Samizdata

The US has decided to shoot down a failed satellite. I am sure you have heard over hyped stories about the expected March re-entry already. Personally I had pretty much written it off as a non-story until now. Satellites re-enter all the time. A few bits reach the ground now and again. T’ain’t no big deal.

The DOD Press release is rather professional obfuscation of what is going on. It is indeed true that hydrazine is really nasty stuff. You do not want to play with it unless you are in a bunny suit. However… the chance the fuel tank containing it will survive re-entry is rather low. Fuel tanks on space hardware are sturdy enough to hold the fuel and not much more. You couldn’t play basketball with them, let alone ram them into a wall of stellar hot plasma at Mach 25.

The real reason they are shooting it down is to keep top secret hardware from showing up on the market in clear plastic pyramids… which is what the enterprising Aussie’s did to the remnants of Skylab.

But whatever the reason, this is going to be interesting and I hope they release the videos they are going to take of the kill.

The US Navy has tested its rail gun at 10 MegaJoules. Railguns will one day become the main armaments on US Navy vessels:

The technology uses high power electromagnetic energy instead of explosive chemical propellants (energetics) to propel a projectile farther and faster than any preceding gun. At full capability, the rail gun will be able to fire a projectile more than 200 nautical miles at a muzzle velocity of mach seven and impacting its target at mach five. In contrast, the current Navy gun, MK 45 five-inch gun, has a range of nearly 20 miles. The high velocity projectile will destroy its targets due to its kinetic energy rather than with conventional explosives.

A very big advantage of kinetic energy weapons is the reduction in size of a warships Achilles heel: the explosives magazine. With a railgun you would not need propellant charges.

The safety aspect of the rail gun is one of its greatest potential advantages, according to Dr. Elizabeth D’Andrea, ONR’s Electromagnetic Railgun Program Manager. Safety on board ship is increased because no explosives are required to fire the projectile and no explosive rounds are stored in the ship’s magazine.

I am not sure I believe you would get rid of all explosives as you might still want to lob an HE shell over the horizon and downwards on a target. If you are firing on a target 200 miles away, you cannot use direct fire unless you intend to blast a tunnel through a whole lot of water. That means the impact velocity on another ship using indirect fire would only be the normal terminal velocity of the falling shell. Nonetheless, the chance of a repeat of the HMS Hood disaster is much decreased.

What I would like to know is: has anyone done the calculations about direct fire at high elevation? Aircraft are naturally one of the targets. One wonders if it could reach out and touch something at a rather higher altitude.

For those unfamiliar with naval battles of WWII, the HMS Hood was sunk by one lucky salvo from the Bismarck that came straight down into the aft magazine. The ship was on the way to the bottom almost before the smoke cleared. There were (I believe) only 4 survivors.

Correction: It was 3 survivors.

With all the attention being on new private initiatives in space travel hogging the headlines, it is worth noting that there is the real prospect of a new space race taking place between China and the United States, with China planning an eventual lunar landing as a prelude to a mission to Mars.

There would be plenty of people who would welcome such a development, but I am not one of them. As I see it, there is a legitimate role for government funded space programs, but there must be a sensible trade-off between costs and benefits. The Voyager Space probes were sensible investments that produced wonderful results; the Apollo Program, for all the hype, was not something that was worth the immense cost.

I say this because the way that technology is developing, private ventures are expanding in their capabilities quite quickly, and they are much more suitable enterprises to carry the torch of humanity into space. The original space race between the USA and the USSR carried awfully nationalistic and ideological connotations, and a future race between China and the USA is certainly going to have a stench of nationalism about it. Private enterprise ventures have a much greater capacity to bring in international participation.

It cannot be denied, of course, that government ventures are capable of achieving far more, and far quicker, then private ones; having the power of the state to extract wealth from its citizenry, and a powerful will, can cause amazing things to happen. The Apollo Program is a case in point, and so was the Manhattan Project. That does not mean that they are justifiable.

China’s space program is still at a relatively modest stage; they only succeeded in putting an astronaut into orbit in 2003. But if they invested enough money in it, they could progress quite quickly. It is simply a matter of how high that they consider it in their list of priorities. If they give it a high priority they could certainly reach their goals, especially given that Chinese taxpayers are not in a position to object.

How long is it going to take private explorers to get to do serious space travel? That point is no longer moot. From 2004 the progress of private ventures has been impressive, and if this momentum can be continued, it might well be that the first private entrepreneur on the moon might not be that far behind the Chinese and American astronauts. Wouldn’t it be wonderful if the first explorer on Mars represented a private consortium?

As I mentioned in an earlier article, Virgin Galactic unveiled the design of SpaceShipTwo in New York on Tuesday. This is the first ever commercial tourist spaceship.

There are two ‘stages’ to this vehicle. A very large mothership, White Knight Two, and a not exactly tiny underslung SpaceShipTwo. The design is similar to that of SpaceShipOne and the White Knight One mothership but much larger. Notice Burt has gone to a dual hull ‘catamaran’ like structure so the space going craft is slung between them instead of underneath a center hull.

Another thing which jumps out at me is the use of four Pratt and Whitney PW308A turbofan engines. These are the sort of engines you would find on a large business jet and they need this sort of power to get SS2 up to the 50,000 foot MSL drop altitude.

White Knight Two test flights are expected to start this summer. If they are indeed going to meet that schedule, I would expect a roll out by late May.

Artists rendering of SpaceShipTwo and the Mothership in flight
Photo: Courtesy of Virgin Galactic.

This is no paper spaceship. Both WK2 and SS2 are under construction. In the photo you can see both hulls and the main plane of WK2 are well advanced.

White Knight Two hulls and main plane on the Scaled Composites shop floor.
Photo: Courtesy of Virgin Galactic.

SpaceShipTwo is also well along, as you can see.

SpaceShipTwo under construction
Photo: Courtesy of Virgin Galactic.

SpaceShipTwo is not a tiny cramped little thing either as you can see in this photo with Burt Rutan providing scale. It is definitely more business jet than Mercury capsule.

Burt Rutan sitting on the flight control panel in the nose of the SS2.
Photo: Courtesy of Virgin Galactic.

This is not a one off deal. There will be many of these produced and each will be flown as often as possible. That means they will need an ongoing training capability for pilots. So… they have a very nice looking flight simulator for training.

Test pilot Brian Binnie sitting in the SS2 simulator.
Photo: Courtesy of Virgin Galactic.

For the technically inclined, here is a cutaway drawing. The real cognoscenti will note SS2 is indeed using the original hybrid propulsion system. Hybrids have been around awhile now: Starstruck and AMROC (Jim Bennett’s old companies) pioneered them in the eighties and others have since developed them further.

Cutaway technical details of SS2.
Photo: Courtesy of Virgin Galactic.

Most of us grew up expecting the flying car would eventually come to pass. One of the more successful attempts occurred in the 1950’s but although some were produced, it never made it into the mass market. Although I cannot substantiate it, I understand the FAA of the time was rather horrified at the thought of such large numbers of people flying. Whether true or not, there are very real problems associated with aircraft which one does not face with a car: you cannot pull an airplane over to the side of a cloud when something goes BONK in the night.

Another issue is flying requires a pilot. Even with the new US FAA sport flying category, getting your ticket is no mean feat. Being a flyer does not just mean you know how to point the thing. It implies you are conversant with the rules of a three-dimensional sea, one whose buoys are marked with radio waves and whose small craft must stay out of the way of large aircraft not just for their own safety but for the safety of the heavy iron as well.

This is not to mention knowledge of meteorology, the jargon required to talk to towers and other pilots in order to communicate critical information quickly through sometimes noisy radio systems and all the rules and regulations which encode the hard won wisdom of a century of flight and the loss of thousands of lives. I could go on for a very long time but I will just say that being a pilot right now requires a skipload of skills and knowledge.

However, as we move deeper into the 21st century, some of these problems are abating. With smart systems and eventually self-repairing systems we will get flying machines which either won’t take off when there is a problem or get you down before it gets serious. With autonomous AI systems development moving along the way it is (think UCAV’s!) the knowledge base of the pilot will more and more be embedded in the avionics and the ‘driver’ will simply point the thing.

For all this to happen there has to be a Transition that opens up the market. And that machine may finally be here:

An aeronautical startup called Terrafugia has developed a small airplane called the Transition that it says can take to the sky as easily as the road. It is about the size of a large SUV and features innovative folding wings that collapse with the press of a button. Terrafugia calls it a “personal air vehicle.”

The team behind the Transition still has to design a drivetrain to propel the craft and a mechanism to transfer power from the propeller to the wheels, but it expects to begin flight tests late next year.

Production could begin as early as 2009, and Terrafugia says it’s already received more than 30 orders.

You will still need to be a real pilot, but at least you can save on the hangar or tie down fees.