Project Diary

September 2011 - May 2012

by the STRATOS Team: Hannah Jones, Larissa Taylor, Lucy Whittaker,

Mary George, Connor Durkin, Vijay Jackson

Contents

September 2011 -

Background information and in-depth

explanation of the project, with problems

that the team must solve.

October 2011 -

Project Outline -

December 2011 -

January 2012 -

May 2012 -

Evaluation

Photos from Near-Space -

Early research into Near-Space photography,

leads to the proposal of the project to teachers and

governors of St Richard's College for funding.

Assembling the team and assigning roles, coming up

with the name of the project - STRATOS - and the

evolution of the logo.

2 pages of equipment designing, planning, buying,

assembling, testing and descent speed calculations

needed for the project, with methods shown.

Engaging the lower school years by presenting in an

assembly and holding a poster competition, plus

application to the CAA for balloon release approval.

Overview of Launch day - the payload

preparations, the launch, and retrieval.

Selection of the best photos

taken by the STRATOS camera

during its 4 hour flight.

STRATOS captured

this photo!

STEMfest & ESAS -

We competed at Big Bang South

East, presented to the East Sussex

Astronomical Society, and have

been invited as a Featured Exhibitor

at Crawley STEMFest 2013

<" >"Project Outline September Contents

Background In early September 2011, St Richard's student Hannah Jones chanced upon an article on the Telegraph's website which caught her eye. The title read "Teens Capture Images of Space with £56 Camera and Balloon" - with an incredible view of the Earth's curvature attached. The article continued... "Proving that you don't need Google's billions or the BBC weather centre's resources, the four Spanish students managed to send a camera-operated weather balloon into the stratosphere."...

The Project The key idea behind Near Space Balloon photography is relatively simple: By attaching a parachute and lightweight payload (inside: a camera set to take photos at short increments and a GPS device) to a helium-filled weather balloon, the balloon will ascend until the gas inside expands so much due to the lower outside pressure, that the balloon reaches bursting point at a high altitude, and falls back down to Earth. The parachute slows the descent to a safe speed, and the payload is retrieved by tracking the GPS coordinates of the device inside, allowing the photos to be recovered, and the equipment reused.

However, there are many problematic variables that must be taken in to consideration when designing the payload and launching the balloon:

• At 100,000ft (the bursting altitude of a 600g weather balloon), the outside air temperature is -60° Celsius, meaning the payload must be sufficiently insulated to protect the electronics inside.

• On the way up, turbulence and wind speeds will reach up to 100mph, so the contents of the payload must be protected from rough conditions.

• The batteries of the camera must cope with the cold conditions and last to take photos continuously for up to a 4 hour flight.

• The size of the parachute and balloon, weight of payload, and amount of helium in the balloon must all be calculated and balanced to ensure the balloon reaches the target altitude of 100,000ft and the parachute slows the payload down to a safe speed, around 5m/s.

• The high chance of a water landing means the payload must be waterproof, but not air-tight since if the expanding air inside the payload has no way to escape, the payload will explode just as the balloon does.

• In the case that the payload lands in an area with no GPS reception and is found, a letter must be included with information to return the contents.

Flight Path Prediction Being able to predict where the payload should land is crucial for deciding whether to go ahead with a launch or not. Even if there is no wind on land, the winds in the jet stream could be very strong. Fortunately, there are online high-altitude balloon flight path predictors. You need to input the time, day and location of launch, and balloon parameters such as size of balloon, amount of helium and payload mass to run the predictor, as shown below:

From original proposal document:

"After further research, I discovered that this is indeed possible to do on a small

budget, and I feel it would benefit students and the college if we were to do it here at St Richards. It is a scientifically fascinating opportunity for St Richard's to capture photographs of the curvature of

the Earth like this."

Balloon & Helium Of the several types of meteorological weather balloons available, a ‘Sounding’ balloon is required for the extreme bursting altitude - around 100,000 feet (30,000 metres) when filled with 1.81 cubic metres of helium gas (a 'V' sized cylinder). A 600gram balloon was chosen to get a high bursting altitude with a small amount of helium. The diameter of the balloon at launch is 1.5 metres, and at burst, 7 metres across. Helium gas is used rather than hydrogen because it is safer to handle. Parachute To slow the falling payload to a safe speed on descent, the parachute must be at least 24" in diameter, since the payload weighs 600g. We calculated the descent speed of it using these values in December 2011. GPS Tracker To locate the position of the payload when it reaches the ground, a GPS device is contained and contacted to make it relay its coordinates, allowing the retrieval of the payload and its contents. Our unit used SMS to communicate.

Insulation and Protection The package used was a polystyrene dry-ice container measuring 27 cm w x 24 cm l x 25 cm h. Polystyrene was ideal because it is lightweight, insulating and protective. Newspaper was scrunched up and placed inside to further insulate the equipment and offer protection from knocks and sways, keeping the contents in place.

Camera A Canon A550point-and-shoot camera was used because it is able to be "hacked" with open-source CHDK software, giving it the ability to be programmed to take a photo every 10 seconds, something other cameras are not able to do, and crucial for STRATOS. A video recorder would be too expensive for our project and not worth the risk losing in case of water landing.

Hand Warmers and Silica Sachets Special iron oxidising hand warmers were used in place of liquid ones because they last for up to 7 hours of +70°C heat, as opposed to 30 minutes, to combat the -60°C temperatures outside. Silica sachets absorbed moisture produced by condensation because of the heat.

Inspired by this, Hannah further researched in to the experiment she had just discovered. She found several online communities who discuss something known as "Near-Space Balloon photography", where motivated hobbyists send cameras attached to weather balloons to "near space" to take photos of the Earth, and hope to retrieve the camera when it lands. The further she investigated, the more she found that the project could be done on a small budget by a small team, and wield stunning results as well as being educationally beneficial. With hopefulness, she proposed the idea to her science teacher, Dr. Durkin, who enthusiastically reassured her that she would speak to the governors at school to get funding for the project. A presentation by Hannah later, and funding was approved - a team assembled, and a plan devised! This diary will follow the events from planning in September 2011, testing, and launch in May 2012, followed by an evaluation of the outcome.

The Equipment

Input data...

Run predictor...

Map shows path prediction...

<" >"September 2011 October Project Outline

Research - Early Stages and Planning In early September 2011, project leader Hannah Jones chanced upon an article on the Telegraph's website which caught her eye. The title read "Teens Capture Images of Space with £56 Camera and Balloon" - with an incredible view of the Earth's curvature attached. It explained the experiment, known as "Near-Space Balloon Photography" vaguely, but focused on the fact that it had been only a couple of students who had achieved it. Taking inspiration from them, Hannah searched for more information online, and found several videos of other people's attempts at this, some of which had worked to give spectacular vistas of the Earth; and

others which had failed, floating off-course or landing in the sea. She found an online community, known as UKHAS, who describe themselves as "a loose collection of people who are interested in launching unmanned high altitude balloons into near space", with a website offering guides to help people in their

own ballooning endeavours. However, the guides focused on "radio tracking" more than specifics about the payload and camera - something which is left for the individual team to work out. Each launch is unique - and each photo from every successful flight is stunning. She recorded information such as balloon suppliers, helium gas suppliers and costs. However, to create a viable project proposal, she needed to make sure that she had all the information needed so that there were

no surprise loopholes that could not be passed at a later date, for example, where to obtain the required Civil Aviation Authority approval? She emailed members of the UKHAS, and received an official "Application to Release" document in reply. Spurred on by this research and information that "a basic flight can cost less than £200" with just a small team, Hannah put together a document of her findings (first page shown on the right) - proposing to her science teacher that the school should fund a Near-Space Balloon Photography project as a Gifted and Talented project. Her science teacher, Dr Durkin, enthusiastically reassured her that she would speak to the governors at

Proposal - Presentation to Get Funding After discussing the project with Dr Durkin (the original brainstorm shown on the right), it was clear the space balloon project (as it was called then), would be great for the school because:

• The unique outcome would be treasured and displayed around the St Richard's - enhancing the school's status as a Specialist Science College,

• It would require the G+T Team to do complex mathematical equations (e.g. parachute descent speed) and problem-solving (eg. how to ensure that the parachute does not tangle, and expands on descent), therefore using the group's scientific knowledge to our advantage.

• It would be aspirational and exciting to the lower years, getting them interested in Astronomy, a new GCSE course offered in Science.

• We could get the lower years (Y7 and Y8) involved by presentations in their assemblies, and offering a poster competition with a prize.

• If the project is successful, most of the equipment can be reused, taking in to account a full evaluation of the previous launch. These points, along with an outline of the project itself were put together in a presentation to show to the governors at school:

The governors showed great enthusiasm for the project, and approved it right away - their only main concerns being a water landing (meaning the photos would not be recovered and equipment lost), the slim but all to apparent chance of the payload coming down on someone's property or on a road causing injury, and timing: with the planned launch to be near the exam season in June 2012 (launch delays taken in to account), it was clear that the project would have to be done before the exams begun to allow full concentration, and aborted if need be.

The next step was to gather a team, assign roles, think of a name and design a logo for the project...

"We're a loose collection of people who are interested in launching unmanned high altitude

balloons into near space."

Hwoyee, Balloon Supplier: BOC, Helium Supplier:

<" >"October 2011 December September

The Team - Assigning Roles and Brainstorming Ideas It was on a routine Thursday lunchtime meeting of the small St Richard's Gifted and Talented in Science group, that the space balloon project was first announced. Project leader Hannah Jones showed the group a version of the governor's presentation, altered to include a list of tasks which needed to be done. Roles were assigned according to the person's skills, shown below:

Lucy Whittaker - Landing Prediction Mary George - Calculations Hannah Jones - Team Leader and Researcher Larissa Taylor - Payload Design Connor Durkin - Project Name and Social Media Vijay Jackson - Logo Design and Camera Hacking

Naming the Project

Logo - Design Evolution

It was decided by the team that the name of the project needed to memorable, clever and recognisable, and linking the space balloon experiment to the school's name seemed like the perfect idea.

"STRATOS" was one of the first ideas we came up with, and although other names were considered (e.g. Project Aether, which in Greek mythology is the God who is "the personification of the upper sky, space, and heaven" - STRATOS seemed better because of its link to the Stratosphere, where the balloon would reach and burst. The acronym itself stands for "St Richard's Adventure to Observe Space", where "Adventure" was originally "Aim" - changed because Adventure connotes more excitement!

It was soon discovered that "Project Stratos" was already the name of a near-space balloon mission from a few years ago - so Vijay suggested we rename ours to "Operation Stratos", and the name stuck. Operation connotes more importance in the event - an individuality that "Project" does not.

S T. Richard's Adventure To Observe Space

Although Vijay was tasked with creating the logo, the whole group was asked to design a logo once the name had been thought of. A variety of designs were made - shown below:

Connor registered a Twitter account for people to follow STRATOS news, advertised on a school board outside the science labs. It was to be used for launch dates and general blogging. We were able to mention Herstmonceux Science Centre's Twitter account (@Observatory_Sci) and get a retweet for them to spread news about the launch.

Connor's was too bland, does not hint at what the project is about.

Larissa's concept was the first to include the full expanded acronym in the logo - something that the team felt was needed in the final design. However, the lack of colour made it feel too 'cold' and thus not reflective enough of the project as a whole.

Mary's concept integrated the balloon as the 'O' in STRATOS - innovative, but the team considered it too confusing for people who did not know the name of the project. However, this design included the first white Earth at the bottom left design element, which was incorporated in to the final logo. Shown in the top left was the original scanned drawing. Under that, an inverted copy, and to the right, the final Computer Aided Design version.

The team very much liked Vijay's original design, inspired by NASA's mission insignias - the badge reflects the purpose of the project and is clean. The first version, to the left, the team felt was too simple - so shadows were added to the Earth, a Union Jack for colour, and finally the balloon assembly itself to the final design. The date was also updated to match the final launch date.

The final logo was chosen because it incorporates all of the favourable design elements of the previous logos. It shows the full acronym along the bottom in the Earth, includes colour (the Union Jack), reflection of "STRATOS" to add a dynamic edge, and most importantly, the balloon with a simplistic though recognisable camera hanging from it, to instantly show what the project aims to do. The font is "Expletus Sans Bold", which has been consistently used as the brand font across the STRATOS project because of its modern, space-like feel. The logo has been used on documents, this diary, and the messages within and on the outside of the payload itself.

<" >"December 2011 Continued October

Buying Equipment and Testing

v = vertical descent velocity, here expressed in ft/sec (English) or m/sec (Metric)

w = weight of the parachute + load, in pounds (English) or Newtons (Metric)

rho = air density, near sea level its value is given by 0.00237 sl/ft^3 (English units) and 1.225 Kg/m^3 (Metric)

dc = parachute drag coefficient which is approx 0.75; same value in both Metric and English units.

s = total surface area of the parachute fabric

The team had settled on purchasing a "StormGuard Tap Cover", used in winter to protect taps from freezing conditions. Its insulating properties and light weight made it ideal, and it had been used in another ballooning mission, as shown, with great success. However, after buying one for STRATOS, we discovered that its dimensions were not large enough to house the camera we had to use. By chance, after a dry-ice experiment in a science lesson, the science technicians had a spare polystyrene dry-ice container which caught our eyes. Although rather large, at 27 cm w x 24 cm l x 25 cm h, and quite heavy, it was perfect for use because of its thick walls, measuring 4cm, giving it superior insulating and protective properties.

To allow the camera to have a horizontal view of the outside and be housed securely within, a hole measuring 5.5cm in diameter was cut through the side of the polystyrene box, at the level of the lens of the camera when on the floor of the payload. Velcro was stuck to the inside walls and relative positions of the camera to ensure that it would remain in place when the package severely rocked, as it could do in the stratosphere because of turbulence.

To protect the camera's sensor from harmful UV radiation and act as another layer of insulation from the -60° celcius outside temperatures, the team decided to glue a UV Filter (shown on the right) in the hole on the side of the payload. We conducted tests to ensure that the glue did not react with the polystyrene, as most glues do. The seal was also tested for its water-proof abilities in the case of the water landing - so that water would not enter the payload through it. Condensation and reflection of the lens on the filter was considered, but not deemed threatening enough to remove the filter.

During online research, Lucy found a data table which matches the size of the balloon and weight of payload with the ideal parachute size. In our case, a 600g balloon and 600g payload, a 24" "ripstop" rocket parachute was recommended. To ensure that it is strong enough to carry the 600g payload, we conducted testing which included filling a cylinder with 700g of play-doh (to allow for a margin of error on launch day) and dropping it from the third story of our school building, as shown to the right. The parachute inflated quickly, survived and slowed the descent to a safe speed - the cylinder did not break. However, the team was not satisfied with not knowing the exact speed at which the payload should be slowed by the parachute at ground level (this calculation was also needed to improve the accuracy of the flight patch prediction):

The finished payload. Visible hole, lens and UV filter, and gaffa tape to secure the rope.

After finalising the name and logo of STRATOS, the next step was to use Hannah's research from her proposal to buy the ideal equipment for project. Using other people's launches as examples, the team evaluated the success of particular components, to ensure that STRATOS had the best chances of success. Next, we needed to test the items - and rethink some ideas.

The camera itself is a Canon Powershot A550, donated to us by the school's Technology department in return for a new camera which matched its specifications. We had to use this camera because it was the only one available at a cheap price and that is able to be "hacked" with free software called "CHDK" (which stands for Canon Hack Developer Kit) to give it extra abilities that are crucial for STRATOS, and not available in other commercial cameras. Vijay was tasked with installing this software on the camera by formatting and installing it on the camera's memory card. He also wrote the code for a 'timelapse script', which allowed the camera to take a photo every 10 seconds. The operation of the software is confusing to use, and Vijay wrote instructions for Hannah on how to use it for launch day since he could not be present. The team decided that

an effective way of conserving battery life was to switch the LCD display on the back of the camera off during the flight - so this meant having to use the software on the camera without the screen - therefore the each step of setting the camera to intervalometer mode had to be remembered off by heart. The camera was also stress tested for how long it could take photos continuously on a full set of batteries. On the left is shown one photo of thousands that it took of a clock to show that a) the camera functioned properly and b) it took the photos every 10 seconds.

Since normal lithium-ion batteries decrease in battery life in very cold temperatures, it was important to find an alternative to these. As suggested by the UKHAS community, we were able to source "Energizer Lithium" batteries. -> These fair far better in extreme temperatures, and reportedly last 8x as long as regular batteries - perfect for multiple hours of continuous usage.

Camera Operation - CHDK and Batteries

Cutting Viewing Hole in Payload and Adding UV Filter

Parachute Calculations and Testing

Method using metric units:

w = 6.377N (weight of parachute, 50g + payload weight, 600g) = 650g converted to Newtons (650*9.81))

rho = 1.225 kg/m3

dc = 0.75

s = �*r2 = pi * (d in cm/2) = �*(60.96/2)2 =�*30.482= 2918.63cm2 Final equation: ! = 2 ∗ 6377

1.225 ∗ 0.75 ∗ !2918.63

! = 2!!ℎ!!!"!!

Cutting Viewing Hole in Payload and Adding UV Filter

= 127542681.49 = 4.76m/sec

Descent speed =

<" >"December 2011 January Continued

The team also brainstormed the likely event of a water landing. The polystyrene box would stay afloat, however it water would enter the payload through small holes

drilled through the side of it so that the payload is not air-tight, as explained earlier. We decided the main piece of components to keep dry was the one used for retrieval

of the equipment: the GPS Tracker. Connor suggested a waterproof camera bag to house the GPS in during the flight - and the team agreed (shown right is the final way the device was packaged, velcro'd to the wall of the payload and sealed with gaffa tape).

Choosing the size of the balloon and the amount of helium needed to inflate it to reach its target altitude was something we also had to calculate. If we opted for a bigger balloon, it would mean we would have to fill it with more gas to reach and burst at the same 30,000m height than a smaller balloon, since the latex can stretch more. This would allow for a faster ascent, but would increase the cost of the equipment substantially. We calculated that a 600g balloon filled with 1.81m3 of Helium (the size of a full "V" canister) would allow the balloon to reach its target altitude, with a 4.46m/s ascent rate.

Since the temperature difference between the inside of the payload and the outside was high - low outside, high inside due to handwarmers, the possibility of condensation forming on the UV filter (blurring images) and internal circuits in the electronics (damaging them) was considered. To combat this, we placed several silica sachets inside the payload to absorb excess moisture that was produced. We placed them at different levels in the payload - bottom, a few by the camera, middle and top of the newspaper layers. We stuffed the payload with crunched up newspaper to keep the components in place, and act as insulation - however, the possibility that too much newspaper could restrict the air circulation within the payload and lead to hot spots that could damage the electronics (upwards of 70° C) was evaluated, so we were careful not to scrunch the newspaper up too tightly.

Attaching the Parachute to the Rope

Attaching Rope to Payload Larissa dealt with the best way to attach the nylon rope that goes from the payload up to the parachute/balloon, to the payload container. Gaffa tape was quickly recognised as the easiest way to attach it without compromising structural rigidity (for example, as cutting slits through the polystyrene would). Stability of the package also had to be considered, and an early (and indeed final) design was drafted on paper, as shown. This ensured there was only one rope that holds all sides of the box level at all times, looping through the curtain ring about half a metre above the container - only requiring one knot to be used, so there are fewer weak spots in the design.

A problem that the team had difficulty with finding a solution to was the issue of how the parachute itself would attach to the 10m rope that leads from the payload

to the balloon - and make sure that it doesn't tangle, fall down or tear during the ascent and descent. This has not been documented online, and so we devised our very own method. Mary suggested tying a washer to a point on the rope, just below where the parachute is when at its highest position, as shown on the original diagram to the right. This would ensure that the parachute does not fall down during ascent, and still be able to inflate fully on descent. A hole in the top of the parachute also allows the single rope to thread from the payload to the balloon with no

weak spots, and exerting no force on the parachute when ascending, since it is in a resting position.

Washer

Choosing Size of Balloon and How to Fill with Helium

Silica Sachets, Newspaper and Handwarmers

Rather than using regular liquid crystallising hand warmers - which last for only up to half an hour at a warm temperature, the team did research and found hand warmers better suited for STRATOS - Air activated iron hand

warmers, shown on the left. They contain cellulose, iron, water, activated carbon (to speed up the reaction), vermiculite (water reservoir) and salt (catalyst) and produce heat from the exothermic oxidation of iron when exposed to air. They typically emit heat for up to 7 hours, at 70°C.

Because the nozzle of the helium canister is thin relative to the large balloon neck, we had to make sure that no gas would escape whilst filling the balloon. Using hot-glue, Hannah sealed a plumbing rubber tube and loop of rope (to tie ballast to hold the balloon down in the case the balloon is let go of prematurely) to a piece of plastic that had previously been used as a "water bottle tornado", as shown - it attached perfectly to the neck with the help of lock ties and gaffa tape.

A Civil Aviation Authority requirement for the "Air Navigation Order 2005, Application to Release Unmanned Meteorological / Research Balloons" states that on the package must be written in large font, "HARMLESS SCIENTIFIC EXPERIMENT". Shown on the left is the final STRATOS payload, with this information included.

Buying Equipment and Testing Continued

<" >"January 2012 December

Lower School Involvement As part of our goal to inspire younger pupils to get involved in science beyond the curriculum, in January 2012, the STRATOS team began to spread the word of our project to the Year 7s and Year 8s. Hannah and Connor did presentations to Year 8's in two of their weekly morning assemblies, telling them about STRATOS - what it aspires to do, how it will do this, why it is exciting - and how Year 8s can get involved.

They could get involved in one of two ways: by either coming to the weekly STRATOS meeting on Thursdays in Lab 6, Dr Durkin's Lab, or by creating a poster for STRATOS - with the best poster winning the student a chance to attend the launch. On the right are shown two examples of poster entries we received:

The presentations in the lower school assemblies were scripted by Hannah, and tailored to the audience. The slides focused on the exciting basics of the project, so as not to bore the students, and the script was interactive with the audience. Some slides and their scripts are shown below:

The Civil Aviation Authority's application to release a meteorological weather balloon document (left) states that the CAA must be notified 28 days prior to launch, for time to be given to officially approve the flight. The team sent the original application in early December, and were told that any later launches from the same location would be easier to approve, and only need a week's notice. We applied for release for most weekends in January - however, each weekend, the online fight predictor showed the balloon being blown off course in to the sea - not a safe flight. This meant postponing the project further and further.

This was a 31 second video Lucy created, showing the year 7/8s the predicted real life video version of the STRATOS.

French Payload Message

Official approval letter from the CAA dated 11 May 2012, which had to be kept in-hand on the day of the launch.

Why Launch at Herstmonceux?

It was hoped that launch would go ahead during January - well ahead of exam season, because the team and equipment was ready. In the eventuality of a foreign landing, we contacted a French teacher, asking them to translate a message we had written to place in the payload: asking for the memory card of the camera to be returned back to the school if the payload was found on French soil. This was an example of planning ahead and seeking the right information using local resources - the reply from the teacher is on the left, and final payload message (with St Richard's header and STRATOS logo) shown on the right.

CAA Approval

Herstmonceux Science Observatory is a world renowned centre of astronomical discovery. It housed some of the world's largest telescopes built in their time, and is used to map star positions, monitor solar activity and keep the national time service (the observatory's atomic clocks were used for the BBC to broadcast the "six-pips" every hour). The geographical location also means it is inland and surrounded by flat, open terrain, with few tall trees surrounding it. The scientific connections of our project meant the staff were more than happy for us to launch on one of their fields early on a weekend morning, and we thank them for their assistance!

May

<" >"May 2012 Photos January

Launch - 9am, 12th May 2012 It was at this date and time that the STRATOS team arranged to meet at Herstmonceux Observatory Science Centre to launch our near-space weather balloon photography project.

Earlier in the week, we received news from Lucy that the online flight path predictor showed a definite land landing in France - and with the first Year 11 exam the next week, it was as good an opportunity as ever that we should launch the balloon. Shown below is the final 4hr flight path prediction on the day/time of launch.

Connor was to bring the helium canister, and Hannah to bring the tarpaulin, CAA approval, checklists, balloon and payload/equipment ready assembled for launch (apart from the camera and seal of the payload, as will be discussed). The entire launch went smoothly, and the team worked as a great unit, each with different roles. Below is a step by step run-through of the things that had to be done on the day:

• Met up at the scheduled time, 9am, at Herstmonceux Observatory Science Centre. • Set tarpaulin out on ground (to ensure the balloon did not burst on something sharp on the grass), and weighed it down. • We set out all the equipment on tarpaulin, making sure no tangles formed in the rope or parachute. • Next, Connor and Mary attached the helium canister nozzle to the filling tube, and the other end to the neck of the

balloon, using gaffa tape and cable ties to secure. A sand bag was also tied to the filling tube and balloon nozzle to ensure

the balloon did not float away if let go. • Payload preparation process: • Mary and Lucy crumpled newspaper and inserted a handful of silica sachets in to the payload. • Hannah checked the GPS was functioning by sending it an SMS and checking that the reply matched their current coordinates. • Connor next inserted the GPS device in to the waterproof bag, and Velcro'd it to the inside wall of the payload container. • Hannah repeated the memorised CHDK actions with the camera's display off to set the camera to take photos every 10secs. • A bottle cap was taped to the top of the camera last minute as an attempt to prevent any newspaper accidentally hitting the shutter button, stopping

the photos being taken. • The UV filter was then cleaned to make sure there was no dust or fingerprints on it which could affect the quality of the photos. • The camera was then placed in the payload, held by a piece of polystyrene to hold it against the wall, and Velcro so that it did not fall up or down. • Two iron handwarmers were opened and placed on the bottom of the payload. • The crumpled newspaper was carefully inserted around the camera and GPS, being careful not to press any of the electronics buttons. • The next two handwarmers were placed in the middle of layers of newspaper to ensure an even spread of the heat. • The English and French payload messages were added to the top of the inside of the box, as shown - the last thing to be placed in the

payload. • The camera was checked to be working as every 10 seconds, the shutter faintly closes and opens, showing it is taking photos • The payload was then securely gaffa taped shut.

• Meanwhile, when balloon has been filled with all the helium in the V-sized canister, the filling attachment and tube are removed, and neck of the balloon closed using cable ties and gaffa tape, winding the rope from the payload to it at the same time to ensure a tight knot, as shown.

By using the checklist, everything had been sorted, and launch was ready. However, not everyone was prepared for a gust of wind that took the balloon out of the hands of the team holding it, and launch on its own accord. There was a scramble to hold down the payload and parachute, but the wind took the balloon, and, after narrowly missing some trees, STRATOS was launched on its 4 hour journey up to 100,000ft, and down again to somewhere in Northern France, taking photos along the way.

Retrieval in France The flight predictor stated that the total flight time should be 3hr 55 minutes, and that the balloon should land near Fauquembergues in North-West France. Project leader Hannah Jones decided to travel to France by a cheap ferry to retrieve the payload - which meant leaving as soon as launch had happened. Arriving at Dover just in time for the ferry, spirits were high as (nearly) everything had gone to plan so far - the exception being the sudden gust of wind and narrow miss of trees, but even they worked out in our favour. Coming up to 4 hours since launch, Hannah tried to make contact with the GPS device in the payload for the first time. However, the device "could not be reached". Countless times she tried calling, and yet nothing was relayed. By the end of the ferry journey, spirits were low, since if the GPS could not be contacted there was no chance of finding the payload and the team would just have to wait - and hope - that a French person would find it and call the school.

On leaving the ferry, Hannah tried calling the GPS again, and this time, the ringing didn't get cut off as abruptly. Shortly later, a text message was received on her phone (shown). The GPS device had sent its coordinates! On clicking the map link, STRATOS was in a field just one hour away from Calais! We rushed to get there before someone found it, anxious with anticipation. We parked off the road in a rural area, 100m away from where the coordinates were pointed. We

could see something white in the distance - could this be our payload? We walked through the maize corn field, only to find that the white speck was a milk bottle used to scare away birds. Again, spirits were low, but Hannah tried to contact the GPS once more, and this time received new coordinates, 200m away from their current location.

When they were about 50m away from the new coordinates, Hannah noticed something orange and yellow on the ploughed soil. It was a moment of joy - and shortly after sprinting towards it, the full payload,

parachute and remains of the balloon became quickly visible. STRATOS had been found, 200km away from its launch site early that morning! The next step was to take it to the car, and open the payload up to see if the photos had been taken. On opening the payload, a blast of hot, moist air from inside was felt - the newspaper was hot, silica sachets dripping with water. It was immediately clear that condensation had formed, but that was little reason to suspect that the photos had been affected too greatly. Hannah took the camera out, and switched it off and on again to turn on the display. The last photo it had taken was just before hitting the ground - and zooming out to reveal all images showed it had taken 1000s of spectacular photos from of the curvature of the Earth - an astounding achievement for the STRATOS team, and whole school community. Every care was taken to make sure the memory card was not lost or stolen on its way back to Engand, of course!

<" >"Photos from Near-Space

May

The camera took a total of 1,486 images on its flight, one photo every 10 seconds, so was therefore in the air for 14,860 seconds, /60 to

convert to minutes = 247.66, /60 to convert to hours = 4.13 hours (the total flight time). Below is a selection of the STRATOS camera's best

photos starting with its first and ending with its last, plus a panorama made by the team using Photoshop:

Evaluation

<" Evaluation Photos

Condensation on Camera Filter

When Hannah received the initial coordinates from the GPS tracker after it had landed, they were 200 metres off from the actual resting position, as noted in the Retrieval story on a previous page. This discrepancy could have been due to poor signal strength of the GPS Tracker, a GoTek 7 (as pictured). We could have improved its ability to capture faint signals by coating the inside of the payload in tinfoil, thereby producing a metallic bowl within which the tracker could sit, acting like a satellite dish. We would have to practically test this theory first.

Of the 1,486 photos taken during the 4hour flight, over 1,000 came out like this:

Midway during the ascent, just above the cloud layer, condensation formed on the inside of the clear UV filter between the camera lens and the outside of the payload. The UV filter had two uses: to protect the camera's sensor from harmful UV radiation (making for a clearer image), and secondly to act as barrier to protect the camera from water in the event of a water landing. Condensation forming as it did was considered, and we took steps to prevent it: by adding silica sachets to the payload to absorb excess moisture, as we have not seen that done on previous projects during research. The team has decided that, if the project were to be done again, a UV filter would not be attached because of this potential for condensation forming on the cold glass surface, and the disadvantages it brings outweighing the advantages - cameras do not get damaged by the UV radiation, as proved by online research in to other near space balloon flights that do not use these filters, and they do not protect from water effectively since water would find other ways in to the payload.

Silica Sachets - were there enough?

Handwarmers - too many? Timelapse Interval - too slow?

Accuracy of landing spot prediction - What went wrong?

How could we have logged extra scientific data?

Launch checklist not complete?

Could we improve the accuracy of the GPS device?

Now that we knew condensation causes problems (and that moisture forms in the payload so considerably that the entire payload was damp inside when Hannah opened it in France), we had to evaluate how many silica sachets we included in the payload, and

the positioning of them. 5 small sachets were dropped in before launch, all placed along the bottom. In hindsight, this was a unwise choice because the limited circulation of air together with the small number of sachets meant that water formed in pockets of the payload that are not near the silica sachets, such as the area between the lens of the camera and the UV filter

resulting in the photos above. Next time, we would place at least 3 times as many silica sachets for good measure, spacing them evenly between the layers of newspaper (such as we did with the handwarmers) to reduce dampness inside the payload and reduce chance of damaging the electrical equipment.

Handwarmers were essential to keeping the contents of the payload warm (and therefore electrical equipment such as the GPS functioning correctly). However, the polystyrene's insulation properties would have reflected the heat produced by the hand warmers (70°C) back in to the payload, keeping the coldness out regardless. This worsened the condensation problem because of the heat difference between inside and outside and limited air circulation due to the tightly packed newspapers. We included 4 handwarmers in the payload because we did not have this hindsight and, after consideration, we have decided that if STRATOS were repeated, we'd use fewer handwarmers.

The length of time between each photo being taken by the camera in the STRATOS payload was set to 10 seconds since we felt that interval would result in a large number of images over the duration of the flight, without filling up the memory card before reaching the highest altitude. The interval selection menu on the camera is shown to the right, in red. However, we have decided that, were we to repeat STRATOS, we would set it to take a photo every 5 seconds, so as to have more of a selection of photos for panoramas. We would also use a larger memory card in the camera whilst keeping the quality of the images - set to maximum - the same, because we do not want to compromise on image quality.

In the morning of the launch, the online predictor showed that the payload should land somewhere near Fauquembergues, France. The actual landing spot, near Lille, was in fact 60 kilometres east of this. After discussion, the team has decided this could have to do with three factors:

• Error in our descent speed calculation - by entering it as faster than it actually was, the payload in actual fact got pushed further east as it got caught in easterly winds in its slower descent;

• Type of balloon error - there are two types of balloon only shown on the "Advanced" balloon selection - we may have chosen "Kaymont" balloon when we in fact had a "Hwoyee" totex balloon.

• Weather shifts - online predictors are just that - they are used to predict, and cannot foresee rapid changes in weather or wind speeds, and should therefore not be used for 100% accuracy.

It was not known to us that during transport to Herstmonceux, one of our parents had put twist ties on the parachute lines so that they would not tangle. This variable should have been foreseen and noted in the checklist, as they were not taken off for the flight, and if too high, could have prevented the parachute from opening fully, causing the payload to descend at an unsafe speed. Next time, we will evaluate all variables such as these and note for them to included in the launch checklist.

During planning, we asked another member of the Science G&T group to create an "Arduino data logger" custom-built to record altitude, pressure, humidity and inside & outside air temperature. However, he did not proceed with this as discussed. If we were to do STRATOS again, we would ensure that we had the ability to log extra scientific data that we could analyse, for example, scripting the camera to record its internal temperatures with each photo. Another such idea was that of putting a point of reference on the lens to calculate the distance from one point on the earth's surface to another, and triangulate that with the point of reference. We would have to research this further before deciding how to implement it.

This page evaluates particular areas of the project that could be improved upon if STRATOS was to be repeated.

>"STEMfest and ESAS

<" STEMfest & ESAS

On July 5th 2012, we exhibited and competed STRATOS in Crawley STEMfest, as part of the regional heats in The Big Bang South East 2012.

We set up a stall with a display stand which we attached various photos, information and logos on to, On the stall we laid out the entirety of the equipment we sent up to Near-Space, which gave people the opportunity to physically touch our project and interact with something that had travelled to near-space and back, which we feel is very special. The event also gave us a chance to talk to interested pupils and teachers about our project and what we learnt from it/where we'll go next. People were genuinely intrigued and it was very fun answering questions about all aspects of STRATOS - from how it was started, to the exact workings of

the GPS Tracker - a whole range of details could be discussed given we were at a STEM event where people love details!

We were also there to talk to a CREST ambassador in the hope of being awarded a Gold CREST Award, and were competing against around 40 other schools and their science projects to win awards, including the regional heats to take the winner through to the Big Bang National Finals in March 2013. Judges came and looked through our report and then asked us questions about STRATOS. The event finished with a "Bigger Bang" show filled with explosives and chemical reactions for younger pupils to enjoy, which was followed by an award ceremony. We were thrilled to receive our exhibition certificate (shown on right) and to have won two main awards, and CREST Gold (below)!

Evaluation

Payload

Parachute

Full Size Panorama

Project Diary

Balloon

Descent calculations and team

photo

East Sussex Astronomical Society and School Presentations

Elekta Award for Science - "Elekta is a world leading company pioneering significant innovations and clinical solutions for treating cancer and brain disorders"

NSEC Intermediate Science/Maths Winner - " NSEC is an initiative of the Department for Business, Innovation and Skills, and is coordinated by the BSA in partnership with Young Engineers and The Big Bang".

Gold CREST Award - Endorsed by UCAS and requiring 70 hours of work, most often completed by A-Level students, we showed that our creative and exciting project with real-world research was Gold CREST Award standard!

In December 2012, we were invited to present STRATOS in one of the East Sussex Astronomical Society's monthly meetings at St Mary's School and College in Bexhill. Hannah created a presentation and video for the event, and we bought along all the STRATOS equipment and project diary. The presentation lasted around 10 minutes, providing an outline of the project accompanied by video of the launch/retrieval and slideshows of the inflight photos which Hannah narrated, and left time for questions at the end for people to ask about more details. One of the slides of the presentation, showing

how the balloon, parachute and payload (plus expanded contents) looked as it ascended, is shown to the right. We look forward to exhibiting STRATOS in the Big Bang Finals in March!

Since STRATOS's success, the team's been spreading the news by sharing our story and photos both at school and outside of school. We have a board outside the Science Labs at school (shown right), and recently presented to the Year 8 yeargroup in one of their weekly assemblies. STRATOS even got mentioned at the school's annual Prize evening by Ms Cronin, our head teacher. She briefly explained the project, and later presented us our Elekta Trophy and Gold CREST awards and congratulated us, which was great!