ALIEN – ALtitude Imaging Entering Near-space

April 30, 2010

ALIEN-1 Launch annoucement

Filed under: Uncategorized — sbasuita @ 21:18

The following text was emailed around to all of those that we could remember the addresses of, and is preserved here.

We are very pleased to announce the expected launch of ALIEN-1 this Sunday 2nd May!

We are a team of three GCSE students from Reading, UK: Simrun Basuita, Alexander Breton and Daniel Richman. With much help from the radio and high altitude balloon (HAB) communities, we have a constructed the ALIEN-1 (ALtitude Imaging Entering Near-space) payload. It will be lifted by a latex meteorological helium balloon to an altitude of ~33km above sea level, taking pictures and temperature measurements along the way before falling back to earth on a parachute. It will transmit its GPS co-ordinates continuously via radio (and SMS after landing) enabling us to track it and recover its stored images and other data.

N.B. We have a lot of links to share, so we’re using a reference format: [#] corresponds to an entry in the list at the end.

The launch site is at EARS (East Anglia Rocketry Society) [1], just outside of Cambridge, UK. The CUSF (Cambridge University Space Flight) balloon trajectory hourly predictor indicates, at the time of writing, that a launch in the morning of Sunday 2nd May is the best for this bank holiday weekend [2]. We encourage anybody to come along to the launch on the day (the more the merrier) – we’ll publish more exact timing details as plans are refined.

We are keen to keep everybody updated live on the project’s progress. Here are some ways you can follow the event:

  • Read/subscribe to the blog [3] for nice summaries and write ups, especially after recovery
  • You can follow the balloon’s progress with the online tracker map whilst its in the air [9]
  • Follow @ssb [5] (Identica) OR @sbasuita [6] (Twitter) for updates throughout the day
    (additionally keep an eye on the #alienhab hashtag [7])
  • If you have any general questions on ballooning, chat to the growing HAB community on IRC (Internet Relay Chat)
    (this is definitely the place to be come Sunday morning; people hang out here whilst tracking – #highaltitude on – the easiest way to do this is through the webchat interface [4])
  • Email one of our team members who will answer any project-specific questions (there are far more experienced users hanging out on IRC who can answer more general questions with far more expertise than us)

However, as well as receiving updates, we hope that you will actively join in and help us with tracking and recovery of the payload. Any person with basic amateur radio equipment can receive the telemetry broadcasts, but more importantly can easily upload them to the centralised tracker that has been set up by the UKHAS (UK High Altitude Society). This is a very efficient system that allows us to easily and automatically pool together receivers all over the country. See the UKHAS Tracking Guide [8] for information on how to get connected up, and feel free ask on IRC if you have any questions.

In any case, here are the technical downlink specifications: [EDIT: I forgot to mention it is transmitting SSB –sbasuita]

  • 434.075 MHz (this will drift at different altitudes due to temperature changes in the electronics)
  • RTTY 7n1 at 50 baud
  • We are using the UKHAS standard format for our telemetry packets, which will look like this:
    $$<Balloon name (A1)>,<Flight computer uptime (secs, decimal) UUUUU>,<GPS time HH:MM:SS>,<Latitude (decimal degrees) DD.DDDDDD>,<Longitude (decimal degrees) DD.DDDDDD>,<Altitude (m) AAAAA>,<GPS fix age (secs, hex) FFFF>,<Satellites locked LL>,<Temperature data (hex) TTTTTTTT>,<Status (45 = all OK)>*<Checksum>For example:

One of the main reasons for the sending of this email is that, over the time we’ve spent preparing for this project, it has been mentioned and discussed with many people who wouldn’t otherwise have had the chance to see the finished result. You can probably tell we’re really excited about getting this project in the air; hopefully come Sunday all will go to plan and we’ll get some beautiful shots of the Earth’s curvature.

P.S. We today learned that the Old Redingensians have granted us a category AA Enterprise Award (this means funding for further launches!) [10]

Simrun Basuita M6SBX <> on behalf of
Alexander Breton <>
Daniel Richman M6DRX <>



April 29, 2010


Filed under: Uncategorized — sbasuita @ 20:09

Here’s a quick picture of all the kit Mike Gathergood G4KFK has kindly lent us:

Launch Imminent!

Filed under: Uncategorized — Tags: , , , , , , , — abreton @ 13:41

After a long period of watching the weather, a bright spot appeared in the CUSF landing predictor. We have been able to secure the elusive last piece in the ALIEN-1 jigsaw: a radio transceiver which is kindly being loaned to us by Mike Gathergood (G4KFK).We will be launching Sunday 2nd May at 1000 UTC. Although cloud and intermittent showers have been forecast at ground level the wind is perfect (finding a good wind is difficult, because the prevailing wind in England is highly unfavourable to balloon launches). Our launch site is also the site of the Big EARS (East Anglia Rocketry Society) meet which will take place at the same time as our launch.

Obviously we will be keeping the blogosphere and twitterati posted with live updates on the balloon’s progress on the day.

December 16, 2009

A little update…

Filed under: Uncategorized — Tags: , , , , — abreton @ 17:59

Well, about time we gave all the ALIEN fans an update. Firstly, the final pieces of the ALIEN jigsaw are about to fall into place: we have finally ordered the latex balloon, cord and chute! Supplied to us by

Secondly, in order to support ALIEN beyond a single launch and into high-budget high-altitude stardom, we will need a sponsor, preferably of the large and corporate sort. The #1 candidate so far is the all-round rather epic BAE Systems, purveyors of the finest jet fighters and all sorts of aerospace/naval/military goodness. A UK based company with a large education programme as part of their corporate responsibility scheme, BAE is the perfect sponsor for an enterprising, dynamic and innovative project such as ALIEN.

November 22, 2009

Construction of a Payload

Today, I bring you some photos from our latest get together. We’ve practically finished building the payload; the only thing left to do is create the transmit antenna, gluegun on the UV filter and test it! (Oh, and coat the whole thing in duct-tape). Note: our camera model has changed. Instead of using the Powershot A80 (which broke, the CCD stopped working) we’re now using a Powershot A560, with the Stereo Data Maker variant of CHDK installed on it to make it automatically take photos!

The A560 offers 3.1 extra megapixels, which in today’s world can only be good. However, it takes an SD card instead of the CF we already have, so the CF is going on eBay before we acquire an SD card. Cutting polystyrene without a hot wire cutter proved a slight challenge, but it wasn’t anything a Leatherman and a grindstone couldn’t fix. A titanic step forward has been made on the project as everything materialises into tangible reality as opposed to dreamworld. Once the latex balloon is ordered we can start thinking seriously about launch!

October 16, 2009

Polystyrene bought

Filed under: Uncategorized — abreton @ 17:02

**** Mark, **** M&A Insulations and their sh*tty Celotex. Rolled down to Wickes and bought some good old polystyrene for the not exactly princely sum of £3.91.

September 21, 2009

Celotex ordered

Filed under: Uncategorized — Tags: , , — abreton @ 16:34

Email has been sent to the glorious Reading-based establishment of M&A Insulations, run by the equally illustrious Mark. We have a 8 foot by 4 foot (1.2×2.4 metres for all you cutting-edge metric wizards) sheet of Celotex PIR board on its way to us. This stuff has twice the insulation goodness of polystyrene, so our 50mm sheet is giving us the equivalent of 10cm of expanded polystyrene! Pics will be posted when we get it!

June 12, 2009

A motherload

Yaesu FT-790R 70cm (~434 Mhz) radio

Yaesu FT-790R (70cm transceiver)

It’s been a while since you properly heard from us… that boils down to three things: Exams, Hard-work and Laziness.

However, quite a few things have happened! So it’s time for one heck of a post to describe them.

Radio work

One of the kind members of UKHAS (#highaltitude on called James Coxon (jcoxon) lent us his Yaesu FT-790R which, while being the first transceiver we’ve touched, as far as we know is very good! Simrun received the stoic brick and seemed to be able to operate it very easily. Eventually I met up with him and we set about wiring up the Radiometrix NTX2 appropriatly. Because we’re running our Atmega on 5V this proved difficult…

The TX Input to the radio is analogue and is centered around 1.2 Volts (ie. giving it 1.2 volts should produce the exact carrier frequency). It’s single side band, so giving it 0.9 Volts would result in roughly 400 KHz less. We’re using RTTY which means that the receiver will emit one of two tones at any instant, one meaning a binary 0 (a ‘space’) and one meaning a binary 1 (a ‘mark’). We chose to use baud 50 – ie. we send 50 marks/spaces a second, and the ‘protocol’ is exactly the same a standard serial interface. We’re using the parameters ‘7n1’, meaning 7 data bits (our ASCII), no parity bits, 1 ‘stop’ bit. Thus for each byte, send a ‘start’ bit as a space, send the 7 data bits, then send a mark (the stop bit). Then you can repeat the process for another byte or remain at a mark level, the idle state. We had to feed the radio 0.9V for a space and 1.2V for a mark… it’s potential divider time!

Radiometrix NTX2 Schematic - Part of the ALIEN1 Flight Computer

Radiometrix NTX2 Schematic - Part of the ALIEN1 Flight Computer

The eventual resistor configuration used is shown in my Eagle diagram to the right.

Having set that up with fixed resistors, we tuned in the radio and heard a whole load of meaningless beeps – but it sounded pretty cool. We grabbed a spare 3.5mm audio cable, connected radio to computer and started fldigi – a super open-source (free) program for decoding anything and everything to do with Amateur Radio. I had programmed the Atmega to do send Hello World (more on that later) and guess what! Up comes onto the screen ‘Hello World Hello World Hello World’. Success!

Aerial to transmit with? We grabbed the nearest piece of wire and connected it to the RF OUT – most likely a horribly incompatible antenna, but hey. Positioning it by the window we headed out to a nearby hill to see how good the range was, and got 800 metres before the beeps were really distorted. We also managed to scare and alienate some locals! Simrun decided that whenever we passed someone, he needed to test the radio… at maximum volume. Finally, we grabbed my old laptop and went out again to the field, and managed to decode it at 600m – we didn’t try 800m because the terrible battery ran out.

So all is good with the radio transmission. Let’s just ignore the failure with the Yagi.

SMS Work

Bad things happened on the w800i front. It turned out that the AT command UART was only a ‘virtual’ one – you can only access it over USB. What a pain! Recommended to us by #highaltitude, we headed over to ebay and instead got an oldschool Ericsson, the t68i, which was so old that it had no usb capabilities and the UART was exposed on the bottom – so we could hook it up to our circuit easily. I also got a USB Cable (DKU-11) for the connector which we would hack.

Step one: Fix wires to the important pins – pin 4 and pin 10. Harder than it sounds! Under the sticker on the DKU cable there’s some screws, which come out really easily. Inside, a circuit board is connected to this metal ‘thing’. Needing to remove the circuit board and get it out of the way, I fetched a hacksaw – not the best idea. You need to preserve the very fragile tabs that have solder on them, as otherwise it’s nearly impossible to fix stuff to the pins. This is a straightforward but fiddely task. If you’re going to try it, good luck!

Step two: The phone takes 2.8V – need to divide the Atmega’s 5v in half (roughly). A simple potential dividor will do the trick! I used two 2K7 resistors.

Step three: As with the GPS, I hijacked the Arduino’s FTDI chip for the inital testing. And then even worse things happened. It’s 9600 baud, and the AT commands are exactly the same as in the w800i. However, note these pitfalls – each one consumed at least 30minutes of me banging my head against a wall:

  • AT protocol needs \r\n: There are two characters that represent the end of a line on computers: a Carriage Return and a Line Feed. Windows uses CR then LF on every end of line, Linux just uses LF, and AT required CRLF… me being a linux user didn’t notice this, and thus spent lots of time and effort wondering why it wasn’t working.
  • The AT protocol echos your input by design. On top of the above problem, I was very confused as to why every character I put in was echoed back out of the TX pin (pin 5, which I had connected to debug). This is normal!
  • Between the AT+CMGS= command and the data you need a short wait – I used a 1 second wait in my programs, simple enough.

Step four: Get the Atmega to send the SMS without any desktop computer help! This was easy, and all the code used is in our SVN repo.

Step five: Solder onto PCB

Step six: Profit!

Flight Computer Work

I decided that it would be a lot simpler and smaller if the huuuge arduino wasn’t taking up space, and set about searching for a suitable Atmega, settling on the Atmega162 because: It has two UARTS (one for the GPS, one for the Phone) and Rapid Electronics didn’t have the Atmega168 in stock. Armed with this, and all the above work, I had everything I needed to begin designing the ALIEN Flight Computer! Pictures (or PDFs) speak better than words, so I’ve attached the Circuit Schematic and the Final Board Layout. Because a chemical process (Reading School Electronics Department) would be used to manufacture the PCB, I’ve used huge traces to minimise errors.

ALIEN1 Schematic · ALIEN1 Board Layout – With bottom traces · ALIEN1 Board Layout – Without bottom traces

The PCB has been manufactured and is now in good working order, programmed with the code in our repository it parses GPS data successfully, sends SMSes, flashes LEDs, and drains batteries like there’s no tomorrow.

All schematics, board layouts and code is Copyright (C) 2009 Daniel Richman and Simrun Basuita.
Further information, including possibly a GNU licensing statement is included in many code snippets and files.
Otherwise all rights are reserved.

Pictures of the last item are still to come, and payload construction is about to start very soon!

In absence of Simrun’s amazing camera that you saw in the Workshop 1 photos, I’ve used the nearest sortof-ok camera to get some photos. The green bag is an antistatic thing, that also makes the white PCB visible.

Overview of the Flight Computer

Overview of the Flight Computer

A good quality close up of the flight computer itself.

A good quality close up of the flight computer itself.

Another angle on the flight computer

Another angle on the flight computer

June 3, 2009

Yagi contruction (Part 1)

Filed under: Uncategorized — Tags: , , , , , , — abreton @ 20:17

Last Thursday saw the ALIEN team over at Daniel’s house in Yateley (wherever that is) in order to build and test a yagi antenna. This piece of apparatus is used to receive the radio signals from the balloon. Being a bunch of cheapskates, my colleagues decided to not buy a pre-made one, but instead googled ‘cheap yagi’. This ended up in them reassuring me that all ‘beef’ was completely nonexistent and that we could build one. I arrived on the scene of the workshop to find those two fools drilling into a PVC with seemingly all sense of precision completely lost into the ether. Much sighing ensued, and to recuperate I dug into Daniel’s extensive supplies of Cadbury’s Twirl. 

After much sighing and usage of duct tape (the star material on the build), we had a complete antenna. It looked…ahem…well….you guessed it-crap. To call it tacky would be an enormous insult to a whole range of toys that come out of China’s factories in their billions every year. Nonetheless, it was time for a test run at nearby Blackbushe airport. To our dismay, it was just as **** as it looked. Even the omnidirectional whip antenna provided with the transceiver was better. Having run out of ideas as to what was wrong, we turned to UKHAS’ IRC channel #highaltitude for advice. There, the crushing statement ‘antennas have to be quite precise’ was delivered-ours really wasn’t. It was a piece of poorly drilled PVC with wire taped to it and supported with duct tape. Our yagi was promptly binned, and we are contemplating what we should do next in light of our complete failure.

April 17, 2009

ALIEN on Google Code

Filed under: Uncategorized — Tags: , , , , , , , , , , — Daniel Richman @ 20:29

Short post just to tell you that Simrun has set us up a SVN repo on Google code, and I’ve committed some examples, notes and a folder structure to it.

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