Nasa unveils Space Launch System vision, 2017?

[yhelothar]

wired had some good posts on space
http://en.wikipedia.org/wiki/KH-9_Hexagon
http://www.wired.com/dangerroom/201...atellite-was-hidden-from-the-world-until-now/
http://www.wired.com/dangerroom/2011/09/space-war-arsenal/

Holy moly
"its giant camera, which boasted a focal length of 77 inches, a 20-inch aperture"

aka... 2000mm F/4 lens

 

[0roo0roo]

and yes...those are satellite balls😀

 

[AstroManLuca]

Oh oh oh! Pick me! I have a better idea! Let's stay here. Let's send robots out to explore space. Sending humans at this point is pointless. Robots can do it cheaper, and we don't have to worry about them getting back home.

Double NASA's budget and have them start doing things that give us a little more bang for the buck. Where's the James Webb Space Telescope? How about the DSCVR satellite? How about we send probes to a few of the water logged moons of the solar system and see if there's life there (before we contaminate all those places with life from Earth.) Answering that question - is there life elsewhere - is one of the most profound questions of mankind. Doing thousands of laps in a low earth orbiting space station is little more than theatrics.

I agree. I find it incredibly sad that Congress decided to cancel the James Webb Space Telescope after so much good work had been put into it, yet now we're talking about a new manned launch system that will cost much, much more and (if the past is any indication) won't actually go anywhere.

Our space program is starting to look like Duke Nukem Forever. Destined to stop and restart over and over again until everyone's lost interest.

I don't think that manned space exploration is totally pointless, or that we should just stop trying. But maybe it would be a better idea to keep it on the back burner, have a smallish department dedicated to doing more research, and then we can come back to it a while later. I don't feel like it's particularly important to come up with new manned launch vehicles until we're ready to take the next step and go to Mars or set up a semi-permanent base on the moon. Maybe focus most of the unmanned missions on making that stuff possible in the long-term future.

The problem is, of course, we're now seen as losing in a new space race to the Russians, who are still using 60s space capsules.

 

[sao123]

Most rockets aren't able to throttle their engine. As far as I know the shuttle is the only launch systems that reduces power going through Max Q.

Also, are you sure about the SRBs? I have never heard of a throttleable solid rocket booster.

ok, well it isnt live (on demand) throttling, its more of a pre-programmed burn. But accomplishes the same nonetheless.

Since the SRB's burn from, the inside out, the shape and density of the solid fuel, and the central open column for the thrust to exit, determines the pattern. A time of max thrust, a time of min thrust, then back to max after Max Q.

The following explanation is from T.R. Heppenheimer's "Development of the Space Shuttle 1972-1981," p. 176:

"The forward portion of each propellant charge was cast with a central perforation in the form of an eleven-point star, with the star's points being long and narrow. This allowed the thrust to vary as planned. The star initially exposed a large burning surface area, for peak thrust after liftoff. The burn spread from the points, widening them and reducing this burning surface. This lessened the thrust and hence the buildup in flight velocity, to prevent overstressing the vehicle through excessive aerodynamic pressure. the SSME's also helped by throttling back to 65 percent of rated power, to further diminish this pressure. Then, ascending amid thinner atmoshpere, the shuttle was free to accelerate anew. The star was completely consumed at fifty-two seconds, leaving a cylindrical perforation that would widen, for a useful increase in thrust."