As we saw in the first instalment on home-made Iron Man-style armor, it's not impossible to make a suit of armor that gives you protection from bullets -– the problem is being able to move afterwards. Even when advanced ceramics and composites are used, it's hard to get the weight down. Medium-sized inserts in Interceptor armor weigh four pounds apiece and are about the size of a sheet of A4, so whole body protection is going to weigh a lot. If you could carry a few hundred pounds extra, wearing this sort or armor wouldn’t be so much of a problem –- and that's when a powered exoskeleton starts looking like a good idea.

Researchers have been working on exoskeletons since the Navy's unsuccessful Hardiman project back in the 60's (I think they borrowed from the design for the Matrix movies though). Progress has been slow and the results have been mixed at best. If you want to build your own, then it's going to take a lot of work and a lot of patience. One of the more advanced projects has been the Berkeley Lower Extremity Exoskeleton (BLEEX), which includes a pair of robotic legs and a backpack. The latest product from Berkeley is the Human Universal Load Carrier (....yeah, that's HULC™....) which is intended to add 200 pounds to your carrying capacity.

The reduction of the wearer's metabolic cost is of paramount importance for long duration missions. This is true because excessive oxygen consumption leads to premature fatigue even if the exoskeleton supports the load. In fact, a very recent BAA from the Natick Soldier System Center requests proposals to conduct a preliminary study on solutions that lead to a reduction of oxygen consumption.

HULC™, fueled by proprietary technology, decreases the wearer's oxygen consumption and heart rate thereby increasing the wearer's endurance.

When the users carried a load, the effect was more pronounced. The oxygen consumption of these users carrying an 81 pound approach load at a speed of 2MPH was decreased by about 15% when using the prototype HULC™.

Video here .

The Army meanwhile has bigger plans. In an article for The Brookings Institution, Peter Singer gives us A Look At The Pentagon's Five Step Plan For Making Iron Man Real. This is the Land Warrior program, now Future Force Warrior, which involves a large number of gadgets and gizmos being assembled into one wearable suite for the foot soldier, including various sensors from super-sights to sniffers, weapons, communitcation and navigation. With that sort of load you're going to need an exoskeleton. But as Singer points out, sometimes the Army get a little carried away:

When the Army-MIT super-soldier project launched, its director, Professor Ned Thomas, extolled, "Imagine the psychological impact upon a foe when encountering squads of seemingly invincible warriors protected by armor and endowed with superhuman capabilities, such as the ability to leap over 20-foot walls."

The problem was that the images his program used on the grant proposal were pretty much lifted from the Radix series, about a female superhero who wears an armored skeleton with just those same superpowers. Comic book creators Ray and Ben Lai threatened the project with a lawsuit, "They're selling this as science fact while we're trying to sell it as science fiction. And people don't even know that we created it in the first place. People might even think we're copying them."

But it doesn’t necessary take big corporate resources to build a working exoskeleton. Inspired by the powered armor in Starship Troopers, Monty Reed, a former Ranger, has built his own version. Called Lifesuit, it is intended to help those who have lost the use of their legs:

The Seattle native, now 40, has used mostly his own money over many of the past 19 years developing a robotic device he devoutly believes will allow even quadriplegics to walk, climb stairs and, someday, perhaps to dance.

A lanky, 75-pound contraption evoking scenes from "Ro

Making and owning an H-bomb is the kind of challenge real friends of Rob seek. Who wants to be a passive victim of nuclear war when, with a little effort, you can be an active participant? Bomb shelters are for losers. Who wants to huddle together underground eating canned Spam? Winners want to push the button themselves. Making your own H-bomb is a big step in nuclear assertiveness training -- it's called Taking Charge. We're sure you'll enjoy the risks and the heady thrill of playing nuclear chicken.

Part 1: Making Your Bomb

The heart of the successful H-bomb is the successful A-bomb. Once you've got your A-bombs made the rest is frosting on the cake. All you have to do is set them up so that when they detonate they'll start off a hydrogen-fusion reaction.

Step 1: Getting the Ingredients

Uranium is the basic ingredient of the A-bomb. When a uranium atom's nucleus splits apart, it releases a tremendous amount of energy (for its size), and it emits neutrons which go on to split other nearby uranium nuclei, releasing more energy, in what is called a "chain reaction." (When atoms split, matter is converted into energy according to Einstein's equation E=MC2. What better way to mark his birthday than with your own atomic fireworks?)

There are two kinds (isotopes) of uranium: the rare U-235, used in bombs, and the more common, heavier, but useless U-238. Natural uranium contains less than 1 percent U-235 and in order to be usable in bombs it has to be "enriched" to 90 percent U-235 and only 10 percent U-238. Plutonium-239 can also be used in bombs as a substitute for U-235. Ten pounds of U-235 (or slightly less plutonium) is all that is necessary for a bomb. Less than ten pounds won't give you a critical mass. So purifying or enriching naturally occurring uranium is likely to be your first big hurdle. It is infinitely easy to steal ready-to-use enriched uranium or plutonium than to enrich some yourself. And stealing uranium is not as hard as it sounds.

There are at least three sources of enriched uranium or plutonium...

Enriched uranium is manufactured at a gaseous diffusion plant in Portsmouth, Ohio. From there it is shipped in 10 liter bottles by airplane and trucks to conversion plants that turn it into uranium oxide or uranium metal. Each 10 liter bottle contains 7 kilograms of U-235, and there are 20 bottles to a typical shipment. Conversion facilities exist at Hematite, Missouri; Apollo, Pennsylvania; and Erwin, Tennessee.

The Kerr-McGee plant at Crescent Oklahoma -- where Karen Silkwood worked -- was a conversion plant that "lost" 40 lbs of plutonium. Enriched uranium can be stolen from these plants or from fuel-fabricating plants like those in New Haven, San Diego; or Lynchburg, Virginia. (A former Kerr-McGee supervisor, James V. Smith, when asked at the Silkwood trial if there were any security precautions at the plant to prevent theft, testified that "There were none of any kind, no guards, no fences, no nothing.")

Plutonium can be obtained from places like United Nuclear in Pawling, New York; Nuclear Fuel Services in Erwin, Tennessee; General Electric in Pleasanton, California; Westinghouse in Cheswick, Pennsylvania; Nuclear Materials and Equipment Corporation (NUMEC) in Leechburg, Pennsylvania; and plants in Hanfford, Washington and Morris, Illinois. According to Rolling Stone magazine the Israelis were involved in the theft of plutonium from NUMEC.

Finally you can steal enriched uranium or plutonium while it's en-route from conversion plants to fuel fabricating plants. It is usually transported (by air or truck) in the form of uranium oxide, a brownish powder resembling instant coffee, or as a metal, coming in small chunks called "broken buttons." Both forms are shipped in small cans stacked in 5-inch cylinders braced with welded struts in the center of ordinary 55 gallon steel drums. The drums weigh about 100 pounds and are clearly marked "Fissible Material" or "Danger, Plut