Venus Express Orbiter Reception - Latest news - updated: (15/05/2009 14:11:23 +0100)
The original page on Venus Express reception is available here
Update from 16th March 2009 - VEX is a consistent signal on 8419.209 and falling, as per the FFT below;
Update from 5th August 2007 - Nice signal from VEX RX'd on 8419.227 and falling.
Update from 5th May 2006 - A nice copy of the beacon from VEX this morning. The space craft is currently 92559499.92 miles from Earth.
Update from 2nd May 2006 - A nice signal from VEX this morning. Using the optimised LNA, a 3dB SNR increase has been achieved. The space craft is currently 90429401.88 miles from Earth.
Update from 25th April 2006 - VEX continues to be an easy to receive space-craft. The signals are consistently 15 to 20dB above the noise. Venus is currently 85497016.68 miles away from Earth. The calculated frequency for VEX should be 8418.703 but its actually being received on 8418.714 due to its orbit around Venus.
Update from 12th April 2006 - A strong signal from VEX today! almost the same strength as MRO.
As can be seen from the picture above, the signal is almost 20dB over noise, which isn't bad considering the distance. There is a good probability that ESA are running Doppler ranging tests for orbit determination. No sidebands could be seen on this signal meaning that no data transfer is taking place. There is a sound file here of the signal from Venus Express. You should process it in a FFT program such as Spectran to see the Doppler shift. The picture below is from the SDR-14, used to locate the carrier initially. The actual frequency this was received on was 8418.6977MHz, where as the actual Doppler calculation based on Venus makes the receive frequency 8418.695081 MHz, so when looking at the audio with Spectran, you could miss the signal!
Update from 11th April 2006 - ESA's Venus Express has reached the planet, and is now in orbit! congratulations to all at the ESA!
The current frequency at 09:25 GMT was 8418.694 MHz, but then at 09:26 GMT it jumped -4 KHz to 8418.690 presumably due to a ground commanded frequency change. Its estimated that the x-band signal was re-acquired here at around 09:19 GMT (too busy manually tracking the antenna and working out Doppler shifts etc ;-)). As can be seen from the above FFT, the Doppler shift is moving the other way! The signal actually appears to be stronger now than when VEX was in transit. According to the ESA press conference, shortly after entering orbit, ESA commanded the x-band ranging mode, so perhaps this is what the frequency shift was.
Update from 10th April 2006 - VEX goes to orbit insertion tomorrow! ESA story here
The above Spectran shot shows the Doppler shift of the space craft, the signal is weak and not copy able in a CW filter bandwidth, so the only way to see it is in FFT. From the ESA website: 11/04/2006 11.07CEST - X-band transmitter on: The X-band transmitter of the high-gain antenna HGA1 will be switched on for the first time in the mission, and will start sending Earth information about the health status of the spacecraft.
An update from 17th March 2006 - recent reception news for the MRO is available here.
VEX (Venus Express) is currently in transit to Venus where it will orbit and perform science. The first signals were received from VEX on the 5th of December 2005 at 15:50UTC, using the 1m offset dish, but the space craft was local, at just over 4 million miles away from Earth.
This morning, at at distance of 52374571 miles, the signal is detectable, but not strong. It was just loud enough to be audible in the head phones. In the Spectran FFT, the signal can easily be seen, it had around 100Hz per minute of Doppler.