Tag Archive | f’sati

No, no, no! It goes like this…

ZACUBE-01

I felt compelled to write this post after seeing the umpteenth, often very wrong, article on what we are doing in the CubeSat program at F’SATI and CPUT. The latest one comes from AMSAT-UK (uk.amsat.org/8930). So here goes…

Students at CPUT/F’SATI have been busy building the 1U CubeSat, ZACUBE-01 which will carry a HF beacon, beaconing at a frequency of 14.099 MHz. The 1U was supposed to be a quick short term, fast track mission to be completed before the planned later 3U mission.

Jason, Nyameko and Danie

Jason, Nyameko and Danie

The ZACUBE-01 mission main payload is its HF beacon. A small low resolution camera was also fitted as an extra. The spacecraft will also, at times, beacon on UHF. ZACUBE-01 conforms to the 1U CubeSat standard and weighs less than 1.33 kg. Nominally ZACUBE-01 will be spin stabilised in a Y-Thomson spin using two magnetorquers. TT&C will operate from the ground station on campus at CPUT with VHF uplink and UHF downlink.

Nominal launch date for ZACUBE-01 at this stage is middle November 2012 with the launch brokered through ISIS.

A big part of both missions is post-graduate training of students, as F’SATI is a post-graduate research centre focussing on Satellite Engineering. The science partner for the ZACUBE-01 mission is the SANSA Space Science directorate (formerly the Hermanus Magnetic Observatory).

ZACUBE-01 in ISIS testPOD

ZACUBE-01 in ISIS testPOD

Most of the numbered points in the AMSAT-UK post relates to the planned 3U mission. The 3U mission will most likely have a higher resolution imager than the 1U mission, store and forward payload, L to S-band transponder and three axis ADCS. The novel ADCS is being developed by the University of Stellenbosch.

The 3U will also carry an S-band transmitter developed at F’SATI/CPUT. This transmitter is also being delivered to Clyde Space for use in the UKube-1 mission and is also for sale through them.

ZACUBE-01 uses a UHF/VHF radio transceiver developed at F’SATI that can operate at 1200 and 9600 bps. The transceiver has selectable transmit power levels up to 2 watt.

Oh… and the picture in the AMSAT-UK article shows Francois Visser (F’SATI Chief Technical Architect) unveiling ZACUBE-01, SANSA CEO Dr Sandile Malinga was present but cannot be seen in the photo.

ZACUBE-01

First contact

I guess it is about time to get things going. The ground station at F’SATI has reached a point where we can start to track satellites. There is however quite a bit work still to be done. One of which is to check that we are actually pointing in the direction we are pointing in 🙂 . SANSA Space Science (former HMO) in Hermanus was kind enough to lend me a proper nice magnetic compass, so I will probably be aligning our antennas to north in the next week or two. Even with the not-so-accurate pointing we have been able to successfully tack some satellites. Most of these however were morse (CW) beacon payloads. That is, until Friday.

Friday I decided to try and see if I could get some telemetry data from Delfi-C3. I was not very optimistic because up to that point we have not had much luck receiving telemetry data and the maximum elevation for Friday morning’s pass was only 26°.

So with SatPC32 and RASCAL fired up I started tracking the pass. The point of maximum elevation came and went without so much as a peep and with the CubeSat starting to move closer to the horizon I resorted to manual adjusting of the radio, rather than having SatPC32 do it.

After a bit of fiddling and tuning we started to hear the distinctive sound of telemetry data over the radio, but no decoded messages were showing up in RASCAL yet. So more fiddling and tuning was needed. By this point the satellite was getting pretty low on the horizon and I was about to give when two telemetry messages showed up in the little terminal screen of RASCAL.

We had successfully received our first telemetry data from a CubeSat using our newly constructed ground station!

And with that the first pass/tracking report was sent off from F’SATI to the Delfi-C3 Team in the Netherlands. I was quite impressed that we were able to track Delfi to almost on the horizon with our ground station (LNA’s enabled). Here are some of the datails:

Our location:   JF96HB (33° 55′ 55.6 S 18° 38′ 35.8 E)
AOS (Acquisition of signal – start of pass): 08:55 UTC
LOS (Los of signal – end of pass): 09:08 UTC

Primary telemetry downlink frequency near LOS: 145.861 MHz.

Equipment:
M² Antennas (VHF/UHF): 2MCP22 and 436CP42
Advanced Receiver Research LNAs
Icom IC-910H transceiver

And the telemetry data received via RASCAL looks a little something like this:

from: DLFIC3 to: TLM    a8 98 9b 40 40 40 00 88 98 8c 92 86 66 01 03
f0 e1 08 a0 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 01 00 01 00 01 00
01 00 01 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 c3 a6 00 00 00 00 4e 5e 01 1d a1 05 a9 7b 52 00 03 63 60 1e
00 00 00 00 00 00 00 00 00 00 50

As far as I can tell this is telemetry data from the AWSS (Autonomous Wireless Sun Sensor) payload on Delfi. Hopefully we’ll be able to get more data on the next attempt early next week.

Ground station - mast and antennas

Ground station - mast and antennas