Saturday, October 11, 2008

Red Gold

Mars ain't the place to send big spacecraft. In fact, it's expensive as hell.

While E Street burns, another debacle is unfolding on the left coast. The superstars of yore, the young kids who gave us Pathfinder and Spirit/Opportunity let success get to their heads and forgot some basic principles that had earlier served them well. That and Tony Spear retired, taking the last rolly polly piece of common sense out the door with him. With a thrice demonstrated air bag landing system for small packages, and a thrice demonstrated propulsive based system for larger items, they went off the reservation and decided to create yet another option...and a jobs program for JPL.

So how did the bank robbing Mars Science Laboratory (MSL) make it to the headlines before it even made it off the launch pad?

Three times as heavy as its earlier cousins, MSL was designed to be too big to fit inside an air bag delivery system. (Where have we heard this before? CEV...EELV?) A number of technical excuses were manufactured by JPL's entry, descent, and landing gurus against using a separate attached propulsive landing system (like Viking or Phoenix). Integrating a propulsion system directly into the rover itself was considered and tossed. No, the JPL minions didn't want to use something tried and true this time around. They wanted to set a new challenge for themselves.

And save their jobs.

You see, every four to six years or so, right around the end of every major spacecraft development that the lab is responsible for, famine sets in. In the past, the lab has been forced to go out looking for extra work from the undeniably "terrible" military establishment. That "distasteful" work carried it through the lean years waiting for the next big planetary mission.

This time around, however, the timing was a little better. Mars missions have the eye of the public and are seeing unprecedented funding levels allowing a new opportunity every two years or so. Coming off the rover high, MSL's timing couldn't have been better for a smooth transition of personnel. No need to go out with sunglasses and tin cups. Or so they thought.

Enter Sky Crane.

Take eight rocket engines, pointed down, connected by a truss under which the MSL is suspended. When you get close to the ground, reel out the MSL on a tether until it just touches the ground. Then, cut the cord and let the rocket helicopter fly away for a crash landing, its job done, and payload resting on the surface. A brand new, complex, expensive, single purpose means of landing on Mars providing hundreds of jobs for those living in Pasadena, La Canada and beyond.

But that's not the worst of it. MSL's untested landing system could turn the rover into JPL's own Genesis Project if it craters on the Martian surface. Its little nuclear power plant would almost certainly melt any subsurface water ice, creating a little oasis of its own for any microbes hibernating nearby. Any remaining hitchhikers from our little blue orb also might find that an attractive place to homestead.

After the sojourning successes of the spirited and opportunistic rovers, now deep into their fourth years of operation, JPL had to go bigger and better. And that, dear friends, is neither faster or cheaper. And since the mission is so expensive, only one can be built. And now it must be rushed to make a 2009 launch date. Seems like we've been to this picture show many times before.

Imagine what could have been accomplished instead with several more Spirits and Opportunities running around the red planet. Each new rover could have been configured with new sets of instruments to explore new destinations and make new discoveries. We already know the vehicles are good for at least four years and we could easily upgrade what is failing now (motors and mechanisms) to incrementally improve their lifetime.

And parts are a lot cheaper when they are bought in lots of 10 than they are when bought individually. And so are rockets.

Need more power? Land a separate smaller power pack trailer to be towed by the rovers. Want to demonstrate precision landing? It could just as easily be done by a smaller rover as well.

But, those little rovers are so old school, you say? What's to keep JPL from becoming the stale workplace many of the other centers have become, lacking technology development programs and an advanced spacecraft program pulling on that development? The can still do all of those things in small packages and fly more frequently. We do not need to put everything in one big basket every time we go to Mars. If we have duplicates, we can afford to take a few loses if something should go awry now and again. Not too mention the fact, that risk of plutonium escaping a bad launch, or a bad landing, is eliminated.

But a once promising future on Mars, like our future in LEO, and on the Moon, has been dashed once again by steroids. This, too, shall become part of the Emperor's legacy. Certainly, there must be a Cook involved in this somewhere as well. That last name just lends itself to technical and fiscal disaster wherever it turns up.


Anonymous said...

Ha! A post before KT. He must have stayed up late bashing everyone on Usenet and every blog on the Internet. Get your rest KT. I'm sure its tough being the smartest person on the Internet.

Another great tome. Thanks Rocket(men).

Anonymous said...

I think Dawn and New Horizons are great missions. I'm always interested in new and mysterious planets.

Anonymous said...

Not an expert on rover design but I strongly suspect that you have to grow in mass if you want a more competent rover. Nothing is preventing them from making more than one MSL either. Half of the available time is spent with the little rovers holed up waiting for spring and praying for a dust devil. While interesting results have certainly been gotten from the existing rovers they also show how limited they really are in terms of travel distance and onboard science.

I thought the skyhook system was rather overly complex given that a post landing jettison of integrated propulsion elements would have been fairly straightforward. And it would seem that any arbitrary sink rate could be obtained with decent closed-loop altitude control. Does anyone really know what the big driver was? Site contamination? Centroid eccentricity tolerance? Space control? Does the skyhook allow landing on more severe terrain? Someday we WILL need to land somewhere other than a billiard table flat plain.

Curious to know the origins. Hoping they take the proper time to get it right.

Alex said...

The airbag system used by Spirit and Opportunity *only* allows landing on those "billiard table surfaces" referenced above. It's not exactly a method that allows a fleet of MER-style rovers to explore the Red Planet's most interesting locales.

Now, that's not to say a skyhook is suddenly the best way to land on Mars (my gut says it's most certainly not), but I believe ten MER's -- even with dedicated, diverse science suites -- would end up giving us nothing more than delightful views of Mars's remaining, unexplored plateaus, plains, fields, drifts, and dunes. zzzz.