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Sonntag, 20. März 2016 - 21:00 Uhr

Astronomie - Sehr große Feuerkugel über Großbritannien

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17.03.2016

AMS Event #1027-2016 caught on tape by the United Knigdom Meteor Obsevation Network
The AMS received over 19 reports so far about a fireball event over UK (England) on Thursday, March 17th 2016 at 3:16 GMT. The fireball was seen primarily from England but witnesses from France and the Netherlands also reported the event. We expect more reports today.
If you witnessed this event please fill an official fireball report.
Below is the map of the first witnesses location and the first estimation of the ground trajectory:
Video-Frams:
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Quelle: AMS
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Update: 18.03.2016
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'Green flash' meteor sighting reports across Britain
A bright meteor has been sighted over Britain in the early hours.
Witnesses have described the object as a green flash moving south to north for a few seconds, leaving a magnesium-white trail.
Sightings have been reported in locations including London, Hampshire, Stafford and on the east coast of England at 03:16 GMT.
Its colour has prompted people on Twitter to describe it as the St Patrick's Day meteor.
'Not uncommon'
Describing the meteor as "spectacular", Dr John Mason of the British Astronomical Association said it was bright enough to be categorised as a fireball.
He believes it was a piece of cosmic rock which almost certainly came from the asteroid belt between Mars and Jupiter.
He said the green colour was caused by the meteor heating up the oxygen in the earth's atmosphere.
"Meteors of this kind are not uncommon," he added, saying he estimated there was at least one a week over the UK.
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Richard Kacerek, from the UK Meteor Observation Network, told the BBC it had received reports from across the country.
He said the network's camera at Church Crookham in Hampshire had captured the meteor from the west.
"This is the biggest meteor sighting we have recorded," Mr Kacerek said.
"It lasted for a few seconds. It was seen for hundreds of miles. We have received a number of emails."
He said the network of astronomy enthusiasts recorded about 10 to 15 meteors every year.
An astronomer at the Institute of Cosmology and Gravitation at the University of Portsmouth, Dr Karen Masters, said thousands of these objects hit the Earth every day.
She said: "Most of them over the oceans or over uninhabited parts of the world. It is quite rare that one goes over such a populated place and be so bright."
She said the size of this meteor would depend on its velocity but it was probably as big as a tennis ball.
Meteors
Meteors are small rocks or particles of debris, mostly no larger than a grain of sand, which burn up as they enter Earth's atmosphere at high speed
On entering the atmosphere, these particles heat the air around them, causing the light which can be seen from the ground
To be called a fireball the meteor has to appear brighter than the planet Venus
Meteors can be travelling through the atmosphere at speeds between 8 and 40 miles per second
If a meteor survives the passage through the atmosphere and impacts with the Earth's surface, it is then called a meteorite
Source: British Astronomical Association
Quelle: BBC
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Update: 20.03.2016
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ST. PATRICK’S DAY FIREBALL FULL REPORT
Composite still of the Clanfield N station data in false colors
Fireball spring season is in full swing and it is no wonder we are seeing more reports and observations of bright fireballs. This time it was the UK’s turn to enjoy a spectacular meteor event, which occurred in the early morning March 17, 2016 at 3:16:54 UT (i.e. GMT). The fireball meteor lit up the countryside for 4 seconds and was observed many bystanders.
Visual observations of the fireball (bolide)
This year St. Patrick’s Day began a rather unusual way; instead of delivering one of his numerous pots of gold, the leprechaun gave people some rare celestial theater – a bright fireball.   Many casual observers in the UK, the Netherlands, France and Belgium saw a bright fireball meteor lasting nearly 4 seconds, illuminate the landscape and with a brightness that exceeded a full Moon. The IMO (International Meteor Organization) database of sightings (as of March 19, 2016) records 54 reports from visual observers from these countries.  Most observers indicate a magnitude in the range of -10 to -20, but some estimated its brightness at -25 (that would make it comparable with the sun).  Observant observers noted fragmentation of the body during the flight, and some of also report accompanying sonic effects. The palette of reported colours is quite varied, but predominant reports are of blue and green. Distribution of monitoring stations from reporting on IMO overview map shows the “density” reports of observers in each country.
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Report locations across the UK, the Netherlands, France and Belgium
Video Observations
Within the UKMON Network (United Kingdom Meteor Observation Network) the bolide was recorded directly by 5 stations (7 cameras).  A camera at the NHM in London) recorded a series of flashes out of sight of the camera. A record bolide’s flight is therefore available from stations Clanfield (Steve Bosley, Hampshire Astronomy Group), Church Crookham (Peter Campbell-Burns), Lockyer (Dave Jones, SPAM Group 2 cameras), Scotch Street (Steve Hooks) and Wilcot (Richard Fleet, 2 cameras).  Videos from all stations are provided below.
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Our calculation of meteoroid’s path through the solar system used data from the initial phase of the bolide’s flight recorded by Norman Lockyer, Clanfield and Scotch Street stations. This procedure allows calculation of a track with a low value of deceleration, which at a height of 80-100 km affects significantly the final track at lower altitudes (between 30-50 km).
In this case, it was a relatively rapid meteor.  Geocentric speed before entering the earth’s gravitational field was 43.5 km / s (including the effect of deceleration, Dv / Dt = -0.7 km / s-2).  The orbital meteoroid path elements were as follows:
a = 3.01 AU (semi-major axis),
q = 0.048 AU (distance perihelia),
e = 0.984 (track eccentricity),
i = 18.3 ° (slope of the runway),
ω = 336, 7 ° (latitude argument perihelion)
Ω = 356.7 ° (longitude of the ascending node)
The bolide was a sporadic meteor (i.e. without affiliation to a known stream) with a geocentric Radiant RA = 205.4 °, DEC = -6.4 °. Projections of the meteoroid’s path through the solar system is shown below (taking into account of deceleration on the geocentric velocity VG.)
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Due to the extent of the image saturation caused by the brightness of the bolide, to calculate the atmospheric path it was necessary to perform measurements on still images rather than video.  All measurements were carried out using the AstroRecord software, and most suitable for this purpose was the Clanfield station videos which covered almost the whole length of the bolide’s flight (3.64 seconds).
The projection of the early atmospheric track was located at coordinates N50.761º W2.089º near the village of Lytchett Matravers (ENG), the height of the meteor at this time was 112.7km above the Earth’s surface. The end projection of atmospheric track was located at coordinates N51.768º W1.528º near the village Curbridge (ENG) and height of the meteor at this time was 38.3km above the Earth’s surface.
The highest absolute magnitude of the fireball measured from the Norman Lockyer station was -14.7, the absolute brightness of a unified path of the above stations was -13.6. The bolide traveled 141.3 km during the ablative phase of its flight through the Earth’s atmosphere having entered the atmosphere with a fairly low angle of 32.1 degrees.
Fragmentation first occurred at an altitude of 68.9 km at the speed of 43.2 km / s, and we estimate that the mechanical strength of the body was 0.16 + -0.02 MPa. Entry speed into the atmosphere was 44.8km / s and speed at its terminal altitude (38.3km) was 26.6km / s.  During the ablative phase of its flight through the Earth’s atmosphere, its mass could be established using am empirical equation (Jacchia, 1969) and was estimated to be 66kg+ -16 kg.  The meteoroid’s path through the solar system indicates it is of a cometary origin.  Its progenitor was probably a comet of low perihelion value, for example, or one of the Kracht or Marsden group of comets.
This orbit is very atypical for what we normally see. Most fireballs and bolides come from orbit between Mars and Jupiter this time of year and we usually see much slower speeds when entering our atmosphere.
Conclusion
Considering origin of the meteoroid, terminal altitude and especially terminal velocity it’s practically impossible anything survived the entry or even fell on the ground as we saw lately with case in Germany on 6 March 2016.
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Bolide 20160317_031654 deceleration during ablation.
Cover image: Composite still of the Clanfield N station data in false colors.
Quelle: UK Meteor Network

Tags: Astronomie 

1546 Views

Sonntag, 20. März 2016 - 16:15 Uhr

Raumfahrt-History - 1956: Raumschiffahrt und Meteoritengefahr

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Aus dem CENAP-Archiv:

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Wissenschaft und Fortschritt

Quelle: CENAP-Archiv


Tags: Raumfahrt 

1309 Views

Sonntag, 20. März 2016 - 14:15 Uhr

UFO-Forschung - Projekt Blue Book - Teil-21

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The 701 Club: Case #1052 February 11, 1952
Don Berlinner describes the event as:
Feb. 11, 1952; Pittsburgh, Pennsylvania. 3 a.m. Witnesses: Capt. G.P. Arns and Maj. R.J. Gedson flying a Beech AT-ll trainer. One yel- low-orange comet-shaped object pulsed flame for 1-2 seconds of a 1 minute straight and level flight.1
Examination of the Blue Book file produced a few more details. There are several different documents describing the sighting but the following specifics can be determined :
• The plane was heading towards the NNE (azimuth 350).
• The UFO appeared at the one O’clock position, which was almost due north.
• The UFO disappeared above or behind a cloud bank at the 5 O’ clock position, which was to the Southeast.
• Duration was about one minute
ATIC suggested it might have been a meteor because the “description was similar to a meteor” .2 However, the intelligence office of Tactical air command disagreed. In a memo dated 6 May 1952, Major Gedson was quoted as stating:
“That he has observed meteors and in this instance the course of the object appeared to be a straight line and did not have the charac- teristic orbit of a meteor.” 3
This statement, in itself, indicates the pilot was not familiar with meteors. Meteors, for the most part, always travel in straight lines. They do not arc across the sky, which is a common misperception by observers. Even more telling is this description of the object:
At first I though an aircraft was on fire because of the brilliance and large size of illumination.4
The object disappeared above and beyond the cloud build-up on our right. Intensity and size of object varied only slightly throughout sighting.5
These are the kinds of descriptions found in bright fireball meteor events. The only reason it might not have been a meteor is the one minute duration that was used to describe the event. However, such estimates can be inaccurate and there are examples of bright meteors reporting such long durations.
The bright fireball of January 12, 1934, which was visible from Argentina, was estimated to have lasted one minute by observers.6 A more accurate measurement for a recent fireball event, on March 31, 2014, indicated a duration of roughly 34 seconds on video.7 The March 31, 2014 fireball appears to mimic the potential fireball for February 11, 1952. It started low one horizon and ended near the opposite horizon. This is the kind of trajectory one sees in an “Earth-grazing” meteor. They enter the earth’s at shallow angles resulting in them “skipping” in and out of the Earth’s atmosphere. As a result they can have long durations.
Solved?
The fact that long duration meteors do exist and can be quite spectacular is something not to be ignored. Blue Book is full of pilots who, upon seeing a bright fireball, reported a UFO because it was unlike meteors they had seen before. There is also the possibility that the time estimate was in error and may have been lower. This gives me all the reason to suspect that it was a bright meteor that the pilots saw and not something “unknown to science”. In my opinion, this case should be reclassified as a probable meteor.
Quelle: SUNlite 1/2016

Tags: UFO-Forschung 

1392 Views

Sonntag, 20. März 2016 - 14:00 Uhr

UFO-Forschung - Unzureichende Informationen in NICAP-Dokument als UFO-Beweis -TEIL 20

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February 2, 1950
This is how the case is listed in the chronology:
February 2, 1950- -Davis-Monthan AFB, Arizona. Bomber pilot chased UFO which left smoke trail. {III]1
When one reads Section III, the following information is available:
2/2/1950 Davis-Monthan AFB, Arizona - Lt. Roy L. Jones B-29 pilot Chased unidentified object which was leaving smoke trail.[13]2
Note 13 states the information came from the February 2, 1950 Los Angeles Daily Mirror.3
Like so much that is found in “The UFO evidence”, details are often lacking and the dates are sometimes incorrect. The actual date of the event was February 1. The media had published accounts the following day.
Searching for additional information
There are no records in the BB files for this event but it was widely mentioned in the news media. While the descriptions were similar to a meteor, the meteor explanation was ruled out by an expert:
Dr. Edwin F. Carpenter, head of the University of Arizona department of astronomy, said no one at Steward observatory saw the object because none of the staff was viewing the sky at the time. However, he was certain of one thing:
He was certain that the object was not a meteor or other natural phenomena.
Couched In the usual careful language of scientists. Dr. Carpenter said he was.,”Inclined to doubt that it was a meteor because of that object’s heavy discharge of smoke. A meteor rarely leaves a visible trail and, when It does, It leaves only a very light trail.”4
Dr. Carpenter’s word was considered gospel but the general description indicated the object was meteor-like:
Cannonballing through the sky some 30,000 feet aloft was a fiery object shooting westward so fast it was impossible to gain any clear impression of its shape or size.
Despite the hundreds of witnesses, there was little actual explanation on which to peg a clear picture of the event This is what most wit- nesses agreed they saw: A fiery object at very, high altitude streaked across the city. Behind It spread a thick streamer of smoke. Out of sight east of Tucson the smoke disintegrated and fanned outward into a broad band.5
The story about the pilot chasing the UFO was more a case of the pilot reporting the object moved too fast for him to catch it:
The radio operator In the Davis-Monthan air force base control tower didn’t know what It was. He contacted First Lt. Roy L. Jones Jr., taking off for a cross-country flight in a B-29, and asked Jones to investigate. They feared the object might be an airplane with a smoking engine that the pilot had not seen. But Jones revved up his swift aerial tanker and still the unknown aircraft steadily pulled away toward California.6
The writer appears to be exaggerating what actually transpired. He implied the B-29 gave chase for some time but the object slowly pulled away. However, the other descriptions indicated something that was so quick that people barely got a chance to see it. More detailed descriptions appeared in the February 3rd issue of the Tuscon Daily citizen7:
Buster Durazzo - “The object, whatever it was, ripped across the sky very quickly and disappeared suddenly about 100 feet over the Tuc- son mountains. It definitely didn’t drop a smoke trail down and behind the mountains...”
Grace Bautista - “My five brothers and sisters and I didn’t get very excited about it because we didn’t see it. However, mother and father were confused because it moved so awfully fast—they were excited for quite a while.”
Sam Marler - “I though it was a jet plane, but going awfully fast, 1 saw it go down over the Tucson mountains - at least 700 miles an hour. It didn’t leave vapor behind. It was definitely smoke.”
This indicated an object that was visible only for seconds. Even more interesting is that it was not a local event. According to anoth- er news article, the object was visible in another part of Arizona:
A deputy had reported the object flashed across the sky at Ajo, Ariz., 120 miles to the west, then quickly vanished.8
This makes me wonder about the statement attributed to Dr. Carpenter. He stated that meteors normally do not leave smoke trails. However, he is wrong. Fireballs that are visible in daylight or twilight do leave dust trails that look like contrails/smoke. The fireball of December 9, 1965, which sparked the Kecksburg story, left a smoke trail in the sky that last many minutes. The Tagish lake meteorite was produced by a fireball in the predawn sky that left an impressive dust trail. Therefore, the reason he rejected the meteor expla- nation is not based on accurate information. A little checking indicated that Dr. Carpenter’s expertise was not in meteor astronomy but in white dwarves and supernovae.9 He probably had never seen or heard of fireballs leaving such trails in the sky.
Conclusion
Looking at the bulk of the news media accounts, it appears that the object was a bright fireball seen in the evening sky. There is no reason to reject this explanation and it should be listed as probable fireball meteor. It does not qualify as “best evidence".
Quelle: SUNlite 1/2016

Tags: UFO-Forschung 

1438 Views

Sonntag, 20. März 2016 - 13:45 Uhr

UFO-Forschung - Die Kecksburg UFO-Absturz Story - Teil 5

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Kecksburg update
The recent effort to explain the Kecksburg case rekindled interest in the subject. My opinion about the Mk2 re-entry vehicle ex- planation was that it was a wasted effort. There is a perfectly good explanation that has existed since 1965. The fireball, which had been seen in Ohio, Michigan, Ontario, and Pennsylvania, had fooled the local population into thinking that something fell into the woods that evening. Nothing was ever found and there are no records to suggest otherwise. The rest of the story that Stan Gordon has been peddling is nothing more than a myth. The only “facts” that support this myth are the decades old testimonies of individuals, who have suspect motives.
Ted Molczan debunking
Ted Molczan pretty much debunked the new explanation with a lot of useful information. There is no reason to recount his rebut-
1 tal here since it is already public knowledge at Vicente-Juan Ballester Olmos’ blog .
Ted also chose to look at the fireball explanation as well as arguments against it. Using Google Earth, he created 2D and 3D trajec- tories based on the Krause/Chamberlain calculations. His results were reasonably close to what appeared in the photographs.
Mr. Molczan decided to start the meteor’s visible path at a height of 60 km (the normal altitude for slow meteors), which is where the red line begins. The white segment is the altitudes for the begin and end point of the debris trail. The subsequent red segment after this is the path any surviving meteorites might have taken to the earth. Ted has since informed me that atmospheric drag would have resulted in a more vertical fall of any surviving meteorites. For the purpose of this article, I am using his diagrams that do not incorporate that drag for the post train line segment. This diagram shows the 3D trajectory and the 2D ground track:
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Ted notes that there are some minor variations in regards to the slope of the path between the photographs and the Google Earth files. He thinks it probably had to do the cameras not being perfectly level with the horizon but it might be due to some distortion introduced by Google Earth. Molczan commented that he felt the variations were not that significant. The Pontiac track is on the left and the Orchard Park track is on the right:
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Mr. Molczan also commented about the possibility that an error was made by Krause and Chamberlain in the path computation:
I find it difficult to imagine any likely error in the analysis of the smoke trail photos, that if corrected, would result in impact near Kecks- burg. It is important to bear in mind that not only the azimuths must intersect, but the elevations of A and B also constrain the solution2.
Ted then pointed me towards an article that appeared in the Beaver County Times on December 10, 1965. It describes the observa- tions of one witness, Andrew Rosepiler, who gave a reasonable precise location for his vehicle. From that position, he gave a fairly accurate description of the meteor’s trajectory:
Rosepiler was westbound on Midland Avenue at Seventh Street, when he saw the “fireball” fall at a “very steep and slightly arched” angle. HE JUDGED the object about the size of a football with a 10 to 25 foot flaming tail streaking behind it. He said it appeared that it would hit a hillside just outside Midland behind the Petrosol Service Station along Route 68 (scientists say this is a common illusion when observing flying objects). Rosepiler said he watched the object because he thought it would explode when it hit. He thinks it hit about two thirds the way up the hill. He said he drove to higher ground for a better view of the hill side, expecting a fire to have started, but said he saw no fire or smoke.3
When Molczan used Rosepiler’s position and his Google Earth trajectory, he got the following result:
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This is a good reproduction of his observation. It also indicates that the meteor did not pass over his position towards Kecksburg.
There are a few other 1965 reports that can be found in the news media, where the witnesses gave locations and directions of ob- servation. I found an article in the Massillon, Ohio newspaper, where several reports were listed. The most precise location came from a driver at an intersection:
Paul McCormick...was waiting for the green light at Amherst rd and Lake ave. NE when he saw the ball of fire in the sky trailing smoke. He said it was so plain, you might have thought it was falling near Traphagen Rd NW.4
Ted put this location into his model and got this view:
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Trepahagan road was a road that ran roughly west to east about 2 miles north of the observer, who was facing in that direction. Once again, this is a close match to the actual trajectory of the fireball in Ted’s model.
Ted’s fireball track mirrors the actual scientific evaluation of the meteor’s track back in 1965-66 by Chamberlain, Krause and Douglas (of the Canadian National Research Council Associate Committee on Meteorites) . Dr. Douglas stated in his report:
On-the-spot interviews of some seventy observers (now close to 100) were made by Mr. Henry Lee, President of the Windsor Centre of the RASC, and the writer during part of January. Reduction of this sighting data confirmed the general ground position of the end-point as was determined from the photographs by Mr. Chamberlain. Contacts with eyewitnesses were obtained through requests in a daily and four weekly newspapers, radio station CJSP, Leamington, and through area high schools.5
As I stated in SUNlite 3-6, the data gathering in 1965-66 confirmed the trajectory of the fireball. I have yet to see anybody demon- strate that these calculations were incorrect or provide accurate descriptions from 1965 that indicates a different track. Therefore, there is no reason to revise it based on the claims made decades later by people interested in perpetuating their participation in the Kecksburg myth.
The Kalp observations
After pointing Ted towards SUNlite 3-6, he chose to plot the appearance of the fireball and resulting debris trail as viewed by the Kalp children that evening. Using the positions of the children provided by Bob Young and the computed trajectory from the photographs, Ted provided us with the view the children had looking at the fireball. As can be seen in Ted’s recreation, one can un- derstand why they thought something had landed in the woods. The debris trail hovering over the trees made it appear that there was smoke emanating from the woods. The conclusion drawn by Mrs. Kalp was that the object had apparently fallen into the woods and she called the authorities. What transpired next is history.
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The fireball explanation still stands
Hopefully, this information will supplement what I already published in SUNlite 3-6. Mr. Molczan’s work, which I greatly appre- ciate, confirms the fireball explanation for Kecksburg. While the proponents of the case can make all the claims they want, the actual science done in 1965 indicates it was a case of a misperceived fireball that evolved into a myth.
Quelle: SUNlite 1/2016

Tags: UFO-Forschung 

1429 Views

Sonntag, 20. März 2016 - 11:49 Uhr

Raumfahrt - NEO Koordinationszentrum entdeckt EXOMARS im Weltraum

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On 14 March, the ExoMars Trace Gas Orbiter and Schiaparelli lander were lofted into orbit by a Proton rocket from Baikonur in Kazakhstan, starting a seven-month journey to the Red Planet.
Following separation from the final stage at 20:13 GMT (21:13 CET), the craft left on a trajectory pointing to where Mars will be in October, travelling at 33 001 km/h with respect to Earth.
For asteroid hunters, ExoMars offers a perfect target because its departure mimicks, in reverse, the approach of a small near-Earth object, or NEO. These include rocky asteroids formed between the orbits of Mars and Jupiter which head towards Earth every so often.
For the ExoMars launch, ESA’s NEO coordination centre in Italy organised an international campaign for ground-based optical observations of the departing spacecraft.
Quick imaging of a rapidly moving object whose location is only approximately known in a short time window is akin to what would happen if an asteroid were discovered on an imminent impact trajectory with Earth.
The predicted path of ExoMars provided by ESA’s Space Debris Office in the Agency’s operations centre in Darmstadt, Germany – home to ExoMars mission control – was converted by the NEO centre into pointing information for telescopes.
This information was then shared widely with ESA’s network of collaborating observatories in the southern hemisphere, from where ExoMars was observable. Excellent images were acquired by Alison Tripp and Sarah Roberts using a 1 m-diameter telescope in Australia, and by Grant Christie at the Stardome Observatory in Auckland, New Zealand.
The most remarkable images, however, were acquired just before midnight local time by the Observatório Astronômico do Sertão de Itaparica team in Brazil led by Daniela Lazzaro, with Sergio Silva at the telescope.
In their images, the spacecraft appears as a bright object surrounded by at least six other fainter spots – elements of Proton’s discarded upper stage – moving together in the sky (see red arrows in annotated version below).
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With ExoMars safely disappearing into deep space, the NEO Coordination Centre campaign ended with very positive results made possible by the enthusiastic and passionate response of the NEO community.
Quelle: ESA
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Tags: Raumfahrt 

1560 Views

Sonntag, 20. März 2016 - 11:30 Uhr

Raumfahrt - Studenten nutzen REXUS Forschungsraketen für Raumfahrtsicherheit und Entwicklung von Minisatelliten

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Am 18. März 2016 ist um 6.10 Uhr Mitteleuropäischer Zeit (MEZ) die Forschungsrakete REXUS 19 erfolgreich vom Raumfahrtzentrum Esrange bei Kiruna in Nordschweden gestartet. Bereits drei Tage zuvor, am 15. März 2016, flog REXUS 20. Auf beiden Raketen der diesjährigen REXUS-Doppelkampagne des Deutschen Zentrums für Luft- und Raumfahrt (DLR) und der schwedischen Raumfahrtbehörde SNSB waren jeweils vier studentische Experimente untergebracht. 45 Studierende von acht Teams aus Deutschland, Schweden, Großbritannien, Spanien und der Schweiz bereiteten ihre Experimente auf  Esrange  vor und führten sie auch durch. Die beiden Flüge dauerten rund zehn Minuten, wobei die REXUS-19-Rakete eine Flughöhe von 78,3 Kilometern und REXUS 20 von 77,4 Kilometern erreichte. Dabei flogen die sechs Meter langen Raketen jeweils zwei Minuten fast schwerelos. Rund ein Jahr lang hatten sich die acht Teams für die Raketenkampagne vorbereitet und ihre Experimente selbständig entwickelt, gebaut und getestet.
Die deutschen Experimente auf REXUS 19 und 20 
Das Team MIRKA2-RX (Mikro-Rückkehrkapsel 2 - REXUS) der Universität Stuttgart entwickelte eine kleine Rückkehrkapsel, die in einem würfelförmigen Kleinstsatelliten (CubeSat) mit einer Kantenlänge von zehn Zentimetern Platz findet. Die Kapsel soll später bei einem echten Wiedereintritt in die Erdatmosphäre Daten über das Verhalten des Hitzeschildes aus wärmeableitendem Material sammeln und zur Erde übertragen. Beim Flug der REXUS-19-Rakete wurden der Auswurfmechanismus, das dynamische Flugverhalten der Kapsel und die Kontaktaufnahme zu einem kommerziellen Satelliten für die Übertragung der Messdaten zur Bodenstation getestet. Eine besondere Herausforderung für die Studierenden war die Unterbringung der Messsensoren und der gesamten Elektronik in der Mini-Kapsel. 
Kommunikation spielt auch für das Team LiME (Link Made Early) der Ernst-Abbé-Hochschule Jena eine wichtige Rolle. Die Studenten entwickelten ein "dynamisches Kommunikationsschema" für Kleinstsatelliten, das durch die Lageinformation des Satelliten gesteuert wird. Nur wenn die leistungsstarke Richtantenne in Richtung der Bodenstation zeigt werden große Datenmengen übertragen. In der Zeit dazwischen kann die kostbare Energie gespart werden. Damit ist eine Kommunikation schon in kürzester Zeit nach der Freisetzung eines Satelliten im Weltraum und ohne Lageregelung möglich. Zum Test unter realistischen Umgebungsbedingungen wurde das Kommunikationsschema in vier Modell-Satelliten implementiert, die während des Raketenflugs ausgeworfen wurden.
  
Die REXUS-20-Rakete ist für das Team PATHOS (Position-vector Acquisition Through Horizon ObServation) der Universität Würzburg eine ideale Experimentierplattform. Mit der leichten Taumelbewegung der ungesteuerten Rakete während des Fluges simuliert diese einen außer Kontrolle geratenen Satelliten. Die Studierenden aus Würzburg testeten einen Algorithmus, um seine aktuelle Lage im Raum für eine Lagekorrektur zu ermitteln. Mit einer Kamera wurden Bilder aus der Rakete heraus des immer wieder im Blickfeld auftauchenden Horizonts aufgenommen. Somit wurde die Horizontlinie und die Richtung zum Erdmittelpunkt und damit die Lage der Rakete zur Erde berechnet. "Für uns ist das REXUS/BEXUS-Programm eine perfekte Ergänzung zum Studium und eine gute Möglichkeit, Projekterfahrung zu sammeln", sagte Teammitglied Moritz Aicher.
Materialien, die in der bemannten Raumfahrt eingesetzt werden, sollten aus Sicherheitsgründen möglichst schlecht brennbar sein. Das lässt sich aus wissenschaftlichen und technischen Gründen nicht immer umsetzen. Tests zur Entflammbarkeit und Flammenausbreitung sind daher unabdingbar. Die Flammenausbreitung im Weltraum stoppt wegen fehlender, von der Schwerkraft angetriebener Luftströmung - und damit neuer Luftzufuhr - früher als auf der Erde. Tests mit Plexiglas-Proben im Labor haben gezeigt, dass Oberflächen mit einer Struktur die Feuerausbreitung wiederum begünstigen. So war das Ziel des Teams UB-FIRE (University of Bremen FIre safety Research Experiment) der Universität Bremen, die Flammenausbreitung an einer glatten Plexiglas-Oberfläche und an solchen mit unterschiedlichen Strukturen in Schwerelosigkeit zu beobachten und zu klären, ob auch dort die Unterschiede im Brennverhalten bestätigt werden können und - daraus folgend - die üblichen Tests mit glatter Oberfläche möglicherweise nicht ausreichend für die Sicherheitsanalyse sind.  
Die europäischen Experimente auf REXUS 19 und 20
Folgende europäische Teams waren bei REXUS 19 und 20 dabei:
Das schwedische SLED-Team (System of free-falling units using LEDs to allow one to track the other) von der KTH Stockholm entwickelte zwei frei fallende Flugkörper zur Messung von Atmosphärendaten. Einer der Flugkörper sendete Lichtsignale, die durch eine Kamera von dem anderen Flugkörper detektiert wurden. Somit konnte die Position der beiden Flugkörper zueinander bestimmt werden. 
Zur Vorbereitung einer CubeSat-Mission testete das Team PICARD (Prototype Inflatable Conical Antenna - REXUS Deployment) der Universitäten von Strathclyde und Birmingham (Großbritannien) die Funktionalität einer aufblasbaren kegelförmigen Struktur, auf deren Oberfläche spiralförmig eine Aluminium-Antenne aufgebracht war. 
Unter Schwerelosigkeit steigen die Blasen beim Sieden einer Flüssigkeit nicht wie im Kochtopf nach oben, sondern verbleiben an der Heizfläche und werden immer größer. Dadurch kann zwischen Heizer und Flüssigkeit kaum noch ein Wärmeaustausch stattfinden, was sogar zum Durchbrennen des Heizers führen kann. Das Team BOILUS der "Polytechnic University of Catalonia" in Barcelona (Spanien) untersuchte den Einfluss von Ultraschallwellen auf das Ablösen von Siedeblasen von einer Heizerfläche. Hintergrund für die Untersuchungen ist eine mögliche Kontrolle von lokal auftretenden Siedeprozessen kryogener, das heißt bei sehr niedriger Temperatur verflüssigter Treibstoffe. Dies lässt sich selbst in Tanks bei bester Isolierung kaum vermeiden.
 
Eine Nutzlast biologischer Art hatte das Schweizer Experiment CEMIOS der Hochschule Luzern mit an Bord. Lange Schwerelosigkeit hat für den menschlichen Körper schwerwiegende Auswirkungen, zum Beispiel  Muskelschwund und die Verringerung der Knochendichte. Bis heute ist nicht eindeutig geklärt, wie die dabei beteiligten Körperzellen die unter Schwerelosigkeit veränderten mechanischen Kräfte wahrnehmen. Wissenschaftliche Untersuchungen deuten darauf hin, dass mechanosensitive Ionenkanäle in den Zellmembranen, damit sind porenartige Proteine gemeint, die auf mechanische Kräfte reagieren, dabei eine Rolle spielen können. Das CEMIUS-Team untersuchte diese Ionenkanäle während des Raketenfluges mit biophysikalischen Messungen an Froscheiern, den sogenannten Oozyten. Die Erkenntnisse aus dem Experiment sind für die biologische und medizinische Forschung ein Schritt, um die zelluläre Wahrnehmung von mechanischen Kräften besser zu verstehen. 
REXUS und BEXUS: ein Programm für den wissenschaftlichen Nachwuchs
Das Deutsch-Schwedische Programm REXUS/BEXUS (Raketen-/Ballon-Experimente für Universitäts-Studenten) ermöglicht Studenten, eigene praktische Erfahrungen bei der Vorbereitung und Durchführung von Raumfahrtprojekten zu gewinnen. Ihre Vorschläge für Experimente können jährlich im Oktober eingereicht werden. Der diesjährige Aufruf dazu wird am 13. Juni 2016 veröffentlicht. Jeweils die Hälfte der Raketen- und Ballon-Nutzlasten stehen Studenten deutscher Universitäten und Hochschulen zur Verfügung. Die schwedische Raumfahrtagentur SNSB hat den schwedischen Anteil für Studenten der übrigen Mitgliedsstaaten der Europäischen Weltraumorganisation ESA geöffnet.
Auf deutscher Seite erfolgt die Projektleitung mit der Betreuung der Experimente durch das Zentrum für Angewandte Raumfahrttechnik (ZARM) in Bremen. Die Flugkampagnen führt EuroLaunch durch, ein Joint Venture der Mobilen Raketenbasis des DLR (MORABA), die für die Bereitstellung der Raketensysteme zuständig ist, und des Esrange Space Center des schwedischen Raumfahrtunternehmens SSC, das über die Startinfrastruktur verfügt. Die Programmleitung liegt beim DLR Raumfahrtmanagement in Bonn.
Quelle: DLR

Tags: Raumfahrt 

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Sonntag, 20. März 2016 - 10:45 Uhr

Raumfahrt - NASA: Atomantrieb ist "effektivster" Weg den Menschen zum Mars zu bringen

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Nasa administrator Charles Bolden has claimed that nuclear thermal propulsion is the "most effective" way of sending humans to Mars.
"We are on a journey to Mars and most people believe that, in the end, nuclear thermal propulsion will be the most effective form of propulsion to get there," he told Congress.
Bolden also praised Alabama's Marshall Space Flight Centre, a nuclear thermal propulsion centre that has been developing the technology for years. "Marshall is the place that people go when they want to discuss in-space and leaving-the-Earth propulsion issues," he said.
Although nuclear-powered engines are smaller, they're much more powerful than conventional rockets. Fluid, usually hydrogen, is heated to incredibly high temperatures to create plasma, which is then channelled through a nozzle to create thrust. But because temperatures can reach 2000°C, Nasa has struggled to find materials that can withstand the journey. 
Earlier this month Russia announced that it would be testing its own nuclear engine for deep space travel in 2018. Experts working on the Russian project believe the new technology could take humans to mars in just six weeks. By comparison, today's engines take up to 18 months to reach Mars.
Getting humans to Mars is a major focus for Nasa over the coming decades. The space agency has been growing vegetables in Martian soil, tested a number of different rocket systems and has recently launched InSight, a mission to explore the planet that could provide the strongest evidence yet for life on Mars.
Quelle: WIRED
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Tags: Raumfahrt 

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Sonntag, 20. März 2016 - 09:41 Uhr

Astronomie-History - 1973: Astronomen sehen Totale Sonnenfinsternis aus einer Concorde Teil 2/2

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A short French documentary about the flight Concorde-001 SoFi 1973

Quelle: Frams YouTube


Tags: Astronomie 

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Sonntag, 20. März 2016 - 09:40 Uhr

Astronomie-History - 1973: Astronomen sehen Totale Sonnenfinsternis aus einer Concorde Teil 1/2

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On Wednesday, a solar eclipse gave people across a swath of Indonesia and the South Pacific the chance to see a generous 4 minutes and 9 seconds of totality: the awe-inspiring sight of the moon completely covering the sun, turning day into night and offering a rare glimpse of the corona, the gas swirling in the Sun’s outer atmosphere.
But in 1973, a small group of astronomers from around the globe had a secret weapon for seeing a longer eclipse than ever before: a prototype Concorde, capable of chasing the eclipse across the Earth at twice the speed of sound.
The future airliner—developed in a partnership between the French and British governments—had first flown in 1969 and was nearing the end of its successful test program. It had shown that supersonic passenger travel was very much possible, and proven easier to handle in the air and on the ground than had been theorized. Under the control and overall direction of French test pilot André Turcat, the French Concorde “001” prototype had set numerous speed and altitude records. An era of supersonic passenger flight was on the horizon, promising to cut trans-Atlantic jaunts to a breezy 3 and a half hours, less than half the time of a conventional jet.
As French and British aviation engineers readied their Concordes for passenger flight, the solar astronomy world was gearing up for its own milestone: the longest total solar eclipse of a lifetime, on June 30, 1973. The eclipse promised a luxurious view if you stood at the right place on the planet: a maximum of 7 minutes and 4 seconds as the moon passed over the Sahara Desert. It would be just 28 seconds short of the longest possible eclipse viewable from Earth; in the preceding several hundred years, there had only been one eclipse longer than this one, and there would not be a longer total solar eclipse until June 2150.
Independently of each other, astronomers in France and the UK saw a happy coincidence in the new aircraft and the upcoming eclipse: In Concorde, they could follow the shadow of the moon as it raced across the planet. In theory, a supersonic transport (SST) could give them over 70 minutes to watch the eclipse, ten times more observation time than they’d get on the ground, and high above any potential clouds and water vapor. Now they just had to get their hands on one.
“I don’t know if this kind of adventure would be possible today. I think now all the structures are way more organized and hierarchical.”
In London, British astrophysicist John Beckman had been using aircraft to do astronomy for years, despite being a nervous flyer himself. “I was working in a pioneer group of far infrared submillimeter physics,” he recalls. “At that time you could do very little work of any kind from the ground. You would have to go to very high mountains, or fly. My scientific curiosity allowed me to overcome my nerves.”
Beckman put in a request to use the British Concorde “002” prototype but was turned down, possibly because the UK test program was lagging behind the French. In May of 1972, just over a year before the celestial encounter, an astronomer from the Paris Observatory called Pierre Léna took his own proposal to French test pilot André Turcat personally. A scientifically-curious pilot, he’d given the young researcher an hour of his time. Over lunch at a restaurant inside Toulouse Airport, Léna sketched out his vision on the paper tablecloth.
“I don’t know if this kind of adventure would be possible today,” laughs Léna, now 78 but still an active member of the scientific community. “I think now all the structures are way more organized and hierarchical. I was lucky I got to do it, and of course I was young. In fact, I was very lucky people even took me seriously!”
The plan seemed deceptively simple. Closing in at maximum velocity, Concorde would swoop down from the north and intercept the shadow of the moon over northwest Africa. Traveling together at almost the same speed, Concorde would essentially race the solar eclipse across the surface of the planet, giving astronomers an unprecedented opportunity to study the various phenomena made possible by an eclipse: the ethereal solar corona, the effect of sunlight on the darkened atmosphere, and the brief red flash of the chromosphere, a narrow region around the sun that’s usually washed out by the much brighter photosphere.
Turcat was impressed. He pitched the idea to his bosses at Aérospatiale, who gave a tentative green light, and agreed to assume the cost of the mission. Turcat and chief navigation engineer Henri Perrier got to work on all the details, factoring in weather patterns and even ground temperatures in the places where Concorde could take off from, which would affect the fuel load. (The Concorde’s engines were optimized for the upper atmosphere, though this made them less efficient on the ground. Just taxiing for take-off, the Concorde burned more fuel than a 737 flying from London to Amsterdam, a fact which contributed to its eventual grounding.)
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Eclipse map of June 30, 1973. Image: NASA
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Léna and his colleagues began thinking of what experiments they would carry with them into the stratosphere and working out the details of actually intercepting the eclipse. After deciding on Gran Canaria as a good starting point, the team planned a route south and then east along the eclipse line. Turcat and Perrier looked into which runways in Africa would be able to handle the 200-foot long aircraft, which didn’t exactly stop on a dime. They pushed as far west as possible, to N’Djamena in Chad, with Kano in Nigeria as a back up. The actual rendezvous would take place over Mauritania, which agreed to close its airspace to commercial air traffic at midnight the night before.
“There was a lot to cover,” Léna recalls. First was the mechanical transformation of the plane. Occuring during the summer solstice and practically along the Tropic of Cancer, the eclipse would be at the zenith: directly above them. To view it properly, they would need to install portholes in the roof and design an apparatus to photograph through it.
The windows would have to resist the pressure difference between the cabin and the outside, as well as the high temperatures—around 100º C—felt on the outer surface of the fuselage in supersonic flight, due to friction. If the porthole were to blow out during flight, that wouldn't necessarily risk the safety of the flight, but it would require an emergency landing and an end to the experiment.
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The Queen Mary College system being tested outside the Aerospatiale factory in Toulouse. Left-to-right: Jim Lesurf, Jim Hall (RSRE), and Tony Marston. Photo: Jim Lesurf
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“As the research advanced and we got more excited, it became clear to us we couldn’t just do the flight without offering it to other scientists too. So we took the decision to use the Concorde’s maximum capacity and share it between five teams.” There would be scientists aboard from the French Institute of Astrophysics, Kitt Peak National Observatory, Los Alamos National Laboratory, Queen Mary University of London, and the University of Aberdeen. “So there were five different experiments, which had the advantage of spreading out the risk of failure. Each had a very different objective.”
When Beckman learned there was room onboard the special flight, “I was absolutely ecstatic,” he recalls. “And a bit worried.” For one thing, time was short. “I had the basic equipment, of course, which was a Michelson interferometer with a helium-cooled detector, but I didn’t have the infrastructure to link with Concorde and track the eclipse path. There was no time to automate it.” Instead, Beckman devised a way to track the eclipse manually, which would require “continuously turning a handle to keep the mirror aligned with one hand, while tilting it down into the observing hole with the other hand.”
At last, in February 1973, with just four months until the eclipse, the scientists received word that the mission was a go. The researchers rushed into final preparations. Besides the time constraints of the rapidly-approaching sun and moon, each experiment would have to cope with limitations imposed by the aircraft itself. Nothing could short-circuit—an onboard fire would be catastrophic—and everything had to be built to withstand the vibrations on takeoff: an afterburner-driven sprint that would accelerate Concorde to 250 miles-per-hour even before lift-off, pinning passengers firmly back against their seats. And, despite the aircraft's clean safety record at that point, in the back of the scientists' minds were legitimate concerns about flying in any experimental aircraft at supersonic speeds.
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Concorde 001 taking off on its eclipse mission. Photo: Jim Lesurf
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At precisely 10:08 am on the morning of June 30, the four twin-spool Olympus 593 engines under the Concorde’s sweeping white wings powered up to full afterburner and launched “001” down the runway of Gran Canaria's Las Palmas airport. Thousands of miles to the east, the shadow of the moon was already racing across the Atlantic at over 1,200 mph, tracing a path eastward from South America toward the African coast.
"There was no room for emotion; that came later."
Léna, Beckman, and the seven other astronomers aboard had no time to enjoy the joyride. “We were running through all the procedures in our minds,” recalls Léna, “and as soon as we got authorization from the cockpit to get out of our seats we got up and got to work. We had to double check the instruments, the pumps, the recorders… there was no room for emotion; that came later.”
Two minutes after take-off, the aircraft hit Mach 1, or about 707 mph at altitude, and headed southeast toward the moving shadow. Climbing up into the stratosphere at an altitude of 56,000 ft., Turcat pushed the aircraft to Mach 2.05, more than twice the speed of sound. Even after a couple of test flights the atmosphere on board was tense—the timing and the equipment had to work perfectly. Helped by Concorde’s two onboard inertial guidance systems, the crew guided the aircraft along the carefully-mapped trajectory and met the eclipse within 1 second accuracy of the planned rendezvous. The chase was on.
“Alone in the Mauritanian sky,” as a French film about the flight poetically put it, Concorde 001 hurtled east along the path of totality. With the eclipsed sun high over ahead, Turcat switched on the night-time navigation lights in the midday darkness. Paintings and stamps issued by various African countries would depict the epic, sci-fi sight, and Turcat would later deliberate about whether to file the flight as a day or night one.
"As the limb of the moon slowly occulted the solar disk, I saw the chromosphere, which flashed out in bright red alpha light.”
Under the four specially-made portholes and along some of the side-facing ones, Léna and Beckman, and others on board focused on the science. Léna and his team concentrated their efforts on detecting dust particles left over from comets in the solar halo, attempting to determine if there was a ring or sphere of them around the sun. Paul Wraith from Scotland used a side-porthole to watch the effect produced by the sudden darkness on oxygen atoms in the Earth’s atmosphere, while veteran American airborne eclipse chaser Donald Liebenberg looked up at the eclipse to measure pulsations in light intensity. From a porthole added to the roof of the plane, he observed, he said, how “the moon appeared to work as a slow camera shutter, slicing off only a tiny piece of the atmosphere each second.”
Beckman, meanwhile, was busy multitasking, with a tape recorder taped to his chest so he could make audio observations about the chromosphere. “Everybody was very concentrated on what they were doing,” he recalls, “but I did have time to glance out of the side window at one point and see the edge of the umbra, the penumbra and the daylight beyond. From the height we were at I could actually see the curvature of the earth, so it was pretty incredible. I was also able to gaze up at the corona and, as the limb of the moon slowly occulted the solar disk, I saw the chromosphere, which flashed out in bright red alpha light.”
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One of the specially-designed instruments for observing the composition of the sun's corona. Photo: Pierre Léna
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The science and the Concorde could have kept going, but the landing site in Chad was coming up fast. Each team wrapped up their observations and managed to steal a few moments gazing out over the sands of the Sahara at a sight few get to witness. In all, the experimenters observed the totality of the eclipse for a record 74 minutes.
Turning south out of the darkness, Turcat began lining up for the approach. “I would have 10 tonnes of kerosene upon arrival,” he later wrote, giving him “forty minutes’ wait, and the right to a missed approach.” In any event, the aircraft landed smoothly, although Beckman remembers that “the aircraft was within meters of the end of the runway.”
“They all played their role in the normal progression of scientific knowledge, but there were no extraordinary results, it has to be said.”
The aircrew and the astronomers arrived to a surreal scene, having descended from the stratosphere at supersonic speed in one of the world’s most advanced aircraft only to emerge under the strange half-light of the African sun, still partially eclipsed. An attempted coup d’etat (possibly timed to coincide with the eclipse) meant that armored vehicles mingled with people on the street who were using smoky glass to gaze up at the sun.
In one flight, Concorde had given astronomers more eclipse observing time than all the previous expeditions last century—generating three articles in Nature and a wealth of new data. But today Léna, who has recently published a book in French and English about the experiment, Racing the Moon’s Shadow with Concorde 001, is modest about what it accomplished.
“The five experiments all succeeded, but none of them revolutionized our understanding of the corona,” he says in a disarmingly honest way about the flight’s immediate impact. “They all played their role in the normal progression of scientific knowledge, but there were no extraordinary results, it has to be said.”
For the 1999 solar eclipse over Europe, one French and two British Concordes briefly chased the moon’s shadow, but the only passengers on board were tourists. The tragic crash of Concorde flight 4590 shortly after takeoff from Paris on July 25, 2000, killing all 109 passengers and crew and 4 people on the ground, marked the beginning of the end for what Léna called the “great white bird.” Planned Concorde eclipse tours in 2001 were grounded, and in 2003 the final commercial Concorde flights touched down for the final time.
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A 1973 French postcard commemorating the mission. Photo: E-space Lollini
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NASA and Lockheed Martin have begun to explore designs for a new, quieter supersonic passenger jet (the Concorde's powerful supersonic booms limited its popularity). In England, a group called Club Concorde is trying to raise enough money to get a single Concorde flying again, possibly for the aircraft’s 50th anniversary in 2019.
Still, Léna doubts their incredible flight will ever be repeated. Today, space-based satellites that can watch the sun 24/7 and create permanent artificial eclipses have revolutionized our understanding of the nearest star to Earth—although observing eclipses on Earth is still useful for astronomy.
“At the time, our knowledge of the solar corona was very very limited,” explains Léna. “Today we have far less need for eclipse flights from a scientific point of view because we can put missions like SOHO in space, which is doing essentially what we were aboard Concorde. Our observation methods have changed a lot, so I doubt if today we’d redo a mission like that.”
It’s often said that scientific inquiry leads to innovation, but the Concorde experiment is a reminder that sometimes innovation offers wild, unexpected dividends to science. Today, the exact plane that chased the eclipse in 1973 sits as a permanent exhibit at Le Bourget Air and Space Museum, complete with the special roof portholes and the eclipse mission logo on its fuselage. Léna, John Beckman and other engineers and astronomers were present for the 2013 unveiling, along with the late pilot André Turcat, who passed away just last month.
“There’s no aircraft flying today that would let us do what we did, nothing that can fly that fast for that long," says Léna. "There are military jets that can fly faster, but not with the endurance of Concorde—and of course they couldn’t carry the instruments. Our record is safe for the foreseeable future.”
Quelle: Motherboard

Tags: Astronomie 

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