Air Pressure, Altitude, Balloons and Rockets

Weather Balloon BurstAir Pressure and how it Affects Balloons and Rockets

By Robert Brand

Rockets

One of the big issues for rockets flying to space is the air pressure it must climb through. As a rocket climbs it gets faster and has to push more air out of the way. As it goes higher the air thins and you can see from the table below that it is exponential. Have a look at the 1/100th  fraction of one atmosphere below and you will see that the atmosphere is 1% of sea level. The change is not linear. The atmosphere thins to a tiny percentage at twice that height, but at half the height it is 10% of the sea level pressure.

NASA says: The velocity of a rocket during launch is constantly increasing with altitude. Therefore, the dynamic pressure on a rocket during launch is initially zero because the velocity is zero. The dynamic pressure increases because of the increasing velocity to some maximum value, called the maximum dynamic pressure, or Max Q. Then the dynamic pressure decreases because of the decreasing density. The Max Q condition is a design constraint on full scale rockets.

fractionof 1 atmosphere (ATM) average altitude
(m) (ft)
1 0 0
1/2 5,486.3 18,000
1/3 8,375.8 27,480
1/10 16,131.9 52,926
1/100 30,900.9 101,381
1/1000 48,467.2 159,013
1/10000 69,463.6 227,899
1/100000 96,281.6 283,076

The Falcon9 reaches the speed of sound at 1 min 10 sec into its flight and then reaches Max Q just 8 to 13 seconds later depending on speed,and air pressure variables. Unlike airplanes, a rocket’s thrust actually increases with altitude; Falcon 9 generates 1.3 million pounds of thrust at sea level but gets up to 1.5 million pounds of thrust in the vacuum of space. The first stage engines are gradually throttled near the end of first-stage flight to limit launch vehicle acceleration as the rocket’s mass decreases with the burning of fuel.

Want to know more? This is not full of maths, just some fun stuff about Max Q and reaching orbit.

Balloons

Well for balloons we have a different issue. Balloons have to displace their weight in gas in the atmosphere and that includes displacing enough gas for the weight of the payload too.

Rate of Climb - Fall vs TimeThe climb to maximum altitude for the most part is linear. I discovered this when analysing the stats from my first balloon flight. It was linear until it reached the point that the balloon exploded. If you launch a balloon that does not explode, it will slow its climb and then float. My best guess is that as the climb becomes more difficult due to the air thinning thus and thus the displaced gas is getting closer to the weight of the balloon and payload, but the air resistance is getting less. The size of the balloon is also increasing with height and has to push away a greater volume of air to climb, but the number of air molecules in the increased mass is way less. All up it produces a fairly linear climb. The graph (left) from uplift-1 shows he linear climb and the exponential fall with the parachute deployed. For the parachute, the air gets thicker as it falls and thus slows more as the altitude decreases. Note the initial glitch was caused by a strong thermal just as we let go of the balloon. Once out of the thermal the climb was very linear. It is obvious when the balloon burst.

Altitude and Air PressureAnother view of th same data is shown on the left from UpLift-1’s flight. Note that the rate of climb is linear, but increasing slightly. This would be affected by balloon size and fill amount. The rate of climb may be fast, slow or medium, but that will also change the rate of change of the volume. Not all graphs are the same, but they tend to be similar. Note also that the size of the parachute needs to change with the weight of the payload. The ideal speed for the average payload would be about 5mto 6m per second at the landing altitude, thus landing at Denver, Colorado, USA will require that you make the parachute a little bigger since it is nearly 2Km above sea level and the air is noticeably thinner.

There are good fill charts on the web allowing you to calculate the size of balloon and the amount of Helium or Hydrogen to determine the altitude at which the balloon will explode. More on that another time. The picture at top of page is a weather balloon exploding at altitude.

All up, air pressure can destroy a rocket if its speed is too great and it will destroy a weather balloon if the air pressure gets too low. Both rely on understanding the effects of air pressure, but the dynamics are totally different.

Too finish off the post here is a video of a balloon burst. They are spectacular, especially as the balloons grow to a huge diameter and fill the screen of most wide angle GoPros!:

13th Australian Space Science Conference Pt1

13th ASSC Uni NSWSpace Education

by Robert Brand

I was fortunate to present at the 13th Australian Space Science Conference at Sydney University a little over a week ago. The only unfortunate thing was a mix-up by yours truly and I ended up there on the wrong day. I was meant to be delivering a talk on “Triple Play in the Space Sector” and poor Alice Gorman, who was hosting the panel, was asking if I had turned up. My biggest apologies ever Alice!

I did however get a chance to present in the education stream and I am including this presentation here. My son Jason came along to help me as it was school holidays. Luckily every talk was about some of the work that he does with me, so it was pretty interesting most of the time.

Below is the PDF version of my PowerPoint presentation. It is interesting to note that we are doing so much that I can easily put together a complete presentation during a few other people’s talks. As you can see I gave my WotzUp website a plug!

You can download it here:  Click to Download

Download (PDF, 3.5MB)

UpLift-1 Prediction

Our First High Altitude Balloon Flight (Archives)

UpLift-1 PredictionUpLift-1 Mission Announced

UpLift-1 Raw Data 28th Dec 2011 (Archives)

WotzUp_Black_logo.135x100.jpg*** Retrieved from Archives ***

UpLift-1 Flight Data 2011-12-28

I have already detailed the top level science that is easily seen from the data returned by radio telemetry from the flight. The radio link returns data approximately every 20 seconds and it has a variety of information as described previously. There are a few plots missing from the start and end of the flight as the tracking system only 863worked when the receivers could see the balloon. We were effectively over the radio horizon due to the distance from the receivers – much like a light house cannot light the ocean around it unless it is on a high headland. There are also 3 plots missing during the 2.5 hour flight. I have added these in to smooth out the plots, but the estimations are all in red. I have not tried to extrapolate data from the landing as I was not present to see the course it took.

The Database information is available in metric form and not imperial. You will need to convert that yourself, but that is very easy.

You can download the database here for educational purposed and similarly any photos are available for education purposes, but are copyright – Robert Brand 2011

CLICK HERE to DOWNLOAD the DATABASE

The file contains both flight data and graphs as used in the posts on this website re UpLift-1′s flight. There is also a list of photograph numbers. Many were unusable due to sun, glare, direction of the photo, etc. All photos indicated with a “1′ are available on this website in subsequent posts.

As far as position accuracy is concerned, the data from the telemetry also contain a parameter called HDOP. Firstly let’s look at DOP:

The following information is from http://gpsinformation.net/main/dopnontech.htm

Dilution of Precision

The DOP factor is used in a very simple equation:

SD(position) = DOP * SD(inputs)

This means that the standard deviation of the position is simply the standard deviation of the inputs multiplied times the DOP factor. Of course, this formula isn’t as simple as it looks, since for GPS a multidimensional solution is required, and therefore matrix mathematics is used. But the idea is good.

One interesting thing about DOP is that it does not depend on the anything that cannot be predicted in advance. It only depends on the positions of the GPS satellites relative to the GPS receiver’s location. The satellite positions can be calculated in advance, so you can determine the quality of your GPS position fix in advance, without even using the GPS system.

Satellite geometry

DOP only depends on the position of the satellites: how many satellites you can see, how high they are in the sky, and the bearing towards them. This is often refered to as the geometry. The satellites move, so the geometry varies with time, but it is very predictable.

HDOP = Horizontal Dilution of Position

HDOP is horizontal DOP. It is one component of the total DOP. Others are VHOP for Vertical DOP, PDOP for 3D positions, TDOP for time, and GDOP for geometic DOP. Altogether they =DOP.

UpLift-1  was outdoors and the receiver facing the sky with only a layer of bubble-wrap and Styrofoam that had already been tested for GPS integrity. It offered no apparent impediment to GPS signals. In fact the entire flight was a DOP=1. This is the lowest error estimate and means the horizontal position information was estimated to be very accurate. It has not been included with the figures. The vertical position also appears to be accurate with the repetition of the data and the expected rates of slowing on descent. The smoothness of the curves attests to the quality of the results.

UpLift-1 Flight Data Pt-2 (Archives)

*** Retrieved from Archives ***

UpLift-1 Facts and Figures 28th Dec 2011 Pt-2

Time for some SCIENCE. I have cleaned up all the data from the flight removing duplicated figures and out of place data that sometimes occurs from having lots of receiving stations all trying to add it to the database. The figures are certainly interesting and even fun to see what is going on during the flight.

Temperature.

Unfortunately, UpLift-1 did not have an external temperature sensor – just a payload sensor. The payload sensor will be useful to see the stresses that the payload has to handle, but due to the thermal properties of the capsule (polystyrene is an insulator) and the thermal wrap around the electronics (bubble-wrap) the payload temperature will be both reduced and delayed slightly. The capsule did have some small penetrations that made its insulation poor and the transmitter also produced some small amount of heat that would have affected the cooling effects slightly. It was mainly the bubble-wrap that protected the electronics from the -40 to -50 degrees Celsius (  -40 to -68F). So what happens and why the cold temperatures?

The atmosphere has many layers and the first that we live in is the Troposphere. The following (Troposphere and Stratosphere) are from Wikipedia:

Troposphere

The troposphere begins at the surface and extends to between 9 km (30,000 ft) at the poles and 17 km (56,000 ft) at the equator, with some variation due to weather. The troposphere is mostly heated by transfer of energy from the surface, so on average the lowest part of the troposphere is warmest and temperature decreases with altitude. This promotes vertical mixing (hence the origin of its name in the Greek word “τροπή”, trope, meaning turn or overturn). The troposphere contains roughly 80% of the mass of the atmosphere.

The tropopause is the boundary between the troposphere and stratosphere.

Stratosphere

The stratosphere extends from the tropopause to about 51 km (32 mi; 170,000 ft). Temperature increases with height due to increased absorption of ultraviolet radiation by the ozone layer, which restricts turbulence and mixing. While the temperature may be −60 °C (−76 °F; 210 K) at the tropopause, the top of the stratosphere is much warmer, and may be near freezing. The stratopause, which is the boundary between the stratosphere and mesosphere, typically is at 50 to 55 km (31 to 34 mi; 160,000 to 180,000 ft). The pressure here is 1/1000 sea level.

Our balloon flight will start at the bottom of the Troposphere 34C (93F) at ground level, pass through the thin Tropopause at a bit less than 17 km (56,000 ft), where temperatures could be as low at -50C (-68F) and into the stratosphere where temperatures could warm to just above or below freezing. The climb will end in the Stratosphere when the balloon expands until it explodes and then falls back to earth and back through the cold. The chart below provides critical data on payload temperatures:

Payload Temperature vs Altitude

Above we see the effect of passing through the very cold temperatures of the Troposphere and then the warming of the Stratosphere – even though it is only warming to about freezing! The descent takes the already cold payload back through freezing conditions in the Troposphere again further cooling the payload to a maximum of -12C (10.4F) before warming to a balmy +3C (+37.4F) by the end of the flight. By the time of recovery 2 hours later the  payload had warmed to outside temperatures.

Thermal delay

The chart below shows an approximation of the outside temperatures encountered during the flight plotted alongside of the payload temperatures:

Payload Temperature and Estimated Outside Temperature

There is a good possibility that the temperature in the Stratosphere was above freezing as the payload was warming up substantially. It is not likely to have been from the electronics as the transmitter was extremely low power with a small duty cycle (10%).

Battery Conditions due to Temperature

Simply put, batteries fail when they get cold. This got a little colder than I would have liked. Extra bubble-wrap would have been helpful or sealing the camera penetration better would have helped. In future, I will do both. The battery volts dropped to very low levels due to the cold, but since they were Lithium batteries they worked okay at -12C (10.4F). Battery volts had fallen from 5.8V at the start of the flight to 5.1 in the extreme cold and returned to 5.8v by the time of recovery of the capsule.

Payload Temperature (C) and Battery Volts

In the graph above the battery voltage had started to recover as the capsule landed on the ground. The size of the batteries meant that they would have remained cold the longest even though the electronics warmed up relatively quickly the thermal mass of the batteries took much longer to warm. The batteries were inside the many layers of bubble-wrap.

More on the flight data in the next post

UpLift-1 Flight Data Pt-1 (Archives)

*** Retrieved from Archives ***

UpLift-1 Facts and Figures 28th Dec 2011 Pt-1

Time for some SCIENCE. I have cleaned up all the data from the flight removing duplicated figures and out of place data that sometimes occurs from having lots of receiving stations all trying to add it to the database. The figures are certainly interesting and even fun to see what is going on during the flight.

Some Facts first:

  • Altitude of the launch site is about 90m or 300ft above sea level. flat farmland was chosen for lack of trees and easy access for recovery.
  • Morning was chosen for air stability and lower wind levels.
  • Weather: Clear with little to no wind. Summer.
  • Flight launch: 10;53 28th Dec 2011 EDST (23:53 27th Dec 2011 UTC).
  • Flight landing: 13:40 28th Dec 2011 EDST (02:53 28th Dec 2011 UTC).
  • Flight time: 2 hours 47 minutes.
  • Maximum Recorded Altitude: 26.181km – 85,896 feet – 16.2681 miles.
  • Distance traveled: 45.6km (28 miles).
  • Direction from launch of 72 degrees.
  • Rate of climb: 3m/sec (5ft/sec) near sea level to near 5m/sec (8ft/sec) at the burst point.
  • Payload temperature during flight: 34C (93F) at ground level to -12C (10.4F) minimum.
  • Maximum recorded rate if fall: 33m/sec (110ft/sec)
  • Anomalies encountered: Thermal at the time of release caused 9m (30ft) initial rate of climb.
  • Balloon: Totex 350g (optimum fill 1.2m, actual fill 1.35m diameter)
  • Gas used for lift: Helium
  • Payload: Polystyrene box with a bit less than 1/2kg weight (1lb) including parachute.
  • Camera: GoPro 7mp still camera set to take photos every 30 seconds – lasted entire flight. Housing included
  • Tracking was via Amateur Radio APRS with Internet and direct reception in vehicle. 145.175MHz Packet radio.
  • Transmitter from Argent Data system with GPS rated for over 60,000 feet and 1/2 watt transmitter.
  • Antenna – precision tuned vertically mounted dipole.
  • Transmitter Power: 2 x mounted on-board Lithium 3V pile batteries.
  • Reporting time: 20 seconds.
  • Thermal insulation for transmitter: Polystyrene capsule and three layers of bubble wrap.

The first bit of data showed that UpLift-1 climbed very quickly. At first I could not believe the rate of climb, but there it was climbing at 9m per second. I now know that this was an anomaly. The simplest and most likely explanation is that at the time that we released the balloon we were in a thermal area where the hot air at that spot was rising quickly were near by air was falling. As it was early in the day, upper air thermals had not formed so the affect was short lived. So here is the graph of altitude for the flight:

Atitude vs Time

At the very start of the flight there is a slightly different rate of climb caused by the thermal that dissipates at about 2km. From then on the climb is steady and near flat. The rate of climb being mainly determined by the size of the balloon (air resistance and lift) and the wright of the payload. As the air thins, the balloon expands keeping the air resistance somewhat the same, but as altitude increases, the ability to lift is also reduced. The result is a fairly consistent rate of climb. At the maximum altitude the balloon bursts and the payload is released. The parachute is ineffective in the free air and the rate of fall is determined by air density producing a somewhat parabolic curve. For most balloon flights with a reasonable rate of climb, the climb to fall ratio is usually between 3:1 or 4:1 for flight estimations.

The rate of climb graph shows the linear and parabolic effects more clearly”

Rate of Climb - Fall vs Time

In the graph above, you can clearly see the high initial rate of climb and the slowing of the rate as it left the thermal event. The rate was not flat, but slowly climbed from 3m/sec (5ft/sec)  to near 5m/sec (8ft/sec) at the burst point. There is a fairly long period of time following the burst point before the payload reaches terminal velocity of greater than 33m/sec (110ft/sec) – remember that the plots are 20 seconds apart. There is one plot during the initial fall that indicated that the payload was accelerating and was showing 9m/sec (30ft/sec) fall and accelerating until terminal velocity is reached – the point where air resistance stops any further acceleration due to gravity.

The payload – a foam box weighing less than 1/2kg (about 1lb) has plenty of air resistance at sea level, but very little in the thin atmosphere. As it falls the air density increases and the rate slows. Where the rate of climb was determined by fairly linear forces, the rapid descent is clearly non linear when plotted against time.

Part two shortly with links to both imperial and decimal data data sets.

UpLift-1 Launch (Archives)

UpLift-1 Takeoff 28th Dec 2011.

UpLift-1 launch weatherBefore we even left home we needed a massive list to make sure that we did not leave anything behind. After all, a 600km / 400 mile trip for nothing would not be a lot of fun. It was a huge list for such a small balloon and payload. It included the balloon, parachute, payload, helium, spare balloon, test equipment, hoses, cameras, tripod, 2-way radios, tracking radios, decoders, computer, USB cables, mobile phones, car chargers and much, much more. But this is not about that story, this is launch day! We traveled to West Wyalong in NSW (Australia) and spent the night in a great little hotel ready for an early morning departure. We still had 100km / 60 miles to drive to the launch site. The first thing was to check the weather. We had already looked at a long distance forecast before setting the date as the Civil Aviation Safety Authority (CASA) in Australia have to issue an alert to pilots for our balloon. CASA have been wonderful UpLift-1 Launch site with Jason Brand age 9and amazingly helpful. A peek out the door reveals a perfect day for a balloon flight. The photo on right shot outside my hotel room reveals a brilliant day with little wind early in the morning. We packed the car and headed to Rankins Springs near Goolgowi. I had fallen in love with this little town in the middle of nowhere. With about 50 people living in town, it was just a speck on the map at the intersecting of some sealed main roads. What struck me was that it was a place that people cared about. The public places were clean and the grass cut, perfect for preparing a balloon flight.

We found a clear grassed area next to an old Railway water tank used for filling steam engines. The contrast was great – the old and the new. This story is going to be a bit instructive so lots and lots of pictures. First I had my son Jason (9) laidUpLift-1 fill - Latex Gloves out the clean plastic sheet for the filling operation. We placed items in the corner in case a breeze kicked up the corners and destroyed the balloon. We also used Latex gloves to stop acids and other oils from transferring from our hands to the balloon and potentially causing an early failure of the balloon when the UV and other chemicals in the air act on it. We could also have used clean cotton gloves. The problem there was two fold. Sweat from our hands filled the gloves and needed to be changed occasionally to prevent and drops from landing on the balloon. The second problem was that every time we wanted to use duct tape, our gloves stuck very well to the tape! That is me on the left taping the hose to the balloon to protect it and getting the gloves stuck to the tape. There were cable ties under the tape and I used the tape to protect the balloon from sharp edges. The cable ties held the balloon to the flexible PVC tube. I also had the other end of the tube over the balloon fill regulator on the helium tank. That was just sealed with duct tape.

It was then time to prepare the payload. I had decided to block off one of the port holes for the video camera as I wanted this balloon to rise quickly. I was also going to overfill the balloon above specifications to ensure that it would explode a bit earlier than normal. All precautions for a first flight. While we were preparing for the flight, Wally, one of the locals came by on his ride-on mower and remembered me calling in at the petrol / gas station a month earlier. He was excited that we had chosen his town for the launch and APRS Tracker being wrapped in bubble wrapwent off to find the kids in town so that they could join in with all the excitement. Wally was the unofficial “mayor” of the town! A lovely character that obviously cared about kids. The photo on the right shows me preparing the GPS transmitter (Amateur Radio APRS). I am wrapping it in bubble wrap as a thermal insulator to protect it from the cold at the outside air temperature at times during the flight will be between -40 (-40F) and -50C (-58F) or possibly even lower. The capsule is also made from Polystyrene so that too will provide some protection from the cold, but with openings for the camera, there will be some cold air entering the capsule. Care was taken to ensure the dipole antenna (the two gold wires) was mounted vertically in the capsule in the correct place and the small GPS receiver was on top so that it would get a strong signal from the GPS satellites orbiting the earth. The balloon was on a 10m (30ft) cord so that the antenna had no chance of puncturing the balloon. The final benefit was that the capsule would never land upside down so the GPS receiver would always be able to receive satellite signals and report its position once on the ground. Lots to consider. The batteries were also the best that we could buy. Failure was not an option and the cold can kill batteries. We also wanted UpLift-1 Tracker competethe transmitter to last for as long as it took to recover the balloon. The unit was switched on and the receiver in my car was used to checked it was operational and all systems working. The unit reported position, altitude, atmospheric pressure, payload temperature and battery voltage. All parameters where checked and normal. APRS normally will allow you to see the track on the Internet, but we were too far away from any receivers to register. That would only happen when the flight was high enough for the distant receivers to “see” the balloon – once it was high enough to overcome the radio shadow caused by the curvature of the earth, allowing “line of sight” radio signals to be heard. Similarly when we landed, we would lose the signal close to the ground. We were going to rely on the receiver in our car to pick up the transmitter signals and read the location. This would be super important in a couple of hour. More on that later. The photo at right show the transmitter with one layer of bubble wrap. Two more were added with the GPS receiver wrapped to the top – above the side that you can see the unit with care taken to get it the right way around.

UpLift-1 CapsuleThe camera batteries were charged the night before and the camera then required special care. We had it in a sealed box with desiccant overnight to ensure that there was as little moisture as possible in the camera. This would otherwise cause condensation during the flight and fog the images. It was inserted quickly into the housing and the almost closed housing was flushed with helium from the filler hose. This ensured that water in the air was removed and the housing was sealed. The camera was turned on and set to commence taking photographs – the counter on the front began incrementing every 30 seconds. Both the camera and the transmitter were mounted in the capsule. The picture shows the camera in place secured with blocks of polystyrene  and the transmitter in place with the GPS receiver at the top. The payload bay was covered and sealed with duct tape and the capsule was ready to fly. All that waited was to fill the balloon.

UpLift-1 Balloon FillWe had brought a large bed sheet to hold over the balloon in case the wind was too strong for a simple fill. The wind was light and we did not need this, but if we had we would have asked volunteers to hold each corner down while we filled the balloon. The balloon fill was simple, but we needed to measure the diameter to get the fill right. If we under filled the balloon then it might never burst or even rise fast enough and drift long distances before popping. Either way I had made a decision to lighten the payload UpLift-1 measuring the diameterby leaving out the video camera and to overfill the balloon slightly. It was, from the manufacturer’s specifications meant to be 1.2m (3.937ft) in diameter.  I was going to fill it to 1.35m (4.43ft). Since the day was sunny, it was easy to accurately measure the diameter. We simply used a tape measure across the centre of the shadow – perpendicular to the rising sun. This meant that any stretch of the shadow from the angle of the sun would not affect the measurement. In the picture at left you can see that the sun is behind me and Jason is in the right place. The local that was helping just needed to move the measure up closer to the camera to get the final measurement (the photo was a few seconds early). We had the right diameter now and were ready to remove the hose and secure the payload. The helium tank valve needs to be shut off at this point in case the hose gets pulled and the tank either topples or adds more helium to the balloon. If the tank falls, then you could damage the regulator.

This next operation was the most difficult part of the procedureUpLift-1 Securing the neck and the payload. We had already wrapped a cable tie in duct tape to lower the chance of tearing the balloon when inserted. it would secure the nylon cord that secures the parachute and payload. First though, we needed to cut away the cable ties securing the balloon to the hose – all without cutting the balloon. The protective duct tape was peeled away and side cutters were used to sever the heads of the cable ties. This kept sharp edges away from the balloon. That is me on the right cutting the cable ties away (sorry no close-ups). Once the hose is removed then the balloon needs to be sealed and secured. I have no photos of this but the fill tube of the balloon is folded once and then a second time (4 folds thick). The cable tie with duct tape that was prepared earlier was inserted in the middle of the bottom folds ready to secure the payload. I then secured the balloon and and its UpLift-1 ready to launch with help from the locals at Rankins Springsgas with three cable ties above that making them tight around the fill tube. It must be tight to keep the gas in during the flight, especially as the outside pressure gets down to a few percent of sea level and the inside pressure remains the same. I cut the loose ends of the cable ties and used duct tape to keep them from touching the balloon. The cable tie that secured the payload was looped and the payload tied to the balloon. Again duct tape was used to secure the knot holding the payload to the balloon. Nothing was left to chance. The knot used was a bowline and few half hitches – sufficient if you have the duct tape to stop them unraveling. We were ready to launch. The local mission control countdown team were assembled (all but one shy kid and a few adults) and provided the all essential countdown – that’s Wally in he green/yellow safety shirt.

UpLift-1 Launch with Jason BrandIt was a great moment. Rankins Springs’ first near space mission. The countdown proceeded with the kids leading the chant. At zero, my son Jason released the balloon and it was away. Note the old steam engine water tank behind Jason – the old and the new. At about 270 metres the distant APRS receivers saw the balloon’s transmissions and we breathed a sigh of relief that we would be able to track and recover the balloon. We saw the updates every 20 seconds on our smart phones with all the details of the flight. We watched as the balloon stayed in clear view right up to 5km. We kept losing site of the tiny white dot, but the odd reflective glint from the shiny black duct tape brought our eyes back to the tiny 1.35m (4.5ft) white dot up in the clear blue skies of central NSW.  It should be noted, that none of these photos have been altered. They are directly from a number of cameras. The colours have not been corrected! The final job was to pack the car and chase the balloon.

It was serendipity that the first photo snapped by the payload camera at around 270m (900ft) was of the town itself. A wonderful memento of the occasion.

Below is the photo from Rankins Springs. You can click on most of the photos above and below to see a large version of the image (requires that you click through an intermediate page). I have uploaded the image of the town in the highest format possible.

UpLift-1 Rankins Springs 60 seconds after launch

60 seconds after release (below). This photo looking east above Rankins Springs:

Success – UpLift-1 Recovered (Archives)

*** Retrieved from Archives *** Success – UpLift-1 Recovered

UpLift-1 Flies to 26.161km Altitude

A quick update to tell you of our success. My son Jason (9) and I did it – 26km up – 15 miles – For 15 minutes we probably had the highest thing on planet earth. We got about 1/4 the way to space! In the photo at right, that is Jason in the field with the balloon about to launch.

The weather was clear and the skies almost clear of clouds when we launched the UpLift-1 weather balloon from Rankins Springs near Goolgowi in central NSW (Australia). We were an hour late but had about 20% of the town out to help! I think that we were told that the area had about 120 people and Rankins Springs has about 50 residents.

The flight lasted about 2 hours 40 minutes and landed about 4 fields from the road and we had great difficulty in driving to the landing site.

During the flight, the electronics got to -12C (12F) and the outside temperature got down to about -50C (-58F). As it climbed out of the Jet Stream, the atmosphere warms up to a balmy 5C on a good day. The low temperature caused the battery voltage to drop to 5.2v on the normally 5.8v battery. After it warmed up on the ground, the battery voltage returned to 5.8 volts.

The maximum recorded altitude was 26.181km – 85896 feet – 16.2681 miles. More in a couple of days. Some photos below for hold you over until the full story can be posted. The tracking worked perfectly.

Launch Site:

Launch Site - Rankins Springs

Path:

UpLift-1 Fulll Path

Landing site (X):

UpLift-1 Landing site

Recovery:

UpLift-1 Recovery

Rejoicing with a ginger beer (soda/soft drink):

Jason and Robert Brand Recover UpLift-1

One of the recovered photos:

UpLift-1 Camera view

More in a couple of days…

The Space Show (Archives)

David Livingston*** Retrieved from Archives ***

Robert Brand – Guest on The Space Show

Robert Brand was a guest of Dr David Livingston on the Nov 1st 2011 edition of The Space Show. The program disussed Do-It-Yourself Space and was well received by all that heard it. The WotzUp website and the various missions were discussed at length during the broadcast.

The program can be hear by Click Here to Listen 

The Space Show page for the show archive can be viewed by Clicking Here to View

The page details are as follows:

Guest: Robert Brand.

Topics: Australian space history, Save Our Space Systems, old style radio dish antennas, space education outreach in Australia. You are invited to comment, ask questions, and discuss the Space Show program/guest(s) on the Space Show blog, http://thespaceshow.wordpress.com. Comments, questions, and any discussion must be relevant and applicable to Space Show programming. Transcripts of Space Show programs are not permitted without prior written consent from The Space Show (even if for personal use) & are a violation of the Space Show copyright. We welcomed Robert Brand as our guest to discuss space advocacy, space interests, education, and projects in Australia. I suggest you visit and have available the following websites while listening to this program: 1) http://wotzup.com. This site has the tabs and pages for many of the programs discussed by our guest. 2). http://echoesofapollo.com. 3) http://pluscomms.com. Click on the Space-Comms tab. In our first segment, Mr. Brand began by talking about the Global Space Network he was creating by utilizing outdated equipment such as 30 meter dishes that have been abandoned. He described his concept in detail, including costs and the likely customer base. Later in this segment, we took several calls from listeners such as the one by Roger that commented on the outstanding space education outreach projects undertaken by Mr. Brand so we moved along to the topic of kids and space education. Robert talked about 3D lunar photography from Apollo and some of his Middle School outreach projects. Later, Monroe called in to mention Team Prometheus and their satellite project as well as the N-Prize. You can learn more about Team Prometheus at www.teamprometheus.org. Kimberly emailed in requesting Robert share his vision for 21st century space awareness. Robert replied saying “making space everyday for everyday people.” Trent called from Australia to ask Robert what he thought were the greatest space needs for Australia. Robert talked about the need for disaster recovery information, data, facilities, etc. using real time space resources. In the second long segment, Robert directed us to his various websites listed at the start of this summary. We talked about Moon Bounce and Space-Quest, amateur radio , the UpLift project with balloon launches, and more. Robert went through the other programs on www.wotzup.com site including SugarShot, MissionTrax, Kidz-In-Space, and we talked about cubesat swarms and owning your own personal satellite. Later, he told us about his building a satellite tracker in his basement, he talked about holding workshops in his area to promote space education and personally owning a satellite, plus getting kids to take ownership of the technology, research, and data which inspires them with the projects, all of which is part of Do-It-Yourself-Space. Later, we talked about Australian space interests, the Australian space program, and space awareness in Australia. During the last few minutes of our two hour discussion, we talked space history, the Apollo program, the Parkes Radio Telescope, Honeysuckle Creek, the Challenger disaster, Robert’s leaving the industry and then his return to promote space education among kids. You can email Robert Brand at Robert.Brand@pluscomms.com

After you have listened, please post a comment on the following blog for The Space Show:

http://thespaceshow.wordpress.com/2011/11/02/robert-brand-tuesday-11-1-11/

UpLift-1 APRS Tracking (Archives)

APRS – The Best Balloon Tracking Solution

There are many ways to track balloons. There is the Radiosonde, Mobile Phone (3G), HAM radio APRS and many more. Since I both work in Radio Telecommunications and I am a HAM radio operator (VK2URB), then it is an easy choice. The amateur radio APRS system is ideal.

So what are these systems in brief:

Radiosonde: Wikipedia says: “A radiosonde (Sonde is French for probe) is a unit for use in weather balloons that measures various atmospheric parameters and transmits them to a fixed receiver. Radiosondes may operate at a radio frequency of 403 MHz or 1680 MHz and both types may be adjusted slightly higher or lower as required.” This sounds more like a license is required and special Radiosonde equipment is needed.

GPS enabled mobile / cellular smart phones: We all know what these are, but do they work?. Firstly you had better hope that your payload drops in a coverage area. These work by sending an SMS to the phone on the balloon and it then relays its position back to you via another SMS. Mobile telephone coverage in rural areas might not allow you to get a fix on the balloon as it parachutes back to earth. There is also the issue of the GPS receiver. Most do not work at heights over 60,000 feet (20kms) and thus you do not know how high it got or when it is descending. Many people on a tight budget try to use cellular phones and many have great success.

UHF Tracking: Similar to Radiosonde, yet it operates on a low power UHF channel, often used for garage door openers, etc. It transmits the co-ordinates for the GPS location and must be tracked by radios especially set up to receive the transmissions. The data is often ported to the internet for display on a web page. Handheld yagi antennas are directional and look like UHF yagi TV antennas seen on rooftops and are used to track the payload when it is on the ground or in the air.

APRS_TestTrackHAM Radio APRS:This is the choice that I feel best suits the situation and given that I already have a HAM license, then I do not have to ask others to help. What is APRS?: Wikipedia says: Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time tactical digital communications of information of immediate value in the local area. In addition, all such data is ingested into the APRS Internet system (APRS-IS) and distributed globally for ubiquitous and immediate access. Along with messages, alerts, announcements and bulletins, the most visible aspect of APRS is its map display. Anyone may place any object or information on his or her map, and it is distributed to all maps of all users in the local RF network or monitoring the area via the Internet. Any station, radio or object that has an attached GPS is automatically tracked. Other prominent map features are weather stations, alerts and objects and other map-related amateur radio volunteer activities including Search and Rescue and signal direction finding. APRS has been developed since the late 1980s by Bob Bruninga, call sign WB4APR, currently a senior research engineer at the United States Naval Academy. He still maintains the main APRS website. The acronym “APRS” was derived from his callsign.

Note the unusual off-white unit connected with wires in the top picture – it is the special high altitude GPS receiver. It will work up to very high altitudes but sacrifices some accuracy.

The picture above is the APRS Test Track around a street block on a hill near my home. Not precise, but very close. I was shaking the thing as I walked to make it hard for the system. I walked counter / anti clockwise from near the top without shaking and then where it goes a funny in the last quarter of the short walk I was really shaking it wildly. The unit reports on many details. These are:

VK2URB-11 is the balloon call sign

2011-09-10 02:59:41z is the date and time in GMT/Zulu

7 km/h was my walking speed

248 degrees was my bearing

alt 80m was my height above sea level

05.8v was the tracker battery voltage

20C was the temperature – about 70F

The other data is pressure, HHMMSS, and number of GPS satellites, the digipeater used (if used) and the iGate used.

Agilant systems APRS transmitter for balloonsPluses and Minuses

APRS is could always be better and there are not too many iGates (APRS gateways into the Internet) in rural areas, so you must check first. In fact I have chosen to have my balloon drop near Parkes for that very reason. There is an iGate in Parkes and the Digipeater (digital repeater) at nearby Mt Canobolas will also pick up the transmissions from my balloon. I have also chosen an area for good 3Gcellular coverage to assist with tracking and maps. Just to be sure, I will have a digipeater in my car so that if I am not too far away the position will be relayed by my car to the Internet for easy tracking. The unit I have chosen is specifically bought for ballooning. It is from Argent Data in the US. The unit weighs only 160 grams (5.6 ounces). It transmits half a watt (500mW). It is pictured top right and is a pre-release model.

The next issue is finding it when on the ground. Radiosonde and APRS are well suited to this task, but the APRS has a few tricks up it’s sleeve. Fist it might be able to radio its GPS co-ordinates to the Internet tracking system. As I get close with the digipeater, it will also do that job if no other iGates are in range. Secondly it may be picked up directly by my handheld radio, nice, but since it only transmits for 1-2 seconds, it will be hard to get a fix on the unit. Finally I can decode the data with my iPhone and simple read its exact co-ordinates. Nice! That is the directly decoded packets on the right. I did the test inside my house so the GPS coordinates will not be seen.

On the minus side, there is the need for an amateur radio license and access to the expense and homemade equipment that is either out of reach of some people financially or technically.

I also replaced the long general purpose whip antenna that you can see on the top image with a highly tuned light weight dipole. It is made of hollow brass and this also makes it easy to slide some stiff wire inside the antenna for tuning. The wire was then soldered in place to get the tuning very precise. This maximizes the antenna’s radiation ability at the precise frequency of the APRS system. We are using VHF at 145.175MHz. The pictures below show the modification. The work was done by my good friend Bruce who I have worked with on and off for over 40 years. He is also an amateur radio operator (VK2ZZM) and I am very appreciative of his advice and help on the APRS side of this project.

APRS Transmitter dipole antenna

The white Styrofoam under the unit is the lid of the UpLift-1 capsule. The antenna is mounted on a small printed circuit board, The copper wire is used to add strength to the copper on the board in case of mechanical failure that may make the copper peel from the board.

APRS Tracker with dipole antenna - back

The rear side above showing the bolts that pass through to the battery mounts on the tracker unit. A small amount of “locktight” was placed on the nuts to make sure that mechanical vibration did not make them fall off.

Spectrum / Network Analyser tuning the APRS tracker Dipole antenna

This is a state of the art network analyzer. It is measuring Return Loss. Send a signal to the antenna and what is not radiated comes back. The dip means that it is tuned to the frequency and radiating well. It is right on the tracker frequency. The Marker frequency. It is perfectly tuned and radiating the signal – not much is being reflected back into the cable. It is best practice as far as radio is concerned.

I will post a link to the tracker website that I will be using just before the day, but this link will let you see the few test drives that I have done in Sydney: http://aprs.fi/

 

UpLift Weather Balloon Series (Archives)

Balloon*** Recovered From Archives ***

Posted By On 22 Aug 2011.
My name is Robert Brand and I am involved in space missions and Balloon Flights to the upper atmosphere. I don’t just read the space news and I like doing things, so Do-It-Yourself (DIY) Space was a natural. Unfortunately high altitude weather balloons don’t get into space, but they do get a long way up. Many make it over 20 miles / 30 kms and the atmosphere is so thing that it is getting close to space. My son Jason (age 9) will also be a big part of tracking and recovering the craft

The UpLift series is a record of my personal weather balloon launches in Blog form. Here you will find everything that you ever wanted to know about high altitude balloon flights, but in more of a blog form – I simply do not have the time to make it a reference site. I will try and not miss anything important and I expect that for the Australian enthusiast, there will be enough detail to even know how to approach CASA (Australia’s Civil Aviation Safety Authority) for a permit to fly. Some flights may occur outside of Australia, but if they are launches instigated by me, they will still carry the name.

The series will be numerically numbered so UpLift-1 is the first flight.

The flights will normally originate from a point in central New South Wales (NSW). They will use amateur radio tracking and where possible they will involve schools and other educational opportunities. They will carry as much scientific payload as possible and the data will be available on these pages. This will include full flight information, time, height, atmospheric pressure, etc as well as photos and videos.