ESA’s ‘sleeping beauty’ wakes up from deep space hibernation

Rosetta Wake-up signal

It was a fairy-tale ending to a tense chapter in the story of the Rosetta space mission this evening as ESA heard from its distant spacecraft for the first time in 31 months.

 

"Rosetta wakes up from deep space hibernation". Video from ESA

Video from ITN on Rosetta Mission

Rosetta is chasing down Comet 67P/Churyumov-Gerasimenko, where it will become the first space mission to rendezvous with a comet, the first to attempt a landing on a comet’s surface, and the first to follow a comet as it swings around the Sun.

Since its launch in 2004, Rosetta has made three flybys of Earth and one of Mars to help it on course to its rendezvous with 67P/Churyumov-Gerasimenko, encountering asteroids Steins and Lutetia along the way.

Operating on solar energy alone, Rosetta was placed into a deep space slumber in June 2011 as it cruised out to a distance of nearly 800 million km from the warmth of the Sun, beyond the orbit of Jupiter.

Now, as Rosetta’s orbit has brought it back to within ‘only’ 673 million km from the Sun, there is enough solar energy to power the spacecraft fully again.

Rosetta calls home

Thus today, still about 9 million km from the comet, Rosetta’s pre-programmed internal ‘alarm clock’ woke up the spacecraft. After warming up its key navigation instruments, coming out of a stabilising spin, and aiming its main radio antenna at Earth, Rosetta sent a signal to let mission operators know it had survived the most distant part of its journey.

The signal was received by both NASA’s Goldstone and Canberra ground stations at 18:18 GMT/ 19:18 CET, during the first window of opportunity the spacecraft had to communicate with Earth. It was immediately confirmed in ESA’s space operations centre in Darmstadt and the successful wake-up announced via the @ESA_Rosetta twitter account, which tweeted: “Hello, World!”

“We have our comet-chaser back,” says Alvaro Giménez, ESA’s Director of Science and Robotic Exploration. “With Rosetta, we will take comet exploration to a new level. This incredible mission continues our history of ‘firsts’ at comets, building on the technological and scientific achievements of our first deep space mission Giotto, which returned the first close-up images of a comet nucleus as it flew past Halley in 1986.”

How Rosetta wakes up from deep space hibernation
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“This was one alarm clock not to hit snooze on, and after a tense day we are absolutely delighted to have our spacecraft awake and back online,” adds Fred Jansen, ESA’s Rosetta mission manager.

Comets are considered the primitive building blocks of the Solar System and likely helped to ‘seed’ Earth with water, perhaps even the ingredients for life. But many fundamental questions about these enigmatic objects remain, and through its comprehensive, in situ study of Comet 67P/Churyumov-Gerasimenko, Rosetta aims to unlock the secrets contained within.

“All other comet missions have been flybys, capturing fleeting moments in the life of these icy treasure chests,” says Matt Taylor, ESA’s Rosetta project scientist. “With Rosetta, we will track the evolution of a comet on a daily basis and for over a year, giving us a unique insight into a comet’s behaviour and ultimately helping us to decipher their role in the formation of the Solar System.”

But first, essential health checks on the spacecraft must be completed. Then the eleven instruments on the orbiter and ten on the lander will be turned on and prepared for studying Comet 67P/Churyumov-Gerasimenko.

“We have a busy few months ahead preparing the spacecraft and its instruments for the operational challenges demanded by a lengthy, close-up study of a comet that, until we get there, we know very little about,” says Andrea Accomazzo, ESA’s Rosetta operations manager.

Rosetta and Philae at comet

Rosetta’s first images of 67P/Churyumov-Gerasimenko are expected in May, when the spacecraft is still 2 million km from its target. Towards the end of May, the spacecraft will execute a major manoeuvre to line up for its critical rendezvous with the comet in August.

After rendezvous, Rosetta will start with two months of extensive mapping of the comet’s surface, and will also make important measurements of the comet’s gravity, mass and shape, and assess its gaseous, dust-laden atmosphere, or coma. The orbiter will also probe the plasma environment and analyse how it interacts with the Sun’s outer atmosphere, the solar wind.

Using these data, scientists will choose a landing site for the mission’s 100 kg Philae probe. The landing is currently scheduled for 11 November and will be the first time that a landing on a comet has ever been attempted.

In fact, given the almost negligible gravity of the comet’s 4 km-wide nucleus, Philae will have to use ice screws and harpoons to stop it from rebounding back into space after touchdown.

Among its wide range of scientific measurements, Philae will send back a panorama of its surroundings, as well as very high-resolution pictures of the surface. It will also perform an on-the-spot analysis of the composition of the ices and organic material, including drilling down to 23 cm below the surface and feeding samples to Philae’s on-board laboratory for analysis.

The focus of the mission will then move to the ‘escort’ phase, during which Rosetta will stay alongside the comet as it moves closer to the Sun, monitoring the ever-changing conditions on the surface as the comet warms up and its ices sublimate.

The comet will reach its closest distance to the Sun on 13 August 2015 at about 185 million km, roughly between the orbits of Earth and Mars. Rosetta will follow the comet throughout the remainder of 2015, as it heads away from the Sun and activity begins to subside.

“We will face many challenges this year as we explore the unknown territory of comet 67P/Churyumov-Gerasimenko and I’m sure there will be plenty of surprises, but today we are just extremely happy to be back on speaking terms with our spacecraft,” adds Matt Taylor.

ORIGINAL: ESA

20 January 2014

ISS Welcomes SpaceX Dragon — First Private Spacecraft at Station

ORIGINAL: Wired

By Jason Paur

May 25, 2012 | 12:59 pm | 

Photo: NASA

The SpaceX Dragon spacecraft successfully berthed with the International Space Station this morning after a long overnight approach including several unplanned maneuvers. The crew at SpaceX headquarters in Hawthorne, California, concluded a long night of flight demonstrations and troubleshooting by watching astronaut Don Pettit control the station’s robotic arm and grapple the Dragon at 6:56 a.m. PDT.

“Looks like we’ve got a Dragon by the tail,” Pettit said from the station’s Cupola module once the capture was made.

Pettit’s successful capture of the Dragon was greeted by cheers at both SpaceX’s Hawthorne headquarters and NASA’s mission control in Houston. For both SpaceX and NASA the capture moment marks the beginning of a shift in how cargo will be delivered to and from the space station, with the eventual goal of changing how manned flight itself is done to low Earth orbit.

But Dragon’s overnight approach was not without hiccups, demonstrating the true test-flight nature of the mission. A problem with the devices used to guide the Dragon as it approached the station forced an initial retreat. In the end there were a handful of changes made to the initial flight plan, but at 6:49 a.m. PDT, the Dragon sat just 10 meters (32 feet) from the ISS when NASA flight director Holly Ridings gave the command SpaceX had been waiting years to hear: “go for capture.”

Early Friday morning the SpaceX team in Hawthorne completed the approach initiation burn of the Dragon’s Draco thrusters to move the spacecraft roughly 1,000 meters to a point where it could change its alignment relative to the station before performing the first series of demonstration maneuvers close to the ISS. The Dragon spacecraft could be seen on Earth by its flashing strobe light against the night sky.

Once in place at 350 meters, Dragon completed a 180-degree yaw rotation to align itself, and then another short burn was performed to move to the 250-meter point where the demonstrations would begin.

At 2:29 a.m. PDT, the SpaceX team confirmed Dragon was holding at 250 meters (820 feet), but Andre Kuipers, the Dutch astronaut on board the station, noticed the spacecraft was slightly forward of where it was expected to be. NASA engineers in Houston said the position was acceptable.

Sketch of the demonstration maneuvers planned for Dragon near the ISS. Image: NASA 

As the ISS and Dragon passed in and out of sunlight orbiting the Earth every 90 minutes, the teams in Houston and Hawthorne prepared for what has long been considered the most challenging and critical part of the mission, demonstrating Dragon can make several different maneuvers in close range to the ISS, with commands being sent from both the ground and from the astronauts on the station.

Just before 3:00 a.m. PDT, with a short burst of the thrusters, Dragon again began approaching the ISS. Minutes later, with the Dragon 220 meters from the station, astronaut Kuipers sent a command via the UHF communications link and Dragon aborted its approach as expected and returned to the 250 meter hold position. Test one was complete.

Kuipers planned to send a command for Dragon to hold at 235 meters, but problems with Dragon’s on-board thermal camera used for the rendezvous with the ISS kept it at the 250 meter point. After a few minutes the test resumed and Kuipers issued Dragon a hold command at 235 meters, but it happened a bit earlier than planned.

Over the next half hour or so, the teams in Hawthorne and Houston were busy evaluating the data from the on-board sensors to make sure both the station and Dragon agreed on their relative positions before moving any closer, particularly inside the simply named “Keep Out Sphere” that surrounds the ISS at 200 meters.

As time progressed, some questions were raised from the data being analyzed from Dragon’s thermal image sensors and the on-board LIDAR (light detection and ranging) sensors. The two different devices are used to independently measure the distance between the two spacecraft. This information is then used by Dragon’s guidance system as it approaches the ISS. The data provided by the thermal cameras was causing the engineers to further evaluate the sensor.

Dragon was sent to an unplanned hold position at 200 meters in hopes of giving the thermal sensors a chance to obtain better data on the position of Dragon relative to the ISS.

Dragon at 30 meters from the station. Photo: NASA

By 4:20 a.m. PDT Dragon was once again on the move, this time to a position 150 meters from the station. After checking the sensors again, Dragon was cleared to fly to the next hold point at 30 meters. But less than 20 minutes later Dragon was held at 78 meters as SpaceX made some changes to the spacecraft’s LIDAR equipment. At 5:21 a.m. PDT the approach was resumed but just four minutes later SpaceX issued a retreat command, moving Dragon away from the ISS.

Dragon returned to 78 meters while a problem with the LIDAR was analyzed. It turns out the laser used by the LIDAR was receiving stray reflections from the Japanese Kibo laboratory on the station. Over the course of the next half hour, SpaceX engineers analyzed how to resolve the problem with the stray LIDAR signals, eventually deciding to narrow the view of the LIDAR. Essentially they put blinders on the sensors so they could only see straight ahead, where the Dragon was set to be berthed with the station.

Eventually Dragon was given the go-ahead to proceed to the 30-meter point, and then to the 10-meter location where it would be captured by the station’s robotic arm. After rescheduling the planed grapple a few times during the morning, the go-ahead was given for a capture at 7:02 a.m., which would take place in the dark as the two spacecraft passed over Australia. Dragon took roughly 20 minutes to fly the final 20 meters to its final hold position.

The station's robotic Canada arm approaches Dragon. Photo: NASA

With Dragon in place at 10 meters, NASA’s Holly Ridings sat at her flight director desk in Houston with a purple stuffed dragon toy on the console above her. She anxiously twirled her pen in her hand as she told astronaut Pettit that Dragon was operating on a single LIDAR and should that one fail, the spacecraft would abort.

But in the final minutes, everything went well as Pettit maneuvered the arm towards Dragon. As the end of the arm inched towards the capsule, lights from the ISS bathed Dragon in an orange glow. A few minutes ahead of schedule at 6:56 a.m. PDT, capture was confirmed by NASA, marking the first time a private spacecraft was attached to the International Space Station.

The capture occurred 3 days, 6 hours, 11 minutes and 23 seconds after the Falcon 9 had lifted off from Launch Complex 40 at Cape Canaveral Tuesday morning. After another hour and a few reconfigurations of Dragon the robotic arm slowly pulled the capsule towards the station and at 8:52 a.m. PDT NASA confirmed Dragon was firmly attached to the station itself and the robotic arm was no longer holding it in place. After tightening the 16 bolts attaching Dragon to the station’s Harmony module, the ISS officially had its first private spacecraft visitor.

Dragon berthed to the Harmony module on the ISS. Photo: NASA

There are several more steps before the hatch between the ISS and Dragon will be opened early Saturday. Once opened, the crew on board the station will spend several days unpacking the 1,014 pounds (460 kilograms) of cargo on board Dragon. Once empty, the crew will load up Dragon with 1,367 (620 kilograms) of cargo before the spacecraft is released from the station and returns to earth with a splashdown in the Pacific Ocean on May 31.

La ISS sobrevuela una noche tormentosa en África (con la Vía Láctea)

ORIGINAL: NASA

(Ver en alta definición en: http://www.flickr.com/photos/lightsinthedark/6726493105)

Este video fue tomado por la tripulación de la Expedición 30 a bordo de la Estación Espacial Internacional. La secuencia de imágenes fue tomada a partir del 29 de diciembre 2011 20:55:05-21:14:09 GMT, en un paso más sobre África Central, cerca al sureste de Nígeria, al sur del Océano Índico, al sureste de Madagascar. El paso completo es el SurÁfrica hasta el océano, centrándose en los relámpagos de las tormentas locales y de la Vía Láctea que se levanta sobre el horizonte.

La Vía Láctea puede ser visto como una banda borrosa de luz blanca al comienzo del vídeo. El paso continúa hacia el sureste hacia el Canal de Mozambique y Madagascar. El cometa Lovejoy se puede ver muy ligeramente, cerca de la Vía Láctea. El paso termina cuando el sol se eleva sobre el océano oscuro.

Video cortesía del Laboratorio de Ciencia y Análisis de Imágenes, el Centro Espacial Johnson de la NASA

A través del portal de Fotografías de Astronautas de la Tierra 

http://eol.jsc.nasa.gov/Videos/CrewEarthObservationsVideos/