I forgot to put this up yesterday, but here goes. Carnival of Space #9 is here, just click on the link and enjoy a whole bunch of space stuff. Most of it went completely over my head, but man there are some pretty pictures.
Impacts
The chances of our beautiful extra-solar-traveling rocket ship ever being hit by something are about equal to the chance of my wife ever agreeing to me buying a motorcycle. (My mid-age crisis has already hit at 31. I also want a PS3.) And the rare times they do, there is almost always a fix that can be applied, or the impact just doesn't do very much damage. But this is changing.
This is me at the age of 29. From hereIt’s (for me) simpler to separate all the dangers by looking at the specific times they can occur. So this week we’ll look at impact dangers during launch, landing, and in orbit, and next week we’ll look at radiation, impact risks during transit between planets, and pirate attacks.
Launch and landing
It’s hard to say which time is more dangerous, launch or landing - because both have elements of complete chaos.
During launch:
Cassini Launch, courtesy Sandia National LabsDangers:
As we all well know, one of the biggest impact dangers is from the spacecraft itself. Bits are always falling off of launch vehicles as they take off: pieces of foam, chunks of ice from the liquid oxygen cooling systems, tools left on the rig by workers. Beyond that, our spaceship could hit a bird, go through a freak hailstorm, or a smack into a passing helicopter that had ignored the airspace restricitons, all of which could have cataclysmic effects.
Most of these things can be mitigated. Cooling systems can be designed so that ice drops off away from the launcher, foam can be better designed to either fall off more quickly (when there is less danger of damage) or to withstand the rigours of launch so that it can be peeled off in orbit, and workers can be whipped until they remember to keep their tools on them at all times. Also, radar systems keep an eye out for flocks of birds, inclement weather, and drunk helicopter pilots, so the chances of something really bad happening are low.
From here, I don't know who owns it
But barring perfect karma, launches will always experience problems, and it’s always better to plan for the worst case scenario. That’s why we need solutions for after something hits our spaceship, not just solutions for how to stop things hitting us.
This won't work.
During launch, though, there aren’t many solutions available.
a) As of right now (June 2007), there are no launch vehicles capable of orbital insertion with fully throttleable engines. This sounds silly, but it's pretty important. Basically, once you light the scary end of your rocket, it stays lit until the fuel runs out.
This is the equivalent of launching a rocket. Except that the observers usually stand a bit further back. Source
It’s like driving a car that only goes 200km/h. Zero or two hundred klicks, nothing in between.
Before you leave your house each morning, you have to put in just enough fuel to get to work. If you put in too much, you crash into the daycare, and too little, you have to get a cab from wherever the car putters to a stop.
(Note to smarty-pantses: I know the engines on the shuttle orbiter are throttleable, but they only supply a part of the total thrust necessary to get into space, so that doesn't help much.)
This is why there are so many launch aborts. There is no way to stop these monsters once they’re lit, so - before they take off - we have to make sure they aren’t going to blow up.
But if we had engines that we could turn off, we could abort launches in mid-launch. To an extent...thus problem 2. Or problem b. Whatever.
J) Even if we could turn off the engines in the case of an emergency, the rocket will still fall like a rock. Again, the orbiter excluded, there are no orbital launch systems capable of achieving even a semblance of lift. So, even if we could throttle the engines to turn around and go back to base, the bloody things won’t fly, they’ll just tumble to the ground. There ain’t no point in having throttleable engines until we have flight surfaces as well.
Next generation NASA orbiter, courtesy of Inn Fusion
During landing:
a) Just like with launch except completely opposite. Most return modules have no fuel to aid in slowing the ship down. Almost all of them rely on parachutes (and air resistance) to slow down the module and to ensure a smooth landing.
The shuttle is a bit different. It has the ability to bleed off speed by flying in S-curves on its way to the landing strip, but it only gets one chance to land. It has no fuel for manouevres. If the pilot undershoots the runway, the shuttle will land in the Gulf of Mexico, Texas, or Disney World (which wouldn't be so bad). If she overshoots, they land in the Atlantic (or Miami Beach, which also wouldn't be so bad.)
Because there’s no fuel, they can’t just accelerate and go for another run. (The shuttle is heavy enough that even if it had fuel, it probably wouldn’t be able to come back for another run anyway.)
b) Again, most return modules have no wings. They don’t fly home; they crash through the atmosphere in a semi-controlled manner. When something screws up, when a calculation is slightly off, the astronauts could end up 1000's of kilometers from their landing point in desperate need of a swimming suit.
In Orbit
Dangers:
There are more than 9000 (2006 link) objects flying around in orbit, and that only counts stuff bigger than about 10 cm. From washers and tools to rocket sections and pieces of crap (literally). Luckily, the chances are still low (anywhere between 0.5% and 3%), but that number gets higher with every launch.
The problem isn’t just the number of objects. For the most part, we can track objects in orbit (except for the smallest), and try and avoid them when orbits are mapped out. The problem is in the parentheses. The smallest objects are the ones that’ll get ya, and every time a piece of junk crashes into another piece of junk, more junk is created (they break apart and become deadly missiles intent solely on human destruction).
See what I mean about being intent on human destruction? This is one scary washer. It's looking at me.
Good News
The good news is that even when we do get hit, when we're in orbit we'll usually be okay. There are a couple of reasons.
Most spaceships are launched in the same direction (to the East) so they can take advantage of the Earth’s spin to get more speed. That’s good news for us because that means that most of the junk flying around in orbit will be going in the same general direction as we are (so relatively slower). To a certain extent, things that are at similar orbits go at similar speeds, so something going in the same direction as us probably won’t be able to do much damage.
However, if the junk comes from in front or from the sides, we have a problem.
A one gram object (like a washer) traveling at 25000km/h has the same destructive energy as a 1000 tonne aircraft carrier traveling at more than twice the speed of sound. That's a lot.
But remember Newton’s Third Law. Every action has an equal and opposite reaction. For that much energy to be released from our one gram object, it has to be stopped completely. What can stop the USS Ronald Reagan traveling at twice the speed of sound? That’s right. Nothing except a mountain.
This is why – thanks Newton – if a one gram object hits the something like the Space Station, it’s unlikely to explode in fiery glory. The object is so small, and the skin of the ISS is so thin, that’s the most likely scenario is that our little washer will end up shooting right through the station, punching tiny little holes in everything it hits as it disintegrates.
That still leaves us the problem of the shotgun-blast disintegration of the washer, but that’s what duct tape is for.
They have different colours now?!?As things stand right now, impacts are potentially catastrophic.
There are no abort procedures for either launches or landings because spacecraft are basically "aim-and-pray" devices, and Junk in orbit is multiplying at a rabbit-like rate.
He knows what I'm talking about. Thanks Warner Brothers. The chances of being hit by an angry washer are still pretty low.
STOP LOOKING AT ME!
More Bad News
Fraser over at Universe Today has the newest Carnival of Space posted. Lots of stuff about exploding stars, space colonists who don't think we need to bother going to space, and...black holes consuming the Earth?
It's wierd. It's wonderful. Get over there.
The June Surf 'n' English article is up at Asahi's website. This month I talked about Japanese bloggers, or rather foreign bloggers who talk about Japan. Check out the article if you feel like it, and then head over to www.japanprobe.com, www.gaijinsmash.net, and ampontan.wordpress.com to see the blogs.
There's a new carnival of space up, and it continues to remind me why it's fun to waste time on the net reading stuff about space written by other space nerds.
Carnival of Space #7
Waste disposal in space stinks. This week, we look at one way to get the stink out.
The astronauts on the ISS pack their waste into a Progress module and send it back towards Earth where it burns up upon reentry. (Thanks to Jeff for the clarification.)
On a completely unrelated note, the Progress module is also known as the world’s most financially inefficient garbage scow. Source ESA
There aren’t a whole lot of elegant solutions to the waste problem. That's why we just bring it home with us. But on a long-term flights, we don't really have that option.
We technically could send the garbage home, but it would be a huge waste of resources. First, we won’t have a whole bunch of spare Progress modules trailing behind our ship, second, any we do have will likely be reserved for emergency situations, and third, we're trying to save as much weight as we can at launch.
We could burn our garbage, but that would use up all the oxygen on the ship and render the point moot. At least for the astronauts still on the ship.
We could just take it with us and dump it wherever we land, but anyone who thinks this is a good idea has never met an angry planetary geologist. They tend to drink a lot and have poor tempers.
We could drop the garbage out of the ship but that would change the ship’s momentum. Dropping trash would only induce very small changes - see Newton’s Law - but if we screw up the calculations even a little, it could mean arriving at the target planet’s position three weeks before it gets there. Unless we have a lot of extra fuel, if there's no planet, we have no brakes.
The pic is horrible, but I still love you NASA.
So how do we get rid of our trash without following Pioneer out of the solar system, and without incurring the wrath of environmentalists and exogeologists?
Well, everyone knows what fertilizer is, and that most people are full of it. And as we talked about in the entries on food and air, hydroponic farms have been designed and tested for us in space. (Though I’m still not sure if research continues.)
Not only do hydroponic farms serve as air and food sources, they also serve as natural garbage bins. The minerals, bacteria, and other stuff in human waste can be used by our plants as fertilizer, which then filters our air, and grows us more food to make poop from. Plants also add a nice splash of colour to our spaceship.
Poop may be the biggest offender, but it’s not the only one. Urine, dirty air filters, filthy and ripped clothing, bandages, sanitary napkins/toilet paper, plastics from food wrappings, the list could go on forever. But there are simple, though not easy, solutions for all of them.
Our urine can be filtered using the same process as the Space Shuttle and ISS, and dumped right back into the drinking water. Or the water can be used by the plants, and partially filtered by the soil network, and we can use the ammonia and other chemicals in urine to keep our space ship’s windows clean.
Paper products can be sterilized and used in the farms. (There could be issues with disease transfer here with stuff like sanitary napkins. But without getting too graphic, blood is a great fertilizer.)
We do have a problem with plastics for perishable items. We can’t just kept the powdered milk in a big Tupperware bin.
Pic "borrowed" from this blog
Actually, we probably could. Look at the seal on those babies.
However, we can’t keep most perishable foods or medicines in Tupperware bins. They must be protected with strong plastics, and separately packed such that using one item doesn’t limit the shelf life of every other item.
Luckily it turns out we’ve had edible plastic for years. (source 2002)
The plastic probably won’t taste very good, so it won’t make a good snack. But because of the nutritional content the waste can be dumped in our farms, or stored in an indoor compost heap for later use. We’d have to worry about the gases generated by a compost heap, but an astronaut can always find a use for gases that burn.
So, just in regards to food packaging, paper, poop and urine, we cut out a large portion of our human-produced waste.
Unfortunately, we also have non-biodegradable wastes. Every time a tool breaks, and every time a motherboard gets fried (in the dangers section you will learn about why motherboards get fried), we end up with waste plastics, metals, and 166MHz CPUs.
The good news is that broken tools and heavy plastics can be kept. Not to throw away upon arrival to enrage the Earth Liberation Front, but to melt down and form into new tools upon arrival.
There are no hardware stores on Mars, and a re-supply mission following the most efficient path would take more than half a year to get from Earth. And that’s if a rocket is already sitting on the pad ready to go.
Stuff breaks, and we’ll need some way to reuse the material in the stuff that breaks. We don’t need to take a smith’s oven, but it ain’t a bad idea to have something that can melt everything down when we’re done with it. Melt it, pour it in a mold, wait for it to cool, and voila! New hammer.
Waste disposal is really one of those things that has no fancy solutions. Many people would say that the hydroponic farm is a fancy solution, and in a way they would be right. A full-scale hydroponics farm has never been tested on a long-term mission.
I may be a bit too optimistic, but I don't think we have to worry about that. Hydroponics is a pretty well-known science – half of my friends are experts – so it should be just a matter of time before we can make it work in space.
Waste removal has only three tenets: reduce, reuse, recycle. If we follow these rules, we'll be fine.
Wait.
Four tenets.
Don’t piss off exogeologists.
I'm really sorry for using your picture twice.
Will be back shortly to finish the Obstacles to Space Exploration series. I'm just trying to finish up a couple of articles that might make me some money.
And I pulled my groin in Karate class. But I'm not sure anyone cares about that.
