Breaking Mach 1, but by How Much?

A Zero Pressure Balloon fill_2610Hitting the Mach.

by Robert Brand

The aim of Project ThunderStruck is hitting Mach 1 and a bit more for good measure. Basically breaking the sound barrier. We may reach Mach 1.5, but that will be very much related to the height we reach with the balloon and few other factors. Project ThunderStruck is about Breaking Mach 1 – anything faster is a bonus.

ThunderStruck will rise to 40Km or more for its record attempt. It will need to use a Zero Pressure Balloon capable of reaching 40Km plus carrying a payload in the region of 20Kg including cameras and electronics on the Balloon.

Thanks to http://hypertextbook.com/facts/JianHuang.shtml for the information below regarding Joe Kittinger’s Record Jump in 1960:

Captain Kittinger’s 1960 report in National Geographic said that he was in free fall from 102,800 (31.333Km) to 96,000 feet (29.26Km) and then experienced no noticeable change in acceleration for an additional 6,000 feet (1.83Km) despite having deployed his stabilization chute.

The article then goes on the mention that he achieved 9/10ths the speed of sound and continued to suggest (with maths) that he would have broken the speed of sound with an additional 1,300 m (4,200 feet) of free fall.

If we assume an average acceleration of 9.70 m/s2, it is a simple matter to determine the altitude at which a skydiver starting at 40 km would break the sound barrier.

 maths to calculate altitude at which the sound barrier is broken

That’s an altitude of about 116,000 feet or 35.36Km. So how fast might we go starting at 40km altitude?

maths to calculate the max speed from altitude

Sorry if the equations are difficult to see – that is the quality from the website.

This is nearly 200 m/s faster than the local speed of sound. At the incredible speeds we’re dealing with, air resistance can not be ignored. A maximum of Mach 1.3 seems very reasonable for a human in a pressure suit compared to the prediction of Mach 1.6.

Given that the altitude of the glider release will be 40Km or more, then a top speed of near Mach 1.5 is possible. If we go higher, then we go faster.

Why is ThunderStruck an Aircraft?

Why is it considered an aircraft if it is in free fall with little to no drag? Simply because it is designed to use the little airflow to stabilise itself. Like and aircraft at lower heights uses its control surfaces for stable flight, ThunderStruck does the same. As you might remember from the jumps in the past by Joe Kittinger and Felix Baumgartner, they had serious trouble controlling spin. ThunderStruck will use the exceedingly thin air to control the spin and other forces acting on the craft during its record breaking dive.

After the dive and breaking the sound barrier, ThunderStruck will pull out of the dive under the control of RC pilot Jason Brand (12 years old) and level off, washing off excess speed. It will then fly to the ground under manual control to land just like any other aircraft.

This piece on Felix Baumgartner from Wikipedia:

203px-Felix_Baumgartner_2013Felix Baumgartner; born 20 April 1969, is an Austrian skydiver, daredevil and BASE jumper. He set the world record for skydiving an estimated 39 kilometres (24 mi), reaching an estimated speed of 1,357.64 km/h (843.6 mph), or Mach 1.25, on 14 October 2012, and became the first person to break the sound barrier without vehicular power on his descent.

Baumgartner’s most recent project was Red Bull Stratos, in which he jumped to Earth from a helium balloon in the stratosphere on 14 October 2012. As part of this project, he set the altitude record for a manned balloon flight,[8] parachute jump from the highest altitude, and greatest free fall velocity

The launch was originally scheduled for 9 October 2012, but was aborted due to adverse weather conditions. Launch was rescheduled and the mission instead took place on 14 October 2012 when Baumgartner landed in eastern New Mexico after jumping from a world record 38,969.3 metres (127,852 feet and falling a record distance of 36,402.6 metres. On the basis of updated data, Baumgartner also set the record for the highest manned balloon flight (at the same height) and fastest speed of free fall at 1,357.64 km/h (843.6 mph), making him the first human to break the sound barrier outside a vehicle.

This piece on the Speed of Sound from Wikipedia:

The speed of sound is the distance traveled per unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 342 metres per second (1,122 ft/s). This is 1,233 kilometres per hour (666 kn; 766 mph), or about a kilometer in three seconds or a mile in five seconds.

The Speed of Sound changes with altitude, but surprisingly this is not due to density or pressure, but with temperature!

512px-Comparison_US_standard_atmosphere_1962.svgDensity and pressure decrease smoothly with altitude, but temperature (red) does not. The speed of sound (blue) depends only on the complicated temperature variation at altitude and can be calculated from it, since isolated density and pressure effects on sound speed cancel each other. Speed of sound increases with height in two regions of the stratosphere and thermosphere, due to heating effects in these regions.

You can click of the image  (left) to enlarge the image. For the purposes of this flight, we will be using the speed of sound at sea level.

Will there be a Sonic Boom?

Yes, but it will not likely to be heard. In fact there will be two. One as it breaks the sound barrier and goes supersonic and one again as it slows to subsonic. Givent he size of the craft and the distance and thin atmosphere, it is unlikely to be heard from the ground.

Zero Pressure Balloon Converter

OLYMPUS DIGITAL CAMERAWeather Balloon to Zero Pressure Balloon Converter.

By Robert Brand

Two weeks ago I was a guest lecturer in Aerospace at a Sydney University spoke about the current space projects I am involved in. It was good to see interest from some students to take part in some of the activities. I stayed on to listen to the second guest lecturer talk about high energy particles and there effects on astronauts and also equipment.

Following the lectures I was invited to talk about a difficult project of taking a science experiment to the stratosphere and holding it there for 3 hours. Now this creates a real challenge. It can either be done by a seriously expensive Zero Pressure Balloon (ZPB), shown in the picture at right, or it needs some way of holding a weather balloon below it burst point, both are not ways i would like to think about. Either big dollars or big problems.

My solution is to turn the Weather Balloon into a ZPB before the envelope pops and the lot comes down. I have designed a Weather Balloon to Zero Pressure Balloon Converter. Due to the commercial ramifications, I cannot give the fine details of the specific way we will do this or the materials used, but as you will obviously realise, it means opening up the balloon canopy so the helium (or Hydrogen) stops expanding the balloon fabric thus the balloon should then find a floating point, provided that the canopy is not too elastic.

Since this will require additional weight and we need to get extreme height to be in the stratosphere at a required altitude and we don’t want the risk of the canopy bursting early, I expect that it will require 2-3Kg weather balloons. Not cheap, but way less than ZPB that probably start at a price of US$7,000 or so.

Now for the hard part. We will need to test to see exactly what happens and how to control the eventual height based on gas fill, elasticity of the balloon, the balloon size / weight and the payload size.

The balloon should survive until next morning in the stratosphere when the sun’s UV will cause the envelope to deteriorate along with the punishment it has received during the night. Given that it is not fully stretched, it may in fact last much longer. This will the subject of more testing.

The next problem is that the stratospheric winds run east to west – the opposite of the jet stream – yes there is balance in the world! the difference is (from our experience over Australia) that the wind starts out light and then increases with strength at height. Several times we have seen stratospheric winds reaching 100kph at altitudes of 33.333Km (/3 the way to space). As that is our highest record and we have been involved in flights by others to that height, it seems a fairly linear increase over height and it may get faster at higher altitude. Only tests will tell, but 3 hours at 33.33Km is a long drive. It means carefully planning our launch points and recovery points. In fact we may need to launch on days when the jet stream is fast to drag the payload a long way to the east (say 150km and then allow the winds in the stratosphere to pull it 300Km to the west and allow it to fall back through the jet stream with a big parachute, allowing time to pull the payload back to near the launch point.

With radio cutdown an option, we need to be close enough for that to work on UHF frequencies of to create a HF cutdown on much lower radio frequencies that will travel further.

Weather to ZPB converterAs APRS is not an option on commercial flights, We will use SPOT3 units in gimbals for the commercial tracking. For non commercial flights I have toyed with the idea of using the HAM radio based APRS to upLink commands for cutdown. As a final cutdown I am looking at a time based mechanism to terminate the envelope or cut down the payload. More testing!

As a  teaser, the photo to the right is some of the “plumbing” without the servo and other systems. It is intentionally difficult to see, but the point is that it is off the shelf technology that is very light weight. In fact not all of this mechanism flies – some is only there for the “fill” and another device (not shown) makes the final configuration. When the cutdown occurs, we will lose the servo and the plumbing – a total cost of about US$15. Total weight of equipment lost will be in the order of 200 grams and the balloon envelope will also be able to fall to earth but since it will not be blown to pieces, it will flutter to a soft landing. I expect to have a number of the mechanisms ready and off the shelf to provide services to customers that wish to have low cost long times in the stratosphere. Note, that if we can keep the payload closer to the lower parts of the stratosphere, the drift is negligible from our general experience for a three hour duration in the stratosphere.

Other benefits here are a new easy fill system that requires no more struggling with cable ties at the last moment while holding on to a big balloon. I expect that we will use a smaller version for smaller balloons. The weight is likely to be an additional 50 grams that we can factor in, but the benefits will be great in securing the payload and ensuring an easy and safe tie off in the final moments. Once we test that I will publish the arrangements. More on the Zero Pressure Balloon Converter in future posts.

Pico Balloon Update

Andy Balloon altitude over AustraliaPico Balloon Departs Australia

Andy’s Pico Balloon Update: It has now passed over the bottom of Fraser Island in SE Queensland and out to sea.

Next stop may be South America in a week’s time. We do not expect to hear from the balloon until then, but it may pass over New Zealand or Tonga.

At right is the altitude details from the spacenear.us website. The balloon took about 2 hours to get to just over 8km altitude and because it is a foil balloon and cannot expand, it then sits at that altitude day and night. You can see a small dip as the sun sets until it warms up again the next day. It then rises as the balloon skin expands in the heat. Air pressure will also cause the balloon to rise or fall as will vertical air currents.

The balloon will change APRS frequencies as it crosses different longitudes but the RTTY frequencies stay standard across the world.

Below is the last track of the balloon crossing the coast today.

Andy says that the payload weighs 13 grams or less than half an ounce and consists of:

  • APRS and RTTY transmitters (10mW)
  • A GPS receiver
  • rechargeable batteries
  • solar panel
  • Insulation

The gas is helium and the metal foil balloon should not deteriorate much in a week. The gas also does not leak out very much from a foil balloon compared to a latex or other non-metal balloon.

Note that because the balloon is so light, it is classified as a small balloon and does not need to involve CASA to be able to fly such balloons.

Andy Balloon departing Australia

UpLift-1 Flight Data Pt-3 (Archives)

*** Retrieved from Archives ***

UpLift-1 Facts and Figures 28th Dec 2011 Pt-3

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.

Wind Speed at Altitude

We all know what the weather is like in our own countries and the news and documentaries will often let you know about other countries. I live in Australia on the SE coast. For my high altitude balloon flight I traveled to the centre of my state (New South Wales – NSW) for a number of reasons. Predominantly it was because of the prevailing winds and the flat open farmland. Easier to ensure a clean landing with few trees and no mountains to have to climb. When I say prevailing winds, I am talking about those at all altitudes that my balloon will be passing through. I mentioned that in previous posts that I use a balloon prediction site and that I get a good idea of wind speeds and thus the direction of the flight. The site even outputs the file as a kml file that can easily be opened by Google Earth.

We can easily use the weather service for the ground winds, but the upper level winds can be a bit fickle and not easily forecast by the prediction service, but the balloon does not stay in those regions too long. The main winds that will govern most of the flight as my latitude (-33 degrees – south of the equator)  are those of the jet stream.

Jet Streams (from Wikipedia):

Jet streams are fast flowing, narrow air currents found in the atmospheres of some planets, including Earth. The main jet streams are located near the tropopause, the transition between the troposphere (where temperature decreases with altitude) and the stratosphere (where temperature increases with altitude).The major jet streams on Earth are westerly winds (flowing west to east). Their paths typically have a meandering shape; jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including the opposite direction of most of the jet. The strongest jet streams are the Polar jets, at around 7–12 km (23,000–39,000 ft) above sea level, and the higher and somewhat weaker Subtropical jets at around 10–16 km (33,000–52,000 ft). The Northern Hemisphere and the Southern Hemisphere each have both a polar jet and a subtropical jet. The northern hemisphere polar jet flows over the middle to northern latitudes of North America, Europe, and Asia and their intervening oceans, while the southern hemisphere polar jet mostly circles Antarctica all year round. Jet streams are caused by a combination of a planet’s rotation on its axis and atmospheric heating (by solar radiation and, on some planets other than Earth, internal heat). Jet streams form near boundaries of adjacent air masses with significant differences in temperature, such as the polar region and the warmer air towards the equator.

So what did we find? The following charts shows the balloon flight right up to burst point and also from burst point to landing. It shows the wind strengths that it encountered in kilometers per hour. For reference 40km per hour = 25 miles per hour. Altitude is in meters and similarly 10,000m = 6.2 miles. The chart showing descent should be similar but the rate of fall is exponential and not linear so there will be some compression and expansion of the horizontal axis. Due to the fall taking 1/3 the time of the climb there will be fewer plot points and also a greater potential for GPS inaccuracy.

Wind Speed vs Altitude - Climb

Wind Spped vs Reverse Altitude - Fall

In the chart below I have labelled the major points of change in the chart. Of interest there were three layers of wind prior to the balloon entering the jet stream or streams. The major point of interest was that there were two jet streams both traveling in the same directions. The winds of the troposphere were approximately half of the strength of the jet streams and in the opposite direction by chance. If the balloon had made it to higher levels in the troposphere, it may have encountered other wind directions, but the winds may have been much lower in strength.

Wind Speed vs Altitude - Climb - modified

Air Pressure and Altitude

The chart below shows plot points and both altitude and air pressure in Pascals. Pascals for those in non metric countries are defined in Wikipedia as:

The pascal (symbol: Pa) is the SI derived unit of pressure, internal pressure, stress, Young’s modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre. In everyday life, the pascal is perhaps best known from meteorological barometric pressure reports, where it occurs in the form of hectopascals (1 hPa ≡ 100 Pa) or kilopascals (1 kPa ≡ 1000 Pa). In other contexts, the kilopascal is commonly used, for example on bicycle tire labels. One hectopascal corresponds to about 0.1% of atmospheric pressure slightly above sea level; one kilopascal is about 1% of atmospheric pressure. One hectopascal is equivalent to one millibar; one standard atmosphere is exactly equal to 101.325 kPa or 1013.25 hPa or 101325 Pa.

Simply at sea level there will be 100,000 Pascals (left side of graph and the start of the plot from the balloon). Air pressure (Pa)  is plotted in red and altitude (m) in blue. The rate of climb is near linear while air pressure is more exponential. Note that the initial rate of climb on the left corner is high as it appears that we were in a thermal or rising air mass.

Altitude and Air Pressure

That concludes the science breakdown of the flight. there are plenty of more breakdowns of the data that can be carried out, but in this and the previous 2 posts I have explored most of the more relevant information that can be derived from the flight. My next post will provide access to the data from the flight.

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: