Random Thoughts, Beyond The Horizon

There is always something about horizons. From Ocean Beach, I always find my attention captured by cargo ships, incoming or outgoing, especially at night with their running lights splitting the fog as they approach the Golden Gate Bridge. This in spite of my reservations about cargo ships, and my leeriness in particular about cargo ships around our bridges, what with the spate of ships, big and small, that have been playing bumper cars with immovable towers of metal of late.

It just seems like such a lonely proposition, steering a hulking metal vessel into the night, across the ocean, even just down the coast.

I wonder where they are going, or where they have come from. There is a small, barely noticeable feature in the Business section of the paper that lists ships scheduled to arrive or depart that day, with their origin or destination listed as appropriate. And I always get a frisson of excitement when a ship's destination or origination is listed as "unknown." That's just too romantic for words, if hardly reassuring or entirely plausible in the days of Homeland Security.

These days, of course, horizons are hardly earthbound. Today at approximately 4:53 p.m., the Phoenix Mars lander is scheduled to complete a voyage started last summer by settling to the cold polar soil of Mars, in an effort to study whether conditions for life could once have existed. Here's the link to the mission's home page.

Space exploration is the proof that we are both capable of great and complex achievements, and also fallible, our efforts not yet perfect. Several recent attempts to land on Mars have met with utter failure.

There is also a strangely poignant quality to this program and the robots. Consider the following capsule summaries of recent missions, taken from the Press Democrat of 4/23/08:

Mars Observer: Communication lost in August 1993 before going into orbit.

Mars Global Surveyor: Orbiter arrives in September 1997. Battery failed in 2006.

Mars Climate Orbiter: Lost on arrival in September 1999.

Mars Polar Lander: Contact lost during arrival at south pole in December 1999.

There is something cold and sterile, yet also just a bit sad in those phrases: "communication lost"; "battery failed"; "lost on arrival"; "contact lost". What would it be like to be an operator on Earth, having spent months, even years, monitoring the progress of these robots, and one day seeing these eyes and ears flicker and vanish?

At the Sunday morning community market at the local school, there happens to be a retired professor who still acts as an adviser to the JPL, and who asked us this morning to keep our fingers crossed for the lander. I asked him if now that the mission is about to pass out of their hands, if there wasn't a feeling akin to watching a child graduate from college, and he agreed that it was something similar. After all, he said, having worked on the lander for so many years, he knows every nut and bolt on the thing.

It is not a simple process, landing a lander, at least not if you want it to remain a Phoenix Mars Lander as opposed to a Phoenix Mars Pancake. There is precise timing required for deploying a parachute, firing retro rockets, etc. The math is staggering to me. Any errors in the following attempted summary, or any incorrect wording, is entirely my own fault.

Frank explained it this way: there is a set of coordinates based on the shape of Mars, with a small target hole that is rotating, as planets do. This target is about 25 km across, which may sound like a lot, but remember the distance they have had to propel this lander, as well as the size of the target in relationship to the rest of Mars. They have wriggle room on this target area of about 1 to 1 1/2 feet, I believe Frank told me. So not only are they trying to thread the eye of a needle, they are trying to throw the thread through the eye of a needle which happens to be rotating constantly, and they are throwing the thread from, say, London, and the needle is in New York (That proportion no doubt does not work except for poetic license; I was an English major, not a mathematician).

Furthermore, they must time the descent and the changes of speed just so, with only a tiny margin of error. They also have to worry about the attitude of the nose of the lander upon descent. If the nose is too high, it will 'skip' across the atmosphere like a rock across a river; if the nose is too far down, it will descend far too quickly, and the atmosphere's friction will overwhelm the heat shield. I may have these consequences mixed up, but you get the idea.

In other words, there is a very good reason why rocket science is used in the phrase "It's not rocket science" or, alternatively, "You're no rocket scientist."

How freaking cool is this stuff?