Space Teddy - The Bear Has Landed

 

Space Teddy has been safely recovered after his latest mission into the upper atmosphere! 

A North Shore Radio Club activity report by Andy Brill ZL1COP

 

Image

SpaceTed lifted off from Forrest Hill School at 12:10pm on Thursday 12 December on his third mission to the edge of space. Firmly strapped into  his replica Tesla car and supported by a weather balloon he set off on  three hour journey to an altitude of 33.4 km (110,000 feet) followed by a descent to safe landing on farmland near South Kaipara Heads. That is higher than a U2 spy plane can fly.

The Space Teddy mission is the brainchild of Marius van Rijnsoever who conceived the idea in 2016 as a practical science project for his children’s school. The idea was to launch and safely retrieve a weather balloon carrying cameras, telemetry equipment and the school Teddy mascot and see how high it would go.

This has become a regular event, with each mission becoming more sophisticated. This year was Ted’s third successful launch and the highest so far. He reached an altitude of 33,431 metres, beating his previous record of 28,500 metres set in 2016.

North Shore Radio Club members led by Julian ZL1ABX have supported the project by helping with the radio communications for the project.  

This year, Teddy travelled in style, mounted in a model Tesla roadster similar to the one put into orbit round the sun by Elon Musk's SpaceX test launch in 2018

 

 

Which is the real Tesla?

Image

Image

The Plan

As well as Ted himself, the Tesla launch vehicle carried an electronics package with cameras, sensors, GPS equipment and a radio telemetry system to send data to the ground.

Teddy’s downlink used a Raspberry Pi computer with a two channel LoRa UHF radio transmitter module operating in the 70cm band at 433.1 (Chan 0) and 434.3 MHz (Chan1), with a power output of about 10 milliwatts to a monopole antenna. Callsigns for the mission were ZL1AB-0 and ZL1AB-1

Telemetry and position information was carried on both channels, and Image data on 434.3MHz. The received data packets were relayed to the HabHub website in the UK via internet connection for processing of the images and display of the current balloon location.

To make sure all the data was received correctly four separate receiver locations were used, each connected via an internet link to a central server. This meant that if any receiver lost the signal, any gaps in the data could be filled in by the other sites. The central server was at the HabHub website of the UK High Altitude Society, and this site processed the image and location information and displayed the balloons position on a map, and the images on a webpage.

The receiver sites were located at Forrest Hill School (Julian ZL1ABX) , Papakura (Ian ZL1AOX), Greenhithe (Dennis ZL1TAY), and a mobile receiver which would attempt to follow the balloon's path (Andy ZL1COP and Graham ZL1GMB)

Setup

Setup of the comms gear at the school commenced at about 10:30am. Two long yagi antennas and a receiver consisting of a Raspberry Pi computer fitted with a LoRa two channel receiver module linked to the school WiFi network were installed near the launch site on the school playing field.

Image

Antennas at the launch site

 

 

Image

Support from the excited onlookers - Aaron ZL1FAT and Kieren ZL1GER take a break in the sun.

Liftoff

Air traffic control had been notified of the launch and issued a Notice to Airmen (NOTAM) to warn pilots of Teds flight. The launch site is within the Whenuapai Airbase  Control Area.

NOTAM #: B7259/19
Class: International

B7259/19 NOTAMN
Q) NZZC/QWLLW/IV/M /AW/000/999/3647S17438E036
A) NZWP
B) 1912112230
C) 1912120106
E) ASCENT OF FREE BALLOON WILL TAKE PLACE FM 36 46 22 S 174 44 54 E (FORREST HILL SCHOOL) APRX 5.8NM NE NZWP. BALLOON IS 2M IN DIAMETER AT LAUNCH. PAYLOAD WEIGHING 1KG SUSPENDED 49 FEET BELOW BALLOON. EST ASCENT TIME 1 HOUR 30 MIN. EST DESCENT TIME 30 MIN ON PARACHUTE
F) SFC
G) UNL

 

Once the balloon was filled with helium and all the electronics confirmed operational Ted ready to go.

Image

                              Final System Checks

 

Image

Teddy boards his replica Tesla convertible car, with paper darts bearing messages from the school children ready to launch.

Final clearance was received from Air Traffic Control and at 12:10pm to deafening applause from the watching crowd Teddy was airborne.

Image

                                        Launch

Once airborne the signals were received immediately by Ian ZL1AOX at Papakura, Dennis ZL1TAY at Greenhithe and Andy ZL1COP who was mobile and heading North along Teddy’s predicted path towards Warkworth.

A check of the Habhub website revealed that we were getting excellent images from the on-board camera with very little packet loss even at low altitude.

Image

              Ted about 2000 metres over Forrest Hill

Teddy rode the breeze northwards, slowly gaining height. By 1:30 pm He was just off the coast at Orewa and passing an altitude of 20km when he entered the westbound Jetstream. He made an abrupt left turn, heading for Helensville and still gaining altitude. At 2:54pm Teddy reached an altitude of 33,431 metres, (109,681 feet). At this altitude the balloon burst over the Woodhill forest and he began his long descent, which was slowed by his parachute as the atmosphere became denser. He finally landed in farmland beside Lake Kereta, 2km inland from the beach and 18 km South of South Kaipara Head.

Teddy was found and recovered later that evening by Marius with help from some of the locals and a hand held LoRa receiver and antenna which detected the signal on the ground

Image

7500 metres over East Coast Bays with Hibiscus Coast and Kawau Island in the background

Image

Heading West in the Jetstream at 22000 metres – Kaipara Harbour in the background

Image

            Teddy on the edge of space. 26,000 metres

Image

Balloon burst at 33,400 metres with a scrap of the balloon in shot. Note packet loss on the image due to the violent movements as teddy begins to fall. Once he stabilized we were back to flawless pictures.

 

Image

Teddys Flight Path

 

Image

 

The telemetry from the temperature sensor shows clearly how the temperature dropped as the balloon rose through the troposphere, reaching a low of -40 degrees C at about 10,000 metres.

Above this level, the temperature starts to rise as the altitude increases. The point at which the temperature starts to rise with altitude is called the tropopause, and marks the boundary between the lower layers of the atmosphere (the troposphere) and the upper layers, (the stratosphere).

When the balloon burst at 34,000 metres the payload dropped back into the troposphere and the temperature plummeted until Teddy reached the more comfortable lowest layer called the atmospheric boundary layer (or peoplesphere).

Image

Temperature graph

 

 

 

Image

Here is a screenshot of the raw data being received from Space Teddy at ZL1AOX. This was taken at the end of the flight and shows a number of errors as the signal level drops off. (The current RSSI shows -121 on Chan 0 and -113 on Chan 1). During most of the flight the RSSI was better than -100 dBm giving error free reception.)

 

How the comms worked:

On board equipment:

Teddy’s down-link used a Raspberry Pi computer with a two channel LoRa transmitter module operating at 433.1 (Chan 0) and 434.3 MHz (Chan1), with a power output of about 10 milliwatts to a monopole antenna. The raspberry Pi was connected to cameras, and GPS equipment and various sensors.

Telemetry and position information was carried on both channels, and Image data on 434.3MHz. The received data packets were relayed to the HabHub website in the UK via internet connection for processing of the images and display of the current balloon location.

 

Image

The four receiving sites were:

Site 1 Forrest Hill Primary School (ZL1AB)

Manned by Julian ZL1ABX, Marius (project leader) Kieran ZL1GER and Aaron ZL1FAT). The equipment was a Raspberry Pi computer with two channel LoRa receiver module, connected to the internet via the School WiFi system.

They used two 70cm Yagis mounted on tripods allowing for adjustment of both elevation and azimuth.

Image

                                  Julian ZL1ABX setting up the receivers at the school launch site

 

 

Site 2 Papakura ZL1AOX

 Ian ZL1AOX was equipped with similar LoRa receiver and tracking antenna connected to the internet via his home network. The antenna was a KLM 40CX 20 element circularly polarized 70cm crossed yagi feeding the two receivers via an Icom 70 cm preamp and a splitter.

Image

Antenna array at ZL1AOX showing the 20 element 70cm crossed yagi at the top.

 

Image

                                 LoRa receivers and splitter used at ZL1AOX

 

Site 3 Greenhithe.ZL1TAY

Dennis ZL1TAY had a single channel LoRa receiver on the Image channel and his antenna was a pole mounted 8db gain omnidirectional VHF/UHF collinear antenna. (Diamond X200)

Image

Antenna mast at ZL1TAY – X200 at the top of the pole. Note the flag hoist with call sign in International Code of Signals!

 

Site 4 Mobile chase cars ZL1COP and ZL1GMB

Graham and Andy provided the chase function, using a single channel LoRa receiver on the Image channel.
Antenna was a 434MHz quarter wave monopole in the centre of the car roof for mobile use and a tripod mounted 6 element yagi for tracking when stationary. Internet connectivity to the Raspberry Pi for data transfer and a laptop for monitoring the HabHub site was via a mobile Wi-Fi hotspot on a smartphone

Image

Graham ZL1GMB looking for Teddy signals after landing at Kaipara

 

Coordination

Coordination between launch site, the receiving stations and the chase car was via 2 metre repeaters, - 670 Waitakere and 7325 Kaipara

 

The results.

The communications were virtually flawless. Both Ian at Papakura and Dennis at Greenhithe were able to receive data immediately after lift off. The images were pretty much error free for the entire flight. The chase car was able to receive almost continuous data while mobile using the quarter wave whip antenna, even through the Dome Valley area near Warkworth where both 2 metre comms on the coordination channel and cellphone coverage were patchy. The use of multiple receive sites meant that if any of the receivers lost signal at any point the gaps in the data could be filled by data from the others.

Ian at Papakura received excellent quality signals until the balloon dropped below 1000 metres in the descent – this over a path length of about 85kms from a milliwatt level transmitter.

 

Thanks.

Space Teddy has been a brilliant project to be involved in and I would like to thank Marius, Julian, and the pupils and staff at Forrest Hill School for the opportunity to take part. I know the learning experience for the kids has been immense, and I also have learned heaps. Not just about radio, but also the intricacies of Raspberry Pi and Linux, balloons, spread spectrum communications etc. But even more important than the learning is the fact that it was great fun to be involved in.

 

More information

Videos of the previous Teddy missions are available on YouTube

2016 

2017 

An unedited video of this year’s launch made by the pupils is available here 

 

The HabHub website - http://habhub.org/

UK High Altitude Society https://ukhas.org.uk/

For more information about  the LoRa mode Google LoRa, and Chirp Spread Spectrum (CSS)

 

 

Comments

You were probably the most engaged of all of us, Andy. Thanks for putting in the effort to write it up for the rest of us.