ASRI Development Tasks

In cooperation with the Australian Space Research Institute (ASRI) we're working to develop and deliver:

• Generic Telemetry Module

• Propulsion Control Avionics

About Lunar Numbat

Lunar Numbat is a team of Australians and New Zealanders who use their skills and Open Source technologies to partner with the Google Lunar X-Prize team "White Label Space". Why? So as to put a Linux powered robotic Australian Marsupial on the moon. Simple really.

The Google Lunar X-Prize awards US$20 million to the first team to safely land a rover on the moon which successfully roves more than 500 meters and transmits back high definition images and video, with bonuses for extra achievements.

"White Label Space" is a Google Lunar X-Prize (GLXP) team we like the look of, which is why we're partnering with them.

The Numbat is a small smart and very cute endangered Australian Marsupial. It's efficiencies and intelligence represent the attributes we aspire to in our rover.

While our primary goal is to assist "White Label Space" to succeed in the GLXP, our reasons for doing so also include bringing about innovations in Space Science using Open Source technologies, to collaborate with other Space Science entities, to educate as to the grand benefits that Space Science provides all people and advocate the formation of a combined Space Agency by Australia and New Zealand. Lunar Numbat can help us not only to get to the Moon, but to get ourselves sorted on Terra Firma.

As for the moon, it's our companion world, our off shore island. Invariably when you learn about the moon, you learn about the Earth. In more ways than may seem self evident, they're linked.

With 2009 being the International year of Astronomy, we'd like to start making Space Science better understood, less expensive and more accessible to everyone.

Sound like fun to you? Then come join us!

Australian Space Research Institute (ASRI)

• ASRI Official site
• Wikipedia ASRI Reference

Rocketry and Propulsion

Ausroc 2.5

• Ausroc 2.5 Project
• What is Ausroc 2.5

SP3 at the Australian National University

• SP3 Space Plasma, Power & Propulsion Group
• HDLT Helicon Double Layer Thruster
• DS4G Dual Stage Four Grid Thruster

Centre for Hypersonics at the University of Queensland

• Centre for Hypersonics

Satellites

BLUEsat at the University of New South Wales

• BLUEsat

Advocacy

National Space Society of Australia

• NSSA

The Mars Society Australia

• Mars Society Australia

Lunar Numbat Build Team

Lunar Numbat has at it's core a driven volunteer Build Team assisted by the Contributors Team and interested people. The Build Team is:

Andy Gelme (Hacker At Large)

As a software engineer with experience in automation systems, the Lunar Numbat mission subsystems of interest are avionics (ACS), data handling (CDH) and communications (COMS).

My personal web-site, blog and twitter.

Lee Begg

Lee will be focusing on video, stills, compression and communication subsystems.

-- LeeBegg

Luke Weston

-- LukeWeston

Jonathan Oxer

• Founder and CTO of Internet Vision Technologies, a web-application development businesses that has its origins way back in 1994
• Past President of Linux Australia, one of the largest FOSS community organisations in the world
• Slightly notorious for implanting an RFID tag in my own arm in early 2006
• Author of a variety of technology-related books including "Ubuntu Hacks", one of the top selling books ever about a Linux distribution
• Interested in the intersection of hardware and software and what it means to embed intelligence into everyday objects
• Co-founder of the Geek My Ride project
• Co-host of the upcoming TV show SuperHouse

My blog, Wikipedia page, and Twitter updates.

Marco Ostini (Project Leader)

Passion for Science, Technology and Aerospace have had a significant presence from my formative years. From the third grade I was writing about Space. Later I dabbled in electronics, started to code badly at 15 and read great slabs of material on anything that flew - especially things that flew fast! (I <3 SR71) One of my favourite reads at this time was a shuttle flight manual issued to the STS flight crew. By the time I was 18 I "accidentally" got a private pilot's license when a friend suggested that I take a trial flight, and I got hooked on the freedom of being in the sky.

After some Tertiary study I switched from IT as a hobby to a career in the early 90's, and have done so ever since. I certainly value the sanity and sustainability of Open Source technologies.

Genuine Research and Teaching are very important to me, which is why I've remained working at a University for over a decade now.

The lack of Genuine "device in microgravity vacuum" Space Science happening in Australia since Wresat has been quite perplexing to me, and slowly I've worked out the difference between promises made and what in fact happens. Australia needs a Space Agency, just as a city needs a Fire Brigade. Without one we leech off neighbours, and are unable to assist when requested, and all the while ignorance of Space Science abounds, which is not good. I believe that Australia and New Zealand together should form a modest Space Agency that cooperates with other's globally.

Lunar Numbat Contributors Team

The state of the Lunar Numbat endeavour is further pushed forward thanks to the efforts of the Contributors Team; developers who support the Build Team with research, code and all the while brainstorming and evaluating new ideas.

Roy Duncan

Some years ago, Roy embarked on a mission which has ultimately resulted in telescope-net.com, a website for astronomy and robotic telescopes. Part of this endeavour has involved the development of two fully-robotic observatories, which in retrospect he admits probably wasn't the easiest thing in the world to do. This mission has also resulted in a Citation for Outstanding Contributions to Student Learning from the Australian Learning and Teaching Council.

Roy is currently employed by a Queensland tertiary institution, where he maintains a number of web-related systems and services, and works to integrate them with their wider IT environment.

• Roy's corner of the Lunar Numbat subversion repository.
• Some iGoogle modules related to the Moon and solar system objects.
• RoyDuncan

Stuart Young

Current things he's looking to play with outside of Lunar Numbat are GNURadio and RepRap? .

Stuart is currently employed as a System Administrator and as a Technical Support person in the barcoding industry.

Paul Schulz

James Purser

WLS Development Tasks

As we work in cooperation with our partner White Label Space, the areas of technical support that are our focus to develop and deliver are:

• Propulsion Control Avionics

• HD Video & Still Transmission

• Radar Altimeter

How do I join Lunar Numbat ?

So you've read a little about the endeavour of the Numbat that could, and you'd like to be part of it?

Welcome!

Lunar Numbat is an Open Source project run by New Zealanders and Australians and open to all those interested.

The first step to joining is to subscribe to the Lunar Numbat Mail List, and in the "Welcome to Lunar Numbat" thread introduce yourself and tell us a little about yourself, describing your skills and abilities interests and passions, why you're interested and what you consider you might bring to the endeavour.

We've also got an IRC Channel where some of us hang out on (#lunarnumbat @ irc.freenode.net).

From there the key is - communicate!

Participate in the discussions, share your ideas, and let us get to know your strengths. Chances are we'll soon find something for you to do.

Task - Class C Rocket Launches

Class C rockets are small, cheap hobby rockets that can be purchased in many hobby shops and launched from a suitable clear area. They have a low operational ceiling of only 100 to 200 meters and can lift a very small payload using expendable solid-fuel motors.

(By "Class C", what we mean is model rockets of a size consistent with (typically) the use of "C" impulse class model rocket motors, typically disposable Estes-style model rocket motors.)

Class C rockets are extremely limited with regard to experiments or development that can be performed, but they are still an excellent way to get a feel for rocketry and gain an understanding of what to expect with larger rockets. Because of their low operational ceiling and cheap motors a series of launches can be performed quickly in any suitable open area without requiring special airspace clearance.

As a fun and simple payload capacity test Jonathan Oxer performed two class C rocket launches with solid chocolate Easter eggs loaded into the nosecone to simulate the mass of a telemetry system. The launches were recorded on video:

http://jon.oxer.com.au/blog/id/327

Datalogging / Telemetry System Development

As a challenge to develop a very small / light avionics package Jonathan is currently working on a payload for a class C rocket that will provide:

• 3-axis accelerometer data
• GPS data
• Local (in-rocket) data storage
• Real-time data transmission

Initial development work can be seen on his blog:

http://jon.oxer.com.au/blog/id/328

http://jon.oxer.com.au/blog/id/330

Task - Class G Rocket Launches

• Related HackerSpace page

Class G rocket avionics / telemetry

This is the first-generation prototype ARTEMIS telemetry / instrumentation board we have designed and built. This board plugs into an Arduino MEGA (pictured) as a shield; it does not contain its own microcontroller. Telemetry is transmitted via an XBee module (2.4 GHz, 1-2 mW). This is not very powerful, but for the limited altitude we have flown to so far, this is sufficient.

This is an example of an Aerotech ARCAS HV model rocket; an example of the same model rocket we have used to fly this payload so far. This is a mid-to-high powered rocket, typically flown on a 'G' motor, or thereabouts.

(By "Class G rocket", what we mean is a hobby rocket of a size consistent with (typically) the use of "G" impulse class rocket motors. This is a simple, rough metric we can use to describe the size of a hobby rocket, in terms of the motor it typically flies on. Both single-use disposable motors and reloadable APCP motor systems can be found in this impulse range.)

• Aiko framework
• Arduino hardware

Planning session for Class G rocket avionics and audio / video

ARTEMIS: Arduino Rocket Telemetry Module and Instrumentation System

Hardware: Overview

• Arduino
• Sensor board(s)
• Audio / Video
• Telemetry
• Power
• Chassis
• Consider Class C retro-fit

Hardware: To Do {MikeB,LukeW}

1. Check Arduino pin usage {????}
2. Definite hardware specifications
   1. Communications (ZigBee ?), storage (DataFlash versus SD card ?)
3. Assemble hardware in one place {AndyG}
4. Triage for hardware decisions, what will be flight ready ?
5. Hand-over to {MikeB}

Hardware: Payload packaging

• Rigid in flight
• Accessible, easy to install and remove
• Testable outside of rocket
• Weight minimized
• Avoid shielding telemetry transmission
• Strength, survive crash landing
• Mounting resilience
• What if payload lost, find how ?

Firmware: Sensor Board(s)

• Communications, e.g. ZigBee mount [serial] {PeteY,AndyG}
• Storage [SPI] {PeteY,AndyG}
• Accelerometer / Gyro (6DoF) [analog x 3, serial] {JonO,AndyG}
• Pressure sensor [SPI] {JonO,AndyG}
• Temperature sensor [1wire] {AndyG}
• Light sensor (LDR) [analog] {JonO}
  • Roll-rate and parachute deploy sensor
• Real-time clock [1wire] {AndyG}
• Power bus monitoring [analog] {SamS}
• GPS [nmea-serial] {JonO}
• VirtualWire [serial pins x 2] {AndyG}
• Current sensor [analog] {SamS}

Software: Aiko framework {PeteY}

• Easy install / update - Linux ?
• Testing: reliable, e.g. real-time timing
• "Aiko-ize" each device, e.g. LCD, 1-wire temperature sensor, RTC
• Determine device sample rates ? Attach time-stamp
• Telemetry -> Storage, after launch -> Upload to host
• Telemetry -> Communications, determine sample rate
• Data ...
  • Launch start / end (button press or 2-way ZigBee communications ?)
  • Checksum data, calculated by Arduino
  • Checked by host
  • Generated every "n" records
• Self-testing: Check-list, provide status, how ?
• Bench testing: Simulated (switches, potentiometer, signal generator)
• Test firmware and host software
• Software test using existing Class C rocket {JonO}
• Simulate using Test Arduino (generate inputs) -> Rocket Arduino

Software: Miscellaneous

• GPS -> RTS -> "millis()"
• Aiko error handling
  • Fatal error code -> provide failure status
  • Non-fatal error code -> ?
• Use 2 person triangulation during launch to check maximum altitude

Generic Telemetry Module

ASRI Requirements

To assist with the Small Sounding Rocket Program (SSRP) ASRI have requested the following 'loose' specifications to promote an initial discussion among the HackerSpace/Lunar Numbat communities:

ADC Requirements

• ADCs with a sample rate of 100 Hz (baseline), with an option for much faster sample rates if necessary. (e.g. Mach shock wave recording.)
• At least 12 bits of ADC resolution.
• ADC samples at 100 Hz are stored on local memory, but 1 in 10 of those samples (at 10 Hz, in real time) are transmitted via RF telemetry.

For example, 16 channels might be a desirable number, divided up as follows:

• • 7 x channels from devices or instruments in the user's payload
  • 3 x accelerometers
  • 3 x gyroscopes
  • 1 x temperature sensor
  • 1 x barometric pressure
  • 1 x spare, or for user instruments.

Note that the GPS receiver is not an analog sensor device, and therefore it has nothing to do with the ADCs. GPSs typically output ASCII data (standardised NMEA strings) over a digital serial interface. 5-10 Hz is the fastest update rate I've seen for commercially available GPS modules.

Before deciding upon the number of ADC channels, however, I think it is valuable to consider what kind of sensors we actually want to use and whether these sensors have analog output and require external ADCs. Many of these kinds of sensors available today have digital outputs.

For example, if we look at the ADXL345 3-axis accelerometer (just as one example), this accelerometer has built-in ADCs and has a digital I2C? /SPI interface.

We can implement both the 3-axis accelerometer and the 3-axis gyroscope using sensors with digital outputs (using e.g. the Analog Devices ADIS16400 IMU module). We can also implement the barometric pressure sensor and the temperature sensor digitally, using a SCP1000 and DS18B20? respectively.

(A Zuni will experience acceleration of about 70 g during engine burn. Is it possible to get MEMS accelerometer chips that can measure accelerations that large!?)

Therefore, we only need 8 12-bit ADC channels available, and we can make them all available for interfacing with sensors or circuits in the user payload.

We also need digital interface pins available, of course, for the SPI, I2C? and 1Wire interfaces for these digitally-interfaced sensors. The GPS is interfaced onto a serial UART. Flash memory for local storage is also needed - I think something removable like an SD card would be the best way to go here.

Video

• 2 x standard definition cameras at 25(?) FPS
  • 1 x up
  • 1 x down

Antennas

• Integrated "Wrap-around" type would be preferable for TLM/VID/GPS

Bandwidth

• 100 Mhz to xmit telemetry, video & GPS data.

Physical Size

• 127 mm diameter x 150 mm long
• Conform with standard bolted interface. Ref ASRI payload user guide.

Physical durability

• Able to withstand an acceleration of 70 g.
• Storage chip protection via resin potting or similar.

Battery

• Li-polymer battery

Desirable

• Option for RF uplink connection

HD Video & Still Transmission

GLXP Requirements

All requirements are after processing.

Stills

• Clearly show what they are meant to show
• >= 8 bit/colour
• SNR 50:1 at albedo approximately equal to 0.1
• =< 0.3 milliradians/pixel (0.017 degrees) - the earth will be about 100 pixels wide
• In colour and colour corrected
• "Reasonable" illumination and contrast
• In "Detail" images all logos clearly ledgable

Video

• Clearly show what they are meant to show
• Must show dynamic content (movement, camera changes)
• Framerate appropriate for action (smooth motion)
• In colour and colour corrected
• Near real-time (NRT) video
  • High priority communication, early as possible
  • At least 320x240
• HD Video
  • 1280 x 720 progressive scan (720p)
• HD and NRT videos can be the same transmission, as long as all requirements are met
• HD must arrive before the end of the mission

Arrival Mooncast

• Detailed content plan required 180 days before launch for GLXP
• Show arrival/initial exploration of the surface
• 8 minutes of video (same videos in NRT and HD)
• Panoramic photo(s) 360 degrees, at least 60 degree vertical view (centred near horizon)
• At least one recognisable "Detail" self-portrait of the craft and any secondary vehicle(s)
• "Detail" images of logo cluster and GLXP payload
• Pre-recorded video (with audio), email and text messages by GLXP (total 10MB)

Completion Mooncast

• Detailed content plan required 180 days before launch for GLXP
• Show exploration and completion of GLXP requirements
• 8 minutes of video (same videos in NRT and HD) including some when vehicle is in motion
• Panoramic photo(s) 360 degrees, at least 60 degree vertical view (centred near horizon), at the end of 500m
• At least one recognisable "Detail" self-portrait of the craft and any secondary vehicle visible
• "Detail" images of logo cluster and GLXP payload

Round Trip Data

• Approx 10MB data to be sent from earth to craft and back

Communications requirements

• All GLXP data must be encrypted and decryption keys given to GLXP

Capture Size and Raw Data size

Images

• Panorama (min, no overlap): 21176x3529, 224190312 bytes (213MB)
• Detail pictures: Depend on distance from logos, size of logos, etc

Video

• 8 minutes of video
  • Each frame: 1280x720, 2764800 bytes (2MB)
  • NRT: 320x240, 230400 bytes (225KB)
  • Frame rate: variable, dependent on speed of rover/camera movement and distance (and angle) from moving items

Other data

• Prerecorded media: 10MB
• Round Trip media: 10MB

GLXP as indicated that the total mooncast size should be around 500MB (total 1GB).

Possible Hardware

• BeagleBoard
• Surveyor camera (based on Blackfin processor)

Approach

There are two components to this problem. One is the capture of the images/video. The other is how to get them to earth.

For the first part, it is suggested that we use JPEG2000. It is a high quality compression format with some neat properties, such as many progressive transmit/display modes (low quality first or low resolution first, for example). There is also a related video format called Motion JPEG2000. This allows one capture and storage format, which is relatively fast and light. The NRT video can be culled directly from the higher quality version without decompression and recompression.

The second part requires data management and protocol/communications systems. This is usually performed by the IHU, Integrated Housekeeping Unit - the main computer of the space craft. Being able to full utilise the communications bandwidth and have high priority information be not subject to high latency requires priority queuing and other protocol features.

Sending video

(Draft) Component diagram for the IHU:

Plan

Video Processing

• Research JPEG2000 and MJPEG2000 standards - A few minor changes to the final committee draft have been noted.
• Develop Proof of Concept (POC) culling program - Done for jp2 files with SOP markers http://github.com/llnz/poc_decimator/tree/master
• Analyse performance of POC program
• Investigate/develop/test asynchronous tasklet-like processing outside of IHU
• Develop culling tasklet

IHU

• Identify major common functional blocks
• Design interfaces for the functional blocks
• Develop Linux architecture support (mainly for testing)
• Develop core functional blocks
• Develop sample tasklets and applications
• Develop ARM architecture support (or likely flight platform)

Task - Propulsion Control Avionics

The goal of this task is to implement a variable throttle valve control mechanism which is controlled via pre-determined instructions on a CAN bus. In cooperation with ASRI's AUSROC 2.5 mission, the LN build team will develop the hardware and firmware required to receive instructions on a CAN bus and translate these to the motion of a ball valve which is ultimately used to control the propellant flow into the rocket engine.

The engineering of the throttle system has three main components:

i. Electronics

The electronic hardware interfaces to the CAN bus and to the motor control board.

At this stage, we have implemented this controller around an AVR microcontroller, specifically the Atmel ATmega328, combined with a Microchip MCP2515 CAN transceiver. The use of an AVR microcontroller which is compatible with the Arduino system is advantageous as it allows leverage of the ease-of-use of Arduino, our existing experience with Arduino and existing Arduino firmware technologies such as the Aiko framework.

(Interestingly, the Copenhagen Suborbitals team have recently found that an ATmega168 microcontroller continues to run normally when immersed in liquid oxygen at 90 K... the AVR doesn't appear to display any "cold bug" effects at these temperatures due to bandgap shifting or carrier freeze-out that can often cause silicon microprocessors to refuse to work at these very low temperatures.)

The servo drive board being used at this stage is the Rutex R2020. Two of these units have been made available to the LN build team by ASRI. The R2000 setup and tuning documentation from Rutex is valuable background reading on this device, as is the other documentation available on these devices from Rutex.

The main power supply that the Rutex servo drive board board takes (via the 16-pin IDC connector) is 24 V, but it requires little current, well under 1 A. If the electronics assembly is supplied with 24 V then this 24 V rail can also be supplied to a voltage regulator on the microcontroller board to provide the 5 V required for the microcontroller and CAN chipset. This is implemented on our boards at present via a LM2675-5.0 switching regulator. This means that 24 V needs to be supplied (over the CAN D-9 connector), and this powers up both boards; the microcontroller/CAN board, and the R2020 servo controller board.

We have determined that the main DC power bus on the AUSROC 2.5 launch vehicle will have ~24 V DC available, and the valve control electronics will be run off this, which will be cabled down into the valve fairing along with the CAN data pair.

The Rutex R2020 board has four large, high current terminals connecting to its internal H-bridge - two connect to the motor, and two connect to the main high-power supply which drives the motor. This motor requires a 60 V power supply to operate at its maximum speed. The continuous current draw of the motor is 5 A, although the peak motor current (the stall current) is 30 A. Building any kind of power supply which can supply 5 A at 60 V is expensive and difficult, and especially so in a launch vehicle where batteries must supply all the electric power, with significant limits to their volume and mass. We are presently supplying 50 V to the motor, with the current required, for testing and development on the ground via a simple linear power supply. 50 V, as opposed to the motor's rated maximum of 60 V, is sufficient for operation of the motor at a sufficiently high speed.

In the launch vehicle, the 50 V motor power supply will be supplied via a pack of lithium-polymer cells within the valve fairing.

The R2020 driver board is rated for a maximum current of 40 A, so under even the worst case motor stall condition (at 27.5 A) it should never be expected to be damaged. However, the main motor power supply should be fused, for example to protect the Rutex board against a motor short and to protect the relatively thin wires connected to the motor, as well as to prevent fire or explosion of the batteries. A 5A fuse seems to work well; even with the gearhead and valve attached to the motor, current consumption of the system is less than 5 A.

The position encoder mounted on the motor is an E5S? -50-250-IEG from US Digital. This encoder outputs 50 pulses per revolution. Therefore, at a rotational speed of 3000 rpm at the motor, the output is 15,000 pulses per minute, or 2500 Hz. This encoder is connected to a Rutex R2210 single-ended encoder interface board, which is connected via a standard Cat. 5 patch cable (both boards have RJ-45 connectors intended for this purpose) back to the R2020 board, completing the servomechanism control loop.

We can communicate with the R2020 board using a very simple direction/step interface.

With a step multiplier of 5, one clock step into the R2020 board rotates the motor until 5 steps have come back from the encoder. Since there are 50 encoder output pulses per revolution, this corresponds to 1/10 of a revolution.

Since the gearhead has a 50:1 gear ratio, this 1/10 of a revolution of the motor corresponds to only 1/500 of a revolution of the valve.

Therefore, to turn the valve by, say, 90 degrees, we need to send a series of 125 pulses to the R2020 controller, at a frequency of at least 500 Hz for appropriately fast motion.

The step multiplier can be set using the Rutex setup (Windows) software, and saved into the EEPROM on the R2020 board. Increasing this step multiplier can be required for fast motion, since the input hardware on the Rutex board can only sample the step signal up to some certain frequency, although a 5 x step multiplier, for example, decreases the positioning resolution of the system by a factor of 5. However, I think 1/500 revolution resolution is pretty good for what we need.

ii. Motor and mechanical powertrain

This subsystem comprises the electric motor itself, the mechanical powertrain between the motor and the propellant valve, and the electromechanical feedback mechanism which provides feedback of the valve position back to the electronic controllers and to the main flight computer (via the microcontroller and the CAN interface).

The motors used are MCG ID23900 brush motors. Here is a datasheet for this motor.

The physical dimensions of the mounting flange of the motor are consistent with the NEMA 23 standard specification. The ID23900 datasheet above says that its continuous torque is 0.42 Nm. This is "stepped up" by the 50:1 gearbox, so you get 21 Nm at the valve. 21 Nm is equal to 2.14 kg-m, or 214 kg-cm. However, the peak instantaneous torque available may be higher.

The existing gearheads are Bayside RA60-050 50:1 right-angle reduction gearheads. (Do we have some kind of manual or datasheet available for these gearheads?)

We now have most of the mechanical assembly complete, with the motor mounting holes re-machined and the motor bolted onto the gearhead assembly. We have sourced a couple of linear motion sensing potentiometers (Colvern LM10 equivalents, #317-780 from RS Components. We're currently designing and implementing exactly how the valve position sensor assembly will fit together.

The position sensors don't quite fit into the holes in the aluminium adapter block... the block requires just a tiny bit of re-machining to enlarge the holes.

We will ultimately enlarge the hole and drill and tap two blind holes on either side of it to screw the sensor onto the side of the block. (As far as I can tell, it doesn't matter which side this goes on, since the block is symmetrical, and can be turned if appropriate.)

Now... the actuator shaft of the valve sticks up into the adapter block, and it fits into the slot/receiver/socket thing on the end of the gearhead, which is also protruding a little way down into the other side of the interface block.

We may also need to mount one or two high-power resistors or other heating elements on the adapter block on the liquid oxygen valve to keep this valve warm and prevent it from freezing or sticking. These will be powered from the external power supply umbilical from the launchpad, in the case of the AUSROC 2.5 vehicle, which will be severed on launch.

iii. Propellant valves

The valves are stainless steel three-piece ball valves, made by Apollo, I think, with 1" Swagelok tubing compression fittings.

Do we know exactly what model of valves these are? Do we have any more documentation or a datasheet? I don't know.
The only markings on the valve are "1000 CWP USA" / "CII CF8M? ". 1000 CWP is cold working pressure (in psig), I don't know what CII means, and CF8M? is the specific metallurgical composition of the stainless steel.

If we assume that from fully closed to fully open corresponds to 90 degrees of angular motion, we can define 0 degrees to be 0% propellant flow and +90 degrees to correspond to 100% propellant flow. The propellant valves are required to transit from fully closed to fully open within not more than 250 milliseconds.

90 degrees of valve travel within 250 ms corresponds to an angular speed of 60 rpm (1 Hz), at the valve. Since that speed is stepped down by the 50:1 gearbox, this corresponds to 3000 rpm (50 rps) at the motor.

The motor's maximum rotational speed is quoted as being 5500 rpm, at a motor voltage of 60 V. Assuming that the motor speed scales linearly with the voltage, then, the minimum voltage required for a rotational speed of at least 3000 rpm is 33 V. A 50 V motor power supply should be perfectly adequate for this purpose.

The propellants used in AUSROC 2.5 are liquid oxygen (LOX) and kerosene. Specifically, I believe the fuel used in past AUSROC 2 firings has been commonly available Jet A1 (jet fuel), as opposed to something like RP-1.

The physical compatibility of the valve materials with cryogenic liquid oxygen is a challenging problem. Oxygen boils at 90 K (-183 degrees C), and the valve assembly needs to not only withstand this temperature but also to withstand the thermal shock associated with the temperature change when the liquid oxygen is initially introduced into contact with the valve assembly, rapidly cooling it down from room temperature to cryogenic temperatures.

The valve assembly needs to be mechanically stable under these thermal conditions and it needs to be able to operate, and operate reliably with the required performance, under these conditions.

Since the failure of the LOX valve to open properly due to icing was one of the main factors which led to the destruction of the first AUSROC II vehicle in 1992, it's certainly important to pay special attention to these issues surrounding the LOX valve assembly.

Pictures and links:

Motor, gearhead and valve assembly, with the valve attached to the gearhead.

Motor connected to Rutex R2020 board, with encoder interface also wired up.

(Photo courtesy of Andy Gelme - thanks!)

AVR / CAN controller boards, designed and assembled by Luke.

(Photo courtesy of Andy Gelme - thanks!)

The motor and gearhead assembly, showing the valve/gearhead adapter block and the (unconnected) motor encoder wiring.

Radar Altimeter

We are also interested in the possible application of software-defined radio (SDR) principles to the design of this altimeter.

Here is a description of the basic technical characteristics of the Chandryaan MIP altimeter (from here):

"The C-band radar altimeter will measure the altitude of the probe in the final descent phase from ~5 km till impact. The radar makes use of an FM-CW type transmitter with the centre and modulation frequencies of 4.3 GHz and 100 Hz respectively, and a transmitted output power of 1 W (CW) with a frequency deviation of ±50 MHz. The receiver has a sensitivity of –78 dBm. A data rate of 5 Kbits per second with an update rate of 100 measurements per second are envisaged. The antennae system has been designed to have a gain of +10 dB and a DSP processor has been used for data processing. The altimeter would have an accuracy of 2 m for heights measured up to 150 m and 3% of the measured height for the range between 150 m and 5 km. A basic field evaluation of the altimeter has been carried out using aircraft sorties and by using an onboard GPS as reference."

MIP radar altimeter key parameters:

• Frequency: C-Band, 4.3 GHz
• Output power: 1 W, continuous wave frequency modulated
• Sweep: 100 MHz (+-50 MHz)
• Sweep period: 100 Hz
• Output sample rate: 100 samples/sec
• Maximum range: 5 km
• Accuracy: 2m when range < 150m, 3% otherwise

Analysis of MIP radar altimeter:

• FFT: 200 times/sec, 64 point
• Max beat frequency: ~670 kHz
• Max sampling rate: ~1300 kHz
• Sampling rate decreases as range decreases, down to ~40 kHz?

Note: WLS could not find any vendor who could provide radar hardware 'out of the box' that has the range required.

Calculations of radar parameter support

Continuous Wave Frequency Modulated Radar

Below is a diagram that describes at a high level the main components of the radar system.

The FFT and calculation stages are done in software. It is also possible that we might perform the ramp generation in software.

Matjaž Vidmar's 4.3 GHz radar altimeters

Slovenian engineer Matjaž Vidmar has designed and built a C-band (4.3 GHz) radar altimeter intended for use on small aircraft - and he has released the designs as "open source"! (NOTE: Vidmar has put all the details up on a public webpage - but I don't know if he has specified any licensing arrangements.)

First-generation radar altimeter (analog signal processing, PIC microcontroller)

Second-generation radar altimeter (digital signal processing, ARM7 microcontroller)

Plus the board designs and source.

This design (the ARM7-based design) is apparently capable of down to 15 cm maximum resolution, and operation at altitudes between 0 and 5000 feet (1524 m).

Block diagram of Matjaž Vidmar's ARM DSP based 4.3 GHz vertical navigation radar: see http://lea.hamradio.si/~s53mv/avnr/adesign.html

Site Tools of the LunarNumbat Web

Lunar Numbat Resources

• Reference Material
• Suitable Software
• Space Science Groups
  • Australian Space Groups
  • New Zealand Space Groups
• Lunar Numbat Team Resources

Miscellaneous Development Tasks

Some projects we do are for educational purposes or even just for fun. These currently include:

• Class C Rocket Launches

• Class G Rocket Launches

Rocketry

NZ Model Rocketry Association http://www.nzrocketry.org.nz/

Aerospace Education http://www.rockets.co.nz/
Education and supply company for model rocketry.

Rocketlab http://www.rocketlab.co.nz/
New (2007) company that is going to build sounding rockets with the eventual goal of suborbital then orbital flights.

Kiwi2Space http://www.kiwi2space.co.nz/
New Zealand team competing in the N-Prize

Spaceflight

NZ Spaceflight Association http://www.nzspace.org.nz/
Group that mostly "sits back and watch" (no plans to do any activities itself except talk).

NZL Sat
Geostationary satellite owner?/manager?/communications licensee (don't bother to visit their website, nothing there)

Massey University Student Space Exploration & Technology Initiative http://www-ist.massey.ac.nz/sseti/
Ground station? and involvement in ESA's SSETI

KiwiSat http://www.kiwisat.org/
NZ Amateur Satellite building project. Plenty of Massey University help, mostly vacuum chamber usage.

-- LeeBegg - 13 Feb 2009

Lunar Missions - Contemporary

-- MarcoOstini - 16 Feb 2009

Lunar Missions - Historic

-- MarcoOstini - 16 Feb 2009

Books

Lunar imaging camera (LIC) : pre-flight tests and operation plan
Akiko M. Nakamura
Japan Aerospace Exploration Agency, 2005.

Thermal characteristics of the moon
Edited by John W. Lucas.
MIT Press, 1972
ISBN 0262120585

A Primer in lunar geology
Ronald Greeley, Peter Schultz, editors.
Ames Research Center, National Aeronautics and Space Administration, 1974?

New views of the Moon
editors: Bradley L. Jolliff
Mineralogical Society of America, 2006.
ISBN 0939950723

Apollo 16 preliminary science report
prepared by NASA Manned Spacecraft Center.
Scientific and Technical Information Office, National Aeronautics and Space Administration, 1972.

The Exploration of Space
Arthur C. Clarke

Space Mission Analysis & Design
James Wertz and Wiley Larson
ISBN: 0-7923-0971-5
LoC? : TL 790.5732
Dewey: 629.4'1'088

Online Resources

Lunar Missions - Contemporary

Lunar Missions - Historic

-- JonathanOxer - 12 Feb 2009

Eagle

Easy to use, schematic capture and printed circuit board design package.

http://www.cadsoftusa.com/

Suitable Software

So as to avoid re-inventing the wheel and to share experience, here are a collection of FOSS or other packages and applications that may prove helpful in the overall Lunar Numbat endeavour. Many of the following should be available in Distro repositories.

(In time this page will likely include a reference table.)

Printed Circuit Board design

• Eagle - PCB design, including schematic capture, board layout, and autorouter.

Simulators

• OpenRocket - Model rocket simulator

Stellar Reference

• Celestia - 3D astronomy app. Dial up date/time/location and observe.
• KStars - Desktop planetarium depicting an accurate simulation of the night sky
• astronomical almanac - Orbital positions of planetary bodies + performs rigorous coordinate reductions

Spacecraft Reference

• Gpredict - Predict the location and visiability of satellites from downloadable TLE files.

50 Recent Changes in LunarNumbat Web retrieved at 01:57 (GMT)

See also: RSS feed, recent changes with 50, 100, 200, 500, 1000 topics, all changes

the LunarNumbat wiki

WLS Development Tasks

As we work in cooperation with our partner White Label Space, the areas of technical support that are our focus to develop and deliver are:

• Propulsion Control Avionics

• HD Video & Still Transmission

• Radar Altimeter

ASRI Development Tasks

In cooperation with the Australian Space Research Institute (ASRI) we're working to develop and deliver:

• Generic Telemetry Module

• Propulsion Control Avionics

Miscellaneous Development Tasks

Some projects we do are for educational purposes or even just for fun. These currently include:

• Class C Rocket Launches

• Class G Rocket Launches

Lunar Numbat Resources

• Reference Material
• Suitable Software
• Space Science Groups
  • Australian Space Groups
  • New Zealand Space Groups
• Lunar Numbat Team Resources

• Site tools for LunarNumbat wiki

Results from LunarNumbat web retrieved at 01:57 (GMT)

See also the faster WebTopicList

• LunarNumbat Web
• Create New Topic
• Index
• Search
• Changes
• Notifications
• Statistics
• Preferences

• TWikiGuest - example@your.company

Web Changes Notification Service

Each TWiki web has an automatic e-mail notification service that sends you an e-mail with links to all of the topics modified since the last alert.

Users subscribe to email notifications using their WikiName or an alternative email address, and can specify the webs/topics they wish to track using one of these bullet list formats:

three spaces * [ webname . ] wikiName - SMTP mail address
three spaces * [ webName . ] wikiName
three spaces * SMTP mail address
three spaces * SMTP mail address : topics
three spaces * [ webname . ] wikiName : topics

In the above examples, topics is a space-separated list of topic names. The user may further customize the specific content they will receive using the following formats:

• Specify topics without a Web. prefix
• Topics must exist in this web.
• Topics may be specified using * wildcards
• Each topic may optionally be preceded by a '+' or '-' sign. The '+' sign means "subscribe to this topic" (the same as not putting anything). The '-' sign means "unsubscribe" or "don't send notifications regarding this topic". This allows users to elect to filter out certain topics (and their children, to an arbitrary depth). Topic filters ('-') take precedence over topic includes ('+').
• Each topic may optionally be followed by an integer in parentheses, indicating the depth of the tree of children below that topic. Changes in all these children will be detected and reported along with changes to the topic itself. Note This uses the TWiki "Topic parent" feature.
• Each topic may optionally be immediately followed by an exclamation mark ! or a question mark ? with no intervening spaces, indicating that the topic (and children if there is a tree depth specifier as well) should be mailed out as complete topics instead of change summaries. ! causes the topic to be mailed every time even if there have been no changes, ? will mail the topic only if there have been changes to it. This only makes sense for subscriptions.

For example: Subscribe Daisy to all changes to topics in this web.

   * daisy.cutter@flowers.com

   * daisy.cutter@flowers.com: Web*

   * TWiki.DaisyCutter: Petal* (1) TWiki.WeedKillers (3) Pretty*Flowers

   * TWiki.StarTrekFan: Star* - *Wars - *sInTheirEyes - *shipTroopers

   * daisy@flowers.com: TWiki.NewsLetter?

   * buttercup@flowers.com: TWiki.NewsLetter! (1)

   * TWiki.GardenGroup: TWiki.AllNewsLetters? (3)
   * petunia@flowers.com: - TWiki.ManureNewsLetter

If a TWiki group is listed for notification, the group will be recursively expanded to the e-mail addresses of all members.

Tip: List names in alphabetical order to make it easier to find the names.

Note for System Administrators: Notification is supported by an add-on to the TWiki kernel called the MailerContrib. See the MailerContrib topic for details of how to set up this service.

Note: If you prefer a news feed, point your reader to WebRss (for RSS 1.0 feeds) or WebAtom (for ATOM 1.0 feeds). Learn more at WebRssBase and WebAtomBase, respectively.

Related topics: WebChangesAlert, TWikiUsers, TWikiRegistration

LunarNumbat Web Preferences

The following settings are web preferences of the LunarNumbat web. These preferences overwrite the site-level preferences in TWiki.TWikiPreferences and Main.TWikiPreferences, and can be overwritten by user preferences (your personal topic, eg: TWikiGuest in the Main web).

Web Preferences Settings

These settings override the defaults for this web only. See full list of defaults with explanation. Many of the settings below are commented out. Remove the # sign to enable a local customisation.

• List of topics of the LunarNumbat web:
  • #Set WEBTOPICLIST = Changes  |  Index  |  Search  |  Go

• Web-specific background color: (Pick a lighter one of the StandardColors).
  • Set WEBBGCOLOR = #D0D0D0
  • Note: This setting is automatically configured when you create a web

• Image, URL and alternate tooltip text of web's logo.
  Note: Don't add your own local logos to the TWikiLogos topic; create your own logos topic instead.
  • #Set WEBLOGOIMG =
  • #Set WEBLOGOURL = http://TWiki.org/
  • #Set WEBLOGOALT = Powered by TWiki

• List this web in the SiteMap. If you want the web listed, then set SITEMAPLIST to on, do not set NOSEARCHALL, and add the "what" and "use to..." description for the site map. Use links that include the name of the web, i.e. LunarNumbat.Topic links.
  Note: Unlike other variables, the setting of SITEMAPLIST is not inherited from parent webs. It has to be set in every web that is to be listed in the SiteMap
  
  • Set SITEMAPLIST = on
  • Set SITEMAPWHAT = Lunar Numbat project pages
  • Set SITEMAPUSETO = ...collaborate on Lunar Numbat
  • Note: Above settings are automatically configured when you create a web

• Exclude web from a web="all" search: (Set to on for hidden webs).
  • Set NOSEARCHALL =
  • Note: This setting is automatically configured when you create a web

• Prevent automatic linking of WikiWords and acronyms (if set to on); link WikiWords (if empty); can be overwritten by web preferences:
  • #Set NOAUTOLINK =
  • Note: You can still use the [[...][...]] syntax to link topics if you disabled WikiWord linking. The <noautolink> ... </noautolink> syntax can be used to prevents links within a block of text.

• Default template for new topics for this web:
  • WebTopicEditTemplate? : Default template for new topics in this web. (Site-level is used if topic does not exist)
  • TWiki.WebTopicEditTemplate: Site-level default topic template

• Comma separated list of forms that can be attached to topics in this web. See TWikiForms for more information.
  • Set WEBFORMS =

• Users or groups who are not / are allowed to view / change / rename topics in the LunarNumbat web: (See TWikiAccessControl). Remove the # to enable any of these settings. Remember that an empty setting is a valid setting; setting DENYWEBVIEW to nothing means that anyone can view the web.
  • Set DENYWEBVIEW =
  • Set ALLOWWEBVIEW =
  • Set DENYWEBCHANGE =
  • Set ALLOWWEBCHANGE = LnGroup?
  • Set DENYWEBRENAME =
  • Set ALLOWWEBRENAME =

• Users or groups allowed to change or rename this WebPreferences topic: (e.g., TWikiAdminGroup)
  • Set ALLOWTOPICCHANGE = TWikiAdminGroup
  • Set ALLOWTOPICRENAME = TWikiAdminGroup

• Web preferences that are not allowed to be overridden by user or topic preferences:
  • Set FINALPREFERENCES = NOSEARCHALL, ATTACHFILESIZELIMIT, WIKIWEBMASTER, WEBCOPYRIGHT, WEBTOPICLIST, DENYWEBVIEW, ALLOWWEBVIEW, DENYWEBCHANGE, ALLOWWEBCHANGE, DENYWEBRENAME, ALLOWWEBRENAME

Help on Preferences

• A preference setting is defined by:
  3 or 6 spaces * Set NAME = value
  Example:
  • Set WEBBGCOLOR = #FFFFC0
• A preferences setting can be disabled with a # sign. Remove the # sign to enable a local customisation. Example:
  
  • #Set DENYWEBCHANGE = UnknownUser
• Preferences are used as TWikiVariables by enclosing the name in percent signs. Example:
  • When you write variable %WEBBGCOLOR% , it gets expanded to #D0D0D0
• The sequential order of the preference settings is significant. Define preferences that use other preferences first, i.e. set WEBCOPYRIGHT before WIKIWEBMASTER since %WEBCOPYRIGHT% uses the %WIKIWEBMASTER% variable.
• You can introduce your own preferences variables and use them in your topics and templates.

Related Topics

• TWiki.TWikiPreferences, Main.TWikiPreferences - site-level preferences
• TWikiUsers - list of user topics. User topics can have optional user preferences
• TWikiVariables - list of common %VARIABLES%
• TWikiAccessControl - explains how to restrict access by users or groups

Tools

• Rename, move or delete this web:
  • Rename/move/delete web..., looking for references in all public webs - See also: ManagingWebs

Web Search

Searched: \.*

Warning

Can't INCLUDE TWiki.WebSearchAdvanced repeatedly, topic is already included.

Statistics for LunarNumbat Web

Notes:

• Do not edit this topic, it is updated automatically. (You can also force an update)
• TWikiDocumentation tells you how to enable the automatic updates of the statistics.
• Suggestion: You could archive this topic once a year and delete the previous year's statistics from the table.

Create New Topic in LunarNumbat Web

Once you have created the topic, consider adding links in related topics to the new topic so that there are more ways people can discover it.

• ASRIDevelTasks
• AboutLN
• AustralianSpaceGroups
• BuildTeam
• ContribTeam
• CurrentDevelTasks
• HowToJoinLN
• IRCChatLog
• LNPatrons
• LNTRASRIDevTaskThrttlCtrlAvncs
• LNTRWLSDevTaskHDVid
• LNTaskClassCRockets
• LNTaskClassGRockets
• LNTaskGenTelMod
• LNTaskHDVideoStillXmition
• LNTaskPropControlAvionics
• LNTaskRadarAltimeter
• LNTeamResources
• LNWebUtilities
• LaunchClassAusRoc25
• LaunchClassG
• LaunchClassHobby
• LaunchClassZuni
• LunarNumbatResources
• MiscDevelTasks
• NewZealandSpaceGroups
• RefLunarMissionNow
• RefLunarMissionThen
• ReferenceMaterial
• SuitSwareEagle
• SuitableSoftware
• TalkLCA2010
• TalkLCA2010HDVid
• TalkLCA2010RadAlt
• TalkLCA2010ThrotAv
• WebAtom
• WebChanges
• WebHome
• WebIndex
• WebLeftBar
• WebNotify
• WebPreferences
• WebRss
• WebSearch
• WebSearchAdvanced
• WebStatistics
• WebTopicCreator
• WebTopicList

See also the verbose WebIndex.