PDA

View Full Version : Ground to Space launches and Weather Conditions



Liosse de Velishaf
03-22-2010, 11:23 PM
Since a fair number of my stories involve craft launched from the earth into space, I was wondering what the deal is with weather conditions. Is it possible or practical to launch craft in storms?

benbradley
03-23-2010, 12:29 AM
Well, yes, sort of. I just saw something about Apollo 12. The Saturn 5 was supposed to be reliable and designed to launch in any conditions. Apollo 12 was launched during rain, and was hit by lightning:
http://en.wikipedia.org/wiki/Apollo_12
http://www.space.com/news/apollo12_blastoff_991112.html

The Space Shuttle appears to be much more sensitive to bad weather, I presume for lots of reasons. I'm guessing raindrops hitting the tiles at launch speeds (it's going 100mph when it clears the tower, and it's going the speed of sound in surely less than a minute) would be enough to damage them.

But if something is hardened and designed to do it, I don't see a problem. Surely ICBM's are designed to launch in any weather.

efkelley
03-23-2010, 02:02 AM
Thunderstorms top out at something like eight to ten miles. Get past that, and you're set. Thing is, there can be an awful lot of unusual wind inside a cell. The Saturn rockets didn't have much in the way of aerodynamic surfaces, but the shuttle itself is an aircraft, and the whole shuttle launch package is four separate parts. I could see it having a bit of a time in an actual storm.

I agree that if something is designed to do it, it'll do it. In fact, unless launching during a storm is a major part of your story, I'd suggest barely even mentioning it.

Liosse de Velishaf
03-23-2010, 02:19 AM
I heard somewhere that damage to the tiles and also water in the shuttle thrusters were the main reasons they don't like the rain.

I was thinking more of lighting or wind as dangers, but it seems like they aren't.

Pthom
03-23-2010, 04:25 AM
The main problem with the Space Shuttle is the foam insulation on the main fuel tank (the big orange bloated thing). A piece of it fell off and clobbered the Columbia's wing during take off. And we all know what happened later.

Liosse, I think you might consider how far into the future your launches are. I have no doubt that such issues as rain, lightning, low temperatures will be managable. Issues of high lateral wind, however, may not ever be something that can be overcome.

Liosse de Velishaf
03-23-2010, 04:26 AM
What are the dangers of high lateral wind, technically speaking. I assume it's something to do with blowing the craft of course, but would there be oppurtunities to correct before reaching space?

efkelley
03-23-2010, 04:44 AM
Lightning will be attracted to the vehicle if it is at all conductive (and usually it will be). Lightning is also attracted to the launch trail, being composed of much heavier elements in relation to the air around it. That said, even modest thought will give protection to the vehicle and crew in case of a strike. Apollo 12 was only barely disrupted. The shuttle would notice it little more than modern aircraft do. You just have to make sure that the energy passes through the vehicle, and doesn't get captured by it.

Wind is a bigger killer, simply because those engines are accelerating you to a pretty ridiculous speed to escape the atmosphere, and getting them pointed the wrong way would be bad. You could get some unusual stresses on a launch vehicle like the shuttle.

So, as long as these things are taken in mind in the design of the vehicle (and 50-ish years of space launches tells us that they're considered today, nevermind a future setting), then you're good. Don't mistake, the shuttle wouldn't be tasked with launching during a hurricane, but it's interesting to note that landing conditions have a much smaller margin of acceptable risk than launch conditions.

geardrops
03-23-2010, 04:51 AM
What are the dangers of high lateral wind, technically speaking. I assume it's something to do with blowing the craft of course, but would there be oppurtunities to correct before reaching space?

:: stepping in with a few physics courses under my belt ::

It's a matter of vectors. If you've got a vector normal to the surface representing the force of takeoff and then a vector parallel with the surface representing the force of lateral winds acting on it, you're going to have to spend more energy to overcome the second vector.

People smarter than me, correct me if I'm wrong kthxbai.

Liosse de Velishaf
03-23-2010, 05:32 AM
:: stepping in with a few physics courses under my belt ::

It's a matter of vectors. If you've got a vector normal to the surface representing the force of takeoff and then a vector parallel with the surface representing the force of lateral winds acting on it, you're going to have to spend more energy to overcome the second vector.

People smarter than me, correct me if I'm wrong kthxbai.


No, that sounds right. *eyes bleed at the memory of calculating vectors.*

Say we're launching an out-and back orbital shuttle of ideal design, what are some reasonable payloads and fuel loads if we refuel after every launch?

Pthom
03-23-2010, 05:51 AM
It's really difficult to "steer" a rocket. Mainly you point them at where you want them to go and fire them off. You might get a little course correction using steering rockets, but we're talking fractions of a degree.

A gust of wind can deflect a bullet fired from a rifle from its course to the target. A bullet is really small, compared to a rocket ship. A gust of wind (or more likely several of them) can deflect a rocket ship more than its capability to correct for the error.

But the siting of your space port is also critical for regular and successful ground-to-orbit launches. Ideally, you want to be near the equator, in a region where there is a low incidence of violent storms such as hurricanes.

Liosse de Velishaf
03-23-2010, 06:35 AM
So, what would we need before ground-to-space launches could go up in high winds?

geardrops
03-23-2010, 10:29 PM
But the siting of your space port is also critical for regular and successful ground-to-orbit launches. Ideally, you want to be near the equator, in a region where there is a low incidence of violent storms such as hurricanes.

Florida was a good choice, then :)

efkelley
03-24-2010, 12:00 AM
So, what would we need before ground-to-space launches could go up in high winds?

You'd need a way for the wind to not affect the launch vehicle, or a way for the launch vehicle to correct for the wind's potential for deflection.


Florida was a good choice, then

Ha. :D Fortunately, you can see hurricanes coming.


Say we're launching an out-and back orbital shuttle of ideal design, what are some reasonable payloads and fuel loads if we refuel after every launch?

I have no idea really, but I'd probably start here: http://en.wikipedia.org/wiki/Space_shuttle

The data panel on the right lists the payload capacity based on destination. Looks like there's a section on fuel as well. I don't see consumption at a glance, but it'll be on the intertron somewhere.

Lhun
03-24-2010, 12:07 AM
What kind of technology are we talking about? Anti-gravity and the like make weather a non-issue. An Orion drive ship is simply to big to care about wind. For chemical drives it all (including payload and fuel consumption) depends on the design. Project Rho has a lot of information on current tech drives. Afaik it's quite reliable too (less so on futuristic but realistic drives such a fusion drives)

Liosse de Velishaf
03-24-2010, 01:35 AM
Definitely not nuclear, and anti-grav is a bit too far future.