A few noteworthy items from dafydd and ehintz

[unixronin]

Anti-abortion activists are spreading FUD about abortion, "but it's for your own good!"  Women in Mississippi, Texas, Kansas and Louisiana seeking abortion must sign a paper stating they've been told abortion can increase their risk of breast cancer, but they aren't told that scientific reviews have concluded there is no such risk.  Abortion foes are pushing similar legislation in 14 other states.  (From dafydd)

On a more upbeat note, the launch date has been set for the first solar-sail spacecraft.  Cosmos 1 will be launched from the Barents Sea on a converted ICBM by a submerged Russian Navy boomer on March 1, 2005.  The countdown clock will be started on Carl Sagan's birthday.  (Also from dafydd)

And from ehintz, how to turn the cheapest, most vile vodka you can find into a very drinkable premium vodka with a Brita water filter.

Comments

It's birth control too

[jilara.livejournal.com]

A little alarming piece appeared yesterday that druggests can refuse to fill prescriptions for birth control pills on "moral grounds." Huh, what century is this? Where's Margaret Sanger when you need her?

http://story.news.yahoo.com/news?tmpl=story&u=/usatoday/20041109/pl_usatoday/druggistsrefusetogiveoutpill

Re: It's birth control too

[unixronin.livejournal.com]

Not just birth control pills. I understand there is a doctrine slated to be put into effect (or maybe it already has, I'm not certain) which allows, or would allow, any medical practitioner, including first responders, to refuse to provide any medical treatment, including emergency services, 'on moral grounds'.

"Naw, I ain't treating this guy. He don't look right to me, y'know whut I mean?"

"But he's bleeding to death!"

"Yeah, ain't he? It's a bitch bein' a sinner."

[juuro.livejournal.com]

I must confess I haven't been quite able to wrap my head around the solar-sail craft physics. With no keel, how do they tack? Even steering downwind appears somewhat restricted to me.

[unixronin.livejournal.com]

It's actually pretty simple. Consider: Thrust from a solar sail comes from essentially two components:

- Capture of heavy ions impacting the sail
- Radiation pressure from sunlight

Heavy ions in the solar wind, naturally, impart a thrust vector from simple momentum transfer, radial to the Sun. Sunlight, however, is reflected from the sail. If the sail is tilted, the light will be reflected opposite to the incident angle. Thus the thrust vector from radiation pressure (which is the major thrust component from a solar sail) is normal to the plane of the sail, and by tilting the sail relative to the sun, you can get a lateral thrust vector. (Of course, the further you tilt the sail, the smaller its effective area, and the less the resultant thrust, so there's probably a maximum tilt angle for optimum lateral thrust, but I haven't calculated what it is. My guess would be 45°.)

Tacking "up-sun", granted, is a bitch. But it can be done too, with patience. (Not that patience isn't required whatever you're doing with a solar sail; at .001G to .01G, you're not going anywhere suddenly. Of course, over days or weeks of acceleration, that .01G adds up.) You angle the sail to point your thrust vector as far forward in your orbit as possible, braking in your orbit, then furl the sail or turn it edge on and fall inward toward the Sun in an elliptical orbit. When you've moved close to as far sunward as you want to go, you unfurl your sail again and angle it the other way, pointing your thrust vector back behind you to circularize your orbit again. To move efficiently away from the sun, angle the sail to accelerate you forward in your orbit.

Remember the orbital vector cycle, as quoted by Larry Niven in The Integral Trees: "Forward takes you up. Up takes you back. Back takes you down. Down takes you forward."

[juuro.livejournal.com]

Orbital mechanics. That's what I was not taking into account. I'm too used to thinking in local, instantaneous reference frames.

Thank you!