For the landing to succeed, hundreds of events have to go right -- many with split-second timing and all controlled by the spacecraft with no human intervention. Enter the Enter Descent and Landing (EDL) engineering team, whose mission was to design a flight plan and a craft that can go from 13,200mph to 0mph in seven minutes to land on Mars' surface. The critical challenges the team addressed included designing a heat shield that can resist temperatures of up to 1,600F and a supersonic parachute (the largest and strongest ever produced, according to JPL engineers) that can withstand 65,000 pounds of force and slow the craft down to 200mph.
Since even that speed can't accommodate a landing, the team also designed a rocket system that will help slow the craft even further, along with a diverter mechanism that will draw the craft away from the parachute and help reduce horizontal and vertical velocity. Operating rockets too close to the ground could cause giant dust storms that could damage the Curiosity's instrumentation and mechanics. Therefore, the team also designed a sky crane that will lower the rover on a 21-foot tether, deposit it gently on wheels to the surface, and cut the bridle so the rest of the craft can fly away and crash safely out of the rover's reach.
"There's an incredibly complicated, orchestrated set of maneuvers to get this thing on the ground, and it will happen all blind," Dave Taylor, vice president of Siemens PLM Software, told us. "By the time [mission control] finds out whether the rover got through the outer atmosphere of Mars, it will have either crashed or successfully landed."
The JPL standardized on Siemens PLM Software tools several years ago, so Teamcenter PLM served as the data management and design collaboration platform via the JT Open format. Overall product design was done in NX CAD, and NX CAE helped the team understand stresses and loads on all mechanical components, perform tolerance analysis, and make sure components fit together optimally.
You are correct that American universities are still top notch, and they still attract the most talented students from here and abroad. That, however, was not the assertion in your comment. Also, I did not mean to impugn your honesty. I regret any suggestion that could be read that wa, especially now that you have clarified your position so well. I intended only to challenge those who, through blind nationalism, continue to insist that the US is "the best in the world" on every count. Here, too, some of the tortoises have overtaken the over-conficent hare.
I certainly agree with you that our country should put much more of its public resources into education and research, both pure and applied. We can regain our former leadership, but in order to do so we have to recognize the areas in which we have fallen behind. BTW, I am also about your age--69.
J-Allen, I'm going to overlook the fact that I have been called less-than-honest. If you evaluate our top engineering schools, and I do that on a regular basis, you will find that we do rank equivalent to those top schools in other parts of the world. NOW, I will admit, the caliber of student we send to those schools is dropping year by year. This is THE reason my wife and I have sent our three boys to private schools. The public educational system in this country is horrible, at best, and our so-called public servents don't really seem to worry that much about it. We are creating a class structure in this country which does worry me. I have a public education all the way--K through graduate school but then again, I'm 70. Things change. I read on a continuing basis the back-and-forth with our school boards, unions, teachers, etc and it is truly regreatable. I feel the answer is let's once again put the students first and the politicians last --- or at least close to last. Just a thought.
At one time we did have the best schools, the best innovation, etc. Many of the senior scientists and engineers on this project were products of that period. Unfortulantly, according to every objective study, competitive exam, and evaluation, the US can no longer make such boasts. Our students lag behind even some formerly "backward" countries in math and science. The number of college grads per-capita, especially in science and engineering, has also fallen behind much of the world.
People who continue to make such jingoistic claims based on long-faded laurels demonstrate that we lag behind the rest of the world in honesty as well.
I had forgotten we are this close to the landing. I think your great article is a "shining" example of how our country leads the world relative to engineering talent. We have the best schools, the best teachers and great opportunities to demonstrate engineering talent and resourcefulness. My great disapointment is our abdication of the manned programs and the loss of talent that will surely follow. Let's hope this landing is a total success.
This isn't such a far-fetched idea. It is VERY similar to the escape gantry used on all pre-shuttle manned space flights. The emergency system was designed to take a post-launch capsule to a sufficient altitude that the main parachute would function safely. This new system simply works in reverse sequence. NASA simply replaced the heavy, bulky metal superstructure with cables. So long as there are no tangles.....
Altitude is determined with a device similar to a laser range finder. At the appropriate altitude, the steps in the deployment/disengagement sequence are initiated.
I gather that they never actually tested a prototype of the 'crane' concept on Earth! That shows an incredible confidence in software!
I presume the fact that there are 8 rockets (2 in each corner?) indicates that there is redundancy in each corner, so only 4 actually need to work. It is going to have to fire the backup really fast if one of the mains fails...
Actually, from watching the press conference last night, a bigger reason for the sky crane vs. a legged-lander (like Phoenix and Viking) is a legged lander would have to land on perfectly flat land, and perfectly upright, or it would most likely topple over. As a retrorocket approaches the ground - given the lack of air pressure and the unevenness of the ground, back-pressure from the rocket exhaust could spike unpredictably.
These two reasons make a legged-lander far less desirable than the sky crane.
The drop-bounce-roll landing (MER, MPF) is also unfeasible as we don't have any cloth - for airbags - that could withstand the impact of a metric ton hitting the ground.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.