Time for the Rocket Age

Stuck in the Jet Age

It’s been nearly 100 years since Guillaume and/or Whittle gifted humanity with the jet engine. And while it is a fantastic thing, it is embarrassing that its replacement is not forthcoming. Arguably by now, we should have airline speed trains for short-haul transit and suborbital rocket planes for long-haul transit.

Consider the physics of suborbital planes. 130 shuttle reentries suggest that reentry just isn’t that big of deal. I personally consider cross-wind landing to be far more problematic. But for suborbital flight, the feat is even less impressive. Whereas the Shuttle reentered the atmosphere at 5 miles per second, a suborbital plane could be sent over the Pacific at about 3 miles per second. This then means that it would only generate about 40% the heat of the shuttle upon reentry. Furthermore, the idea of reusability would not be seen as some groundbreaking feat that required a Godzilla launch tower.

Perhaps the biggest obstacle to getting past the jet age is our leadership class. NASA can’t even launch a rocket even at 20 times the cost of SpaceX. Lockheed Martin can’t build a fighter for less than $100 million. And to think that both these industries started 100 years ago on a shoestring budget with far simpler technology. Perhaps if humanity is lucky, some of the trillions of dollars looking for a good investment will find its way to someone who is a decent engineer who isn’t a natural-born kleptocrat. It is so weird that investors will back stupid stuff like a plane that is 5% more efficient but not one that is 1000% more efficient.

Let me throw some numbers out there. A rocket can only put 5% of its mass in low Earth orbit. Therefore, a rocket that must only be accelerated to 60% of orbital velocity can put aloft something closer to 20% of its total mass. For a 200 passengers, that’s 40,000 lbs for a rocket that weighs 200,000 lbs. But this a not an apples-to-apples comparison since a plane has the additional weight of wings and landing gear such that the actual payload fraction is likely to be closer to 10%. This then suggests a takeoff weight of 400,000 lbs which is around half that of a wide body aircraft.

The point of throwing these ballpark numbers out is to show that a plane that carries enough fuel to plow through the atmosphere for 15 hours is technologically commensurate to the requirements of a rocket plane. However, the economic and qualitative advantages of a rocket plane are so much greater that the failure of this technology developing is so illogical as to be implausible. It so begs the question, “who is running this show?”.

So let me pitch what I would do if any investors are listening. First, you pick up a scrap airframe of maybe an old DC-9. You put a liquid oxygen tank in the fuselage. Then you attach a raptor rocket motor and a smaller rocket motor to the tail of the plane. Based on some calculations, you may need to add water cooling or a heat protector at the most vulnerable points on the frame such as the wing roots and nose. You then install remote control servos to the flight controls and test fly it. After the plane exceeds an altitude of 60 miles, the small rocket motor achieves the desired velocity and maintains altitude.

This entire scenario could cost little more than the rocket motors and the fuel. Almost certainly, the plane would survive the one-hour trip and once landed, investors would be lined up around the block. Now of course developing a certified plane will then take years, but a simple demonstration flight is all it takes to paint the way. The fact is that crossing the Pacific in an hour while also experiencing space is not only long overdue but is also a financial gold mine.

For one thing, it creates about half the greenhouse gases which is about all it takes to sell something these days. Aside from half the fuel cost, each plane can make at least 6 times as many transits and odds are the ticket prices could pull in maybe 5 times the going price for decades to come, not to mention the savings from not having to serve meals or have flight attendants. Then there is the savings on the jet engines as rocket motors are likely to knock $50 million off the cost of the plane. As a first approximation, a rocket plane might be nearly 50 times more cost-effective. If the savings from the six-fold transit increase and 50% lower fuel costs were passed on to customers, it could probably triple or sextuple the size of the industry all by itself.

There is a mythology that self-interest and greed is what drives society forward. However, the failure for anyone to capitalize on this opportunity suggests that there is something holding the world back. I wonder if it is simply that a dollar today is better than 2 dollars tomorrow or is it just that people like Steve Jobs and Elon Musk are not the kinds of people who are promoted or who run hedge funds.