Alliant Techsystems

http://www.bbc.co.uk/news/science-environment-18017216

The industrial team that aims to make an astronaut launcher by marrying parts of the US space shuttle and Europe's Ariane rocket says it now has a complete system.

Known as Liberty, the launcher would be sold to Nasa to take its crews to the International Space Station (ISS).

Utah-based Alliant Techsystems (ATK), whose side boosters got the shuttle off the pad, is leading the project.

The company expects Liberty to launch on its first manned mission in 2015.

"Today, we don't have the ability to launch astronauts from the United States, so showing up with this service quickly is very important," said ATK's Kent Rominger.

They convinced me at a presentation in Huntsville (2012)

http://good-times.webshots.com/photo/28 ... 3760AXcEly

I see a slide with a graph, but I'm not getting the point. Apparently it's safer, but why? Do solids have a different thrust profile than liquids?

It's an irrelevant point from their presentation, that is supposed to show how safe the trajectory is compared to "other vehicle"...

Some things that are wrong with the graph:

a) Thy y-axis reads "altitude", the x-axis "time". So it is a chart that shows the altitude of a rocket as it varies over time? Ok fine, but why does it decrease at the end?

b) What has altitude over time to do with "launch abort effectiveness"?

c) What other vehicle? Ares I? Atlas V? Falcon 9? It cant' be the Shuttle because there was no launch abort capability.

@Atlas V: I've read somewhere, that ULA has to adjust the trajectory of the Atlas V for crewed launches as well. For satellites that can tolerate much higher g-loads you want to get out of the atmosphere ASAP (so you go almost straight up at the beginning), but for crew you wan't to take a smoother transition from vertical to horizontal.
Regarding LAS systems of the vehicles that will fly on Atlas V not too much is known. So how do the Liberty guys know about their "yellow and black zones" (indicated red in the graph )?

@Falcon 9: SpaceX claims that their SuperDraco thrusters allow for abort all the way to orbit through all phases of the launch. If true, then they have no "yellow or black zones".

@ Ares I: That was what I was thinking when I saw that slide during the presentation. I remember that there have been some issues with launch abort on Ares I for some portions of the flight, where the required g-loads to escape the solid first stage would have been so high that they would kill the crew or something. So maybe that was the point of that graph? In my opinion this makes sense cause I have the feeling they have to fight the bad reputation of Ares I more than any competitor.

But then I arrive at a question I can't answer myself: how does swapping out the Ares I upper stage for an Ariane 5 core stage solve the launch escape problems during the solid phase?

Perhaps the point is that the solid first stage is not powerful enough to get the rocket more than a few miles up? At such an altitude, if there's a leak in the spacecraft, the astronauts will still be able to breathe, which is of course much safer than a rocket that would launch them into space.

It seems likely that this rocket exists because ATK want to continue their SRB business in the post-Shuttle era, and Arianespace want access to the US launch market. Commercial space flight government style . I wonder what this thing will cost...

lol, thank you Lourens, your post has just made my day

Most likely I agree. I think they were addressing the concern/criticism of the Ares system.