Author Archives: Marco S.

International Feedback and acknowledgements

4M has performed its flyby this night bteween 0030 and 0215 UTC.

From now on, please use either the tracking information on our website or use the AFTER.TXT TLE  that has been provided earlier. Here is the link for your convenience :

As soon as we have refined trajectory, I’ll update the TLE and provide it on this blog.

Here at LuxSpace, we are really thankful and grateful to all the RadioAmateur community who definitely is a major actor of the success of this mission. Special thanks to Roland PY4ZBZ who was the first to send his report (and allowed me to feel relieved)

I reproduce here his mail:

Subject: 4M received in Brazil !

First transmission !

191500  0 -27  5.491  -19 50                                           
191600  0 -25  2.020  -19 29                                           
191700  0 -25  8.491  -19 17                                           
191800 16 -10  1.845 -127  1*      110V222A +33C             1   0   0.0
191900 20  -9  1.847 -127  3*      MANFRED FUCHS             1   0   0.0
192000 18 -11  1.855 -124  2*      RNODATA                   1   0   0.0
192100 16 -10  1.857 -124  1*       VISIONARY                1   0   0.0
192200  6 -17  1.855 -121  3*      LX0OHB-4M0000             1   0   0.0
192300 12 -15  1.855 -118  3*      149V234A -16C             1   0   0.0
192400  8 -16  1.852 -116  1*      HUMOROUS  SUC             1   0   0.0
192500  3 -16  1.892 -110  3*      RA. C3B65U                1   0   0.0
73 de Roland PY4ZBZ GH70un


Thanks also to Wayne VK5APN, who awakened me several times in the night, he really committed and his mail is also worth to reproduce:

Thanks for the fun and excitement here in Australia and the nice chat on the phone.
Arrived 30min late for work, but that is fine
Thanks heaps for the challenge and fun.  Sure to be monitoring when I get home.


Special thanks also to LX1DB, Willy,  Lucien, F1TE and the quality of his reports, Edward, KL7UW, Dave KB5WIA and so many others who contributed.

So far, we had reports from Europe, China, Japan, Australia, New Zealand, Argentina, Brazil, Malaysia, Mexico, India, Russia, to name a few. 29 Stations have been continuously feeding the database using the java client that was developed by LSE Space with more than 100 registered. Some made real achievements to be part of this exciting project, with only one antenna hand pointed with a compass (CX8AT).

The radiation dosimeter is a real success. IC-Malaga made a top here.

Michael Johnson is now processing data acquired by the LOFAR, and we hope to provide a really accurate trajectory.

4M has still plenty of energy left and should continue its transmission for several days. It has now entered its final orbit, i=50°, Perigee around 60000km, apogee around 400000km, for a 15 days period.

There will be 2-3 days of non visibility for northern mid and higher latitudes, as 4M will be very south. Southern station will have great time. Signal will get stronger and easier.

The first perigee is expected to occur between the 2nd and 5th November, and Europe will be much favoured with almost 48 hours of continuous visibility and strong signals. Useless to say that we are eager to get radiation dosimeter messages.

Ghislain. LX2RG

Flyby has occured this night

4M has had its Moon encounter this night as observed by the Doppler. Special thanks to KL7UW and KB5WIA who took care, amongst many others. Signal of 4M is steady. The dT is now 7 seconds and manual offset introduction will be required in WSJT to keep synchronisation. I suggest that +5 seconds is entered to have a consistent report. The graph below shows the Doppler, Moon distance variation. (Click to enlarge)


In the coming days, we shall try to get the best determination of the trajectory after the flyby and produce TLE or injection vector. Until we have a clear trajectory determination, it may be possible that manual adjustments of the Azimuth and Elevation are required. Doppler observation is useful.

4M now starts another part of its mission and will provide radiation measurement in far southern parts of the magnetosphere, which is largely unexplored. South hemisphere stations will have great time. In the North hemisphere visibility will crease to zero until 4M passes its perigee, which should occur between 5 and 7 November. So far, the energy budget of 4M is as expected and we can hope for an extension of the mission.

Ghislain LX2RG


The USA West coast, South America and Australia will be best placed to observe the Doppler. The main sign of the flyby is the Doppler going more negative than the previous pass, but only by 100Hz.

The best operating way to observe it is to tune your receiver to 145.9795 MHz and uncheck ‘freeze’ in WSJT and NOT changing it from 27/10 to 29/10 October. Even the undecoded messages are valid for this observation provided you have a “*” after the W parameter because it means that WSJT has succeeded in finding the sync vector and that the dT and dF are valid.

Doppler should be slightly positive in the beginning of the passes starting from 27/10 00:00 UTC (due to Earth rotation and very low radial speed wrt Earth Center before the flyby). The lowest Doppler occurs after the flyby since 4M will then regain speed and radial speed will be negative. Maximum Doppler is -400Hz.

The highest Doppler will occur just before flyby and should reach +50Hz and should occur between 1200 and 2200 UTC on 27/10

Lowest Doppler should occur between 28/10 0100UTC and 1000UTC on 28/10.

In addition of using the java 4M client, it is kindly asked that you also send your ALL.TXT, since it contains the demodulator information that is useful even if you do not decode much messages.


The contest closes on the 30/10 and the global messages will be visible on the web site.

Status update on the 4M spacecraft

In a few hours, 4M will be at 1 light second from the Earth.
So far, 29 stations are providing continuous data and we are missing very few messages. More than 100 stations are registered to the dataware house and more are sending their ALL.TXT files. Warm thanks to all stations !!! Those saying that radioamateurs no longer exist are wrong.
Now, we can disclose a secret: in a few hours also, the global messages will loop, and they will be transmitted again. So, the stations that have not received them can give it another try for the contest. Of course, this will not be the case for the DRALUX experiment nor the callsign/mission elpased time messages, which are all unique.
From the telemetry, we can see that the rotation of the last stage is slow, and we are getting sun for roughly 5-7 minutes every 20 minutes or so. It is visible when the rechargeable battery and the solar array take over the non reachargeable high energy density cells from SAFT.
Do you know that the same cells are onboard the Philae due to land on comet Gerasimenko ? The same cells will also be used on EXOMARS, the ESA Mars  mission.
As the temperature is 7°C (2°C on the telemetry), each cell can roughly deliver 29W.hour. We have 28 of them, so a total energy of 812W.hours.
Given that the 4M draws 3.5W (14V x 0.244mA + some losses), this gives us a minimum autonomy of 232 hours starting from 23Oct 19:18 UTC.
With the help of the sun and the rotation of the last stage, we may expect a longer lifetime, although it is quite difficult to estimate. Possibly in one or two days, we’ll have a good integration of the energy and a better outlook.
IC-Malaga has already processed the results of the two dosimeters. Graphs will be soon published. they clearly show that the van Allen belts are not a comfortable place, that we fortunately crossed quite fast. The good news is that the results of the two dosimeters are in a very good concordance. Quite an achievement for a newly developed chip!!!!
Chang’e 5T1 is ahead of us by some thousand of km and will perform its flyby before us. Quite natural politeness to let our host take precedence ! (Space mechanic is no stranger to that although)
This is a very ambitious and critical mission for China’s exploration program.
Again, we are really delighted, (not to say overwhelmed) by the reports we are getting, and we thank again all the stations that provide their time and skills for the success of this mission.

Successful Launch!!!

We are happy to announce that the launch of the 4M was successful and in time. The spacecraft passed its activation sequence and the first signals were already received in Brazil. Pictures and further updates will follow soon… We wish you all good luck for receiving the signals!