Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 12/08/2012 14:30:01
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Gary Shavit asked the Naked Scientists:
HI guys;
In the last podcast of Naked Astronomy (http://www.thenakedscientists.com/astronomy) (great show-as usual), you reported about the Swedish Spaceport.
I remember something about launching into space nearer the equator being easier because of the circular momentum of earth.
Would launching from Sweden be more expensive in terms of energy needed to reach orbital speed?
Regards
Gary Shavit
Netanya, Israel
What do you think?
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"Would launching from Sweden be more expensive in terms of energy needed to reach orbital speed?"
Yes.
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Wouldn't it make a difference whether one is launching to a polar orbit vs an equatorial orbit.
If one is launching a geostationary satellite, then it needs to be launched eastward. One can utilize the intrinsic motion of the earth which would have faster movement at the equator. Plus, one would have to move the satellite to the equatorial orbit.
If one is launching a polar satellite (such as a weather satellite), then I would think there would be little difference in cost between launch locations. Would there be a benefit of launching a polar satellite from the poles?
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Right. The more I thought about it, I realized that it isn't an issue. Launching from near the equator is important to achieve orbital or escape velocity. But for space tourism, they just want to get past the atmosphere, get the t-shirt and drop back down to earth.
But another thought came to mind. They mentioned doing space flights during the Aurora Borealis. Do you think that would expose the passengers to too much radiation?
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If your goal is parabolic flight without achieving orbit, then one might be able to use a modified Tu-144 (http://en.wikipedia.org/wiki/Tupolev_Tu-144), or Concorde (http://en.wikipedia.org/wiki/Concorde) to graze the lower edge of space, although one would still need to add some kind of rocket boost to gain the higher altitudes, as well as additional heat shielding for the descent.
But, you wouldn't need to carry enough fuel for intercontinental flight. What would the flight distance be? Perhaps one would choose a one-way hop from Sweden or Finland to England, then shuttle passengers back on a conventional jet while the supersonic jet refuelled and took additional passengers in the reverse direction. Keeping in mind, of course, that one might achieve better altitudes and flight speeds launching eastward.
If fuel capacity was an issue for an eastward flight, perhaps hops around Norway, Russia, Alaska, Canada, Greenland, Iceland, etc.
The Aurora Borealis would be interesting. I'm seeing that it would actually be visible from space. According to this, the Aurora Borealis is about 60 to 200 miles in altitude (http://odin.gi.alaska.edu/FAQ/#altitude), so if one was grazing space, one might only hit the bottom edge of it. It still would be spectacular.
Radiation of all types is usually a dose risk. So, flying into a solar storm would increase the radiation dose to the passengers somewhat, but for the occasional passenger, the overall dosage would be low, and likely much less risk than flying on a jet/rocket hybrid plane. Pilots and flight crew, however, might be at significant risk for a larger cumulative dose. The electronics in the plane would also have to be protected from EMP.
I assume they flight jets in the North in the winter (when the Aurora Borealis is greatest), but I'm not sure I'd want to land a supersonic jet on an ice field. The X-15 (http://en.wikipedia.org/wiki/North_American_X-15) used skids for landing gear. Imagine the stopping power of the skids on ice.