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.
This is a very complicated and strange landing sequence. It is, of course, dictated by the environment and size of the craft, but it is still fantastic. The only way to plan this out is simulation. That in itself is a big process. The delay in communications caused by the great distances in space has always made commanding interplanetary craft complex. You don't command it like a RPV. In effect, you send up a program that handles the maneuver, and hope it works. Here's hoping this one works on Mars.
There will no doubt be a ton of nail biting over this landing. It is so complex and in some ways, appears so convoluted, but I suppose that is what's necessary for this particular exploration. The whole notion that they are dark for seven minutes before knowing if the mission was a success or not is pretty mind boggling.
This is gong to be fun to watch, once the rover is safely down. This lading sounds quite a bit different from the rover landing in the late 1990s, when the rover was enclosed in a big ball that bounced on the surface and then opened once it came to a rest.
Wow, Beth – thanks for that article. What a difficult scenario to resolve! Two lines sum it up:
,,,,, seven minutes to travel from atmosphere to surface, but 14 minutes for a signal ,,,,,
,,,,,, By the time we get a signal back, it will have either crashed or successfully landed ,,,,,
Talk about the Kobayashi Maru!! Accordingly, the entire sequence has to perform autonomously, perfectly, and without any correctional interventions. What a fantastic challenge; I'll be watching Space.Com and other sites on August 5th for news on this!
Beth Stackpole: It does seem like a lot of things must go right. The most confusing thing to me(I understand why) is the crane. I just can't wait to see it on tv. Wish they had the swamp people camera crew there to film it, that'd be awesome!...lol
Not to go off subject, but if any cameramen are out there that knows how those swamp guys get those shots I would sure like to know. I can figure out most of them, but some just leave me thinking...how the heck did they do that?! It might be a strange show, but unbelievable camera work.
The crane is what they came up with to lower the rover on to the surface after vastly decelerating it with rockets. Apparently, if the rockets get too close to the surface, they kick up a dust storm that would ruin the equipment and rover itself, so they required a more streamlined and less intrusive way to lower the rover to Mars surface.
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.