Category Daily Updates

Jan 31 2012

Bright sparks redefine propulsion

CubeSats, like STRaND-1, are essential for the breakthrough of new technologies in the space industry. The relatively inexpensive CubeSat enables institutes and companies to test technologies and gain valuable flight heritage without risking millions (or even billions) of pounds of investment.

STRaND-1, the joint project between SSTL and the Surrey Space Centre (SSC), is one of these exciting experimental satellites and it’s not only its smartphone that makes it exceptional. Engineers at the Surrey Space Centre have also developed a unique mass and power saving plasma propulsion system to fly on the satellite. This system will be the first propulsive technology to provide very precise attitude control and pointing.

Pulsed Plasma Thruster flight hardware
Pulsed Plasma Thruster flight hardware

STRaND-1 will carry both a Resistojet and a Pulsed Plasma Thruster (PPT) module on board. The PPT will consist of eight micro thrusters; four located at the top of the satellite stack and four located at the bottom. The micro thrusters operate by discharging a discrete train of pulses. Each pulse is a plasma discharge that forms between two metal electrodes, much like a small lightning bolt or electrical spark. The spark erodes the metal from the electrodes and electromagnetics accelerate the eroded mass out of the nozzle, which produces thrust. This is known as the Lorentz force.

Surrey Space Centre has developed two ways of minimising mass and volume. Firstly, the electrodes which form the plasma discharge also function as the propellant. As metal is highly dense, more propellant can be stored in a smaller volume than that of conventional chemical propulsion systems. The total weight of the propellant for the whole STRaND-1 PPT system is just 10g.

Secondly, Surrey Space Centre’s novel discharge initiation system uses a mechanical contact trigger built out of a tiny piezoelectric motor only 5mm in length. This takes up less space than the conventional spark plug system which requires volume intensive circuitry.

The Pulsed Plasma Thruster module firing
The Pulsed Plasma Thruster module firing

Not only does SSC’s PPT module reduce mass and volume, it also uses less power than other propulsion systems. Between each pulse, energy is stored in a capacitor. This substantially reduces the power requirements for the thruster, making it perfect for small satellites such as STRaND-1. In fact, the power requirement for the system flying on STRaND-1 is only 1.5W, about the power needed to operate a bicycle light.

If successful, the STRaND-1 PPT will be the first propulsion system to provide full axis control on this class of satellite. Having an active propulsion system in orbit would open up new possibilities for future CubeSat missions like rendezvous and docking, and flyby inspection. The flight heritage and experience gained in using the PPT on STRaND-1 could then be transferred and scaled for other SSTL missions providing a low cost, mass and volume solution for future endeavours.

For updates on STRaND-1, visit the Facebook page or follow @SurreyNanosats on Twitter!

Read about STRaND-1 in a free sample issue of OSCAR News at http://www.uk.amsat.org/on_193_final.pdf

Jan 31 2012

Masat-1 satellite

Masat-1 satellite will use the amateur radio frequency band to downlink telemetry data. The downlink data will not be encrypted, so everyone will be able to receive it, decode and process.

Frequency bands employed

  • Earth-to-satellite (uplink) on 2 m
  • Satellite-to-Earth (downlink) on 70 cm

Masat-1 callsign: HA5MASAT
Satellite’s telemetry transmission frequency: 437.345 MHz +/- 10 kHz Doppler

 

The reason for the Doppler shift is the orbital velocity of 7-8 km/s, as when a transmitter is getting closer to the receiver the received signal’s frequency is shifted upwards, and when the transmitter is getting away from the receiver the received signal’s frequency is shifted downwards.

The satellite’s modulation scheme: (A1A) CW and 2-GFSK with 625 Hz frequency deviation (CW is clocked at 120 characters/minute, which is well-audible by ear).

Data rate of the 2-GFSK digital packets: 625 or 1250 bits/second (a PC with sound card and demodulation SW is required)

 

Minimum list of devices required for receiving Masat-1

  • antenna suitable for the 70 cm band (in open air, pointed towards the sky)
  • tuneable radio receiver with 70 cm SSB USB mode, such as FT-817, FT-897D, TS-2000, etc.
  • PC with sound card, running the telemetry packet decoder SW in JAVA environment. The demodulator software can be downloaded from this website.

Continue reading →

Jan 30 2012

Vega Satellite Deployments

Artists impression of Vega launch

Artists impression of Vega launch

Vega is presently scheduled to launch at 0900 UT on Thursday, Feb 9, with eight student built amateur radio satellites.

The launcher will first deploy the main payload,  the LARES the Laser relativity Spacecraft and will then make an additional firing of the final Attitude & Vernier Upper Module (AVUM) stage before deploying the secondary payloads. the planned timing for these deployments are as follows:

T0+ 4245.30secs first PPOD, with (in order of ejection) XatCobeo, e-st@r, and Goliat
T0+ 4255.30secs second PPOD, with (in order of ejection) Robusta, MaSat-1 and  PW-Sat
T0+ 4265.30secs third PPOD, with UniCubeSat only
These Cubesats will not deploy their antennas until >1800 seconds after they leave their PODS
T0+ 4275.30secs  AlmaSat-1 – it is not known how soon this spacecraft will start transmitting after deployment

Pre-launch TLEs have not yet been made available but all the teams will certainly appreciate reception reports on the day. All observers are being encouraged to join the CubeSat IRC chat channel to pass on their news and comments in realtime. Using the irc.freenode.net server please join the #cubesat channel. It is recommended that you change you nickname to “name_callsign”.

For frequencies of the eight student amateur radio satellites to be deployed by Vega see http://www.uk.amsat.org/4180

Vega Elliptical Orbit Video http://www.uk.amsat.org/4119

Jan 30 2012

Working the FM-Sat SO-50

Saudisat SO-50

Saudisat SO-50

Simon 2E0HTS has released a video that shows him making contacts via the amateur radio satellite SO-50.

This satellite carries an FM transponder that receives signals on 145.850 MHz and retransmits them on 436.795 MHz (+/- 10 kHz Doppler shift). Operation is a little more complex that some other satellites since the transponder needs to initially be activated by a CTCSS (PL) tone of 74.4 Hz which starts a 10 minute timer and then a 67 Hz tone is used for the contact.

The order of operation is: (allow for Doppler as necessary):
1) Transmit on 145.850 MHz with a tone of 74.4 Hz to arm the 10 minute timer on board the spacecraft.
2) Now transmit on 145.850 MHz (FM Voice) using 67.0 Hz within the 10 minute window.
3) Sending the 74.4 Hz tone again within the 10 minute window will reset the 10 minute timer.

You can set the memory channels in your handheld as follows:
Ch     TX              RX            CTCSS
1     145.850     Timer Reset 74.4 Hz
2     145.850     436.805       67 Hz
3     145.850     436.800       67 Hz
4     145.850     436.795       67 Hz
5     145.850     436.790       67 Hz
6     145.850     436.785       67 Hz
At the start of the pass tune to 436.805 and then decrease the frequency during the 10+ minute pass.

Watch Simon 2E0HTS working CT2GOY, F0FVK, SP5XSD & EA6SW/portable 6, via SAUDISAT 1C SO-50

Simon 2E0HTS Ham Radio Operator Blog http://www.hamradiooperator.blogspot.com/

You can read Howard G6LVB’s SO-50 article at http://www.g6lvb.com/Articles/operatingSO50.htm

SO-50 http://www.amsat.org/amsat-new/satellites/satInfo.php?satID=4

N2YO Real Time Satellite Tracking http://www.n2yo.com/

Satscape Satellite Tracking Software http://www.satscape.info/home/?q=node/2

John Heath G7HIA’s article  ‘Getting started on amateur radio satellites’ can be downloaded from http://www.uk.amsat.org/267

Jan 30 2012

Student Amateur Radio Satellites on Vega

Artists impression of Vega launch

Artists impression of Vega launch

Vega is planned to launch on Monday, February 13, between 1000-1300 UT from the ESA launch site at Kourou in the Caribbean. It will carry eight student built amateur radio satellites comprising seven CubeSats and a microsatellite called ALMASat-1.

ALMASat-1 – University of Bologna, Italy
437.465 MHz 1200 bps FSK and 2407.850 MHz
http://www.almasat.unibo.it/02_projects/almasat-1/almasat1.htm

e-st@r – Politecnico di Torino, Italy
437.445 MHz 1200 bps AFSK
http://areeweb.polito.it/ricerca/E-STAR/

Goliat – University of Bucharest, Romania
437.485 MHz 1200 bps AFSK
http://www.goliat.ro/

MaSat-1 – Budapest University of Technology and Economics, Hungary
437.345 MHz GFSK 625/1250 bps, CW
http://cubesat.bme.hu/en/

PW-Sat1 – Warsaw University of Technology, Poland
There are 5 modes of operation on the 145.900 MHz downlink:
– Receive only – no downlink
– CW Beacon CW – On-Off Keying (OOK) CW 12 WPM
– BPSK Beacon – BPSK 1200 bps AX25 (1 frame on 20 sec)
– Control communication mode. Downlink BPSK 1200 bps AX25
– Voice Repeater mode (aka “AO-16” mode) – uplink 435.020 MHz FM and downlink 145.900 MHz DSB
http://tinyurl.com/CubeSatPW-Sat

Robusta – University of Montpellier 2, France
437.325 MHz? (website says now 437.350 MHz) 1200 bps FM telemetry with one data burst of 20 secs every 1 min
http://www.ies.univ-montp2.fr/robusta/satellite/?lang=en

UNICubeSAT -University of Rome, Italy
437.305MHz 9600 bps FSK
http://www.gaussteam.com/index.php?option=com_content&view=article&id=97%3Aunicubesat&catid=36%3Aunicubesat&Itemid=145

XaTcobeo – Universidade de Vigo, Spain
437.365 MHz FFSK with AX.25
http://www.xatcobeo.com/

Watch the launch live at http://www.videocorner.tv/

The student teams have requested reception reports. All observers are being encouraged to join the CubeSat IRC chat channel to pass on their news and comments in realtime. You will need an IRC client such as ChatZilla for Firefox or mIRC to join the cubesat chat. Use the irc.freenode.net server. Then join the #cubesat channel. Many users set their chat nickname to “name_callsign”.

Preliminary Vega TLE’s (KEPS) for launch at 1000, 1100 and 1200 UT here

Assuming a 1000 UT launch the satellites should deploy their antennas and start transmitting at about 1140 UT. It looks like the first to get good reception will be Central America followed quickly by a pass up the East coast of North America. The first pass for the United Kingdom should be a horizon skimmer across the NW at around 1207 UT.

Vega Elliptical Orbit Video http://www.uk.amsat.org/4119

N2YO Real Time Satellite Tracking http://www.n2yo.com/

Satscape Satellite Tracking Software http://www.satscape.info/home/?q=node/2 

IZ8BLY Vox Recoder http://antoninoporcino.xoom.it/VoxRecorder/

Free Sound Recorder http://www.sound-recorder.biz/freesoundrecorder.html

For the latest information on newly launched satellites check the AMSAT Bulletin Board (AMSAT-BB) http://www.amsat.org/amsat-new/tools/maillist/

Jan 28 2012

CUSat-1/2 to launch on SpaceX

CUSat-1/2

The IARU amateur satellite frequency coordination panel have agreed frequencies for CUSat-1/2, planned to launch on a SpaceX mission in the last quarter of 2012.

CUSat-1/2 is a 45kg satellite that will split into two parts sometime after separation from the launcher. Image and positioning data will be downlinked using 9k6 AX25 packet on 70cm from a 2 watt transmitter. Cross linking between the two parts will also take place on 70cm.

The coordinated frequencies are:
– CUSat-1   437.405 MHz
– CUSat-2   437.485 MHz
– Cross link 437.305 MHz

Using centimeter accuracy carrier-phase differential GPS, the two satellites will perform autonomous relative navigation. One satellite will capture imagery of the other satellite and send these images to a ground station on Earth for the reconstruction of a 3-D model of the partner satellite. The images will also act to verify the relative GPS implementation. Doing so will demonstrate how one spacecraft can diagnose the structural health and configuration of another.

CUSat http://cusat.cornell.edu/