End of 4M mission

4M has transmitted its last message at 0135UTC on the 11th of November. The last messages have been received by Rein, W6SZ,

>01:25 LX0OHB  4M5256
>01:35 084V381A -16C

Some transmissions yet occurred but were not demodulated and the cells were at the lowest limit of discharge.

After more than 438 Hours, 4M has largely exceeded its design lifetime and by all accounts is a huge success as it fulfilled all its goals.

Serendipity was even there and brought us unexpected learnings.

The most wonderful thing that happened is the amount of participation of the radio amateurs. They were (and we were also at LuxSpace) the central piece of the success. We hoped for 10, more than 60 participated! … And we were overwhelmed by the return, the mails, and the participant number to the contest.

It is amazing to see to which great lengths some went in order to receive even few messages and could say: ‘I did it’. From Eggbeater antenna with Funcube dongle or small hand pointed Yagi set on wooden ladders and to large arrays for EME, all the taxonomy of amateur station was represented.

Each one will receive a dedicated and printed certificate that will be shipped by postal mail using special stamps. Those not yet having sent their postal address, please quickly do so at moon@luxspace.lu

The most gratifying thing was all the positive comments we received, save only one.

“When is the next one?” could not be more rewarding and encouraging.

Not only did we receive all data from the radiation dosimeter experiment, but it also allowed a pretty accurate orbit determination after the flyby.

Thanks to Anatoly, UA9UIZ for pointing out that many talks took place in Russia.

Contest result

The result of the contest is the following. Thanks to LSE Space, who setup the automated data collection, it was pretty easy to summarize all the results. Half of the logs were received by mail and had to be manually processed. We sincerely hope to have not messed up too much. Congratulations to Lucien Serrano F1TE

 

F1TE 2248
VK5APN 1842
LU1HKO 1732
DG0OPK 1579
ES5PC 1525
ZL2MQ 1373
wd0e 959
pa3ark 871
py2gn 802
cx2sc 633
yl3ct 623
vk5hi 617
ua9uiz 559
w8wn 552
df2zc 488
iz1gza 447
lu1kcq 439
pe1itr4m 423
kb5wia 418
lu4eou 397
dh4faj 394
f6beg 382
vk4amg 381
zs1ls 380
kl7uw 353
on4khg 343
dj9pc 324
bx1ad 280
on4bsm 268
k1or 241
dk3bu 231
ja0caw 227
on4hf 218
n7zo 212
sp3rnz 204
ki4tz 199
kb1tci 197
dj3ak 169
uy0ll 162
vk5fa 162
py4zbz 160
dk3wn 147
pa3fxb 142
f5vkv 142
w9eq 136
gm4jtj 119
sp5uln 116
df6sm 110
je1cvl 102
kg7hf 98
g4fev 95
lu1cgb 83
f1afz 75
dk6ug 68
pu9wil 62
oe3nfc 62
vk2vl 56
ja5blz 51
oh3aa 47
lrttumlse 46
hs2jfw 38
iw2fzr 33
dh6mb 31
9m2cqc 23
ik3vzo 19
zl3ty 19
hb9q 16
m0dts 14
w7kke 12
ve7til 10
ok1teh 10
PY2sdr 9
oh2fqv 8
ik0smg 4
lz1ny 3

 

 

We have one regret: no intercontinental team registered.

We sincerely apologize if some errors still remain in the counting and ranking. We shall rectify upon request.

Recorded messages

All recorded messages were received. All those who entered a greeting message will receive a certificate of reception including who received their message and when.

There were some long sentences cut into 13 characters chunks.

The first message was simply a copy of the memorial page to Pr Fuchs

We also had:

REMEMBER THE SPACE PIONEER MANFRED FUCHS.

REST IN PEACE MANFRED FUCHS.

DAMIT ALLE MENSCHEN AUF DERWELT IN FRIEDEN ZUSAMMEN LEBEN.

LA LI LU NUR DER MANN IM MOND SCHAUTZU WENN DIE KLEINEN KINDER SCHLAFEN UND SO SCHLAF AUCH DU. (A traditional German lullaby)

DO NOT GO WHERE THE PATH MAY LEAD GO INSTEAD WHERE THERE IS NO PATH AND LEAVE

A TRAIL.

ALL LIFE IS AN EXPERIMENT. THE MORE EXPERIMENTS YOU MAKE THE BETTER.

Tracking

We understand that some have been a little bit frustrated by not having accurate pointing elements. Therefore, some explanations are required.

4M was attached on the last stage of the LM-3C launcher. There were reasons for that. The main mission was limited in time, it was on the funds of the company, and we had planned to 6 days minimum lifetime in the expenditures plan. The team needed also to rest after 5 very dense months.

Being attached to the last stage also meant that the injection vector was not very accurate. We worked on the best estimates to generate the first two lines elements.

After the flyby, it soon appeared that the best estimates were quite off the mark. The first indication was being given by an unexpectedly high Doppler. However, as the Local Oscillator of 4M was not precisely stable (+/-5ppm), we initially thought that the temperature drop was in cause. It was soon found out that it was not the case and 4M was received in Europe (on the back lobes of the antenna) much sooner than expected.

The process to determine the new orbit began. For those not familiar with this kind of exercise, suffice it to say that is no simple game, especially when you have no real information on the frequency accuracy nor of the time stamping accuracy of the receiving stations (and of 4M neither). Very small variation of the vector at flyby injection led to widely dispersed trajectories.

We managed to have a first rough estimate that allowed a course pointing to get enough Doppler information.

Finally, a special group endeavoured to determine the orbit using the Doppler information, and we thereafter worked together to refine the solution, which finally happened around the 6th November although we had already rough and useable estimates as soon as the 1st of November.

It is also recalled that TLE’s are not really meant for this kind of orbit. In addition some amateur softwares are really picky on the input format. This made for some days of apparently random publications as I had to figure out what was wrong in some softwares that would not accept the parameters.

Results

JT65B link

Given the severe constraints on the launcher, the antenna was all but optimal, and I had to cope with that. I did not succeed in transforming the last stage into an isotropic antenna. We made EM simulations to have an estimate of the radiation pattern, but the incomplete data (and limited amount of resources/time) rendered this estimate closer to a wild guess.

The average gain was initially estimated to -6dBi, with a lot of uncertainty, therefore a huge margin ( from a telecom engineer point of view) was introduced so as to make sure the signals would be received at 400Mm, albeit not with a single medium gain Yagi.

It turned out that the average EIRP was in the order of 50mW, rather than 250mW.

Despite this inconvenience, 100% of the messages were received up to the flyby, and 50% after the flyby, which, I recall, sent the 4M up to 420Mm. Quite a DX for 50 mW EIRP !!

There was lot of fading (QSB) due to the mounting. No way was practicable to solve the problem in the design and within constraints, and this was also a justification for the huge margin.

Unfortunately, this huge margin was detrimental to the lifetime. As the illumination was not guaranteed, and that we wanted the mission (i.e. going round the Moon) to succeed, it was required to provide for enough internal energy. This was achieved by putting 28 cells LSH20HTS from SAFT. (The same as on board Philae). In the worst case of low temperature (-40°C), the cells were able to give enough energy for a 4W payload during 100 hours. (Adding that their small internal dissipation would keep them above -40°C due to the thermal insulation)

A secondary source of power was a solar panel and rechargeable batteries (that we both had at hand from a previous project). They clearly contributed to extend the lifetime.

JT65B link proved to be extremely robust in these conditions. Additional ‘analog information’ was provided at the end of the sequence, mainly as to allow pattern recognition and setting the dSec of WSJT demodulating software.

Reason is that the OBC clock (that we also had at hand from a previous project, and that proved to be highly reliable) was known not to be accurate and thus could widely drift during the mission.

The OBC clock was set at integration in such a way that the known drift would make 4M start to within 1sec of the UTC minute at activation therefore allowing an easy tracking of the drift during the mission. (4M started at the exact planned minute after launch i.e. 1918UTC)

The PL architecture was rather simple. An OBC, an interface control board, an IQ modulator, a RF PA (provided by RFPA.com, their 6th PA we successfully put in orbit), a radiation dosimeter (from IC-Malaga), some bits and pieces to couple all the cells, batteries and solar panel. I’d add that a severe counter EMI design was adopted as we were located 50cm away from a 1kW EIRP S band transmitter.

The OBC’s internal DAC’s were generating I&Q signals for the IQ modulator (MiniCircuit, followed by MMIC driver from Avago and filter from TemWell). My colleague Klaus wrote an heroic piece of software to fit the JT65B encoding, the IQ generation and all the PL housekeeping in the flash memory of the OBC, in addition of the messages.

Radiation dosimeter

This experiment was designed and setup by IC Malaga, and worked as long as expected, providing very useful data. The results have been published, and brought in the nice result of coming very close to the simulations provided by HOMER.

IC Malaga designed and manufactured the dosimeter in 3 weeks. It used their entirely new chip, which possesses a very high potential and nothing could have barred us to test it in real life, avoiding months of difficult qualification tests.

The curves are self-speaking (you can find them in the radiation experiment section of this website). The most impressive part is to see the steep increase in dose when crossing the van Allen belts soon after the launch and during the first hours.

There is strictly nothing new, but seeing this curve is dramatically spectacular if you are not convinced by the abstraction of the simulations. (And even more if you think that RadHard and RadTol components or architectures are just excessive)

The reason why DRALUX (the intimate name of this experiment) stopped working after 215 hours is not yet clear.

TDOA and FOA

A totally unexpected result and success is the orbit determination using the Doppler. Again, there is nothing new in it, but that it worked well in such conditions is much of a finding. Serendipity happens.

Thanks to the special group and my colleague Jean-Baptiste who came up with a complete algorithm in two days during his free time.

TDOA did provide what was expected: not much. Reason is not linked to the 4M, but on the limitations of WSJT and the lack of accuracy and precision of the time stamping process.

There are lot of improvements to be made in the radio amateur stations regarding this aspect. A separate article will be published, based on the findings of the 4M mission and the requirements to achieve this.

It is not an academic or wishful thinking, 4M is for sure the first mission of its kind and can be inscribed in the amateur historical record, but it certainly will not be the last. Navigation of interplanetary probes is a critical item, and I cannot imagine that future amateur or commercial small probes could rely on DSN or very few big dishes. (May be to Mars, but to the Moon, this would be an overkill, would work up to Lagrange point L1 with reasonable means).

Spatial thanks

To Roland PY4ZBZ, who relieved me just after the launch by providing the first reports.

To Cees Bassa, Scott Tilley

To Wayne, VK5APN, for keeping me awake and aware that all was going well. (no joke)

The Moon.net list and all very active and most interesting comments the participants provided.

To all those who provided comments, expressed thanks and above all: enjoyed this mission.

Will there be another one ?

The Japanese are going to launch a probe in December. They have included a JT65B link on 435MHz. this will be an exciting experiment and a bigger DX for sure.

As for us, if we can, we surely will do it again.

4M orbit determination after data processing

4M orbit determination after data processing.

After processing of all the received data, we finally have a very nice parameter set. It has been obtained by the solution of a least cost error function using the dF data that were transmitted by all OM’s that participated and our own received data.

You may download it here:

https://cloud.luxspace.lu/public.php?service=files&t=13bf5e92095a1d21b3d1d9bc4589cc67

0 4M_DopplerFit

1 40284U 14065B   14307.75000000 -.00000015  00000-0 -36726+7 0 00002

2 40284 061.6967 069.0661 6145515 000.5872 038.5007 00.07379169000029

 

The following graph shows the fit of received data (Doppler) and the corresponding Two Lines Elements.

Many thanks to Jean-Baptiste for this wonderful work.

Doppler

Tracking elements

tentative TLE for 4M tracking.

1 99005U 14999A   14309.99765069  .00000000  00000-0  00000-0 0    06
2 99005  54.8633  66.2405 5888217 357.3960  90.3779  0.05812806    04

Alternatively you can download it following this link

https://cloud.luxspace.lu/public.php?service=files&t=fe069c0ba38d8140a40001413a6ef33b

4M is now around 400000km, and signals are copied quite well with 2 x 8elts yagi and LNA.

Still some days left in the cells, so, it is still time to enjoy.

4M Team

4M has entered Earth Orbit

After some days of incertitude, we now have several things for certain:

-          We had a perigee in the night of Saturday to Sunday

-          We have strong signals in Europe

-          4M has energy left for another 2-3 days

It appears that the injection during the flyby was much closer to the one of Chang’e 5T1 than the estimated elements after passivation. This led to a return to Earth quicker than expected. Although we had some inkling since Thursday, which show a higher than expected Doppler, it was difficult to sort it out.

We have now (3Nov 1340UTC) a negative Doppler and a quasi stationary pointing (Az 290°, El 80°), along with strong signals, that lead to the conclusion that 4M is somewehere around 40000km, in an orbit with a inclination of 50°, and with a negative radial speed showing it has not reached its apogee.

Apparently, the Dosimeter experiment (DRALUX) has stopped functioning. But this may also be normal due to its technological nature, and it may restart.

Stay tuned and keep on uploading your reports using the 4M data client.

We’ll try to provide TLE as soon as possible using all observations and Doppler.

Thanks to Viljo, ES5PC, Geroge VK4AMG for their help.

Contest is closed since 30/10 0300UTC

The contest is closed since 30/10 0300UTC. We now shall process all files and automated reports.

The messages appear now in clear in the datawarehouse.

For all that have not used the 4M java client to automatically upload their data and that have registered to participate in the contest, we kindly ask you to send a summary of your log in the form:

Date (from 0000UTC to 2400 UTC) : Number of decoded messages

So, their should be 23, 24, 25, 26, 27, 28, 29 and 30 October.

Why has the contest lasted exactly 151.5Hours ? Because the number of global messages was repeating it self every 50.5 hours. And why this duration ? To make sure all global messages would be transmitted approximately twice in the vicinity of the Moon (and once on the forward trip), so that all that have posted can righteously say that their message was received from the Moon. And they all have been.

All that have posted a message will receive a certificate with their message and when it has been received. Please send a mail to moon@luxspace.lu, with your postal address, the login you have used to post your message, and your message.

All OM’s that have sent data, either automatically, either by mail, please send your postal address at moon@luxspace.lu. If you have used the automated client, please indicate your login to the database.

Greetings and thanks from all the 4M team!

Remark on the 4M client message queuing (messages in waiting…)

Some users recently noticed that the 4M client is queuing messages and not sending them to the 4M data warehouse. The JT65B History view shows in this case messages in a Waiting… delivery status. Although the concern is definitely understood, we want to inform you that this behaviour is not due to bugs or malfunctioning of the client.

The reasons behind this has to be found in the way the client has to recognize the initial sequence type of a message and the bad link budget due to the far distance of the spacecraft.

The client synchronizes on a message of sequence type 1 (Callsign) and upon that is able to mark all the queued messages and deliver them to the data warehouse.
Since the probability of a messages to be decoded in case of bad link budget (the situation we are facing in the last days) is low, the client might queue a remarkable number of messages before getting the sync.

As soon in sync, all the messages in the queue are sent at once and from that moment on all the received messages are delivered to the data warehouse upon their reception.

As explained this is not an issue or a bug, and requires the user to only wait for the synchronization to occur. We’d like to inform that closing the client in this case is not needed; if the client is closed the queued messages are saved along and reloaded on next startup.

We apologize for the confusion and the concern this behaviour might have created and we hope this will not prevent you to keep using our client.

We’d like to thank all the OMs who are contributing to the mission and hope you are enjoying it as much as we are!

4M: Energy

During 12 hours after the activation, 4M lived on its rechargeable batteries, then switched automatically to the non rechargeable high energy density cells.The raises in voltage show that the solar panel is getting illumination, recharging the battery and powering the payload but not enough to provide for a positive power budget, nevertheless extending the lifetime. (left ordinate: voltage in 1/10 Volt and current in mA, right ordinate: temperature corrected from offset)

291020141

Following graph is consumed power, that incidentally shows the better efficiency of the Buck and buckboost converters in the 9-14V input voltage interval.

291020142

These figures tentatively show that the expected end of life will occur at the  end of the 2 November, assuming a 29W.h cell capacity, but do not account for the incoming power of the solar panel , nor the first 12 hours.

And the first winner is…

…PY4ZBZ, Roland who figured out that putting all the bits and pieces would lead to a text. Congratulations!

From: Roland Zurmely
Sent: 28 October 2014 16:35
To: Ghislain Ruy
Subject: Re: 4M received in Brazil !

Dear Ghislain,

Finally recovered from 158 JT65B messages received on Oct 23

during 158 minutes uninterrupted, the main text message transmitted

in 2 segments of 13 characters every 5 minutes !:

MANFRED FUCHS VISIONARY HUMOROUS SUCCESSFUL AND CARING.
THAT S THE WAY HE WAS AND EVEN MUCH MORE THAN THAT.
WE ARE MOURNING THE LOSS OF OUR FOUNDER PROF. DOTT.-ING. H.C. MANFRED FUCHS
WHO PLAYED AN OUTSTANDING ROLE IN THE EUROPEAN SPACE INDUSTRY OVER THE LAST DECADES.
HE DIED APRIL 26TH AT HIS HOLIDAY HOUSE IN ALTENBURG/KALTERN SOUTH TIROL AT
THE AGE OF 75 YEARS. MANFRED FUCHS WAS BORN IN LATSCH ITALY IN 1938.
AT THE AGE OF 17  HE BECAME THE YOUNGEST PILOT IN ITALY. HE CAME TO GERMANY
AT THE AGE OF 18. AFTER  STUDYING AVIATION ENGINEERING IN MUNICH AND HAMBURG
HE EMBARKED IN 1961 ON HIS CAREER WITH SPACE TECHNOLOGY COMPANY ERNO
PLAYING A KEY ROLE IN PROJECTS SUCH AS ARIANE-1 SPACELAB AND COLUMBUS.
IN 1981 HIS WIFE CHRISTA TOOK OVER A SMALL COMPANY CALLED OTTO H…..

73 de Roland.

There are still other hidden texts in the messages…..