## >> Monday, December 9, 2013

I consider myself a fairly tolerant person and try to keep judging to a minimum. I try not sweat whatever beliefs and political positions people take, though I prefer you think about it before you spout them around me, because I challenge nonsense reflexively. But one thing I don't get is how otherwise decent reasonable human beings can become downright callous and irresponsible when their OWN actions threaten the well-being of others.

It's one thing (if not particularly admirable) to deliberately misuse people for your own benefit. It's something else to continue to do things against your own best interest that also actively threaten the safety and even lives of total strangers (who ironically have done next to nothing to contribute to the problem). To regard it of no consequence, a joke, literally makes me sick. I just don't get it.

Sadly, I could be talking about a number of subjects including universal healthcare, but I'm not. I'm talking about global climate change and the delight people have in spreading misinformation that refutes those nasty greedy scientists, (95% of which don't stand to make an individual dime from this issue) and just underscores how little they get the concept. Case in point, a friend noted (gleefully) on facebook that water vapor was the most prevalent and worst greenhouse gas we have. Since we can't control it, it just "proves" that global climate change is hooey.

Do I have to explain how fallacious that argument is? Or that, her lack of understanding makes her impervious to the implications of what she's saying (i.e., since water vapor is a natural phenomenon, we have little impact except by upping the temperature and air to carry more water vapor, thereby magnifying the effects of any greenhouse gases we produce that make the system, um, warmer). When challenged, it was all about tossing sources at me that showed water vapor was a greenhouse gas (duh, wasn't refuting that) - didn't I trust NASA and NOAA and peer reviewed journals - and then, when I noted those sources universally agreed that we were having an adverse affect on the global climate, changing her position to that we produce only a small amount of the total natural CO2 environment created (and giving me a source, mind you, that noted that, though that's true, the amount we added is small, it is tipping the scales and sending the balance out of whack). Then it was all about getting China and India and Russia to curb their ways first.

Pardon my language, but bullshit.

Even if China and India (with their higher populations) were using energy like we were, we use far more per capita, more than twice. And China I know is actively pursuing alternative energy (they have like a dozen solar cell factories being built there, ironically by a US company who can't get anyone to build one in his own country). But that doesn't matter either because we don't have control over them and are hardly going to look credible if we tell them to cut back while still burning up more than twice the fuel per capita (fuel we have to import while they don't). But we can, no really, make a difference in the energy we use and expend. And what the source of that energy is. It's a drop, but, drop by drop, people in this country have far more impact than almost everyone else in the world.

Truth is, I can't understand how anyone of good conscience can't care about this, can't care that people in third world nations, who depend on shrinking glaciers for survival or live within inches of sea level but contributed next to nothing to the problem are threatened. So many blameless people and could be decimated if rivers that provide water for millions of people dry up or islands are swallowed whole because we couldn't cut back even a little of our energy usage. I can't see how this is made a joke (in the end, my "friend" likened our disagreement to two women fighting over a large lollipop). How can people be so callous? [Note, these are the same people who get out their torches and pitchforks if you bring up prayer in school or offer to wish them a happy holiday rather than Merry Christmas. We should never forget that Christians stole that pagan holiday, fair and square.]

I've talked before about the science, recommended doing homework, but even that seems inconsequent. If there was even a slight possibility (instead of overwhelming evidence - there are people suffering in the Andes from the recession of glaciers right now) that the concerns are justified, why wouldn't you do what you could? Aside from the financial advantages of using less energy or renewable sources. Just because you made it home safely after driving drunk in the past doesn't mean you'll always be so lucky. I totally don't get why people still do it. Who would want someone else's death on their conscience?

Still, though we'll be among the last to feel the effects of our excess, we will not go unpunished. Our refusal to embrace alternative energy and efficiency is fairly singular (like our adherence to "standard" units of measure). While we're congratulating ourselves on our higher and higher electrical bills and not "falling for" the "hype", China and many oil producing companies are investing heavily in alternative energy so that, when the cost of oil gets so high even we can't pay it (or the results from burning fuels force us to change our ways), those same folks will have us over a barrel again because we didn't come up with alternatives or curb our wasteful ways.

And we'll have deserved it.

## >> Saturday, November 23, 2013

So, someone I know on facebook posted a link to an ad by GoldieBlox, touting the notion that girls don't have to be stuck with "girl toys" that don't do anything and doom them to particular life roles/preclude them from certain professions. It's a cute ad, but I'm afraid I feel they still don't get the concept.

Here's a quote from their "about" page: "By tapping into girls' strong verbal skills, our story + construction set bolsters confidence in spatial skills while giving young inventors the tools they need to build and create amazing things." So, by tapping into a stereotypical quality girls are supposed to have, you think you can help them overcome a stereotypical deficiency.

But stereotypes are the problem. Oh, not the whole problem. It is certainly possible, even probable that, overall, more girls are genetically predisposed to verbal skills over spatial reckoning, etc.  So what? First of all, since neither motor skills or spatial reckoning is my strength, I can say that the lack thereof hardly precludes becoming an engineer, excelling at math, excelling at physics, and making a career in that field, because, hey, I did it.

More importantly, what is "generally" true doesn't mean diddly to an individual. There are any number of dead-eye female pilots who have spatial reckoning (and generally other aspects of science and or engineering like Eileen Collins, the first female Space Shuttle commander) or engineering intuition, or math skills out the wazoo. Each girl, like every boy out there, is an individual, who might be dead on the money on some stereotypical feature and blowing the curve on the next.

The problem isn't the toys. It's what you hear and what you see and what you're shown growing up. It's the level and tenor of the expectations your parents and teachers and mentors and even peers have that discourage girls from pursuing engineering and science and math. If you don't change that, nothing changes.

Because, here's the thing. If you find "girl" toys too limiting for your little princess, there isn't a thing in the world that keeps you from getting her building blocks (they come in pink, too)  or robots or tinkertoys or trains or remote control cars or science kits. Getting her those things won't stop her from being your princess any more than Barbies and babydolls and Hello Kitty stuff will make her a princess if that's not what she wants to be. Not only can you do it now, you could ALWAYS do it.

I'm a parent. I buy the things my kids show an interest in. My son likes wooden puzzles and Legos and cars and blankets. He likes stuffed animals, too, but his sister steals them (he steals her blankets so it's all good). His sister loves dolls and tea sets and cars and figurines of any kind and stuffed animals. I've bought her puzzles, but she's not interested in them though she completely conquered a set of latches in seconds. They both inherited 9000 books and I keep buying them more though neither will let me read to them.

I will continue to buy my children things they show an interest in, not worried about gender or stigmas because, in this house, there's no stigma if my son plays with a doll or wants to get his toenails painted (he does, if I'm painting nails). There's no stigma if my daughter plays with cars or Legos - why would there be? And that is how I'll raise my children, how I raised my eldest daughter. I will tell them, and absolutely believe it and show it in word and deed, that nothing is automatically beyond them, that the only limits on them are in their talent and the limits they set themselves.

I won't make a big deal out of it because I don't have to. I just have to keep from getting in their way. No one had to tell me I could do complex math as well or better than anyone else because it never occurred to me that I couldn't. No one had ever told me I couldn't so why would I think so? No one had ever imposed any restrictions on my abilities or told me I had no business learning X subject or Y subject so I grew up figuring out what I was good at and wasn't good at by myself, through exposure. I never had teacher say, "I don't think a girl like you belongs in physics" any more than I had a parent who said, "Girls should stick to home ec or typing." Actually, I think my mother wanted me to take both subjects, but I stunk at them. But no one stopped me from taking science or math or engineering or anything else I wanted. I do know women, many of them engineers now, who DID have that happen, with parents or college professors or boyfriends, etc.

I was able to find my own limits because no one imposed their own limits, or their perceptions of my limits, on me. And that, boys and girls, is the key, I think. You can't make a boy good at math because he's supposed to be any more than making him play football and learn kung fu will keep him from being a drag queen if that's what he's got a hankering to do (as many a homophobic parent has discovered). People set their own limits and gravitate to the things they excel at or enjoy. If you haven't set any limits, they may still aim small. Or a direction you never saw. But there's nothing wrong with wanting to be a kindergarten teacher or a nurse or an oral hygienist. Nothing wrong with being a drag queen either if it makes you and others happy.

It's when we set preconceived limits upon our children that we limit their potential. If we tell our girls over and over that girls just can't do math, chances are, when they take algebra, they'll be convinced it's beyond them, whether it really was or not. If we tell our children that they can't ever go to college because they're too poor and will have no choice but to work, those children might very well never even try for opportunities intended for kids just like them because they've decided it's hopeless. If we treat children who are Latino (and may struggle with English especially at first) or black as if one couldn't expect much from them, they will likely fulfill our expectations, even if those expectations are unvoiced.

There are many who believe children from the far east are inherently smarter. I don't think so. Their culture values education and parents routinely make sacrifices and have huge (perhaps too huge) expectations of their children. That has its own issues but instilling unnecessary limitations isn't one of them (though there is notably a difference, even now, in what's expected from boys and girls in those cultures). I think this difference in emphasis and expectations is the key to their relative success.

You want your child to fulfill their potential? Buy them toys and games and books and encourage activities that excite, interest, and challenge them. Not you, not other people's children, but them, your children, the individuals. Their imagination might take off with building sets or action sets. It might be dolls and doll houses. It might be puzzles and physical toys. Talk to them, get to know them, encourage their interests and strengths. Find what each individual child responds well to and what encourages those children in subjects or fields that might have not interested them before.

But, whatever you do, don't get in their way. Don't ever let your own limitations or perceptions of their limitation get in the way of their succeeding where you never expected it. Kids can do that, more often than you think.

If we'd just let them.

At least, that's how I see it.

## >> Saturday, November 9, 2013

I haven't actually died. Just been sick and overworked which isn't a combination I recommend. But I haven't forgotten I had more to say on this subject. So I touched on the EVA things that drove me nuts on the the first post , but that wasn't all that made me a little bit crazy with Gravity. And, in the second post, I touched on why orbital debris IS a big problem, but not exactly a problem in the way portrayed. But, yes, there's more.  And I'll be describing them, so they'll be spoilers, so STOP HERE if you don't want details on what happened in Gravity.

Seriously, spoilers below, I'm not kidding.

First, foremost, most importantly, zipping around from Hubble Space Telescope (HST) to the International Space Station (ISS) to Tiangong (Chinese Space Station) using the dregs in an MMU and then some retrorockets in a Soyuz by eyeballing the target is utter nonsense. Not slightly nonsensical but completely noncredible. I'm going to start with a picture here (from Wikipedia) so you can quickly see why it's not possible.

So, at the start of the movie, the ISS is visible from the HST quite clearly. So, using the diagram above, we could assume they were at the same spot off the coast of Africa at the same instant, but still 130 km apart since HST is in a higher altitude. Note this is BEFORE the orbital debris entered into the picture. If we, quite optimistically, assume that it took 15 minutes  from the time Bullock was ordered to abort, was attacked by flying space junk, separated from the Shuttle, hyperventilated enough to use up most of the remaining oxygen (since she wasn't cleaning up, she should have had at least an hour left because they need to clean up for the last half hour), was fetched miraculously by an astronaut using obsolete hardware to the time they returned to the now dead Shuttle/HST with it's floating corpses, the ISS would be, say over Greece and HST would be over Saudi Arabia. Maybe within sight, but at best  as a speck in the distance, physically 1500-2000 km apart at a WAG (wild ass guess).

If, instead, we assumed all that took 46.45 minutes rather than 15 (which would make more sense), in theory, they are close to crossing orbits at near the same time again (that magic witching hour when the debris comes winging by again, but I digress) since that's when ISS would likely cross HST's orbit again, but close in space doesn't mean within arm's distance. HST, though it's going faster (8.16 km/second) has a larger orbit so it takes longer to go around. So, when ISS is "there" HST is some 1.55 minutes "behind" which doesn't sound like much but let me remind you of the speed: 8.16 km/s which translates to about 759  km in addition to the 130 km altitude difference.

So, assuming that changing inclination and altitude wasn't even part of the concern, but just straight translation, you'd be going more crossing more than 800 km outside your established orbit (so you get to supply all the force) to hit a moving target that's also going pretty damn fast (7.6 km/s) but not in the exactly same direction you're going in. And "not exactly" is as helpful as "close" in space.

But let's say, I'm sitting on a viable propulsion source that can propel me the 800 km at 5 gees (5X the force of gravitational pull on the earth which probably way more than the body can withstand without support - the Shuttle, during launch pulled less than three). At a constant acceleration (of 50 m/s^2) and "zero" initial velocity  the formula for distance is x=1/2at^2 which means t=SQRT(2x/a)=~179s, which is pretty fast (just under three minutes). Only problem is that the ISS is now 1360.4 km from where you last saw it. If you went at a more reasonable acceleration, it would be even further away. Plus you are now going an even faster clip and, even if you hit it, you'd be hitting it at a speed of 8950 m/s, yes many times faster than a speeding bullet. In fact, you'd probably want to spend half of that time slowing down the same rate you'd been accelerating, but that will cost you more time and the ISS will get that much further. But I digress.

Perhaps you can see why eyeballing this operation is, um, not effective. Could it be done? Not really, because, in order to do so, you'd have to know where it would be some 3 minutes later and the relative motion in zero g is very hard to gauge give the lack of landmarks, even for seasoned pilots, which Bullock was not. And this is at the best possible conjunction after you first saw it 46 minutes before. By the time you get to where you were in perfect conjunction some 90 odd minutes earlier, that distance has at least doubled and it just gets worse from there. Over the next hours, the distance lagging gets larger and larger so you get one shot really and one only to tag it. But wait, there's more.

Now the thrust to perform this nigh impossible task in theoretical conditions that have nothing to do with reality would require F=mass*acceleration with the mass of two EMUs (at a svelte 124.7 kg apiece per here) + the mass of two astronauts, let's say 81 kg for Clooney (180 lbs for you non-science American types) and 54 kg for Bullock (119 lbs), the total mass is 384 kg. With our acceleration at 50 m/s^s, we have a total force required of 19.2 kN (for 179s, I might add), which  is somewhat less than, say, an Orbital Maneuvering System engine (used by the Shuttle to deorbit at the end of mission) which has a thrust of 26.7 kN, but is nothing to sneeze at. That should, in fact, give you an idea of the kind of thrust you're going to need: more than 1/4 of the thrust (two OMS/vehicle) needed to deorbit the Space Shuttle Orbiter vehicle (which clocks in at 68,600 kg EMPTY) though the burn is much much longer. Do I have to point out that the MMU doesn't have anywhere near that propulsive power?

[Hey, if you're a real rocket scientist or a physicist yourself and note a dozen things wrong with my calculations, I hear you, you're right. I've got so many simplifying assumptions to make these doable that it's nonsense. It's all buffalo chips. I'm trying to make a point here.]

Unfortunately, that very simplistic, but effectively impossible, example is many times more impossible than that because, in order to interact with said ISS (cause you don't really want to punch into it at 9km/s, which, when combined with your existing orbital velocity, would likely have sent you out of orbit and off into outer space, but I digress), you need to match orbits at least to some extent: that means changing altitude and changing inclination. Impossible? No. Easy? Not exactly (haha).

Well, to change altitude (lower) in space is relative easy. You just slow down, inject delta V in the opposite direction you're going (which changes your orbit from "circular" to elliptical), than speed back up a little when you reach the right altitude to go back to a circular orbit.  Not something I'd want to do by eyeball or feel myself, but relatively simple, actually much simpler than the hypothetical translation I was talking about earlier and uses relatively little fuel, just enough delta V to go from 8.16 km/s to 7.6 km/s (or 0.56 km/s). Space craft do that kind of maneuvering quite a bit. Usually just a couple times a flight, though because it uses fuel (going down and going up).

Inclination changing, however, is a different beastie. To calculate delta V to change inclinations, assuming you have two circular orbits of the same altitude, you can use this equation:
$\Delta{v_i}= {2v\, \sin \left(\frac{\Delta{i}}{2} \right)}$ where v is the orbital velocity, delta i is the change in inclination and delta v sub i is the delta v required.
In this case, v=7.6 km/s (assuming we've already gone to ISS altitude) and i=-23.15 so delta v required is -3.05 km/s, nearly 6 times more than required to change altitude. And, of course, to match orbits, you'd have to do it just when the orbits conjoin (which is not exactly something you can eyeball) or, instead you'll just travel in parallel (from behind of course, since you were already behind and have had to slow down bunches to lower orbit and increase inclination. Space vehicles do NOT ordinarily change inclination during flight since launching at the right inclination is far more efficient than changing it after the fact (moving up in inclination from the ground is easier than moving down, which is why the ISS is at an inclination friendly to the more Northerly Russians). It's a big hairy deal.

Everyone still with me? Anyone go into a math coma?

No matter how you slice it, this maneuver that looks so cool in the movie,  (a) takes resources our free floating astronauts didn't have, notably a handy rocket engine, many times their mass in fuel, and time and (b) requires really tricky calculations done by big computers that know where everything is and will be in the near future. Eyeballing it ain't gonna fly. Even then, not sure it's possible because you have to simultaneously slow down (to change inclination and altitude) and catch up (because it's ahead of you). You might be able to if and only if you had those resources and a good lead.

I'm guessing I don't have to explain that the same holds true for bouncing over to Tiangong (which is at yet another (far smaller) inclination and even lower altitude.

So what? Why do you care? Why do I care? (And, yes, I do).  I'll tell you why. I've mentioned this was a beautiful movie, lots of very realistic space scenes going on. I don't think it would upset me so much if that weren't so. There is already a large faction of people who are of the opinion they could run the space program better, that this isn't so hard, that, for Columbia, if someone had noticed the damage, we could have done something.

No. We couldn't. Even if we had seen the damage (assuming it was readily visible), there was no way to repair it with anything we had at hand (no duct tape would not have sufficed), no way to get to the ISS (which was on a different inclination, just like HST).

If we had miraculously made it there, there was no way to hang out there long enough for someone to come rescue Columbia's crew because, unlike the movie, there are generally just enough Soyuz rescue crafts to take the number of people on the ISS down, no more no less (largely because that's how most of the crew gets there) and limited amounts of consumables.

We don't have extras return vehicles waiting around. I don't know about Tiangong, but I'm guessing it wouldn't have a rescue craft sitting there with the crew gone either. It's too expensive getting stuff into space to just leave it up there without a good reason.

It's a great movie to give you some hint of the challenges and dangers of being in space, how cool it is, but it hardly scratches the surface on how tough it is, how unforgiving the physics is, why for every crewmember on orbit, there are dozens of people round the clock to help out in case of danger. Exactly how much planning and know-how and technology goes into what they nominally do in space. And it could easily give the layman a skewed view of what options the crew really has in an emergency. Fortunately, as I mentioned last time, the danger scenario we're using isn't particularly realistic, but what happens afterwards is pure fantasy.

I could go on about how stupid I think it is she tried to take off in Soyuz when she knew it was tangled up in the ISS and a dozen or so rather minor issues like the likelihood of the Tiangong's escape capsule being usable by an non-pilot who doesn't speak Chinese, but the physics trumps everything and it's absolutely no go in that way.

So, no more party pooping. I'm done. Please, enjoy the show. ;)

## >> Sunday, November 3, 2013

So we touched on the EVA things that drove me nuts on the last post, but that wasn't all that made me a little bit crazy with Gravity. And I'll be describing them, so they'll be spoilers, so STOP HERE if you don't want details on what happened in Gravity.

The premise behind the catastrophe at the center of Gravity is that the Russians shot and destroyed one of their own satellites for some reason. This is not outside the realm of possibility. Both Soviet Union/Russia shot down several of their satellites as did we in the 80's. As we now understand the debris concern better and hopefully got less paranoid, we stopped doing those sorts of experiments until the Chinese tried for the first time in 2007, to quite a bit of furor from everyone else. The furor caused, not only because no one likes the notion that someone else could shot down one's own satellites, but because it was at 500 miles altitude, a wonderful spot to rain down debris on a sizeable portion of our most expensive Low Earth Orbit (LEO) assets (and other countries' assets) such as HST, ISS, etc. The U.S. shot down one of our own soon after, ostensibly to prevent a tank of hydrazine from reentering, but it was at a much lower orbit so the impact on the orbital debris was pretty minimal.

(Lower orbits get cleaned up naturally by the friction of the atmosphere which slows them down and encourages them to reenter. Higher orbits have less friction so it takes much longer, sometimes decades, to fall out of the sky.)

Is orbital debris a big deal, a real and significant hazard for our space assets? Oh, absolutely. No doubt about it. Not just because of the junk we send up there and stunts like deliberately blowing up some of it (or inadvertently doing so, as has happened with leftover fuel in various discarded stages), but also because each time debris is left or created from an impact, it can go on to hit more hardware which creates more debris and so on until, even if we never send any more up there, the debris environment will get uglier on its own (something called the Kessler Effect).

So, if orbital debris is a legitimate problem and shooting down a satellite is within the realm of possibility, what's my beef? I don't have a problem with the notion of orbital debris causing cataclysm - that's a legitimate concern - but how this cataclysm is portrayed doesn't work for me, for several reasons.

• One of the reasons orbital debris is so very dangerous are the extremely high speeds with which it moves, and, if it's going to opposite direction in orbit, that relative speed is doubled  so that, instead of objects moving at 8 km/s (which is what orbital velocity of everything in low earth orbit is, more or less), the impact speed could be as high as 16 km/s for a head-on collision. Why is that important? Well, for one thing, one needs perspective. The muzzle velocity of an M16 rifle is ~1 km/s, so orbital velocity is 8-16X faster. That also means that, for the same size impactor (say 4 g like a bullet that impacts with ~1800 J of energy), the amount of energy imparted by impact is 64-256x greater (115,200-460,800 J=1/2 stick of dynamite for a 4g impactor) since impact energy is 1/2mv^2. That high energy/speed has two major implications.
1. The big chunks of debris depicted in movies, like Gravity and many other films, aren't necessary to do catastrophic damage. Tiny objects far too small to track, like a nut or a screw, can punch through heat shields or pressure vessels. Although we track the big stuff because we can track dead satellites and expended stages, and large chunks (say the size of a wrench or larger), in many ways they are less of a concern because we can track them and move out of the way. But the smaller items, which are 10s, 100s if not 1000s of times more prevalent, we can't track and can't avoid. That's one reason orbital debris is such a big threat - because the stuff we can't see can still kill us. It seems unimportant - after all the big chunk thing is way cooler in the movie, and that's quite true - but by reinforcing the stereotypical concern, there's a very real risk to expend efforts to battle a section of the orbital debris problem that is a tiny fraction of the whole. Sadly, this perception is not limited to laymen.
2. The other aspect is that, when stuff is coming toward you at a relative speed large enough to do real damage, that can easily mean several times faster than a speeding bullet. Which means dodging, even seeing the debris, is virtually impossible. Ironically, if you can see it approach, the relative velocity is a tiny fraction of what it could be and it is therefore far less destructive. It's important to note that, though I mentioned relative velocities of 16 km/s (head-on collision) and 8 km/s (effectively hit dead on from the side), one can also be hit from a similar close by orbit at velocities from close to 8 km/s to a fraction of a m/s. Its because of this relative velocity thing that ships can match velocities and dock in space without damaging each other.
• As part of the film, all our communications, notably with the Shuttle, are knocked out. Um, no, not possible while still being an immediate threat to the Space Shuttle etc. The primary mode for communication with the Shuttle is the TDRSS Satellite system, which whirls around the equator (along with almost all communication satellites of the world) in geosynchronous orbit, some 35,800 km above the surface of the earth as opposed to the altitude of HST (559 km), ISS (~417 km) and Tiangong (~370 km). Although it's not impossible that an impact would could send a few chunks high enough to intersect (not match) geosynchronous, they would be unlikely to be a big threat since they'd either be tossed out of orbit (if they obtain escape velocity) or are in a highly elliptical orbit where the bulk of its time is spent at other altitudes. To match geosynchronous orbit, it would need another influx of force to circularize the orbit. The volume of space in  geosynchronous is also much larger than LOE. True, most of the satellites are clustered around the equator, but any debris originating from LOE are likely to be at another higher inclination such that they would only intersect the equator twice an orbit, reducing the potential for impact in geosynchronous orbit.
• And all this discussion on why communication would not be wiped out brings up something else very important about debris: there is a great deal of it, but the volume of space is really vast, which is why debris tends to be a threat over time. Not that one can't be hit by debris in a limited window of time, but that the smaller the window is, the less likely there is to be a significant impact. That's one reason why the risk to ISS is so great over its entire lifespan, but the risk is small on a per year or per month basis.
• Now there are several possibilities for Russian satellites to shoot down, but most of them are of high inclination since their launch sites tend to be further north than the U.S. and China, but the different orbits, at different altitudes and inclinations argues that there would be minimum interaction with all three space assets (HST/Shuttle, ISS and Tiangong) which are all at different inclinations and altitudes. Now, eventually, over time, the debris cloud will expand and affect all orbits below it to some extent, but this would be a process that occurs over months and years, not hours. And would pretty much negate the 45 minute window of time that they described as the time to expect debris.  Remember (or discover), two orbits that have different inclinations will only intersect twice an orbit (assuming they are comparable altitudes) but there's no saying that the object of that inclination will be at exactly the same spot unless they have identical periods (which is unlikely for debris which is likely to be in a more elliptical orbit, especially if it threatens objects at different altitudes). Please note that discussing the intricacies and complexities of orbital mechanics with words is bound to be confusing.
• One other key thing to note about debris is that the most important risks for human spaceflight are pressure vessel damage (as they showed for Shuttle) and damage to the heat shields of reentry vehicles where even small damage can cause catastrophic damage (as evidenced by Columbia, unfortunately). Yet, most of the damage shown was more in keeping with damage inflicted by large (relatively) slow moving impactors.
So, why is this important? True, we're taking liberties and amplifying the threat and time table of orbital debris, but the threat of orbital debris is real, if not as represented. Well, because the perception of the threat and the cause of the threat is important and determines what we do to address that threat. And even science minded folks can be misled. Space Safety Magazine, for instance, a magazine I admire greatly (I am a charter member of one of it's publishing organizations: the International Association for Advancement of Space Safety [IAASS]) recently published an editorial that talks about the plausibility of Gravity, saying "The film, however, has a stronger basis in fact than you might imagine," and then noting the real dangers of orbital debris. But by not clearly pointing out the impossibilities in the movie (as opposed to the unlikeliness of the various scenarios), the position, in my opinion, is misleading.

And, yes, that bothers me. Given the length of this post, I'll have to hold off until next time why traipsing from HST to ISS to Tiangong (among many other impossibilities) is just not going to happen. And why it's important to understand that.

### Party-pooper: Gravity Part 1

As promised, here's some rocket science for ya.

Now, although it's not true of all rocket scientists, in my particular career, I've made something of a specialty out of telling people stuff they didn't want to know, because, well, that's really what safety engineers do. If someone's excited about their work and progress, and it's all hunky dory, safety people don't have to say anything. But, if it's not, safety engineers get the (not surprisingly) thankless task of telling engineers that their baby is ugly and needs some sort of makeover.

That mindset, looking for flaws, either becomes engrained in some of us, or, as I suspect is true with myself, we gravitate to positions like that because we're natural pick-aparters, devil's advocates, skeptics. And, if we have a thick enough skin (I'm nearly a solid), and stick to our guns, we can actually do good things because many a design has been passed over by enthusiastic supporters (aka reviewers) only to fail cataclysmally in reality. Safety folks, if they have a vestige of a spine, help keep that from happening.

But I digress. What I'm here to do is rain on the parade regarding the science of the movie Gravity. Yes, there will be spoilers, so, if you don't want to read them, stop HERE. Now, of course, the first thing people will tell me is to let it go: it's just a movie. After all, I had a great time watching Iron Man III (and the first two Iron Man movies) and the science is quite thoroughly whacked, though just as pretty (I love watching him don/doff suits). I understand what you're saying, I really do, but there's a reason I don't just let it go for Gravity and actually enjoy the Iron Man nonsense, and I'll explain why at the end (which will probably be in a later post).

Gravity is a very pretty movie, with excellent effects, notably the space scenes, and some fairly effective acting. The zero-g footage was particularly spectacular and well-done. When the ISS broke up, the movements involved, including the way the oscillation caused bending moment effects was pretty cool and likely based on some fairly correct physics. Orbital debris is also a significant risk for space vehicles, particularly those in low earth orbit as all the space stations, Hubble Space Telescope and the Shuttle (when it flew) were tied to. In principle....more on that later.

Aside from that, there was almost nothing that was right.

First, I think the movie owes astronauts and the people who train them an apology. The main character, whose name I forgot, is a strong female protagonist and scrappy, etc., which is great, in theory. However, she is also far more ignorant of basic EVA protocol, space information, science, training, etc. than any astronaut I've ever met, including those who were never planning to go EVA. EVA, in particular, is my baby, so let me point out a few things.

• First of all, you DON'T go out spacewalking while nauseous because puking in the suit=dead astronaut. That's why they don't do spacewalks the first few days after launch so they can get acclimatized to the zero g (which sets many a tummy a-flutter), which means, if they were late in the flight, as they were supposed to be, if she were still so nauseous they would not LET her go out and would probably be worried she had something else wrong with her.
• Secondly, one doesn't send out three astronauts at the same time without desperate need. Sending three astronauts out would have to be for a heckuva a reason (only once, in the entire history of spacewalking, has anyone (US, Russia or China) sent out three spacewalkers at once [STS-49 to try to retrieve IntelSat IV F-3 - which they managed to do]). We don't send out three at once for the very good reason that everything is designed for a pair. There are connections for two suits in the airlock (which has to hold a suit tech and two suited crewmembers and is probably smaller than your shower stall). We don't send out just one person any more either, but pairs have managed to get the job done over and over again.
• If one were desperate enough to have to send out three EVA crewmembers, it certainly would not be to piddle-poo around with a jet pack that looks amazingly like the Manned Manuevering Unit, that stopped flying before I started working in the space industry in 1989 - (flew in 1984 only). And certainly not on a Hubble Servicing Mission, given that those are always wall-to-wall back-to-back EVAs (where, interestingly enough, no one has enough free time to go bouncing up and down on his safety harness - shudder). They do those missions with a staff of four EVA astronauts that go out in pairs on alternating days (because doing EVAs on successive days is tremendously tiring - EVAs are hard physical labor working against the pressurized suit, mean usually 16 hour days [at least], and are taxing to hands in particular). And, on HST, much like they do on ISS, EVA crewmembers work their tails off each EVA and have half a dozen other tasks to do if they miraculously get finished early.
• EVA crewmembers are drilled continuously and at great length, both on safety requirements, contingencies and actual tasks in the Neutral Buoyancy Lab. Preferably 10 hours in the water for every one on orbit. This is particularly true on something like HST where they EVAs are packed, challenging, gruelling and frequently run into snags.  The crews that perform EVAs (and I know it from personal experience with HST) are smart as hell, driven, capable, knowledgeable and professional. I personally was a little offended on their behalf at the behavior of the crewmembers in the movie.
• And, no, crewmembers do not bounce back and forth on their tethers for entertainment, because (a) that's stupid, (b) they don't have time, and (c) most importantly, it's not safe. Crews count on the tethers to save them if they get separated, but bouncing on that puts forces on them, adds to the risk of them rubbing on something (and failing when you need it) and also imparts forces on the ship you're attached to, which is trying to hold the arm and HST still at the same time.
• You don't manipulate computer boards on EVA for a couple of reasons, not the least of which is that pressurized gloves don't have that kind of dexterity. The gloves are ballooned out and you have to work against them without being able to really feel what you're manipulating. But, far more importantly, circuit boards are covered with sharp edges, those little solder-tipped spots where ICs poke through. In a suit where glove material can be torn open with anything even vaguely sharp, no way you'd handle a circuit card or slide it into a card cage with all those resultant pinch points. I might add the HST folks that design those challenging EVAs are very cognizant and work very hard to make all the unusual equipment they send up EVA friendly and safe. But, if they had managed to send this contraption, it would never have gotten past the crewmembers or me or any other EVA Safety Engineer.
• When they tell you to come in because there's danger, you do it. No one is more cognizant of how close to death they are than an EVA astronaut. Space is completely unforgiving and there's no second chance if your suit fails catastrophically.
• Even if the airlock wasn't sound (and with the catastrophic damage to the shuttle, I wouldn't trust it either), the system to provide power and oxygen to the suit via umbilical in the airlock might still have worked. Given how low her oxygen was, I would have tried that before setting forth for the station (if that were viable, which it isn't - more on that later). Still, there is an emergency oxygen supply, intended to provide oxygen in case of a "hole in the suit" scenario. Not saying you want to use it, but this is probably sufficient emergency to justify it. It's not unnexpected, with the hyperventilating, that her oxygen went low first, but the CO2 would also also likely gone up since CO2 scrubbing capability and oxygen supply are generally about the same capability.
• As has been noted by others, crewmembers do not don the suit in just their skivvies. They have socks and diapers, and, most importantly, a liquid cooling garment, necessary to keep from dumping a liter of sweat out when they doff the suit (as happened on EVAs before we had the liquid cooling garment). No argument, though, that the skivvies look better on the big screen.
• Orlans, the Russian spacesuit presumably stored in the Soyuz capsule, would be plenty heavy to sink like  stone in water (120 kg), but doffing it, since you slide out the rear swifter than most spacesuits, rather than peeling them off like long johns, still would take five minutes, even if you could get it open in the pressure of underwater.
There's more, of course. I haven't even touched on the orbital mechanics involved, the orbital debris scenario and the issues with communications satellites. Sigh. Still, this should be enough for one post. Several of you are already having your eyes roll into your heads at the stuff I tossed at you. So, next time, how far can you go with an MMU? Not nearly as far as they showed, seriously.

## >> Sunday, October 27, 2013

No, really. I've decided to stop being a lazy slob and blog again, blog with purpose even and will start refilling this blog with science related snarkiness and general philosophical whatnot, just like always.

But, in the meantime, I have an announcement:

As I might have mentioned once or twice before, I write fiction (yes, I'm back to present tense) and last year I had a story included in SQ e-zine.  This year, they're publishing that story among their bests and it's available for purchase in both print and ebook (my story and eighteen others) in a book called Star Quake 1. I don't know everywhere it's available, but I know it's available at both Barnes & Noble and at Amazon.

It's not a big thing, as real writing goes, but it's big for me.

More news, I'm gearing up to take my rather large backlog of novels and short stories and self-publish in ebook form (some of many different flavors of electronic book at once). Not because I don't believe in it, but because I do. I don't want to get rich. I want to tell stories. I want people to have the opportunity to actually read them.

One way or another, that's just what I'm going to do.

Stay tuned.

## >> Wednesday, September 4, 2013

Kia Corporate Office Headquarters
11 Peters Canyon Rd.
Irvine, CA 92606 USA

To Whom It May Concern,

I am writing this letter to protest the pricing policy your company apparently has with regard to repairs.

On August 22, 2013, I took my 2007 Kia Spectra in to be repaired to the Family Kia dealership in Dickinson TX. I went because that the airbag light was on. I was perfectly aware of what was behind the problem (I am an engineer and can do research on the web) and that I would personally have no use whatsoever for the fix, since the switch is intended to protect children whose parents place them in the front seat so they aren’t injured by the airbag. As I would never do so with my children or allow anyone else to do so in my car, the switch is superfluous. I know this, but recognize why it’s necessary (I’m actually a safety engineer) and also that my safety inspection sticker, due in September, would require the problem to be addressed. I was expecting some level of extra surcharge for a switch likely worth a few tens of dollars (which I have since verified with research). I was expecting to pay a few hundred for the privilege since I have to have a Kia dealer fix it.

I was NOT expecting to be charged $1200,$1088 for the entire bottom seat assembly (which inexplicably must be replaced entire and unbelievably costs about 1/15 the original price of my car) and expected hundred or so for labor. Since it's a safety matter, I have no choice to get it fixed and no choice but to use a dealership.

Which of course provides the rationale for the monstrously overpriced part I have to have for my fully functional car. I have no choice so your company has chosen to use that monopoly to gouge me shamefully for a ridiculously high profit, taking advantage of a safety regulation for your own enrichment.

While I can accept this behavior to a reasonable level, this clearly goes beyond all reason into the fantastical, insulting, and reprehensible. Effectively swindling, with perfect legality, even those who are well aware they are being cheated does not sit well with me. More so, in that I can do nothing to prevent it. Not only did I have no choice but to accept the unreasonable offer, but I left empty-handed (having ordered the ridiculously priced part) and am still awaiting notification that it has come in (I’ve been waiting for 13 days so far for the part that should come in in about a week) so I can have it installed for the quite reasonable labor charge (or at least that’s theory).

I’m a single mother of two special needs children. Fortunately for me, I’m a professional making a good salary and can weather this kind of financial impact, though not entirely painlessly. But my children will have to wait longer for a cedar playset in the back yard. I will not have to wonder how I’ll make the house payment or get my children the medicines they need. No one will go hungry. But, someone, who might be attracted to the relatively low prices for family friendly cars as I was might be devastated by a sudden intractable bill for more than thousand dollars. I’m outraged on their behalf as well as my own.

I am thoroughly disgusted. It doesn’t matter at all that other car manufacturers likely have similar policies. I have not run into this level of price gouging before and, if I did, I would cease all business with them as well. I cannot condone such practices and, although I cannot prevent the fact I’ve already been gouged (but not yet repaired), I can make damn sure it doesn’t happen again.

So, though I have no choice but to fix my car, you can be assured I will never buy any Kia or Hyundai vehicle again nor work with a dealership that sells them. That may not be much of a threat, but I’m letting you know because I’m unlikely to be the only one to have that reaction. While gouging someone because you can is good short term strategy, I maintain it is bad in the long run. Two weeks ago, with a seven year old car (less than 60K miles) that had virtually no functional issues except for a few little blips handled early, I would have been the first to recommend, with gusto, my Kia or something similar to a friend or family member. I shall now be just as vehement to recommend against it (and have already convinced one friend not to purchase a Kia).

Because what I buy next and into perpetuity, what I tell my friends who respect my opinion, is within my control.  Your practices have lost you what would have been a very loyal customer.

I don’t expect my opinion to make any difference to you or to have any effect on your practices. But I thought I would give you the opportunity. Most people I know, they’ll just never have dealings with you again without a word.

Note that I’m also posting this letter openly on my blog and passing it along to as many layers in the Kia organization as I can manage.

Have a nice day.

Stephanie Barr

I think that says it all