Are Virgin Galactic’s Green Claims Hot Air?

Virgin Galactic's VMS Enterprise. Photo Credit: Sam Coniglio

The Independent‘s Guy Adams casts a more skeptical eye toward Sir Richard Branson’s space tourism venture, noting problems with Virgin Trains and questioning the environmental claims that are being made:

It’s difficult not to admire the dynamism that brought him to this point. And it was actually rather affecting, at Monday’s unveiling in the Mojave Desert, to meet the “future astronauts” who boldly intend to entrust their lives to a spacecraft developed by a man whose state-of-the-art locomotives are unable to negotiate fallen leaves.

My ardour, however, began to cool dramatically when I gazed down Sir Richard’s press literature and saw a section touting, ludicrously, the project’s environmental credentials. “It’s almost zero carbon output,” he was quoted saying. “We can put people into space for less carbon than, say, a flight from New York to LA and back. I think in time, we’ll almost definitely get to zero.”

There was no scientific source mooted for these extravagant claims. Neither was there any explanation offered as to how VSS Enterprise, powered largely by nitrous oxide, can ever hope to be either “carbon neutral,” or remotely environmentally friendly.

Sir Richard knows a bit about “greenwashing,” though. After a life promoting airliners, he recently made David Cameron-style trips to the Arctic to “raise awareness” about the very global warming his companies exacerbate.

I can’t say much about Virgin Trains, having never ridden on one. But, I am skeptical on the environmental claims being made for SpaceShipTwo. Virgin Galactic summarizes them as follows:

Environmental Credentials

• Air launch means short rocket burn
• Reusable spaceship – no space debris
• The carrier aircraft uses latest highly efficient turbo fan jet engines
• SpaceShipTwo re-entry and landing are unpowered
• CO2 emissions per passenger on a spaceflight will be equivalent to approximately 60% of a per passenger return commercial London/New York flight.  Around 70% of the spaceflight CO2 emissions come from the carrier aircraft. This is a clean spaceship!
• SpaceShipTwo and its carrier aircraft will provide space access, to paying tourism passengers and to scientists for research, with an incomparably smaller environmental impact, lower cost and greater flexibility than anything that has gone before. We need space but we need better access to it.

Well, let’s take a look at some of these claims one by one:

Air launch means short rocket burn

True. The two-stage nature of launch system shifts emissions from the upper-stage rocket to the first-stage WhiteKnightTwo aircraft.

Reusable spaceship – no space debris

Space debris is a problem in orbit – which is where most Virgin Galactic flights will not be going. The company will be launching small satellites into orbit using a rocket attached to WhiteKnightTwo in place of SpaceShipTwo. Presumably, the rocket will have a low emission profile and produce no debris.

The carrier aircraft uses latest highly efficient turbo fan jet engines

That’s good.

SpaceShipTwo re-entry and landing are unpowered

“Look Ma! No engines!” Great from an emissions standpoint. From a safety standpoint…not so much. It means you’ve got one shot at landing. No engines for a go-around. No second chances.

“Dead stick” landings are not unknown. NASA’s space shuttles land without engines, as have many research aircraft like the X-1 and X-15. Even passenger planes have touched down safely after engine failures. But, it’s an unusual selling point – particularly with a high-profile project with millionaire clientele.

CO2 emissions per passenger on a spaceflight will be equivalent to approximately 60% of a per passenger return commercial London/New York flight.

This seems like an apples and walnuts comparison: a heavy 747 aircraft that flies point-to-point in the lower atmosphere, and a pair of lightweight vehicle designed to reach maximum altitudes. Different designs, different purposes and different specs.

The crew and passenger load for the WhiteKnightTwo/SpaceShipTwo combination is probably 10 people (four pilots, six passengers), which is smaller than the full crew for a 747. You’re also not carrying luggage, cargo, carry-on bags, food and beverage carts, personal entertainment systems, first class beds, and everything else that gets stuffed into a passenger plane.

Around 70% of the spaceflight CO2 emissions come from the carrier aircraft. This is a clean spaceship!

Again, most of the emissions come from the WhiteKnightTwo, which comprises the first stage of the launch system. Those will be emitted in the lower atmosphere (up to about 50,000 feet).

SpaceShipTwo and its carrier aircraft will provide space access, to paying tourism passengers and to scientists for research, with an incomparably smaller environmental impact, lower cost and greater flexibility than anything that has gone before. We need space but we need better access to it.

This is an interesting point, because there are few no direct comparisons to what Virgin Galactic plans to do. If you want to go into space, you can either go all the way to orbit on a conventional rocket (space shuttle, Soyuz, Shenzhou). Or you can send experiments up on suborbital sounding rockets – which go up and come back down. The sounding rockets don’t carry people.

Virgin Galactic’s system does not get you anywhere close to orbit; however, it does open up suborbital to space to both people and experiments in new ways with more frequency and a lower cost. So, that’s true.

However, whether that will done at an “incomparably smaller environmental impact” than previously remains to be seen. Because of a lack of direct comparisons, this claim is difficult to assess.

Then there’s the question of flight frequency. Even assuming that WhiteKnightTwo/SpaceShipTwo is cleaner than existing sounding rockets, then a large increase in flight rates into the hundreds or thousands per year could well have a bigger environmental impact overall.

We’ll see how this environmental debate plays out. In the meantime, it would help if Virgin Galactic were to release some of the calculations behind these claims. There are a lot of assertions here, but no real numbers to back them up.