Blinded by the Light

In my first post, I said I would talk about what’s going on in the space industry as best as I can.


I’ll start with the MESSENGER spacecraft that’s currently orbiting Mercury. It was launched in 2004 and, after a circuitous trajectory around the inner solar system, arrived in Mercury orbit in 2011. To date, it has mapped all of Mercury, found water ice on the poles, characterized the planetary magnetic field, and analyzed the chemical composition on the surface. Below is a diagram of the trip MESSENGER took around the inner solar system before its final destination.


Why must this journey be so torturous? Why did it take 7 years and several flybys of Earth, Venus, and Mercury? It’s because Mercury is deep inside the Sun’s gravity well, to a much greater degree than Earth is when seen from Mars. Traveling from Earth to Mercury requires a much greater change of velocity than a Earth-Mars trip would take, even though Mercury is almost the same distance from Earth.

In everyday life, we talk about a trip in terms of distance (“I walked/drove/flew from point A to B”). But in space, a trip is best measured by the change in velocity (deltaV) required to “jump” from one orbit to another. It’s like saying “I sped up at orbit A in order to catch the planet in orbit B”.

Because Mercury is closer to the Sun than Earth, the spacecraft must lose velocity in order to drop in closer to the Sun. The simplest way to do this is with a well-timed rocket burn. But since the deltaV in this case is so huge, the required propellant would cost too much to lift from Earth. MESSENGER had to rely on a series of flybys of Earth, Venus, and Mercury in order to lose enough velocity to be captured by Mercury’s gravity.

Even though MESSENGER is officially a NASA mission, it is presently controlled from the Applied Physics Laboratory at Johns Hopkins University. The following is a link from someone who worked on that mission. It offers a snapshot into the day-to-day lives of the spacecraft’s controllers.

To me, a lot stands out about this story. The fact that this spacecraft is being controlled from an university campus, not from a NASA center like JPL, tells me that a trend is developing in favor of increased university control over space science missions. A similar thing happened with the Mars Phoenix mission. The LIDAR instrument on that mission came from York University, and had two York professors as investigators on it. I had one of these professors for my planetary science class last year, and it was a hell of an experience to listen to him talk about that.

Once the costs of launch and space hardware drop (which SpaceX is doing right now, with reusable launch vehicles) there’s nothing stopping universities from funding their own space missions themselves. That’s why I’m so optimistic about the long-term future of this industry despite the recent cuts to NASA’s funding. It’s an exciting time to be alive.

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