'ing of this topic, but has anyone made a chart about VASIMR's effectiveness with more electrical power? How would, say, 400 MW make it steam? Or a gigawatt?

 

[hobbsyoyo]

No need to apologize. This thread is open for any and all space and aviation discussion. I'm even ok with more general science-y discussion since I can usually rope that back into space somehow. I would do some searching on Ad Adstra Rocket Company as they are the ones developing VASIMR. I know they are going to install a test unit on the ISS soon.


Aeroject Rocketdyne has finished producing their first AR-22 rocket engine for Boeing's Phantom Express rocket plane. This engine is basically a modernization of the Space Shuttle Main Engine (SSME) that is mean to be easier to service and re-use. The Phantom Express will take off like a conventional rocket, go to very high altitude, then fire off a small piggyback second stage that will carry a small payload. The plane then returns to land at a conventional airfield. The whole system is meant to be cheap and allow for rapid/on-demand deployment of small satellites.

https://newatlas.com/first-phantom-express-engine/54925/

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The Russians have upgraded the video cameras on their Soyuz launcher. Here's a view of the Soyuz capsule separating from the rocket's upper stage. 3 new astronauts are on their way to the ISS.

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Virgin Orbit shipped their first LauncherOne rocket:

 

[warpus]

Rocket engines look so complicated. I realize there's redundancies for redundancies, but looking at that image all I can think is: "If one of those parts stops working..."

 

[Michkov]

The first rule of rocket club isn't "Always assume it will explode" for a reason.

 

[Imaus]

Rocket engines look so complicated. I realize there's redundancies for redundancies, but looking at that image all I can think is: "If one of those parts stops working..."

The first rule of rocket club isn't "Always assume it will explode" for a reason.

Also, IIRC, these engines are intentionally more complex to get more power. They have a gas turbine and an injector and a turbopump. You could just make a more 'dumb' engine, maybe even a more 'dumb' liquid fuel engine, but I doubt any one singular 'dumb' engine can approach the F1 and its other deviates.

 

[hobbsyoyo]

Also, IIRC, these engines are intentionally more complex to get more power. They have a gas turbine and an injector and a turbopump. You could just make a more 'dumb' engine, maybe even a more 'dumb' liquid fuel engine, but I doubt any one singular 'dumb' engine can approach the F1 and its other deviates.

I was going to say 'all engines have injectors, they aren't special' and then I saw this picture of an injector being built and yeah, it is special.

Spoiler :

The space shuttle main engines were special for a few reasons. The biggest reason is that they are among the largest hydrogen-oxygen engines ever built. This fuel choice makes them highly efficient but it's a very difficult technology to scale. It took a lot of work to get them right and in the end they had to install this huge, parasitic pogo system to dampen oscillations from the combustion process that wanted to rip the vehicle apart. The other thing that makes them special is that unlike just about all other rocket engines, these things had to work from lift off all the way to orbit. Most engines only work for a discrete segment of the flight, the SSME's had to work the whole way.

Because the density of air changes with altitudes, they essentially had to build two-nozzles in one to work correctly. There is a ramp inside the nozzle that detaches the flow at low altitude so that it has the correct expansion ration and then as the vehicle rises, the expanding nozzle plume re-attaches to the nozzle past the ramp. It was a pretty clever setup.

One thing that absolutely boggles my mind is how open the US was about this vehicle's development. The Russians really were able to copy a lot of the design of the space shuttle, not by traditional spycraft but just by obtaining free and public documentation. Even right now you can find 100+ page design reports on these engines on the internet that go into very low-level details of the design. It's pretty remarkable.

 

[uppi]

One thing that absolutely boggles my mind is how open the US was about this vehicle's development. The Russians really were able to copy a lot of the design of the space shuttle, not by traditional spycraft but just by obtaining free and public documentation. Even right now you can find 100+ page design reports on these engines on the internet that go into very low-level details of the design. It's pretty remarkable.

I am tempted to say: Sure, there is a lot of public documentation for anyone who would have wanted to copy the design of the space shuttle. But why would anyone want to?

Another one: Maybe they want the Chinese to copy it, so NASA can buy cheap Chinese space shuttles.

Getting serious: If your goal is to further space exploration, you would want others to copy your successful designs and improve on them. Otherwise, it is all too easy for good ideas and knowledge to get lost.

 

[hobbsyoyo]

I am tempted to say: Sure, there is a lot of public documentation for anyone who would have wanted to copy the design of the space shuttle. But why would anyone want to?

Another one: Maybe they want the Chinese to copy it, so NASA can buy cheap Chinese space shuttles.

Getting serious: If your goal is to further space exploration, you would want others to copy your successful designs and improve on them. Otherwise, it is all too easy for good ideas and knowledge to get lost.

I completely agree that these engines are useless for weapon systems and that having them developed out in the open advances space technology for everyone.

For some reason Congress was thoroughly shocked when the Buran debuted and started trying to find where the spies in NASA were. In reality everything the Russians wanted (as far as design data) was basically available for free. It's also worth pointing out that although the two shuttles did look very similar, they were actually quite different and the fact that they superficially looked the same is down to that shape being basically the best aerodynamic profile for the types of missions they were designed for. In other words it was more convergent designs rather than outright theft - and they didn't have to really steal any data to begin with, just obtain legal copies.


As to the question of why they published all the data in the first place, I don't really have a good answer for that - especially since the shuttle was designed to perform classified missions for the DoD. Knowing what the shuttle was capable of can help put a boundary box on the kind of classified satellites it could haul but at the same time, the shuttle was pretty versatile and could carry a massive payload to LEO so the boundary box would be so big as to be useless.

 

[Lexicus]

Keep in mind that Uranus and Neptune were only discovered with the advent of telescopes. If something similar sized is lurking much further out it's going to be very faint, especially if the orbit is as elliptic as proposed. The time it spends close to the sun is going to be short.

In the case of Uranus, that's closer to half-true. We didn't realize it was a planet until telescopes, but it can be seen with the naked eye.

 

[uppi]

Knowing what the shuttle was capable of can help put a boundary box on the kind of classified satellites it could haul but at the same time, the shuttle was pretty versatile and could carry a massive payload to LEO so the boundary box would be so big as to be useless.

Unless they had classified all the civilian payloads as well, the Russians would have arrived at a fairly good estimate after some missions, anyway.

 

[Cutlass]

I am tempted to say: Sure, there is a lot of public documentation for anyone who would have wanted to copy the design of the space shuttle. But why would anyone want to?

Now no one would. In 1980s, different story.

 

[hobbsyoyo]

Rocket engines look so complicated. I realize there's redundancies for redundancies, but looking at that image all I can think is: "If one of those parts stops working..."

There's a lot less redundancies than you'd think. Things tend to skew much more towards 'if one of those parts stops working' than, 'we've got a backup for those parts'. Why? Because mass.

 

[warpus]

There's a lot less redundancies than you'd think. Things tend to skew much more towards 'if one of those parts stops working' than, 'we've got a backup for those parts'. Why? Because mass.

Aren't you describing a redundancy? Or do you mean that if the whole engine stops working, the shpis is simply designed to work whether 3 engines are on or 8?