RE: The Five-Billion-Star Hotel / propulsion
I didn't say it was safe. I was just forwarding information from
astronaut Scott Horowitz who now works for Thiokol. I admit I'm no
rocket scientist.
> -----Original Message-----
> From: Mark Reiff [mailto:markreiff@xxxxxxxxxxxxx]
> Sent: Friday, February 18, 2005 12:03 PM
> To: sf-discuss@xxxxxxxxxxxxxxx; Jason
> 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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