Since my last post on the ISEE-3 Reboot Project, the team determined that it was impossible to restart the propulsion system due to the absence of the nitrogen pressurant gas needed to force fuel into the thrusters. They spacecraft therefore cannot be put into an orbit in the Earth-Moon system and will instead continue on its orbit around the sun.
The rest of the spacecraft system, including science instruments, are in good shape. So they plan to continue the project, focusing on carrying out citizen science activities with the data from the spacecraft:
While our original goal was to place ISEE-3 in a L-1 “halo” orbit, it will now do a flyby of the Moon and resume an orbit around the sun – an orbit nearly identical to Earth’s. We have begun the process of shutting down systems that are no longer needed and reconfiguring ISEE-3 to maximize science operations. We are also implementing plans that will allow us to listen to its science data no matter where it goes.
We will be beginning the “ISEE-3 Interplanetary Citizen Science Mission” on 10 August 2014 as the spacecraft flies by the Moon. We have a functional space craft that can do science and is already returning new data. All of our original citizen science objectives remain unchanged and are ready for implementation. In fact, we’ll be announcing some new partnerships shortly that will serve to turbocharge our efforts in this regard.
This will be the first citizen science, crowd funded, crowd sourced, interplanetary space science mission. A more detailed summary of recent activities and our partnership team will be posted at http://spacecollege.org/isee3
The New Horizons spacecraft is steadily closing in on Pluto as it heads for a fly-by next July. The spacecraft can now distinguish Pluto from its moon Charon with its long range camera.
Pluto and Charon dance in this sequence of images taken over 6 days. (Large image)
Like explorers of old peering through a shipboard telescope for a faint glimpse of their destination, NASA’s New Horizons spacecraft is taking a distant look at the Pluto system – in preparation for its historic encounter with the planet and its moons next summer.
“Filmed” with New Horizons’ best onboard telescope – the Long Range Reconnaissance Imager (LORRI) – this movie covers Pluto and almost one full rotation of its largest moon, Charon. The 12 images that make up the movie were taken July 19-24, from a distance ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto’s surface.
New Horizons snapped this image sequence as part of the mission’s first optical navigation campaign. The mission team uses these “op nav” images – which focus on Pluto’s position against a backdrop of stars – to fine-tune the distance that New Horizons will fly past Pluto and its moons. New Horizons is aiming for a precise close-approach point near Pluto in July 2015, so these and images to come – which help navigators and mission designers to get a better fix on Pluto’s position – are critical to planning the encounter operations.
Pluto’s four smaller satellites (Nix, Hydra, Styx and Kerberos) are too faint to be seen in these distant images, but will begin to appear in images taken next year as the spacecraft speeds closer to its target.
“The image sequence showing Charon revolving around Pluto set a record for close range imaging of Pluto—they were taken from 10 times closer to the planet than the Earth is,” says New Horizons mission Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colo. “But we’ll smash that record again and again, starting in January, as approach operations begin.
“We are really excited to see our target and its biggest satellite in motion from our own perch,” he adds, “less than a year from the historic encounter ahead!”
As August begins, New Horizons is near the end of its final pre-Pluto annual systems checkout and instrument calibration before Pluto arrival. The New Horizons mission operations team at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, will put the spacecraft back into hibernation on August 29 – just four days after New Horizons crosses the orbit of Neptune on August 25.
That final “rest” lasts only until December 6, when New Horizons will stay wake for two years of Pluto encounter preparations, flyby operations, and data downlinks. Distant-encounter operations begin January 4, 2015.
A 3D view of the comet composed from images taken by the OSIRIS camera and NavCam. The resolution of the two cameras is quite different, so it took some processing to make it work as a stereo pair. The left-eye image is the original OSIRIS photo; the right-eye image is a synthetic one made by warping the OSIRIS photo to the shapes of features visible in the NavCam photo. ESA / Rosetta / NavCam / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA / Daniel Macháček
Close-up detail of comet 67P/Churyumov-Gerasimenko. The image was taken by Rosetta’s OSIRIS narrow-angle camera and downloaded today, 6 August. The image shows the comet’s ‘head’ at the left of the frame, which is casting shadow onto the ‘neck’ and ‘body’ to the right. The image was taken from a distance of 120 km and the image resolution is 2.2 metres per pixel.
The European Space Agency’s Rosetta spacecraft after ten years has finally made its rendezvous this morning with Comet 67P/Churyumov–Gerasimenko. Below is the official announcement. (Note that unlike NASA, ESA has a policy of not releasing images in real time for its science missions. This is apparently to insure analysis of them by its researchers is not scooped by scientists elsewhere. So some of the images released this morning are not necessarily the latest from the spacecraft.)
6 August 2014 After a decade-long journey chasing its target, ESA’s Rosetta has today become the first spacecraft to rendezvous with a comet, opening a new chapter in Solar System exploration.
Comet 67P/Churyumov–Gerasimenko and Rosetta now lie 405 million kilometres from Earth, about half way between the orbits of Jupiter and Mars, rushing towards the inner Solar System at nearly 55 000 kilometres per hour.
Comet 67P/Churyumov–Gerasimenko as it appeared on August 3.
The comet is in an elliptical 6.5-year orbit that takes it from beyond Jupiter at its furthest point, to between the orbits of Mars and Earth at its closest to the Sun. Rosetta will accompany it for over a year as they swing around the Sun and back out towards Jupiter again.
Comets are considered to be primitive building blocks of the Solar System and may have helped to ‘seed’ Earth with water, perhaps even the ingredients for life. But many fundamental questions about these enigmatic objects remain, and through a comprehensive,in situstudy of the comet, Rosetta aims to unlock the secrets within.
The journey to the comet was not straightforward, however. Since its launch in 2004, Rosetta had to make three gravity-assist flybys of Earth and one of Mars to help it on course to its rendezvous with the comet. This complex course also allowed Rosetta to pass by asteroids Šteins and Lutetia, obtaining unprecedented views and scientific data on these two objects.
Sequence of images as Rosetta approached the comet.
“After ten years, five months and four days travelling towards our destination, looping around the Sun five times and clocking up 6.4 billion kilometres, we are delighted to announce finally ‘we are here’,” says Jean-Jacques Dordain, ESA’s Director General.
“Europe’s Rosetta is now the first spacecraft in history to rendezvous with a comet, a major highlight in exploring our origins. Discoveries can start.”
Today saw the last of a series of ten rendezvous manoeuvres that began in May to adjust Rosetta’s speed and trajectory gradually to match those of the comet. If any of these manoeuvres had failed, the mission would have been lost, and the spacecraft would simply have flown by the comet.
“Today’s achievement is a result of a huge international endeavour spanning several decades,” says Alvaro Giménez, ESA’s Director of Science and Robotic Exploration.
“We have come an extraordinarily long way since the mission concept was first discussed in the late 1970s and approved in 1993, and now we are ready to open a treasure chest of scientific discovery that is destined to rewrite the textbooks on comets for even more decades to come.”
Comet 67P/Churyumov-Gerasimenko activity on 2 August 2014. The image
was taken by Rosetta’s OSIRIS wide-angle camera from a distance of 550 km.
The exposure time of the image was 330 seconds and the comet nucleus is
saturated to bring out the detail of the comet activity. Note there is a
ghost image to the right. The image resolution is 55 metres per pixel.
The comet began to reveal its personality while Rosetta was on its approach. Images taken by the OSIRIS camera between late April and early June showed that its activity was variable. The comet’s ‘coma’ – an extended envelope of gas and dust – became rapidly brighter and then died down again over the course of those six weeks.
In the same period, first measurements from the Microwave Instrument for the Rosetta Orbiter, MIRO, suggested that the comet was emitting water vapour into space at about 300 millilitres per second.
Meanwhile, the Visible and Infrared Thermal Imaging Spectrometer, VIRTIS, measured the comet’s average temperature to be about –70ºC, indicating that the surface is predominantly dark and dusty rather than clean and icy.
Then, stunning images taken from a distance of about 12 000 km began to reveal that the nucleus comprises two distinct segments joined by a ‘neck’, giving it a duck-like appearance. Subsequent images showed more and more detail – the most recent, highest-resolution image was downloaded from the spacecraft earlier today and will be available this afternoon.
“Our first clear views of the comet have given us plenty to think about,” says Matt Taylor, ESA’s Rosetta project scientist.
“Is this double-lobed structure built from two separate comets that came together in the Solar System’s history, or is it one comet that has eroded dramatically and asymmetrically over time? Rosetta, by design, is in the best place to study one of these unique objects.”
Today, Rosetta is just 100 km from the comet’s surface, but it will edge closer still. Over the next six weeks, it will describe two triangular-shaped trajectories in front of the comet, first at a distance of 100 km and then at 50 km.
At the same time, more of the suite of instruments will provide a detailed scientific study of the comet, scrutinising the surface for a target site for the Philae lander.
Eventually, Rosetta will attempt a close, near-circular orbit at 30 km and, depending on the activity of the comet, perhaps come even closer.
“Arriving at the comet is really only just the beginning of an even bigger adventure, with greater challenges still to come as we learn how to operate in this unchartered environment, start to orbit and, eventually, land,” says Sylvain Lodiot, ESA’s Rosetta spacecraft operations manager.
As many as five possible landing sites will be identified by late August, before the primary site is identified in mid-September. The final timeline for the sequence of events for deploying Philae – currently expected for 11 November – will be confirmed by the middle of October.
“Over the next few months, in addition to characterising the comet nucleus and setting the bar for the rest of the mission, we will begin final preparations for another space history first: landing on a comet,” says Matt.
“After landing, Rosetta will continue to accompany the comet until its closest approach to the Sun in August 2015 and beyond, watching its behaviour from close quarters to give us a unique insight and realtime experience of how a comet works as it hurtles around the Sun.”
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Rosetta will release a separate spacecraft called Philae to land on the comet:
From the caption;
Extended version of Philae touchdown animation to include visualisations of some of the science experiments on the lander.
The animation begins with the deployment of Philae from Rosetta at comet 67P/Churyumov–Gerasimenko in November 2014. Rosetta will come to within about 10 km of the nucleus to deploy Philae, which will take several hours to reach the surface. Because of the comet’s extremely low gravity, landing gear will absorb the small forces of landing while ice screws in the probe’s feet and a harpoon system will lock the probe to the surface. At the same time a thruster on top of the lander will push it down to counteract the impulse of the harpoon imparted in the opposite direction. Once it is anchored to the comet, the lander will begin its primary science mission, based on its 64-hour initial battery lifetime. The animation then shows five of Philae’s 10 instruments in action: CIVA, ROLIS, SD2, MUPUS and APXS.
Rosetta’s Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI.
Here’s an animation showing the release and landing:
