August 2017 - Opening the High Frontier

Making spaceflight affordable to everyone is the single most important issue that needs to be addressed if we are ever going to build a spacefaring civilization. Without it, there will be no cities on the Moon or Mars, no space colonies or orbiting hotels, no spaceports where you can go to purchase a ticket for a ride to orbit, and no orbiting factories or research stations other than those that are funded by the government. Like it or not, making spaceflight affordable to everyone is an absolute necessity that needs to happen if we are ever going to open the high frontier for large scale settlement and development. Unfortunately, making spaceflight affordable to everyone is a task that has been ignored for far too long.

Currently, the best idea for making spaceflight affordable to everyone is a combination launch system with a non-rotating skyhook. But that is not the only way to reduce costs. There are smaller ideas that will not by themselves make spaceflight affordable to everyone but will still significantly reduce costs. These are ideas that fall under the category of “working smarter, not harder.”

An example of one of these ideas is the way we currently resupply the International Space Station. The three spacecraft that are currently used to do this are;

the Russian Progress spacecraft which has a launch mass of 7,150 kg and a cargo capacity of 2,230 kg,

the enhanced Cygnus spacecraft which has a dry mass of 1,800 kg and a payload capacity of 3,500 kg when launched using the Atlas V launch vehicle,

and the Dragon spacecraft which has a dry mass of 4,200 kg and a payload capacity of 6,000 kg.

So in regards to making spaceflight affordable to everyone, the question becomes, how cost effective are these vehicles in terms of dollars per pound to orbit?

As part of the Commercial Resupply Services program, NASA paid SpaceX $1.6B for 12 resupply flights to the ISS using the Dragon spacecraft. Assuming that each of those flights carried the maximum possible payload of 6,000 kg (13,200 lbs), that works out to a cost per flight of $133.3M, and $10,100 per lb of useful payload delivered.

NASA also paid Orbital Sciences $1.9B for 8 resupply flights using the Cygnus spacecraft as part of the same program. Assuming that each of those flights carried the maximum possible payload of 3,500 kg (7,700 lbs), that works out to a cost per flight of $237.5M, and $30,800 per lb of useful payload delivered.

Now divide the total cost of those two programs ($3.5B) by the total amount of useful payload that could have been delivered by those 20 flights if they had carried the maximum possible payload (220,000 lbs), and the cost average for those two programs works out to $15,900 per lb.

No matter how you look at it, that is a lot of money to pay for hauling the freight. Putting it in more mundane terms, it means that the 2 oz granola bar you ate the other day while standing in line at the grocery store would cost you $1,987 if you were on the International Space Station.

An Alternate Method (Working Smarter)

When used as an expendable launch vehicle, the Falcon 9 Full Thrust rocket can boost 22,800 kg of payload to a low Earth orbit that has an inclination of 28.5 degrees. When flying to the orbit of the International Space Station it can lift approximately 20,000 kg. Now assume that this payload is loaded into a pressurized cylindrical canister like the one used on the Cygnus spacecraft and that this container has a guesstimated empty mass of approximately 800 kg. That means the Falcon 9 rocket without the Dragon spacecraft could deliver a useful payload of 19,200 kg to the same orbit as the ISS. Now assume that a reusable on-orbit serviceable and refuelable version of the service module that propels the Cygnus spacecraft is kept at the ISS for retrieving these pressurized payload containers and that it uses approximately 400 kg of propellant in the process of doing that. That leaves a useful payload delivered to the ISS of 18,800 kg.

Think about this for a moment. This is not a big change. There is no new hardware to develop, and there is no new technology to develop. It is just a different way of doing what we are already doing with existing hardware. It is a simple change in how we operate.

So what is the big deal, why bother to change anything?

The cost of a flight on the Falcon 9 without the Dragon spacecraft is $62M. Now divide that cost by the 18,800 kg (41,360 lbs) of useful payload delivered to the International Space Station by this method. The result is $1,500 per lb to orbit.

The cost of that granola bar just dropped from $1,987 to $187.

This is an example of working smarter. While it still does not lower the cost of spaceflight enough to make spaceflight affordable to everyone, it definitely is a step in the right direction and it is something we can do right now. It is also not the only idea that we can use to reduce the cost of spaceflight.

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Month: August 2017

Making Spaceflight Affordable