SpaceX Launch Successfully Delivers Satellite Into Orbit

Roger · Post by **Roger** » Sun Jul 19, 2009 4:23 pm

Delayed from earlier this year, Space X delivers:

http://www.wired.com/wiredscience/2009/07/spacexlaunch/

Betruger · Post by **Betruger** » Sun Jul 19, 2009 5:55 pm

Still a bit wobbly..

MSimon · Post by **MSimon** » Mon Jul 20, 2009 2:30 pm

I wonder if this could be the Pony Express vs the Telegraph re: Polywell and space travel.

Of course Polywell for Space Travel is at least 10 years away - if it works.

jmc · Post by **jmc** » Mon Jul 20, 2009 5:04 pm

Polywell space travel is alot more than 10 years away, even if it works. Look how slow progress has been with nuclear fission power rockets.

rcain · Post by **rcain** » Mon Jul 20, 2009 7:28 pm

where there's a will, there's a way, just no real will at present.
good to see the Aplollo 11 crew wheeled out recently, we can all do with a bit of futurist ra-ra from time to time.
just wait till they discover oil on venus... should see a resurgence of interest in space.
(ps. love the control room commentary on the vid)

MSimon · Post by **MSimon** » Tue Jul 21, 2009 12:35 am

jmc wrote:Polywell space travel is alot more than 10 years away, even if it works. Look how slow progress has been with nuclear fission power rockets.

That is a political problem i.e. no one wants a very radioactive core with Plutonium byproducts dispersed in the atmosphere upon failure.

Polywell will be an easier sell.

derg · Post by **derg** » Tue Jul 21, 2009 3:02 pm

Couldn't they use chemical rockets to get to a safe distance before firing the nukes?

kunkmiester · Post by **kunkmiester** » Tue Jul 21, 2009 4:20 pm

There's still the problem that people are paranoid about devices designed and overengineered to not fall apart falling apart and spraying them with radioactive stuff. Extra-atmospheric, fission rockets aren't that big of a deal, and there's even designs that would work quite well inside the atmosphere without spraying fallout everywhere.

KitemanSA · Post by **KitemanSA** » Fri Jul 24, 2009 1:41 am

DavidWillard wrote: One destructive test of the rover KIWI rocket did scatter uranium waste downwind to when the wind changed direction from the Nevada test area at Jackass Flats towards Los Angeles.

So all that Jackass stuff wound up in LA. I guess that could explain it!

Roger · Post by **Roger** » Fri Jul 24, 2009 2:10 am

DavidWillard wrote:
Remember the Greens and Greenpeace having a total cow over the Cassini Saturn probe

Yes, I called the WHHHHAAAAAambulance on them. My landlady whined to me about that, I sent her a bunch of links about improved safety on these sorts of devices, nukes in general....

....and then showed her all the incredible pictures, including the probe that went to the surface of Titan.....

Fixed her ass right quick. LOL. Cassini has been a absolute treasure trove of data and Pix.

MSimon wrote:
That is a political problem

I concur.

ravingdave · Post by **ravingdave** » Fri Jul 24, 2009 2:59 am

Maybe they could link it up with this ?

http://www.newscientist.com/article/dn1 ... -mars.html

David

djolds1 · Post by **djolds1** » Fri Jul 24, 2009 3:36 am

ravingdave wrote:Maybe they could link it up with this ?

http://www.newscientist.com/article/dn1 ... -mars.html

Anyone know how scalable VASIMR is? Thrust levels if input power is ramped up seriously? One Jovian range manned notional model uses a 10MW core. How about 100MW? 500MW?

Aero · Post by **Aero** » Fri Jul 24, 2009 3:51 am

Anybody have an idea of how thrust scales with energy?

But they hope to ramp up to 200 kW of power in ongoing tests, enough to provide about a pound of thrust.

Then maybe we could estimate the power needed for one g acceleration using a BFR. We can guesstimate the mass of different sized BFRs. Of course we can be simple minded and say thrust scales linearly by adding thrusters but can't really do that, the mass penalty is to great.

chrismb · Post by **chrismb** » Fri Jul 24, 2009 8:52 am

Aero wrote:Anybody have an idea of how thrust scales with energy?

Inversely!

The quicker your propellant, the less efficient is the flight.

But that's not the point, the issue for space vehicles is the limited finite mass of the vessel, so anything you 'let go of' out the back end to get you going forward needs to be going as quick as possible, else you run out of it quickly! So it's a trafe-off between how much energy you've got available versus how much mass. An unlimited amount of energy, like solar, means you want to accelerate every single thrust atom as fast as you possibly can.