Re: The Five-Billion-Star Hotel / propulsion


From "Ellen Hughes" <fishbone123@xxxxxxxxxxxxx>
Date Fri, 18 Feb 2005 13:23:58 -0800

What would you say is a "safe" fuel for space flight?

Ellen Hughes
fishbone123@xxxxxxxxxxxxx
Why Wait?  Move to EarthLink.


> [Original Message]
> From: Mark Reiff <markreiff@xxxxxxxxxxxxx>
> To: <sf-discuss@xxxxxxxxxxxxxxx>; <JASON@xxxxxxxxx>
> Date: 2/18/05 11:03:54 AM
> Subject: Re: The Five-Billion-Star Hotel / propulsion
>
> Jason,
>
> A SRB as a safe propulsion system?  Apparently you are not old enough to 
> remember the Challenger accident.
> Solid propellant has fuel and oxidizer mixed together.  It is inherently
unsafe, 
> especially when you have the SRB segmented with o-rings sealing the
joints 
> between the segments.  Now if you remove the oxidizer and use a hybrid
solid 
> rocket, where liquid oxygen is pumped through the fuel core - that is an 
> inherently safe rocket motor.  That is what Rutan's SpaceShipOne uses.
>
> Using an SRB as the basis for a manned launch vehicle sounds like what a
NASA 
> contractor would propose, in order to keep their SRB production line
open.  Not 
> that man-rating the EELV will be a cheap or quick thing to do either. 
Both are 
> poor choices for a cheap, quick and safe manned launch option.
>
> As for the capsule, it has some inherent safety features as well as
drawbacks. 
> It does allow relatively uncontrolled safe atmospheric re-entry and
launch 
> escape by using a tractor rocket.  Of course it necessitates the use of a 
> parachute/parfoil to ensure a survivable landing.  The reliability of 
> parachute/parfoil systems has it's limits.  And if you have ever seen a 
> flight-like capsule up close, you will know that is quite cramped inside.
Also 
> the landing targeting is problematic.
>
> Mark Reiff
>
> Jason wrote:
> > 
> > Following up Patrick's comment about using existing propulsion systems,
> > I've included some pertinent information from astronaut Scott Horowitz.
> > 
> > "It started as an idea of safe, simple, and soon," NASA astronaut Scott
> > Horowitz said during a plenary session of the Mars Society's annual
> > conference in Chicago last month. "After the Columbia accident, a few of
> > us in the office were thinking about how we can do this better. How do
> > we get to the point where we can launch lots of people to and from low
> > Earth orbit?"
> > 
> > That philosophy of "safe, simple, and soon" led them to adopt a capsule
> > design for manned spacecraft. Horowitz said they then turned their
> > attention to a launch vehicle for that capsule. "I was thinking, 'What
> > is one of the most cost-effective, safest pieces of hardware that we
> > have to use as a lower stage?'" Horowitz recalled. "I said, 'Hey, what
> > about a solid rocket booster?'"
> > 
> > Combine it with an upper stage, proponents argue, and an SRB could carry
> > CEVs into orbit sooner and less expensively than an EELV.
> > 
> > The whole article can be viewed at
> > http://www.thespacereview.com/article/226/1.  
> > 
> > Jason Klassi
>
> -- 
> Mark Reiff <markreiff@xxxxxxxxxxxxx>
>
> -- 
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