Engineering Feats: NASA's Seven Minutes of Terror

It seems to me we had some discussion on the tungsten weights used some time ago...

"Much of the reduction of the landing precision error was accomplished by an entry guidance algorithm, derived from the algorithm used for guidance of the Apollo Command Modules returning to Earth in the Apollo program.^[132] This guidance uses the lifting force experienced by the aeroshell to "fly out" any detected error in range and thereby arrive at the targeted landing site. In order for the aeroshell to have lift, its center of mass is offset from the axial centerline that results in an off-center trim angle in atmospheric flight. This is accomplished by a series of ejectable ballast masses consisting of two 75 kg (165 lb) tungsten weights that were jettisoned minutes before atmospheric entry.^[132] The lift vector was controlled by four sets of two reaction control system (RCS) thrusters that produced approximately 500 N (110 lbf) of thrust per pair. This ability to change the pointing of the direction of lift allowed the spacecraft to react to the ambient environment, and steer toward the landing zone. Prior to parachute deployment the entry vehicle ejected more ballast mass consisting of six 25 kg (55 lb) tungsten weights such that the center of gravity offset was removed.^[132]"

^{https://en.wikipedia.org/wiki/Mars_Science_Laboratory}

http://www.jpl.nasa.gov/news/press_kits/mro-arrival.pdf

Oh, that explains what hit our boat when....

You were sailing on Mars?

No, just riffing on a scenario, as if this had been tried on earth.

Can you say "photoshopped"?

Could you spend one more paragraph explainint this to a chemist?

"Balance mass devices are generally used when a capsule is approaching a planet for entry into the atmosphere....

"Balance Mass Devices traditionally see the jettisoning of weights from the spacecraft upon entry into a planetary atmosphere. For example, when the Curiosity Rover approached Mars, two tungsten weights totalling 150kgs were expelled from the spacecraft. The jettisoning of such weights help to shift the center of balance of the spacecraft, placing it at an angle on its approach to the planet's surface. This angled entry helps the spacecraft to generate lift, which subsequently aids in a more controlled landing. "

http://www.outerplaces.com/universe/technology/item/6011-nasa-announces-$20000-prize-for-new-mars-balance-mass-challenge#sthash.h36VhDB2.dpuf

http://cr4.globalspec.com/thread/97772/Use-of-Payloads

That itself was impressive. Combine that with the supersonic parachute and the crane lowering the rover from the hovering capsule under thrust and it is an insane engineering proposition!

All that cool W just lost

How many expired lightbulbs gave up their next resurrection as something else tungsten (such as rounds for a WartHog) for that?

Exactly! I have kind of a fascination with tungsten because it's so dense. I would love to have 12" long x 3" dia bars of tungsten, steel and aluminum for demonstration purposes. Approaching the density of gold, the demonstrees would then see that those movies where they show the thieves blithely chucking gold bars into bags is just stupid!

"the demonstrees would then see that those movies where they show the thieves blithely chucking gold bars into bags is just stupid!"

Or the movies should have a scene where they drive the getaway truck to a locked gate, and the thieves get out and collectively throw the truck over the gate, showing how ludicrously strong they must be to chuck gold bars around like nothing.

Or, alternately, have it revealed that the thieves stole the 'dummy'/'bait' bars, which were gold-plated aluminum.

No wonder they are expensive.

Thank you. I thought that was more or less what was being said earlier, but something had me confuzzied.

Well, dang, I guess we were just too dumb and unimaginative when we put two Viking Landers on Mars in 1976 using just parachutes and retro rockets all the way to the surface. Musta been we were just lucky.

Hooker

The Viking Landers were light and tiny.

Curiosity was like trying to air drop a Ford F-150 from orbit.

"Parachutes and retro rockets all the way" would have likely tripled the weight of the Rover & Decent Vehicle combo.

Going to space is always about conservation of layload to the extreme, and engineering novel ways to safely deliver the payload to destination.

Tiny????????? Lighter in mass, yes, but hardly tiny.

Have you ever personally seen the full scale model of a Viking lander?

The 3 landing pads form an equilateral triangle measuring over 7 feet on a side. And they massed about 1260 lbs. Not to mention that the sensors and computing power was comparatively primitive back then, demanding a more brute force approach.

And, yes, I worked on a working prototype during development, manufacturing the stereoscopic cameras and core memory.

Hooker

Perhaps 'tiny' was the wrong word, I should have said 'spindly,' they cover a large area when deployed but much of the area in their 'bounding box' (to borrow a videogame term) is open air. Curiosity, on the other hand, due to its designed mobility, is very densely occupying its 'bounding box.'

I think we've probably split hairs down to the micron level so I'll retire from the fray.

And don't mind me. I'm passionately proud of the projects I worked on at NASA to a fault. Viking, Apollo, Skylab, the Shuttle, and a bunch of unknown aviation projects that only rarely made news but led to what we have today. It was a helluva ride, never to be repeated, only to be built on.

Regards,

Hooker

"And don't mind me. I'm passionately proud of the projects I worked on at NASA to a fault. Viking, Apollo, Skylab, the Shuttle, and a bunch of unknown aviation projects that only rarely made news but led to what we have today. It was a helluva ride, never to be repeated, only to be built on."

I don't mean to offend, but I *WILL* mind you.

You, sir, built the world I live in, and inspired my dreams. I never went into Space Exploration myself, however, thanks to Carl Sagan, Gene Roddenberry, and you and your co-workers, I have always believed that our destiny is to colonize other worlds, explore this vast universe, and keep Humanity alive and thriving, even after our collective birthplace reaches its end and becomes Earth-that-was.

THANKS.

It is said of my cousin who worked at NASA during the Golden Years, he could carry on about ten conversations simultaneously.

As to finding this sort collectively over the entire population, I seriously doubt the talent level exists as a high percentage of the population. It depends on what is being "engineered" though, and less technical groups can carry out equally elegant tasks, in their own right, as long as they are not planning a space shot.