NASA Breaks a Balloon Altitude Record

L. Paul Verhage KD4STH

Re: Barometric pressure sensor for HABs?

Hank Riley

Yes, the first step is at 36K as mentioned in my first post.  The next two are at 65.6 Kfeet and 105 Kfeet.

So up to 105 Kfeet there are three regimes of the Standard Atmosphere:  0 - 36, 36 - 65.6, and 65.6 - 105.

I believe adequate accuracy can be achieved by a single formula fitted to that entire range 0 - 105.

On Wednesday, September 12, 2018, 7:36:29 AM EDT, Mark Patton <kc0d@...> wrote:

There is one equation for calculating altitude at launch, and another for high altitudes.  I don't recall what the second equation is or what altitude it kicks in at off the top of my head.  I think it is around 36K feet..

Re: Barometric pressure sensor for HABs?

Mark Patton

Hi Mike,

We've flown the MS5611-01BA03 with good success. It is specified down to 10mb.  Even without setting the local barometric pressure, it is generally within 100 Ft  of actual altitude at launch.  At birst altitude, it can be off by a thousand feet or more.

Be sure you factor in temperature and the factory calibration data.  The data sheet does a good job of explaining the steps to get to temperature compensated barometric pressure with modifications for low temperature.  Watch out for the the size of the resultant math.  They specify 32 and 64 bit integer math which can introduce errors if not done right.

There is one equation for calculating altitude at launch, and another for high altitudes.  I don't recall what the second equation is or what altitude it kicks in at off the top of my head.  I think it is around 36K feet..

I hope this helps.
Mark - KC0D

Re: Barometric pressure sensor for HABs?

Steve G8KHW / AJ4XE

The  MS5611 is a better chip to use for HAB - its rated down to 10mbar (approximately 28km).   Both the BMP180 and BMP280 have an erratic output value issue outside of their rated range.

Steve G8KHW

On 12/09/2018 01:39, Michael Hojnowski wrote:
Heya,

I've been using GPS for altitude on my balloons, but I'm working with a student who's interested in trying a barometric pressure sensor attached to an arduino with my next HAB flight.   I've got a pile of BMP180s laying around, but  they only seem to be rated for 9,000m.  It looks like the BMP280 has the same issue.  I'm expecting 36,000 meters or so.  So, two questions.

1) Is there a better series of devices to use?
2) The last time I screwed with the BMP180, the altitude formulas I found didn't seem to work.  It was thousands of feet off, just at ground level.  If there is a "defacto" subroutine to use for calculating altitude from a pressure sensor that everyone's using for HABs, I'd love a pointer.

Thanks for any tips!
Mike / KD2EAT

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Re: Barometric pressure sensor for HABs?

Hank Riley

You could get a sounding for the day for a little refinement.  I just tried that and there was a difference of 360 meters from the Standard Atmosphere.  That height is subject to the radiosonde system inaccuracies as well.

I would definitely encourage you to fly at least a BMP180/280 to see how it does higher up.

On Wednesday, September 12, 2018, 2:53:57 AM EDT, Hank Riley via Groups.Io <n1ltv@...> wrote:

By the way, no matter what sensor you use, you'll be happy to get within a few thousand feet of the correct altitude for those higher ranges of altitude owing to the small pressures being measured and the fact that the standard atmosphere is just an approximation of your slice of the atmosphere at launch.

Re: Barometric pressure sensor for HABs?

Hank Riley

I've been using GPS for altitude on my balloons, but I'm working with a
student who's interested in trying a barometric pressure sensor attached
to an arduino with my next HAB flight.   I've got a pile of BMP180s
laying around, but  they only seem to be rated for 9,000m.  It looks
like the BMP280 has the same issue.  I'm expecting 36,000 meters or so.

The limit of 9000 meters is a matter of staying within the very high accuracy performance specs of the Bosch devices.

They may well work acceptably at much higher altitudes.  There's quite a high range of pressures to handle over that span of 0 to 100,000 feet, from around 1000 mb down to 11mb.

So, two questions.

1) Is there a better series of devices to use?

Certainly nothing I know of that's digital, low priced, and very accurate at lower altitudes.  It would be very worthwhile to test how well the BMP devices work outside of their intended range on a flight with GPS for comparison.

2) The last time I screwed with the BMP180, the altitude formulas I
found didn't seem to work.  It was thousands of feet off, just at ground
level.

If the actual local barometer is not taken into account, errors of about a thousand feet can happen assuming the average sea level pressure of 1013 mb is presumed by the formula and the barometer is either low or high in comparison.  There must have been something wrong for it to be off by thousands of feet at ground level.  Notice that the Adafruit formula gives 0 feet elevation for ground level because the pressure equals the local pressure (1 raised to any power = 1).

This formula, used by Adafruit for the Arduino, is correct up to the first step (start of tropopause) in the standard atmosphere at about 36,000 feet:

Note: Altitude is in meters

altitude = 44330 * {1-[(pressure/local_pressure) ** (1/5.255]}

I can create for you a more complex fitted curve that will cover 0 to 100,000 feet, or you can just use a table for the standard atmosphere or a spreadsheet.

By the way, no matter what sensor you use, you'll be happy to get within a few thousand feet of the correct altitude for those higher ranges of altitude owing to the small pressures being measured and the fact that the standard atmosphere is just an approximation of your slice of the atmosphere at launch.

Hank

Barometric pressure sensor for HABs?

Michael Hojnowski

Heya,

I've been using GPS for altitude on my balloons, but I'm working with a student who's interested in trying a barometric pressure sensor attached to an arduino with my next HAB flight.   I've got a pile of BMP180s laying around, but  they only seem to be rated for 9,000m.  It looks like the BMP280 has the same issue.  I'm expecting 36,000 meters or so.  So, two questions.

1) Is there a better series of devices to use?
2) The last time I screwed with the BMP180, the altitude formulas I found didn't seem to work.  It was thousands of feet off, just at ground level.  If there is a "defacto" subroutine to use for calculating altitude from a pressure sensor that everyone's using for HABs, I'd love a pointer.

Thanks for any tips!
Mike / KD2EAT

Re: Floater balloon

Bruce Coates

Hi Bill

That would be great.

Thanks

Bruce

------ Original message------
From: Bill Brown via Groups.Io
Date: Tue, Aug 28, 2018 1:45 PM
Cc:
Subject:Re: [GPSL] Floater balloon

Bruce. No more than 3 grams free lift. But if using two Mylars you can use 3 grams of free lift each. I have never tried to do a Mylar 36-inch with that heavy of a payload. My heavies! t successful floater was about 22 grams i believe. Use Qualatex brand. There is a spreadsheet by the UKHAS folks for predicting float altitudes   I can email u after work. - Bill WB8ELK

On Aug 28, 2018, at 7:29 AM, Bruce Coates <bruce.coates@...> wrote:

Hi

I'm planning on launching a floater balloon from Saskatoon in the near future and it just occured to me that i know just enough to be damgerous.

My payload  is complete and weighs in at about 40 grams, quite a bit heavier than i had hoped. I have 36 inch mylar balloons which should provide over 75 grams of neck lift if they were fully inflated with hydrogen.

I have just 3 questions:

1. Given the mass of the payload, how much net lift should I use?  I'm thinking of 5 to 10 grams.
2. How do I run predictions for a floater?  Given my northern latitude, I want the initial part of the flight to travel southward over southern Canada or the US so I can track it for the first part of the flight.
3. What other questions should I be asking?

I'm all ears.

73, Bruce - VE5BNC

Re: Floater balloon

Bill Brown

Bruce. No more than 3 grams free lift. But if using two Mylars you can use 3 grams of free lift each. I have never tried to do a Mylar 36-inch with that heavy of a payload. My heaviest successful floater was about 22 grams i believe. Use Qualatex brand. There is a spreadsheet by the UKHAS folks for predicting float altitudes   I can email u after work. - Bill WB8ELK

On Aug 28, 2018, at 7:29 AM, Bruce Coates <bruce.coates@...> wrote:

Hi

I'm planning on launching a floater balloon from Saskatoon in the near future and it just occured to me that i know just enough to be damgerous.

My payload  is complete and weighs in at about 40 grams, quite a bit heavier than i had hoped. I have 36 inch mylar balloons which should provide over 75 grams of neck lift if they were fully inflated with hydrogen.

I have just 3 questions:

1. Given the mass of the payload, how much net lift should I use?  I'm thinking of 5 to 10 grams.
2. How do I run predictions for a floater?  Given my northern latitude, I want the initial part of the flight to travel southward over southern Canada or the US so I can track it for the first part of the flight.
3. What other questions should I be asking?

I'm all ears.

73, Bruce - VE5BNC

Floater balloon

Bruce Coates

Hi

I'm planning on launching a floater balloon from Saskatoon in the near future and it just occured to me that i know just enough to be damgerous.

My payload  is complete and weighs in at about 40 grams, quite a bit heavier than i had hoped. I have 36 inch mylar balloons which should provide over 75 grams of neck lift if they were fully inflated with hydrogen.

I have just 3 questions:

1. Given the mass of the payload, how much net lift should I use?  I'm thinking of 5 to 10 grams.
2. How do I run predictions for a floater?  Given my northern latitude, I want the initial part of the flight to travel southward over southern Canada or the US so I can track it for the first part of the flight.
3. What other questions should I be asking?

I'm all ears.

73, Bruce - VE5BNC

Re: 360 Balloon Launch

Bruce Coates

WOW

I can't wait to get home and try my vr goggles.

Thanks for posting this

73, Bruce

------ Original message------
From: David Stillman KI6YMZ
Date: Tue, Aug 21, 2018 9:21 AM
Cc:
Subject:Re: [GPSL] 360 Balloon Launch

Phew, editing 360 video sure does take time!

I ran the video files through the GoPro software to stabilize it using the IMU data, and that took about 60 hours and resulted in a single file that is half a terabyte. I cut it down a bit and put it on YouTube, they have a nice 360 player and support most VR systems. I'd not recommend watching the burst and landing in a headset if you get seasick!

I tagged the launch, burst, and landing in the description if you're just after the juicy bits, and edited in a bit of time in between to get a sense at various altitudes on the way up and down.

I can upload the full flight if there is any interest.

Thanks EOSS for a great launch and recovery! We were fortunate to be a quarter mile from the landing location and watch the payload land. If you look close you can see our line of cars on the road nearest the landing location.

73,

David Stillman
KI6YMZ

On Sun, Aug 19, 2018, at 16:36, dampguy wrote:
I flew one 3 years ago. A picture is posted here somewhere :D

Re: 360 Balloon Launch

David Stillman KI6YMZ

Phew, editing 360 video sure does take time!

I ran the video files through the GoPro software to stabilize it using the IMU data, and that took about 60 hours and resulted in a single file that is half a terabyte. I cut it down a bit and put it on YouTube, they have a nice 360 player and support most VR systems. I'd not recommend watching the burst and landing in a headset if you get seasick!

I tagged the launch, burst, and landing in the description if you're just after the juicy bits, and edited in a bit of time in between to get a sense at various altitudes on the way up and down.

I can upload the full flight if there is any interest.

Thanks EOSS for a great launch and recovery! We were fortunate to be a quarter mile from the landing location and watch the payload land. If you look close you can see our line of cars on the road nearest the landing location.

73,

David Stillman
KI6YMZ

On Sun, Aug 19, 2018, at 16:36, dampguy wrote:
I flew one 3 years ago. A picture is posted here somewhere :D

Re: 360 Balloon Launch

dampguy

I flew one 3 years ago. A picture is posted here somewhere :D

Re: 360 Balloon Launch

David Stillman KI6YMZ

I flew a GoPro Fusion on Saturday and have about 150GB of footage... it certainly is a lot to process :) I'll see if I can cut it down and get something online soon.

On Thu, Aug 16, 2018, at 20:35, L. Paul Verhage KD4STH wrote:
The problem I foresee is having a PC powerful enough to stitch the video in a reasonable amount of time.

On Thu, Aug 16, 2018, 8:29 PM Bruce Coates <bruce.coates@...> wrote:
Great stuff.  I'll be watching.

Weather (and forest fire smoke) permitting we're going to fly SABRE-27 next weekend.  Nothing special.  Just a traditional camera payload.

On 2018-08-16 8:11 PM, L. Paul Verhage KD4STH wrote:
I will fly one soon, but it may be a huge file when done.

On Thu, Aug 16, 2018, 7:16 PM Bruce Coates <bruce.coates@...> wrote:
Hi Paul

You had me all worked up for a minute thinking you had flown a 360 degree camera.

Very interesting though.

73, Bruce - VE5BNC

On 2018-08-15 10:30 AM, L. Paul Verhage KD4STH wrote:
I posted a short 360 video I recorded of the balloon launches at the Nebraska Star Party.

I shared a balloon with NSTAR and the second balloon was launched by the Nebraska Space Grant.

The video is located at, https://youtu.be/--p-FAzLLmo

--

Dr. L. Paul Verhage
Near Space Evangelist

Re: 360 Balloon Launch

L. Paul Verhage KD4STH

The problem I foresee is having a PC powerful enough to stitch the video in a reasonable amount of time.

On Thu, Aug 16, 2018, 8:29 PM Bruce Coates <bruce.coates@...> wrote:
Great stuff.  I'll be watching.

Weather (and forest fire smoke) permitting we're going to fly SABRE-27 next weekend.  Nothing special.  Just a traditional camera payload.

On 2018-08-16 8:11 PM, L. Paul Verhage KD4STH wrote:
I will fly one soon, but it may be a huge file when done.

On Thu, Aug 16, 2018, 7:16 PM Bruce Coates <bruce.coates@...> wrote:
Hi Paul

You had me all worked up for a minute thinking you had flown a 360 degree camera.

Very interesting though.

73, Bruce - VE5BNC

On 2018-08-15 10:30 AM, L. Paul Verhage KD4STH wrote:
I posted a short 360 video I recorded of the balloon launches at the Nebraska Star Party.

I shared a balloon with NSTAR and the second balloon was launched by the Nebraska Space Grant.

The video is located at, https://youtu.be/--p-FAzLLmo

--
Dr. L. Paul Verhage
Near Space Evangelist

Re: 360 Balloon Launch

Bruce Coates

Great stuff.  I'll be watching.

Weather (and forest fire smoke) permitting we're going to fly SABRE-27 next weekend.  Nothing special.  Just a traditional camera payload.

On 2018-08-16 8:11 PM, L. Paul Verhage KD4STH wrote:
I will fly one soon, but it may be a huge file when done.

On Thu, Aug 16, 2018, 7:16 PM Bruce Coates <bruce.coates@...> wrote:
Hi Paul

You had me all worked up for a minute thinking you had flown a 360 degree camera.

Very interesting though.

73, Bruce - VE5BNC

On 2018-08-15 10:30 AM, L. Paul Verhage KD4STH wrote:
I posted a short 360 video I recorded of the balloon launches at the Nebraska Star Party.

I shared a balloon with NSTAR and the second balloon was launched by the Nebraska Space Grant.

The video is located at, https://youtu.be/--p-FAzLLmo

--
Dr. L. Paul Verhage
Near Space Evangelist

Re: 360 Balloon Launch

L. Paul Verhage KD4STH

I will fly one soon, but it may be a huge file when done.

On Thu, Aug 16, 2018, 7:16 PM Bruce Coates <bruce.coates@...> wrote:
Hi Paul

You had me all worked up for a minute thinking you had flown a 360 degree camera.

Very interesting though.

73, Bruce - VE5BNC

On 2018-08-15 10:30 AM, L. Paul Verhage KD4STH wrote:
I posted a short 360 video I recorded of the balloon launches at the Nebraska Star Party.

I shared a balloon with NSTAR and the second balloon was launched by the Nebraska Space Grant.

The video is located at, https://youtu.be/--p-FAzLLmo

--
Dr. L. Paul Verhage
Near Space Evangelist

Re: 360 Balloon Launch

Jim Reed

We flew a couple 360s a couple years ago. Cool footage.

I enjoy reading the conversations you folks have. You are a knowledgeable group. We just know how to do it. 😀

Jim

On Aug 16, 2018, at 8:16 PM, Bruce Coates <bruce.coates@...> wrote:

Hi Paul

You had me all worked up for a minute thinking you had flown a 360 degree camera.

Very interesting though.

73, Bruce - VE5BNC

On 2018-08-15 10:30 AM, L. Paul Verhage KD4STH wrote:
I posted a short 360 video I recorded of the balloon launches at the Nebraska Star Party.

I shared a balloon with NSTAR and the second balloon was launched by the Nebraska Space Grant.

The video is located at, https://youtu.be/--p-FAzLLmo

--
Dr. L. Paul Verhage
Near Space Evangelist

Re: 360 Balloon Launch

Bruce Coates

Hi Paul

You had me all worked up for a minute thinking you had flown a 360 degree camera.

Very interesting though.

73, Bruce - VE5BNC

On 2018-08-15 10:30 AM, L. Paul Verhage KD4STH wrote:
I posted a short 360 video I recorded of the balloon launches at the Nebraska Star Party.

I shared a balloon with NSTAR and the second balloon was launched by the Nebraska Space Grant.

The video is located at, https://youtu.be/--p-FAzLLmo

--
Dr. L. Paul Verhage
Near Space Evangelist

360 Balloon Launch

L. Paul Verhage KD4STH

I posted a short 360 video I recorded of the balloon launches at the Nebraska Star Party.

I shared a balloon with NSTAR and the second balloon was launched by the Nebraska Space Grant.

The video is located at, https://youtu.be/--p-FAzLLmo

--
Dr. L. Paul Verhage
Near Space Evangelist

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