The Rocket Science of Public vs. Private

SpaceX's ongoing attempts to land a reusable rocket booster back on to its platform barge in the Atlantic have triggered much discussion about the virtues and value of public versus private ownership of such big projects.

In our work on climate finance and economic development, similar debates can often be heard and as our Chief Engineer Willie Munden – who also happens to be my father – spent several decades working at NASA, I figured he might have something interesting to say about the ongoing attempts. 

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Me: So, what do you think about SpaceX? Is it a good idea for us to be privatizing our efforts to reach space? Or are we better off with the public?

Willie: If Space X can be successful at this space flight rocket launch industrialization, than we will be all the better for it. It will allow many things to be done in space that are presently cost-prohibitive; the launch of more science instruments into low earth and geosynchronous orbit for earth climate missions, fundamental space science missions, communications satellites and the like.

The private, commercial space flight rocket programs are the “industrialization” of space flight launches for satellites, instruments, space station supply and finally manned space flight. This is being done to reduce the cost of payload and human launch costs by making the rocket build programs more like an assembly line and less like the current small-batch, highly quality assured manufacturing approach. 

NASA, ESA and the Russian/Soviet, Chinese and Indian space programs have had more than a few mission failures similar to the recent SpaceX problem. And the potential cost reduction is significant, in that past rocket launch costs could be up to 50% of the total mission cost.

Politics and project ownership aside we must always look at each project in a systematic way with attention to all the details of each requirement for the project. If you get the science wrong the mission will fail due to the harsh space flight environment and flight dynamics, or the design will fail to deliver data and information that is fundamental to the programs’ goals and requirements.

In my experience from NASA, space engineering is fundamentally best when science is driving the program and mission selection process. I suspect this is true of all organizations that are science and engineering based. What actually happens at NASA is that politics get added in to the mission selection, design, development, testing and deployment process which increase both mission risks and costs.

One example of this is the selection of where to produce the Solid Rocket Boosters (SRBs) for the now decommissioned Space Shuttle. The engineering best practices said to build the SRBs in one large piece, not in sections, for each SRB. The politicians, from states other than Florida, didn’t like this; basically because they wanted some of the Space Shuttle money spent elsewhere.

So the SRBs were designed and built in Utah and the SRB designers were forced to make the design in sections, which contributed to increased testing, transport and probably contributed significantly to the eventual SRB explosion on Challenger.

Me: What are the biggest challenges of engineering for space?

Willie: One is the thermal environment. There is no atmosphere in space therefore no thermal convection, leaving only conduction and radiation as ways to transport heat and keep components in proper temperature operating ranges.

Putting a fan next to something to cool it is of zero use, since there is no fluid (atmosphere) to convey the heat. All the thermal energy generated by the satellites’ electronics, pumps, mechanical friction must be dissipated by conductive and radiative means.

All space craft in low earth orbits (300-1000 km) are thermally influenced by Earth’s and our Sun’s warm and hot radiation and simultaneously by deep, black space’s extremely cold radiation. A single spacecraft can see thermal gradients of over 100 degrees Celsius from the deep space side to the Sun side of the space craft.

To combat this harsh thermal environment designers use multilayer insulation, louvres, radiators, heat pipes, thermal coatings and even heaters on the cold side to properly control the temperature of each component during the mission life cycle.

The second issue is the electromagnetic (EM) radiation environment. Unlike long wavelength thermal radiation, high energy and very short wavelength EM radiation particles pass right through basically all usable space flight shielding. Therefore they can directly impact the junctions of transistors causing permanent damage to the integrated circuit and likely mission failure or degradation.

To mitigate this problem designers have developed very specialized space flight electronic components that have completely different construction and quality assurance testing methods from our commercial electronic components we use on Earth for our computers, TVs and the like. These space flight qualified components are much more costly to design and manufacturer than commercial components but are very EM radiation tolerant where the commercial components are not.

The third issue is the zero gravity of outer space. This is the environmental factor that most people think of when they think about outer space but in fact zero-G is the least problematic of the three space environmental factors listed here for most space flight components.