Il 6 ottobre 2008, tra 22 giorni da oggi, avverrà il 2 ° Flyby di Mercurio!
Nel corso degli ultimi sei mesi, gli ingegneri sono stati impegnati nella realizzazione dei comandi software necessari per l’esecuzione delle osservazioni durante il prossimo flyby.
Il 12 settembre gli ingegneri di missione hanno completato con successo la prova finale dei comandi sul simulatore di hardware.
I comandi verranno inviati in un’unica sequenza al veicolo spaziale il 29 settembre.
Ci sono grandi aspettative sui prossimi risultati, per il fatto che questa volta verrà sorvolato l’emisfero opposto a quello visitato a gennaio, passando a meno di 200 km dalla superficie.
Il flyby funzionerà anche come ultimo gravity assist, prima di far immettere Messenger su di una rotta che, al prossimo incontro con il pianeta, gli permetterà di diventare il primo veicolo spaziale in orbita attorno a Mercurio, nel 2011!
Immagine della copertura fotografica del 2° flyby che si tradurrà , in pratica, nella prima copertura fotografica dell’intera superficie: Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Con questo secondo flyby dovremo quindi aver completata la copertura della superficie di Mercurio! Una bella soddisfazione per la NASA dopo ben 34 anni dal Mariner 10!
Effettivamente la NASA, con Mercurio, ha ormai l’esclusiva…
Anche se…Bepi Colombo…italiano… la sua parte l’ha fatta!
Legando il suo nome alla storia dell’esplorazione di Mercurio!
Sempre più vicini…quinta immagine di una serie di riprese ad uso navigazione!
peccato non poter vedere in diretta…
Immagine del 4/8//08…pubblicata oggi!
Ho creato una animazione dell’avvicinamento dalle immagini fino ad ora inserite nel sito di Messenger, dovrebbero riprenderne ancora almeno 3 serie che inserirò nell’animazione quando le avrò tutte!
MESSENGER’s engineering and operations teams convened at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., this afternoon to confirm the health and readiness of the spacecraft. “All spacecraft sub-systems and instruments reported nominal operations indicating that MESSENGER is ready for its second encounter with Mercury,” said MESSENGER Systems Engineer Eric Finnegan of APL.
At 6:05 p.m. EDT the last bits of data from the spacecraft were received as it transitioned from high-gain downlink to beacon-only operations, and the spacecraft reoriented itself to begin science operations. Before turning away, however, the spacecraft returned a set of optical navigation images (available online at http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=212) of the terrain not yet seen up-close by any spacecraft to whet our appetite regarding the discoveries to come.
For the next 10 hours or so, the spacecraft will take repetitive scans through Mercury’s comet-like anti-sunward tail, pausing now and then to take a color image and a high-resolution mosaic of Mercury with the Mercury Dual Imaging System instrument.
“The operations team is now preparing for the period of time about an hour prior to closest approach [at 4:40:21 a.m. EDT], when we will be transitioning our support from the Canberra ground station to the Madrid ground station that will capture the flyby,” Finnegan said. “High-gain communications with the spacecraft will be re-established on Tuesday at 1:14 a.m. EDT at approximately 52 kilobits per second, and playback of the data stored in the solid-state recorder will start approximately 30 minutes later.”
“MESSENGER is now on its own. The MESSENGER team is confident that our probe will carry out the full flyby command sequence, which was developed and thoroughly tested by the many dedicated engineers and scientists on the MESSENGER flight team,” said MESSENGER Principal Investigator Sean Solomon of the Carnegie Institution of Washington. “We all look forward with excitement to the flyby data set that we will start to glimpse Tuesday morning. We’ll be seeing at close range, for the first time, a region of Mercury larger in area than South America. Discoveries are just hours away.”
At a little after 4:40 a.m. EDT, MESSENGER skimmed 200 kilometers (124 miles) above the surface of Mercury in the second of three flybys of the planet. Initial indications from the radio signals indicate that the spacecraft continues to operate nominally. The spacecraft is now collecting images and other scientific measurements from the planet as it departs Mercury from the illuminated side, filling in the details of much of Mercury’s surface not previously viewed by spacecraft.
Tomorrow at 1:14 a.m. EDT, the spacecraft will turn its high-gain antenna back toward Earth to start down-linking the data stored onboard. The first pictures from the flyby will be released around 10:00 a.m. on October 7, 2008. Additional information and features from this encounter will be available online at http://messenger.jhuapl.edu/mer_flyby2.html. Be sure to check back frequently to see the latest released images and science results!
From Mariner 10 to MESSENGER
On Wednesday, October 8, 2008, MESSENGER Science Team member Mark Robinson, from Arizona State University, will talk about what we’ve learned about Mercury in the last three decades and release new pictures from MESSENGER’s second flyby of Mercury. The event, to be held at the Kossiakoff Center on the campus of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., will begin at 4 p.m. To RSVP, go online to http://messenger.jhuapl.edu/RSVP/.
When Mariner 10 flew past Mercury three times in 1974 and 1975, the probe imaged less than half the planet. In January, during MESSENGER’s first flyby, its cameras returned images of about 20 percent of the planet’s surface missed by Mariner 10. Yesterday, at 4:40 am EDT, MESSENGER successfully completed its second flyby of Mercury, and its cameras captured more than 1,200 high-resolution and color images of the planet – unveiling another 30 percent of Mercury’s surface that had never before been seen by spacecraft.
“The MESSENGER team is extremely pleased by the superb performance of the spacecraft and the payload,” said MESSENGER Principal Investigator Sean Solomon of the Carnegie Institution of Washington. “We are now on the correct trajectory for eventual insertion into orbit around Mercury, and all of our instruments returned data as planned from the side of the planet opposite to the one we viewed during our first flyby. When these data have been digested and compared, we will have a global perspective of Mercury for the first time.”
Today, at about 1:50 a.m. EDT, MESENGER turned to Earth and began transmitting data gathered during its second Mercury encounter. This spectacular image – one of the first to be returned – was snapped by the Wide Angle Camera (WAC), part of the Mercury Dual Imaging System (MDIS) instrument, about 90 minutes after MESSENGER’s closest approach to Mercury, when the spacecraft was at a distance of about 27,000 kilometers (about 17,000 miles).
The bright crater just south of the center of the image is Kuiper, identified on images from the Mariner 10 mission in the 1970s. For most of the terrain east of Kuiper, toward the edge of the planet, the departing images are the first spacecraft views of that portion of Mercury’s surface. A striking characteristic of this newly imaged area is the large pattern of rays that extend from the northern region of Mercury to regions south of Kuiper.
This WAC image is one in a sequence of 55: a five-frame mosaic with each frame in the mosaic acquired in all 11 of the WAC filters. This portion of Mercury’s surface was previously imaged under different lighting conditions by Mariner 10, but this new MESSENGER image mosaic is the highest-resolution color imaging ever acquired of any portion of Mercury’s surface.
Additionally, some of the images in this mosaic overlap with flyby data acquired by the Mercury Atmospheric and Surface Composition Spectrometer and Mercury Laser Altimeter instruments, resulting in the first time that these three instruments have gathered data of the same area of Mercury. The combination of these three datasets will enable unprecedented studies of this region of Mercury’s surface.
This image, acquired about 89 minutes before the craft’s closest approach to Mercury, resembles the optical navigation images taken leading up to the flyby. The resolution of this image is somewhat better than that obtained by the final optical navigation image set, and the surface visible is newly imaged terrain that was not previously seen by either Mariner 10 or during MESSENGER’s first flyby.
However, the added resolution is not the main scientific advancement that will be provided by this image. This WAC image is one of 11 viewed through different narrow-band color filters, the set of which will enable detailed color studies of this newly imaged area. In addition, the Narrow Angle Camera (NAC) acquired a high-resolution mosaic of most of this thin crescent view of Mercury at a resolution better than 0.5 kilometers/pixel (0.3 miles/pixel) that will enable the MESSENGER team to explore this newly imaged region of Mercury’s surface in more detail.
About 58 minutes before MESSENGER’s closest approach to Mercury, the NAC captured this close-up image of a portion of Mercury’s surface imaged by spacecraft for the first time. It is one of 44 in a high-resolution NAC mosaic taken of the approaching crescent-shaped Mercury, as seen at lower resolution in the optical navigation images and the approach WAC color image set.
As the MESSENGER team is busy examining this newly obtained view, data from the flyby continue to stream down to Earth, including higher resolution close-up images of this previously unseen terrain. Collectively, these images and measurements made by other MESSENGER instruments will soon provide a broad range of information for understanding the formation and geologic history of the innermost planet.
Ricevo e posto questa email dove si accenna al fatto che il flyby prefissato, 200 km, è stato mancato di 600m !
Un errore che probabilmente avrà rallentato ancor più la sonda favorendo di conseguenza la prossima immissione in orbita.
Inoltre viene commentata l’immagine dello spettacolare cratere Vivaldi, la seconda postata da RikyUnreal.
MESSENGER Mission News
October 8, 2008
MESSENGER Sets Record for Accuracy of Planetary Flyby
By using solar sailing – rotating the spacecraft and tilting its solar panels to use the very small pressure from sunlight to alter the spacecraft’s trajectory – MESSENGER navigators have achieved a new record for the smallest miss distance between the intended and actual closest approach distance during a flyby of a planet other than Earth.
On October 6, 2008, the probe flew 199.4 kilometers (123.9 miles) above the surface of the planet. “Our goal was to fly 200 kilometers from the planet’s surface, and we missed that target by only 0.6 kilometers,” explained MESSENGER Mission Design Lead Jim McAdams, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
That’s pretty remarkable targeting, given that MESSENGER has travelled 668 million kilometers since its last deep space maneuver in March, McAdams says. “It’s as if we shot an arrow from New York to a target in Los Angeles – nudged it three times mid-stream with a soft breath – and arrived within the width of the arrow’s shaft at the target.”
New Mercury Images Available
The MESSENGER Science Team has released five new images from the probe’s second flyby of Mercury. When the spacecraft flew by Mercury in January, one of the more dramatic images captured was of the Vivaldi crater at sunset. Two days ago, MESSENGER’s cameras took this image of Vivaldi at sunrise.
This striking view of Mercury, taken about 54 minutes before closest approach, shows the northern portion of the sunlit, crescent-shaped planet seen as the spacecraft approached Mercury. As MESSENGER continued toward Mercury, the Mercury Dual Imaging System (MDIS) captured this image of previously unseen smooth plains.
The MDIS Wide Angle Camera snapped this image, part of a high-resolution color mosaic of the planet, just 8 minutes and 47 seconds after the MESSENGER spacecraft passed above Mercury’s surface. The probe’s closest approach occurred over the dark night side of Mercury, as can be seen in this animation, so the MDIS cameras had to wait until the sunlit surface was visible before beginning to image while departing from the planet.
This image shows a view of Mercury as imaged by the Mariner 10 spacecraft in the 1970s, alongside a view of the planet with the gaps largely filled in by MESSENGER during the recent flyby. Filling in this gap will help the Science Team to use both Mariner 10 and MESSENGER data to characterize the diverse geological processes that shaped the surface of Mercury over time.
