Curiosity Rover Parachute size Proves NASA Lies

Originally posted by jlafleur02

Originally posted by Soylent Green Is People
reply to post by Watcher26

 

First of all, as 'bullwinklekicksbutt' pointed out in his post above, you need to consider total volume of the parachute -- not just the diameter. A chute has 3 dimensions; you cannot directly correlate the diameter of the chute on Mars compared to on Earth just by dividing by 100 -- you need to correlate them using the volume of the chute.

Secondly, the parachute was not designed to slow Curiosity down enough for a soft landing. It was still falling at 170 mph when the parachute was cut from the rover (although that is still quite a bit slower than the 1,500 mph it was falling before the chute was deployed).

edit on 7/17/2013 by Soylent Green Is People because: (no reason given)

You also have to consider the coefficient of friction is applied across the larger surface area than that used for similarities to the earth parachute.

Good point. Thanks.

You also need to consider the coefficient of drag of a nitrogen-oxygen atmosphere (such as earth) compared to the drag of a carbon dioxide atmosphere (such as mars). It may be true that Mars' atmosphere is 1/100 that of Earth, but does that mean the drag will be 1/100 as much, considering the atmospheres are made of different things? Or will the difference in coefficient of drag be something less than 1/100, since carbon dioxide is a heavier molecule than nitrogen (and earth's atmosphere is 78% nitrogen)?

reply to post by Watcher26

The link you provided there is hogwash. Gosh, my eyes rolled back into my head.

At first, I thought maybe you were onto something, but I kept thinking there's no way NASA would miss something like this if their intent was to lie. It's just too obvious.

Of course, after reading the thread, I think you're very wrong.

Like one guy said, the chaps at NASA are a lot smarter than you. Stop linking unassociated things, like how you claimed the news about high radiation levels on a trip to Mars meant NASA was trying to stop a manned mission. You're in mega conspiracy mode. Pull back and deflate your ego.

This is what makes me tired of ATS. It's conspiracy porn. That's mostly all it's.

Humans didn't make the wheel in one day. Have more trust in NASA. These people are mostly the real deal and if they lie it's the small kind of lie we're all guilty of using. The kind where you're feeling angry about something and a person asks how you're feeling and you say "Good."

Seriously, we got many years of progress ahead of us. The radiation levels will not stop us from visiting Mars. Look at what Zubrin said in that link about the radiation levels:

However, other experts believe that the risk is manageable. New materials could improve the shielding against cosmic and solar radiation and astronauts could be selected on the basis of their genetic resistance to radiation damage, which increases the risk of cancer by damaging DNA.

“These results show that cosmic rays are not a showstopper. This confirms what you might expect: the radiation risk is quite acceptable. Frankly, it's a modest portion of the risks on a Mars mission,” Robert Zubrin, president of the Mars Society in Colorado, told the journal Science.

TextTextreply to post by Watcher26


What a great thread- this theory is excellent and with all the flak you are getting I do believe you are on to something. It seems logical that if there isn't much atmosphere then a parachute will not function correctly and will need to be much bigger. No one in my opinion has disproved you. What we need here are facts and unfortunately the only ones with the info are the guys calling the shots. I am sure only time will tell or does anyone have that Snowden chap's email

I was going to make a valid comment but then I realized how long it's been since I landed a rover on a planet. So having forgotten what I once knew I'd be guessing at best. I'm just going to have to rely on the Op's expertise here I guess!

Originally posted by druid1
TextTextreply to post by Watcher26

 

What a great thread- this theory is excellent and with all the flak you are getting I do believe you are on to something. It seems logical that if there isn't much atmosphere then a parachute will not function correctly and will need to be much bigger. No one in my opinion has disproved you. What we need here are facts and unfortunately the only ones with the info are the guys calling the shots. I am sure only time will tell or does anyone have that Snowden chap's email

Thanks. And I believe that you are correct - nobody has disproved my original post, and there are people trying to sidetrack it onto petty arguments about wording, rather than giving counter facts to try to prove me wrong. There's no getting away from the fact that using an Earth sized parachute on Mars wouldn't work, unless Mars has a much greater atmospheric pressure than we have been led to believe...

Originally posted by druid1
TextTextreply to post by Watcher26

 

with all the flak you are getting I do believe you are on to something.

I 100% agree with you. Whether OP is correct?...I dont know. But I do know that particular subjects attract a particular gang of posters who rarely offer anything other than ridicule.

Well done OP. Dont let them wear you down.
S&F for you

Originally posted by druid1
TextTextreply to post by Watcher26

 

What a great thread- this theory is excellent and with all the flak you are getting I do believe you are on to something. It seems logical that if there isn't much atmosphere then a parachute will not function correctly and will need to be much bigger. No one in my opinion has disproved you. What we need here are facts and unfortunately the only ones with the info are the guys calling the shots. I am sure only time will tell or does anyone have that Snowden chap's email

He actually hasn't provided any evidence that the chute is too small except his "feeling" that it is.

First of all, the chute IS bigger than chutes on Earth. MSL's chute was about 20 meters (about 65 feet) in diameter. That's a lot bigger than most chutes used on Earth.

Secondly, the point of the chute is not to slow down the craft enough for a gentle landing. It only needs to slow it down enough for the retro rockets to fire.

Most of the speed of the craft was NOT reduced by the parachute, but instead before chute deployment during aerobraking. Plus, the shape of the craft (with the aeroshell cocoon still around it) was a lifting body, meaning the falling craft created its own lift, which help guide it and slow it down as it fell, chuteless.

The chute deployed once the craft was moving 450 m/s (1000 mph) and only needed to slow the craft down to 100 m/s (220 mph). The chute was cut away from the craft while it was still moving at 220 mph. the chute was cut away about one mile above the surface, meaning there was no parachute at all for the final 1 mile down.

A little after the chute was cut, the retro rockets then fired, which slowed the craft down enough for a soft landing.

So, yeah, the OP is right in a way because it is true the parachute would not be big enough to slow it down enough -- but it didn't have to. That's what the retrorockets were for.

Someone (as the OP did) may ask if the parachute was even able to slow the craft down enough (from 1000 mph to 220 mph) before the retrorockets fired. The OP's thought was that the air was 100 times thinner, therefore the chute would be 100 times less effective. Granted, the OP also took into account the lower gravity (38% that of earth) so he said that would mean the chute would be 38 times less effective...

...using his logic, that would mean a chute would need to be 38x bigger.

However, his logic is wrong. Well, not his logic, but his belief that the chute would be 100 times less effective in 100 times thinner air. That isn't true, because the drag force generated by the chute is NOT directly proportional to the density of the atmosphere. So 100x thinner air DOES NOT mean 100x bigger parachute is required. The math doesn't work like that.

Here is a link to a similar question asked about the chutes used for the smaller mars pathfinder mission (but the physics apply to all Mars missions)

mars.jpl.nasa.gov...

...the drag FORCE a chute generates (therefore its deceleration), is proportional to the square of the velocity and only linearly proportional to the atmospheric density; so even a thin atmosphere and a "small" chute will do much to slow our entry vehicle down once the heatshield'

And here is a link to calculations and simulations that were done for Curiosity's parachutes:
(link opens directly to a PDF file) ntrs.nasa.gov...

Originally posted by wmd_2008


YOU made a claim that the atmosphere is not thick enough to generate the force required to lift dust up so explain the dust devil gif!!!

It's THAT SIMPLE !!

You are missing the point! I believe that the atmosphere is much thicker than NASA says it is. So the dust devil is possible. It's just not possible if the atmosphere on Mars is 100 times thinner than on Earth.

reply to post by Watcher26

Yes, instead of things falling with an acceleration of 9.8 metres/sec sqrd, they fall with an acceleration of 3 metres/sec sqrd.
in the first second of free falling on Mars, something would fall 3.7 metres; in the second second of falling, it would fall 7.4 metres, in the third second of falling, it'd fall 11.1 metres

Not sure if anyone else has addressed this but your free fall calculations are incorrect.

Martian gravitational accelerations are around 3.7m/s^2. To find the distance traveled you multiply the time by the acceleration, divide by half and then multiply this number by the amount of time again.
Example;
1 second x3.7x.5x1=1.85 meters.
2 seconds x3.7x.5x2=7.4 meters.
3 seconds x3.7x.5x3=16.65 meters and so on…

The reason you divide by 2, or multiply by .5, is to average out the constant acceleration. You then multiply this average acceleration by the amount of time to get the distance traveled.

10 seconds of freefall on Mars will gain a distance of 185 meters.
On Earth you would travlel 490 meters.
Hope this helps.

reply to post by Watcher26


Parachute Descent Calculations

my.execpc.com...

Use these established calculative proven methods and substitute with gravity and air density of mars. Im feeling too lazy to do calc myself.

Originally posted by Soylent Green Is People
reply to post by Watcher26

 

First of all, as 'bullwinklekicksbutt' pointed out in his post above, you need to consider total volume of the parachute -- not just the diameter. A chute has 3 dimensions; you cannot directly correlate the diameter of the chute on Mars compared to on Earth just by dividing by 100 -- you need to correlate them using the volume of the chute.

Secondly, the parachute was not designed to slow Curiosity down enough for a soft landing. It was still falling at 170 mph when the parachute was cut from the rover (although that is still quite a bit slower than the 1,500 mph it was falling before the chute was deployed).

edit on 7/17/2013 by Soylent Green Is People because: (no reason given)

several things he didnt factor in first and foremost being that the lander used rockets which were fired on descent.And that Mars atmosphere is 95 percent co2 which is heaver then o2. And lets not forget mars gravity is only 38 percent of earths. So factor in co2 and gravity and the fact as soylent pointed out only meant to slow decent and total volume of the chute and get back to us.Heres a hint chute volume increases exponentially as you make it bigger.

several things he didnt factor in first and foremost being that the lander used rockets which were fired on descent.And that Mars atmosphere is 95 percent co2 which is heaver then o2. And lets not forget mars gravity is only 38 percent of earths. So factor in co2 and gravity and the fact as soylent pointed out only meant to slow decent and total volume of the chute and get back to us.Heres a hint chute volume increases exponentially as you make it bigger.

by dragonridr

The heavier molecular weight of CO2 makes zero difference to the fact that the atmospheric density is according to NASA 1/00th of that on Earth. Your comments above seem to me to be designed to confuse readers.The weight or 'drag' of a gas is proportional to its density - in other words, to how many molecules of the gas are present.

From: science.nasa.gov...

"Atmospheric friction slows the capsule containing Sky Crane -- an eight-rocket jetpack attached to the rover -- from 13000 to 1000 mph. [Mars' atmosphere is too thin to slow it more.] The friction burnishes the capsule's heat shield to a glowing 3800 degrees Fahrenheit (2100 degrees Celsius). Then a 60-foot diameter parachute deploys and inflates above the capsule on 160-foot lines. What's left of the heat shield jettisons, giving Curiosity its first look at its new home below."

[...]

"After the payload slows to about 200 mph, explosive bolts free the chute and Sky Crane free-falls for a second. Then its retrorockets fire."

The parachute was opened at a height of 11km, and the chute had to slow the payload from 1000mph to 200mph before the sky crane fired up. I doubt that the parachute would have done the job if the atmospheric pressure is as Nasa says. But I have tried to calculate using the equations at the URL below. They don't work out, but I don't know how heavy the sky crane was...

my.execpc.com...

Curiosity carries the Rover Environmental Monitoring Station (REMS) which measures atmospheric pressure and other parameters (temperature, wind speed, etc.). It was contributed by Spain and Finland, and delivers regular "weather reports" and other data to the public and scientists.

msl-scicorner.jpl.nasa.gov...
phys.org...
Official site: cab.inta-csic.es...

Latest data:


Are you also going to dismiss this data as lies? I think it would be preposterous to think that NASA are fooling all other scientists and space agencies around the world.

reply to post by Watcher26

I'm not saying they lied about the parachute size - but about the atmospheric pressure on Mars.

So why not use that in the title instead of this...

Curiosity Rover Parachute size Proves NASA Lies

You do see where that title is very misleading....

Originally posted by wildespace
Curiosity carries the Rover Environmental Monitoring Station (REMS) which measures atmospheric pressure and other parameters (temperature, wind speed, etc.). It was contributed by Spain and Finland, and delivers regular "weather reports" and other data to the public and scientists.

Latest data:


Are you also going to dismiss this data as lies? I think it would be preposterous to think that NASA are fooling all other scientists and space agencies around the world.

I don't think for a moment that NASA are beyond making things up, but I think I'm going to have to admit defeat on this matter - I accept that the atmosphere is as thin as stated.

Thanks to all who contributed to this thread.

reply to post by wmd_2008


I know all about rayleigh scattering. That is also why the sky is not pink on Mars, but pale blue. But the question is, at that pressure and density, why is it any color at all? The sky above a person on Mt Everest is black in the daytime. And Mars atmospheric pressure is supposed to be many times less than on Mt Everest.

It should be black, not pink or blue, but black.

Originally posted by Robonakka
reply to post by wmd_2008

 

I know all about rayleigh scattering. That is also why the sky is not pink on Mars, but pale blue. But the question is, at that pressure and density, why is it any color at all? The sky above a person on Mt Everest is black in the daytime. And Mars atmospheric pressure is supposed to be many times less than on Mt Everest.

It should be black, not pink or blue, but black.

The sky above a person does NOT look black as viewed from Mt Everest in the daytime. That is a myth.

Consider this -- when you view the sky above you from a jet airliner flying at 30,000+ feet, the sky still looks blue (I've been in many a passenger jet; I know from personal experience that the sky is still blue above me. A slightly darker blue, sure -- but still blue).

...and those jet airliners are flying higher than the height of Mt. Everest.

Originally posted by Soylent Green Is People

Originally posted by Robonakka
reply to post by wmd_2008

 

...and those jet airliners are flying higher than the height of Mt. Everest.

Not much higher - Everest is over 29000 feet high...

Originally posted by Watcher26

Originally posted by Soylent Green Is People
Originally posted by Robonakka
reply to post by wmd_2008

 

...and those jet airliners are flying higher than the height of Mt. Everest.

Not much higher - Everest is over 29000 feet high...

That's fine, but the point is that the sky above you as seen from an airliner flying higher than Mt. Everest still looks blue. Therefore, the idea that the sky above a person at the top of Mt. Everest would look black is false.

This is taken from the cockpit of a U-2 on a mission. They routinely fly above 70,000 feet. You can still see blue in it.




A funny of the recent jump from over 100,000 feet. Notice the background.

themetapicture.com...