« February 2004 | Main | April 2004 »

March 30, 2004

Space Junk

One of my AvantGo channels I download to my Palm to read on MARTA is space.com. I'm not sure how they make money, but they have a lot of good space-related articles. Today they had one on space junk, all the pieces of old rocket motors, dead satellites, loose screws, and other pieces of debris in orbit around the earth travelling thousands of miles per hour. Even a paint chip travelling at 10,000 miles per hour can knock a hole in a satellite or spaceman. So it is a significant problem and there are all kinds of efforts to minimize any cast-off material or debris. Also there is a project to track every known piece of junk to make sure critical satellites, the space shuttle, space station, etc. can move out of the way if they are in danger of being hit.

This article is about a series of old Russian satellites that had nuclear reactors on board for elecricity. The Russians didn't want the satellites to fall to earth with reactor cores in them so they included a booster rocket that would, after the satellite was no longer needed, launch the reactor core into a much higher earth orbit that would take thousands of years to degrade. By the time the core would re-enter the earth's atmosphere so many half-lives would have passed that it would no longer be dangerous. So that was a neat idea right there.

But then it seems that after the cores were ejected, the leftover part sprung a leak in its liquid coolant. A stream of drops came out of the satellite. Each drop is a piece of space junk and some of the "drops" are a couple of inches in diameter. So now there are 10,000 drops of Sodium-Potassium coolant in orbit waiting to hit anything in space at extremely high speed. Oh, and each drop is radioactive.

Then they said that because these satellites were all at roughly the same orbit, that even the non-leaking ones are now subject to be hit by one of these droplets, causing further leaks and even more space junk. In fact they said people are doing research to see if there is already a "critical mass" of space junk that will just keep colliding into each other and producing even more pieces of debris that will cause more collisions and so forth.

Fifty years of exploring space and we may have already ruined it.


Old Soviet nuclear powered satellites leaked a trail of menacing radioactive droplets that have become a debris threat to other spacecraft.

Tiny spheres of liquid sodium-potassium (NaK) reactor coolant dripped from the former Soviet Union's radar ocean reconnaissance satellites, known as RORSATs. This class of satellite -- no longer launched -- carried a nuclear reactor to power a large radar dish that enabled day/night snooping of Earth's oceans.

After a RORSATs tour-of-duty was over, the reactor's fuel core was shot high above Earth into a "disposal orbit". Once at that altitude the power supply unit would take several hundred years before it reentered the Earth's atmosphere.

This Soviet Union placed a series of radar-equipped ocean reconnaissance satellites, known as RORSATs in the west in low Earth orbit beginning in 1967. Employing powerful radars and working in pairs, they located and targeted U.S. ships for destruction by Soviet naval forces. Nuclear-powered RORSATs launched in the 1970s occasionally malfunctioned, including one that crashed and spread radioactive debris across northern Canada in 1978. Image credit: Smithsonian/DIA

NASA's Long Duration Exposure Facility (LDEF) was deployed in orbit in 1984 by the Shuttle Challenger. After floating through space for well over 5 years, the bus-sized spacecraft - outfitted with dozens of experiment trays -- was returned to Earth by shuttle Columbia in 1990. Once inspected, sodium potassium coolant from Russian reactors was identified as impacting LDEF. Credit: NASA

Ground-based radar first caught glimpse of an abnormally high concentration of objects drifting through space. The objects were later identified as droplets of reactor coolant that eked from leaking Russian space reactors. Shown here are Haystack and HAX radars located in Tyngsboro, Massachusetts. These radars collect hundreds of hours of orbital debris data each per year. They are NASA's primary source of data on centimeter-size debris. Credit: NASA/JSC Orbital Debris Office

Earth is encircled by space debris, big and small bits of human-made flotsam. This computer generated image depicts orbital debris currently being tracked around the Earth. Menacing space litter includes over 100,000 tiny droplets of reactor coolant that escaped from Russian-built military spacecraft. Credit: NASA/JSC Orbital Debris Office
More Stories

NASA Asks Pentagon to Examine Space Station for Damage

Space Debris Experts Debate Possibility of Columbia Impact

'No Littering' Plea Extended to Space Junkyard

Radar Satellites Began With the Space Age

However, in ejecting the core from the main body of a RORSAT, a plumbing problem plagued the satellite design. Faulty seals permitted the NaK coolant to leak, leaving thouands upon thousands of droplets to spill freely in to space.

Hazard to spacecraft

RORSATs were orbited by the Soviets starting in 1967 and stopped in 1988.

There is evidence from ground-based radar measurements that 16 of a total of 31 RORSAT nuclear reactors orbited lost coolant following core ejection into disposal orbits.

Paula Krisko, a space debris specialist working for Lockheed Martin at NASA's Johnson Space Center (JSC) in Houston, Texas, noted in a recent newsletter dedicated to orbital debris research that the NaK droplets have been observed over the last decade.

Not only have the spheres come under scrutiny by several NASA radars, Krisko explained, they were also found to have dinged the Long Duration Exposure Facility, better known in NASA lingo as LDEF. This school bus-sized spacecraft floated through space for well over 5 years before being plucked from orbit and returned to Earth by shuttle Columbia in 1990.

Krisko explained that a study of the NaK coolant droplets circling Earth, floating about in varying sizes, is estimated to be 110,000 to over 115,000 in number.

"This population represents an orbital debris hazard to spacecraft in low Earth orbit," she stated.

Radar studies

Credited with first flagging the Soviet leaking reactor problem was Don Kessler. He has over 40 years of experience in the scientific study of human-made space trash, a large chunk of that time spent at the NASA JSC delving into the problem of space debris.

Kessler is now an orbital debris and meteoroid consultant in Asheville, North Carolina.

There has been a significant change in the RORSAT story since Kessler and his colleagues first reported the problem in 1995. "It is now accepted by all, even by the
Russians, as being correct and is now part of all orbital debris models," he said.

NASA's main source in spotting the drifting droplets was the Haystack radar. That facility is operated by Massachusetts Institute of Technology's (MIT) Lincoln Laboratory and has been collecting orbital-debris data for NASA since 1990 under an agreement with the U.S. Air Force.

Kessler led the effort to discover the cause of an abnormally high concentration of objects that was detected by the Haystack radar. These small objects were zipping about the Earth between roughly 530 miles (850 kilometer) and 620 miles (1,000 kilometer) altitude.

Something strange going on

"Our first clue that something strange was going on," Kessler said, was the high concentration of objects near 600 miles (900 kilometers) above Earth. That intensity of objects could not be explained by an explosion, which would have dispersed the debris over a larger altitude range, he added.

"The concentration was so high that, whatever the source, it represented the most significant impact hazard for spacecraft operating at those altitudes... and still does today," Kessler said.

Early work involved techniques using the Haystack radar to sample the environment by simply counting objects as they passed through the radar beam. The advantage of this was that researchers were able to statistically sample the environment of much smaller objects, Kessler explained. Altitude and radial velocity of the droplets could be accurately measured. But only rough measurements of motion direction and size of the objects could be ascertained, he said.

Stare and chase

The final proof came when NASA asked MIT to develop a "stare-and-chase" procedure where they could track some of the larger objects long enough to develop orbits.

"We used all this information, plus other sources of information, to determine the source," Kessler said. That source of spheres made of NaK coolant was found to come from the seeping RORSATs, he said.

Kessler told SPACE.com that follow-on NASA work has pegged the total mass of leaked NaK as over 360 pounds (165 kilograms) -- greater than he had orginally estimated.

A report on the RORSAT leakage in 1997, led by Alessandro Rossi, a researcher at the Centro Nazionale Universitario di Calcolo Elettronico (Electronic National University Center for Calculation) in Pisa, Italy, pointed out another issue.

Rossi stated that, although the NaK coolant leakage may have been confined to a specific class of satellite no longer launched, "the probability that a debris impact might puncture the radiator of one of the RORSATs still in graveyard orbit, inducing a new leak from the secondary cooling circuit, is far from negligible."

Well-defined and publicized

"The issue has been well-defined and publicized," said Nicholas Johnson, Program Manager and Chief Scientist at the NASA JSC's Orbital Debris Program Office.

There is a large population of NaK droplets primarily around 560 miles (900 kilometers) altitude above Earth, Johnson explained. Some of the largest of these are in the roughly 2 inches to 3 inches (5 to 7 centimeters) diameter category. They have been cataloged by the U.S. Space Surveillance Network and are routinely tracked, he said.

The vast majority of the droplets are smaller, down to less than an inch in diameter, Johnson said. "They are not decaying rapidly, although some very small particles have reached lower Earth orbits."

Johnson told SPACE.com that "they pose potential mechanical damage to other spacecraft, just as more conventional debris of the same size."

Radioactive droplets?

There is one added element to the RORSAT reactor coolant saga. Are those droplets radioactive?

Any object, large or small -- a paint fleck or a tiny radioactive sphere -- whizzing about Earth at high speed is troublesome to both piloted and automated spacecraft. Furthermore, eventually those NaK spheres will nose-dive into the upper atmosphere.

There is no doubt that the NaK coolant was radioactive when a RORSAT was running, said Gerald Kulcinski, associate dean for research in the College of Engineering and a professor of nuclear engineering at the University of Wisconsin at Madison. In the process, both Sodium-24 and another isotope, Argon-39 would have been created, he said.

While the radioactive Sodium-24 is short-lived, any Argon-39 released would have a half-life of 270 years, Kulcinski noted.

That being said, however, just how much of that Argon-39 radioactive isotope is encapsulated within a space-frozen NaK coolant droplet is not immediately clear, Kulcinski added. Specific engineering details of how the RORSAT reactor was designed and functioned would be required. Yet another unknown factor is what impurities could have been resident within the NaK coolant, he said.

Runaway threshold

The NaK droplets represent only the "short-term" issue, Kessler said. He underscored another concern -- terming it a "runaway threshold". That is, collisions in space would increasingly produce large quantities of smaller debris over the next 50 years or so.

"Since we began looking, we have measured debris not only from sources like the NaK, but from solid rocket motors that eject large amounts of centimeter-to-micron-size objects, paint flecks from painted spacecraft surfaces, copper needles from U.S. Air Force communication tests, and more fragments than expected from explosions in space," Kessler said.

"In the long-term, debris resulting from collisions is still the major problem, and will be the most expensive to control," Kessler said. "We are on the threshold, if we have not already exceeded it, of reaching a "critical density" of objects in low Earth orbit, where collisional fragmentation will cause the debris environment to slowly grow even if all other sources are eliminated."

March 29, 2004

Katie's surgery Part 2

This is a continuation of the original post

Katie is now half-way through her recuperation. The staples were taken out two weeks ago and the doctor seemed satisfied with the progress, but I still have to take it easy for the full eight weeks. They seemed a little disappointed that Katie had gotten a couple of staples out and the scar hadn't grown together perfectly. In parts where the staples stayed put there's just a little line, but other parts are still red even at 4 weeks. I would guess the scar is about 85% healed. She still licks it some. At least half the hair has grown back on her leg so she is at least all black again.

At eight weeks they will take x-rays and make sure the bone has grown back together and then we can start doing therapy by taking progressively longer walks.

Katie is doing pretty well. I haven't been taking Clio for walks either so we are all suffering and getting stir crazy (and gaining weight in the case of me and Clio at least; Clio and I have gone to Stone Mountain with Susan and her dogs the last couple of weekends). Katie still doesn't put much weight on the hurt leg, but doesn't keep it raised off the ground either. She really wants to play but we can't do anything physical.

See a follow-up entry.

March 21, 2004

Market Timing Part 2

I posted my first entry on market timing last May. The market had bottomed out and was on the rise and I wanted to a way to stay out of future declines while still being invested during rallies. Market timing seemed to be a way to do that and I decided to play around with it in my deferred compensation account which allows me to get in and out of my mutual funds without paying capital gains taxes or incurring sales charges. I was going to do it with only Fidelity Over-the-Counter (ticker: FOCPX, 20% of my portfolio) but decided to apply to my others as well including Vanguard Index 500 (VIIIX, 60%), American EuroPacific Growth (AEPGX, 10%), and Ariel Fund (ARGFX, 10%). I would use the 50-day moving average. When the current price drops below the 50-day moving average you sell. When it goes back above the 50-day moving average you buy it back. You can refer back to my original posting to see how well this can work.

But the theory and the reality are a little different. First, you don't get to sell right when the price goes below the 50-day average. You have to wait for the fund to close below the average (unless you try to anticipate the closing price; more on that later) and then buy it the next day (if the market doesn't rise enough to get back above the 50-day average). The problem is the price line moves the most on days with big losses or gains so often you end up well below the 50-day average. Here's my first cycle of Buy and Sell:

As you can see I waited for the price to go below the 50-day average (the brown line) and sold the next day when the market actually moved up a tiny notch. That was August 5 and I sold 165 shares for $27.18. For the next couple of days the market didn't do much but then it started going back up, crossing the line just a few days later, indicating time to buy. I didn't want for the price to dip right back below the line again so I waited a couple of days and bought back my shares at $27.94. I bought the shares back at a higher price than I sold them so essentially I missed out on $125.40 of gains which to me is like a loss of 2.8%. That's okay because that is fairly cheap insurance and even Merriman says you will lose out more often than you gain, but the big trends will make up for it. Still, the 50-day average moved much less than 2.8% in those days (maybe $0.20 per share or 0.7%), so the theoretical looked a lot better than the actuality. So it turns out that every time you buy and sell on a blip like this, you will probably lose a couple of percent.

The market continued to rise and I was fully invested so at least I wasn't missing out on the continuation of the rally. There was time in late September that I almost had to sell but the price stayed just above the 50-day average and the rally continued again. Then in late November it started going down again. The bull market had sent this fund up around 30% so I was worried that we were due for a correction. On October 24 the previous closing price was above the line but in the afternoon the market indexes (Nasdaq for FOCPX) were showing a loss that would push the price below the 50-day average. I anticipated and sold that day. A small end of the day rally made the loss not quite as bad as it had been earlier in the day and the closing price fell right on the 50-day average.

The next day the market went back up. Afraid of a false rally I stayed on the sidelines for another day or two before finally realizing I needed to be back in. So I wound up selling 180 shares for $30.55 and buying them back at $31.48. This time I missed out on a 3% rise, or $167.40. Combined with the earlier blip I had lost out on about 5% of a 30% rally.

Really, I should have bought my shares back the very next day, but that seemed so inefficient. I do worry that if I jump in an out too often that my deferred comp plan will cut me off or change their policies. Interestingly, at about this time the Department of Justice started investigating some mutual fund companies who were allowing certain large clients to do market timing, jumping in an out of funds like I was doing. Many of the funds had rules against allowing small investors doing this. The effects of big moves on a mutual fund company is they have to keep cash on hand or buy and sell shares more often, hurting their overall performance (which is divided out among all shareholders, even the ones who have bought and are holding like you're supposed to).

The market continued to be kind of volatile as it seemed to be reaching some upward resistance and I wound up selling again in November after the price dropped below the indicator again, selling 164 shares at $30.87 on November 17. Again the market soon went back up but I figured the rally was about out of gas and decided not to buy back the shares. I felt like the timing thing is a good indicator, but you also have to trust your own comfort levels and I felt more comfortable keeping that 20% of my portfolio on the sidelines for the time being (plus I wasn't thrilled with FOCPX in general).

The next graph shows what happened afterwards up until today. My intuition was correct and the market dipped back below the 50-day average again just a week or two later. Then it went back below again. I had a good chance to buy my shares back at close to the average around December 20, but felt it would go back below the average for good. Well, it didn't. Instead it went up like a rocket all the way up past $34 a share, 10% more tacked onto the rally.

Merriman says it takes discipline to do market timing and stick to it. I can see what he means. I didn't want to do too many Buy-Sell loops because I was losing a few percent every time. Also it is worth noting that Merriman recommended using the 100-day moving average as an indicator which was never crossed until March 2004. So that would have kept me invested the whole time, avoiding my 2% and 3% missed opportunities and my big one when I gave up on timing for a little while.

At the same time this was going on, I was also doing timing with my other mutual funds with similar results. With VIIIX I lost 3.8% and 1.1%, but ultimately stayed invested until recently when it dipped below the 50-day again. With ARGFX I lost 2% and 1% and am still invested now though I probably am below the 50-day average right now. And finally with AEPGX I only had one buy-sell cycle where I missed out on 3% and sold recently.

My conclusions so far: I think it is still worth following. One of the advantages of timing is that it reduces volatility. That means your investments don't fluctuate in value as much, a positive thing. If you could invest in a fund making 10% per year with very little volatility vs. one making 10% and is all over the map, you'd want with lower volatility.

Also you have to be very strict about following the strategy, even if it means you sell one day and buy the next for 1 or 2 percent more. It's painful to do this when the price is crossing over the indicator often so it still takes some intuition. I could try the 100-day indicator but I still feel like you miss a lot of smaller trends with the longer period.

See a follow-up entry.

March 19, 2004


When I'm filling in album names and song titles I would get kind of confused on what words you capitalize and which you don't. I found some tips on the internet somewhere that were very helpful:

Don't capitalize:
a an the (articles)
at by for in of on to* up (prepositions)
as but if or nor (conjunctions)

except if it is first or last word

except in parallel with words that are capitalized: Homes In and Near Ohio

*do capitalize in infinitives: One Life To Live

March 9, 2004

Letter to CBS and Viacom

Today my satellite provider pulled the plug on Viacom stations including MTV, VH1, and Comedy Central. Fortunately the Osbournes season was over, but I will miss The Daily Show. Although some CBS stations were pulled, the Atlanta station is still on. The disagreement stems from CBS charging Dish Network to carry their signal. Not only were they increasing the rate, but also requiring Dish Network to carry their Viacom stations which they also charge for. The end result is everyone pays more for their cable bill. But what bothers me the most is that they charge providers *anything* since they should be getting their revenue from advertisers. CBS makes these signals available free over the air but charge the cable providers to carry them. It makes no sense.

Dear CBS and Viacom,

If you didn't run commercials on all of your programming then you should be able to charge whatever you want to cable companies to carry your signal just as HBO does. But because you burden your viewers with commericals (more than ever) you should not charge cable or satellite companies anything to carry your signal. Nor should they charge you to carry your signal since you need viewers and they can supply them. I blame CBS and Viacom for the constantly increasing cable and satellite bills. Dish Network on the other hand is trying to look out for its subscribers by resisting your attempts to extract more money from the viewers. I applaud Dish Network and their efforts to keep rates low. And I ask that CBS and Viacom not only go back to their old rates, but stop collecting fees from cable providers altogether and support your programming via the advertising that you subject us to. Until then I will continue to enjoy watching other networks and other programming and watching their commericials.

Thank you for your time,

March 6, 2004

iPod Battery Pack tests

I ran a test on my home-made iPod battery pack. Just running the iPod at 50% volume through a playlist and otherwise not touching it, it will last 7.8 hours. By using the battery pack to recharge the iPod when its battery meter goes down to 1 bar out of 4 and charging for an hour I was able to 4 charges plus part of a 5th charge. This gave me a total of 27.7 hours including the 4.5 hours of charging when I was playing it too.

Read all about the test and the battery pack


I'm always looking for ways to invest. Lately gold has gone up a lot from $300 per oz a few years ago when all the countries were selling off their gold reserves up to $400 per oz now. So I was wondering how you can buy gold even though I'm not really seriously considering it (Motley Fool points out that if you bought $1 of gold in 1802 that today it would be worth $0.98 adjusted for inflation (now gold is up some so that might be $1.30); US bonds $304; regular bonds $952; and stocks $599,605) but I wanted to know how it would work.

It's hard to just go out and buy gold without paying a big premium. A lot of places want a 10% premium and will charge premiums when you want to sell the gold too. I found a place called Bullion Direct that seemed to be pretty fair, it is a marketplace for buyers *and* sellers (most places just want to sell to you). It charges only 1% in transaction fees and ships to you for only $5.95 plus actual UPS rates so you can then bury it in your back yard (or they will store it for free). Here's what I wrote to myself:

BullionDirect is kind of an Ebay of gold trading. They have a market of buyers and sellers of all metals broken down by metal, brand (e.g. American Eagle, Kruggerand), weight ($50-1 oz, $25-0.5 oz, $10-0.25 oz, $5-0.10 oz for American Eagles), and sometimes specific by year. They show you all the sell orders and all the buy orders in the queue (which isn't much) with bids always below the asking prices. You can enter a bid or sell your gold. If you are buying at an asking price then the transaction is executed immediately.

They charge 1% and store the gold for free. Or you can have it shipped for $5.95 plus UPS ground rates. They also have catalog sales where they will sell to you at current asking rates but then you must take delivery.

Pure gold coins: Canada Maple Leaf, Australian Kangaroo Nugget, Vienna Philharmoniker, Chinese Panda

22k gold coins (weigh more than 1 oz so they stil have 1 oz of gold; more durable than pure gold): Krugerrand, American Eagle, Britannia