Thursday 27 November 2014

[UPDATED] Re-entry of Soyuz third stage 2014-074B from Soyuz-TMA 15M launch observed from the Netherlands and Hungaria.

Update 23 Dec 2014: further analysis of imagery in new post
(28 Nov 2014, 10:45 UT: updated with more imagery)

click image to enlarge

Today Carlos Bella alerted the seesat list that Hungarian amateur astronomers had captured imagery of a re-entry in the early morning of November 26.

It concerns the re-entry of 2014-074B, the Soyuz third stage from the launch of Soyuz-TMA 15M which launched expedition crew 42 to the ISS on 23 November 2014.

Below is one of several casual phone-camera video's also shot from Hungaria Serbia, showing the fragmenting fireball:

(video by Aleksandar F, Belgrade)

According to the TIP message of  JSpOC, the re-entry happened near 3:39 UT on the early morning of 26 November, 2014, near 47 N,  17 E. This perfectly fits the Hungarian observations. See also the map above, which shows the predicted trajectory of 2014-074B resulting from processing the last known orbital elements with SatAna and SatEvo.

Moreover, the speed determination by the Hungarian meteor camera network, 7.4 km/s, confirms this is not a meteor but a re-entry. The speed is too low for a meteor (which are always faster than 11.8 km/s, the earth escape velocity) but matches the speed of an object re-entering from Low Earth Orbit.

Realizing that the rocket stage made a pass over the Netherlands/Belgium only minutes earlier,  I asked the operators of the DMS All-Sky meteor cameras to check their imagery of that morning. As it turns out, three Dutch All-sky stations did capture the re-entry: Bussloo (Jaap van 't Leven), Oostkapelle (Klaas Jobse) and Ermelo (Koen Miskotte).
Detail of the Bussloo Public Observatory all-sky image (courtesy Jaap van 't Leven)

Detail of the Cyclops Oostkapelle all-sky image (courtesy Klaas Jobse)

Detail of the Ermelo image (courtesy Koen Miskotte)

Parts of the three Dutch images (courtesy Jaap van 't Leven, Klaas Jobse and Koen Miskotte) are shown above. All stations have it very low above the horizon at elevations of 20 degrees or lower.

The Oostkapelle image shows that the incandescent phase of the re-entry already started over the UK, as the image shows the trail well to the west (and Oostkapelle is on the Dutch West coast).

As soon as I can find some time, I will analyze the imagery to see whether I can get altitude data from them. It would be nice to document the last minutes of this rocket stage in this way!

So stay tuned for an update....

UPDATE 23 Dec 2014: new post with a further analysis with trajectory and altitude reconstructions based on observations from the Netherlands, Hungaria and Germany now available

(I thank Jaap van 't Leven, Klaas Jobse and Koen Miskotte for permission to use their imagery)

Monday 10 November 2014

Live blog from ESOC, Darmstadt: Philae (Rosetta) Landing on comet Churyumov-Gerasimenko:


I (am) was on-site at ESA's European Space Operations Center (ESOC) in Darmstadt for the Philae landing on comet 67P/Churyumov-Gerasimenko
This blog-post will be live updated as the events unfold. 
Be sure to hit refresh upon a new visit!
 I will also  be tweeting through @Marco_Langbroek)

15 Nov

01:45 The communications link has broken. This is it. Philae has gone to sleep, perhaps to never wake up again...or will it? So far it has kept amazing us all, after all...!

01:29 Philae has been switched into standby mode. All instruments powered off, but communications llink still active. Time to go to sleep now, brave little friend....

01:00 Battery power is dropping fast but Philae is not giving up! More and more data is being received. This is History written large, with a capital H. Truely epic science History!

00:28 Philae's rotation, over 35 degrees, was successful.

00:20 Philae is alive and the drill has worked! At the moment, they are trying to rotate the lander to get more sunlight on the panels. I think we can safely say now that nothwithstanding all that went different from what was planned, the mission has become a resounding success!

14 Nov

15:10 Brief recap of the Google+ briefing of this afternoon: Matt Taylor apologizes for #shirtgate. Contacts Rosetta-Philae are very stable. 80% of the most important science data from the first science sequence are now in. Rosetta has not imaged Philae on the surface yet, but there are still images in the pipeline and the search continues.  Holger Sierks suggests that in fact, they should have caught the lander just before touchdown at 500 meter above the surface, and during the first bounce in the images from the first two hours after touchdown, which have not been downloaded yet. These images should give the direction of the rebounce.
Lomatsch told that Philae has not moved at all since finally settling. Philae is in a difficult position however, surrounded by walls, limiting sunlight reaching the solar panels.From what she said, I get the impression that hopes for a lander revival once 67P/ is closer to the sun, should not be too high.
During the Q&A Ulamec indicated that it is unlikely that cometary jets will blow the lander from the surface as activity increases, as it has a too high density.
The DS2 drill is already extended 25 cm below base plate, but as there is a (scheduled) loss of contact right now, it is unsure whether it can/has reached the surface yet. New (and perhaps last) contact with Philae near 22 CET this evening. A command to go into low power mode did however not reach Philae, so it is going to get really close wether the next contact will be successful.

9:55 Philae's batteries will run out of power tomorrow. Coming night the operators will try to rotate the lander such that the largest solar panel will be facing the sun (via @elakdawala)

4:55 Although it will be under "very risky conditions", SD2, the core drilling tool, will be employed. it will take subsurface samples that will be analysed by COSAC and Ptolemy, two instruments that o.a. look for organic compounds and determine the isotopic composition of water in the comet. The latter will yield information whether water may have been brought to Earth by comets.

00:45 MUPUS is communicating the first "science" temperatures (but not subsurface yet)

13 Nov

23:25 After first attempt failed, second upload attempt of MUPUS commands succeeded!

21:58 The commands to deploy MUPUS failed to upload:

20:55 Tonight the MUPUS  (MUlti-PUrpose Sensors for Surface and Sub-Surface Science) instrument will be deployed, for about 20 cm of its 30 cm length. The probe, which contains several temperature sensors, will be slowly hammered into the subsurface. The goals are amongst others to gather data on subsurface consistency, and a subsurface temoperature profile. It also provides calibration data for the thermal mapper onboard the Rosetta orbiter. 

    19:40 More details have been released. Philae bounced twice, at 15:34 GMT (first contact of lander with comet) and 17:25 GMT, before settling on the cometary surface at 17:32 UT. It rotated around the Z-axis (the vertical axis) after the first bounce (this rotation was the first sign yesterday evening that the lander did not settle at first contact). It is working though, although there are indications that some of the solar panels are in shadow (perhaps due to a nearby boulder? [update: it's a cliff]). It hence does not have full power. 

    So that first bounce took two hours, while the second bounce appears to have been mild. As the harpoons did not work, Philae is not well anchored to the comet. This will interfere with some of the planned activities (e.g. coring the subsurface).

    See also:

    17:20 (This post comes belated as I am still travelling homewards...)
    ESA has released the first panoramic image by Philae. It is obviously a rather dark world out there... Of all the extraterrestrial landscapes imaged, I feel this one beats them all! This truely is a Primeordial world... (photo: ESA)

    16:30 (back on Dutch soil, but stil in the train) The place where Philae finally landed has been located. It is about 1 km offset from the original location. In the image below, the cross is the original landing site, the box where it finally ended up.

    (image: ESA)

    12:05 News now is that Philae is on the comet, but not anchored well. This means the coring of the subsurface cannot happen, which is a bummer. Still, no doubt much new scientific data will be gathered. Given that we knew this landing effort was very risky, we can say Philae is a big success anyway!

    I am at Darmstadt railroad station currently, about to return home to the Netherlands, so this will be my last blog update today for now.

    11:50 CET  Great news! Philae is alive and has send the first images of the comet' surface!
    below you can see one of the lander legs, and part of the surface. The image is a composite of two images taken by Philae's CIVA camera.

    Image : ESA

    12 Nov

    20:25 Gist of the press briefing: some data might indicate that Philae briefly left surface again after touchdown, i.e. it bounced and then settled again at a slightly different spot. Data need to be evaluated now. Next briefing is tomorrow 14:00 CET. No word about those images shown by the French...

    19:10 This is reportedly the first image of the comet's surface (but image is unconfirmed, at least it has not been shown yet here at ESOC):

    18:12 Ulamec just told reporters that a lot is still uncertain about the spacecraft condition and safety. Also said option to try to re-fire harpoons is risky, as the non-working gas thruster cannot produce the counterforce necessary. This mean the counterforce of (re-) firing the harpoons could result in Philae being ejected from the comet surface.

    17:42 Flight controller Geurts reports that the gas thruster indeed did not work, and that the anchors did not fire. Incredible that the landing nevertheless still seems to have been succesful!
    Geurts mentioned they might retry to fire the anchors.

    17:04 Philae has landed!!!!! They are receiving telemetry. Harpoon has been fired, landing gear is in. Its on the surface!!!!

    16:50 Nailbiting at ESOC!

    16:28 Touch down window has started.....fingers crossed!

    15:52 cool image of Philae on its way down as imaged by the Rosetta orbiter! note the three extended landing legs.
    Think about what this image exemplifies: To boldly go where no-one has gone before! Exploration!

    15:18 Image of Rosetta imaged by Philae has been shown now. Descend so far is "going as planned". Image is here:

    12:33 Deployment of Philae landing gear confirmed.

    12:07 Datalink Philae-Rosetta confirmed! Datalink with both objects is healthy. This is an important moment! Over the next hours Philae data from the descend phase will be relayed to the control center. In about 5 hrs from now, Philae should touch down.

    11:00 My ESOC source tells me that for the cold gas thruster to work, a membrane was to be punctured. And this might actually have happened, but the returned sensor data that should confirm this was "contradictory". So the system might actually work, but it is not certain.

    10:20 First data relay from the still descending lander expected about 2 hours from now. Telemetry plus a picture of th orbiter seen from the lander. The lander will reach the cometary surface in about 7 hours from now. The big wait has started.....

    10:20 Dr Churyumov:

    10:04 Separation confirmed!!! Alea Jacta est, to quote old Julius

    9:50 Matt Taylor: "This is our Longest Day" 

    9:36 Separation of the lander is actually happening now, but we won't know for a while as it takes the confirmation signal 28 minutes to reach us

    9:30 The problem with the cold gas system means they have to land without it. This introduces the risk that the lander will bounce back from the cometary surface because of opposite forces when they fiire the anchor harpoon.

    8:15 We have a GO!

    8:00 CET - The go/no of last night has been delayed. The cold gas sytem of Philae has a problem. This cold gas drives the small thruster on top of Philae that pins the lander to the comet surface in the first few minutes.

    11 Nov - The go/no go decision of this evening has given a 'go' as verdict. Early tomorrow morning there will be a second, and last, go/no go moment.

     (player provides a live stream from ESOC by ESA)

    Announcing a Live Blog from ESOC during the Philae landing on 67P/Churyumov-Gerasimenko

    On Wednesday November 12, Philae, the lander of ESA's Rosetta mission, will attempt to land on comet 67P/Churyumov-Gerasimenko.

    I will be at ESA's Space Operations Center ESOC when this happens. If the WiFi doesn't fail on me, I will attempt to live-blog the events of that day on this blog, as well as live tweet the events via my Twitter account (@Marco_Langbroek).

    So stay tuned here (or on Twitter) next Wednesday!

    Meanwhile, here is a nice interactive 3D model (model courtesy of ESA) of the comet to play with (requires WebGL enabled browser: might not work in iOS):

    Saturday 1 November 2014

    Brightness variation of the USA 198 Centaur rocket stage on October 30, 2014

    Earlier today I posted this image of the USA 198 Centaur rocket (2007-060B) passing close to M33 galaxy in Triangulum:

    click image to enlarge
    I noted a slight but clear brightness variation in the trail segments on subsequent images (the stack above is a stack of 19 individual images). I therefore decided to use the images to create a brightness variation profile.

    click diagram to enlarge

    The result is the diagram above (grey crosses are individual pixel values; the blue line is an 11-point sliding average; the red dotted line a sinusoid with a period of 37 seconds). This is the result of combining measurements of the trail brightness variation on 20 images. The individual pixel values are noisy, the result of using a high ISO setting of 2000 (which results in noise) but a pattern is visible, even more so in the 11-point sliding average.

    The diagram shows a modest but clear semi-regular brightness variation with a peak in brightness approximately each 37 seconds. There is perhaps also a regularity visible in that each second valley in the curve is more shallow than the first. The pattern suggests a slow tumbling motion.

    Below is one of the original individual images:

    click image to enlarge

    USA 198 r/b passing the M33 galaxy

    click image to enlarge

    Last Thursday evening was very clear. I tested a clip-in CLS filter on my Canon EOS 60D, employing the 2.8/180mm Zeiss lens and a motorized tracking mount.

    One of the targets was M33, a big galaxy in Triangulum. As it happened (it was not planned), I captured a classified object in the series: the USA 198 r/b (2007-060B). It can be seen passing M33 in the image above, which is a stack of several 20-second images (breaks in the trail represent short moments inbetween consecutive exposures).

    As the images do not have the timing accuracy of my usual tracking images, they are probably of little use for astrometry. But I do seem to see some slight brightness variation, so I might try to construct a brightness curve.