The thread for space cadets!

[hobbsyoyo]

It surprises me quite a bit that Musk got into all this without having a plan for all those boosters. He doesn't seem to be a guy who gets ahead of himself.

Having said that I understand the "if it becomes a problem then it will be a good problem to have" philosophy, in the sense that if it's a problem then it means that the business is working.

I didn't really mean that he nor the company had no plans - it's just there are only so many things that you can do at a given time with finite resources and time. Especially so when you realize that we couldn't be certain which boosters would make it back and in what condition they would be in.

One plan we always had and recently put into action was erecting our first landed booster in front of the factory as a monument:

Death Star confirmed

Less SW and more BSG.

 

[warpus]

Sexy asian cyborgs confirmed!!

 

[Cutlass]

I can't recall if I asked this before. Golf balls have dimples on the surface to reduce air friction and fly further. Why don't planes have that? The skins of them always look smooth.

 

[uppi]

I can't recall if I asked this before. Golf balls have dimples on the surface to reduce air friction and fly further. Why don't planes have that? The skins of them always look smooth.

Because planes are not restricted by rules (and the desire for the ability to roll on the ground) to be a sphere. Instead, they have been optimized for aerodynamics and dimples would actually increase drag (and I am not sure, the dimples on golf balls actually decrease drag, they might be to increase lift).


In other news: Proxima Centauri b has been confirmed:
http://www.nature.com/news/earth-si...rby-star-is-astronomy-dream-come-true-1.20445

Proxima Centauri, the star closest to the Sun, has an Earth-sized planet orbiting it at the right distance for liquid water to exist. The discovery, reported today in Nature, fulfils a longstanding dream of science-fiction writers — a potentially habitable world that is close enough for humans to send their first interstellar spacecraft.

As always, the news stories exaggerate, but this seems to be the perfect target for our first interstellar probe.

 

[Evie]

I wonder if that's going to give some new impetus to development of very high speed propulsion technology, now that we're starting to find planets we can theoretically reach in a single generation without needing to somehow magick up FTL technology.

 

[Lexicus]

Solar sails anyone?

 

[Cutlass]

Solar sails may be efficient, but the acceleration is going to be very low. The problem that leads to is that we have to build a machine that will continue to operate, with repairs, for an extremely long period of time. Longer than any human made machine has ever worked without repairs before.

 

[Gigaz]

There's a recent work related to the Breakthrough Starshot initiative which is cautiosly pessimistic about relativistic probes because dust appears to be a significant obstacle for small probes at high velocities.

http://arstechnica.com/science/2016/08/could-breakthrough-starshots-ships-survive-the-trip/

 

[Michkov]

Because planes are not restricted by rules (and the desire for the ability to roll on the ground) to be a sphere. Instead, they have been optimized for aerodynamics and dimples would actually increase drag (and I am not sure, the dimples on golf balls actually decrease drag, they might be to increase lift).

The dimples create vortices which in turn keep the flow attached further around the ball. That reduces drag compared to a smooth ball.
Airplanes use other devices to induce vortices to improve their stall characteristics, but these tend to only work at certain angles of attack or are too draggy to be deployed when cruising

 

[hobbsyoyo]

In case anyone needed a reminder that the Russians can build some awesome rockets:

damnit the gif won't play here. Follow the link for awesomesauce.

http://i.imgur.com/O4fNbhC.mp4

 

[Thorgalaeg]

I find interesting the mini-stage they use for the silo launched SS-18 Satan ICBM in order to eject the rocket out of the silo before starting the main engine. Any reason for using such complex and apparently dangerous system instead of starting the main stage since the beginning?


Link to video.

 

[red_elk]

I think this has something to do with the type of main engine and safety of launch vehicle/launch pad equipment. Some air defense missiles have similar 'ejecting' start


Link to video.

While some ICBMs don't (Topol-M)


Link to video.

 

[hobbsyoyo]

Because it's so massive and buried in a bunker. I imagine that the size of a booster needed to simply pop the rocket out of the bunker is much smaller than the actual main engines of the rocket itself, so you do less damage to the bunker by doing it this way. Submarines use similar boosters to pop their SLBM's out of their hatches as well and I imagine it's for much the same reason. But I am only speculating.

Plus IIRC, that booster uses hypergolic propellants so igniting them inside the bunker is going to seriously contaminate the hell out of it. I'm sure it still gets contaminated when it gets launched anyways but not to the extent that it would without the 'pop-out' SRB motor.

 

[Cutlass]

Submarines pop the missile out of tube before igniting the motors because if they ignited the main motors in the sub, it would melt the sub and sink it. In ground missile tubes don't have that problem, because the control room can be far enough from the silo that the crew remains safe, even as the silo is slagged. Also, concrete isn't as meltable as steel.

There still could be a reason to not ignite the main rocket engines, as the silo is a confined space. And so the flames from the rocket engine surround the missile until it has lifted clear. That missile looks like a 2 part liquid fuel engine. I'd speculate that the Soviets blew up a few of them in the testing phase, and they decided that it was just too likely to result in blowing up in the silo if the main engine burn was being forced back up the sides of a liquid fueled rocket.

 

[trader/warrior]

Oh my...

 

[hobbsyoyo]

Yeah, it was a bad day.

 

[Timsup2nothin]

Because it's so massive and buried in a bunker. I imagine that the size of a booster needed to simply pop the rocket out of the bunker is much smaller than the actual main engines of the rocket itself, so you do less damage to the bunker by doing it this way. Submarines use similar boosters to pop their SLBM's out of their hatches as well and I imagine it's for much the same reason. But I am only speculating.

Plus IIRC, that booster uses hypergolic propellants so igniting them inside the bunker is going to seriously contaminate the hell out of it. I'm sure it still gets contaminated when it gets launched anyways but not to the extent that it would without the 'pop-out' SRB motor.

Submarines blow the missile out with compressed air. Nothing ignites in the tube, unless things have changed drastically since my day.

 

[Hakim]

@hobbsyoyo: do you know anything about the announcement Musk is supposed to do this month? When is it? Will it be about the Mars Colonial Transporter?

nvm, it's International Astronautical Congress 26-30th. I hope the announcement won't be watered down by the incident.

 

[hobbsyoyo]

@hobbsyoyo: do you know anything about the announcement Musk is supposed to do this month? When is it? Will it be about the Mars Colonial Transporter?

nvm, it's International Astronautical Congress 26-30th. I hope the announcement won't be watered down by the incident.

Yeah he's supposed to talk about our Mars plans at that conference. And I too hope it isn't taken over by the incident.

In other news, they found Philae!

 

[r16]

that's what happens when you insult the valet .