Rosetta mission extended

This announcement is mirrored from the main ESA web portal.

Rosetta_approaching_comet_largeThe adventure continues: ESA today confirmed that its Rosetta mission will be extended until the end of September 2016, at which point the spacecraft will most likely be landed on the surface of Comet 67P/Churyumov-Gerasimenko.

Rosetta was launched in 2004 and arrived at the comet in August 2014, where it has been studying the nucleus and its environment as the comet moves along its 6.5-year orbit closer to the Sun. After a detailed survey, Rosetta deployed the lander, Philae, to the surface on 12 November. Philae fell into hibernation after 57 hours of initial scientific operations, but recently awoke and made contact with Rosetta again.

Rosetta’s nominal mission was originally funded until the end of December 2015, but at a meeting today, ESA’s Science Programme Committee has given formal approval to continue the mission for an additional nine months. At that point, as the comet moves far away from the Sun again, there will no longer be enough solar power to run Rosetta’s set of scientific instrumentation efficiently.

“This is fantastic news for science,” says Matt Taylor, ESA’s Rosetta Project Scientist. “We’ll be able to monitor the decline in the comet’s activity as we move away from the Sun again, and we’ll have the opportunity to fly closer to the comet to continue collecting more unique data. By comparing detailed ‘before and after’ data, we’ll have a much better understanding of how comets evolve during their lifetimes.”

Comet 67P/Churyumov-Gerasimenko will make its closest approach to the Sun on 13 August and Rosetta has been watching its activity increase over the last year. Continuing its study of the comet in the year following perihelion will give scientists a fuller picture of how a comet’s activity waxes and wanes along its orbit.

The extra observations collected by Rosetta will also provide additional context for complementary Earth-based observations of the comet. At present, the comet is close to the line-of-sight to the Sun, making ground-based observations difficult.

As the activity diminishes post-perihelion, it should be possible to move the orbiter much closer to the comet’s nucleus again, to make a detailed survey of changes in the comet’s properties during its brief ‘summer’.

In addition, there may be an opportunity to make a definitive visual identification of Philae. Although candidates have been seen in images acquired from a distance of 20 km, images taken from 10 km or less after perihelion could provide the most compelling confirmation.

During the extended mission, the team will use the experience gained in operating Rosetta in the challenging cometary environment to carry out some new and potentially slightly riskier investigations, including flights across the night-side of the comet to observe the plasma, dust, and gas interactions in this region, and to collect dust samples ejected close to the nucleus.

As the comet recedes from the Sun, the solar-powered spacecraft will no longer receive enough sunlight to operate efficiently and safely, equivalent to the situation in June 2011 when the spacecraft was put into hibernation for 31 months for the most distant leg of its journey out towards the orbit of Jupiter.

In addition, Rosetta and the comet will again be close to the Sun as seen from the Earth in October 2016, making operations difficult by then.

However, with Rosetta’s propellant largely depleted by that time, it makes little sense to place the spacecraft in hibernation again.

“This time, as we’re riding along next to the comet, the most logical way to end the mission is to set Rosetta down on the surface,” says Patrick Martin, Rosetta Mission Manager.

“But there is still a lot to do to confirm that this end-of-mission scenario is possible. We’ll first have to see what the status of the spacecraft is after perihelion and how well it is performing close to the comet, and later we will have to try and determine where on the surface we can have a touchdown.”

If this proposed scenario were played out, then the spacecraft would be commanded to spiral down to the comet over a period of about three months.

It is expected that science operations would continue throughout this period and be feasible up to very close to the end of mission, allowing Rosetta’s instruments to gather unique data at unprecedentedly close distances.

Once the orbiter lands on the surface, however, it is highly unlikely to be able to continue operations and relay data back to Earth, bringing to an end one of the most successful space exploration missions of all time.



  • Rok says:

    Can you explain why you can't maintain an intermittent link to Earth after landing? Is the antenna not movable?

    • dta says:

      I don't think Rosetta was designed to land anywhere. Should it somehow survive, then it would have to have landed in such a way as to collect enough light to operate, AND somehow get data to earth.

  • Peter says:

    Great news 15 more months of data and pictures. and a fitting end,

  • Kasuha says:

    Congratulations to having the mission extended, that's really great news. Figuring out what and how has changed on the comet during perihelieon will certainly bring lots of additional information about comet's structure and composition.

    I'm still not sure if landing the orbiter on the surface is a good idea. The comet is going to disintegrate over time and will leave the probe floating alone through space in any case. I would probably prefer leaving it in a reasonable bound orbit. Even when low on propellant, it could still be potentially used to study the comet from that orbit next time it gets close to the Sun. Or perhaps be woken up to check if anything strange happens, such as the sudden brightening of the nucleus as it happenes during initial approach.

  • Stefan says:

    faszinierend was Sie da geleistet haben! allein der jahrelange Anflug versetzt Laien in Staunen. die schöne Animation die die Reise darstellt ist crazy. Vor einigen Jahren hatte ich das Glück hailbob? am Nacht-Himmel mit blossem Auge zu sehen-ein Moment der Magie. Viel Glück mit Ihren Plänen! und was machen Sie als nächstes?

  • Marco says:

    I think landing on the comet is too final and unnecessary. A 67P-synchronous orbit would be both very close to the comet as a "finish line" spot, and there may be a dynamically stable point between the lobes somewhere on a synchronous orbit, similar to an L4 or L5 lagrangian point. Leave about 5% fuel in the tank, spin it up and hibernate for the "end of mission". Leave it for future teams if they want to fund a second "wake up Rosetta " campaign and for that matter, Philae too. Sure, it may not work, but it would still be way cheaper than a new mission and is lower risk because it worked last time...

    • Kamal says:

      Somewhere I remember seeing mentioned an option of moving a few thousand km behind the comet and trying to go through the tail. Would that be risky enough to be called "perhaps final" ?

    • Harvey says:

      Its very unlikely any such orbit would be long-term stable.
      The comet's gravity is so low than any tiny perturbation, from photon pressure, gas drag, changes in the nuclues mass & rotation due to jets etc etc would make the orbit unstable over longer periods.

      There is quite a body of literature on stable orbits round low mass objects, but generally 'quiet' bodies, & even then its tricky.

      I this sood any chance at all it would be worth considering seriously, but I rather doubt that it does sadly; I'd be surprised if ESA hasn't looked at it.

  • David says:

    Thank you Emily,
    Very exciting news about the end of a great and successful mission, it would be incredible if the orbiter managed to soft land on the comet and remained viable for a short time, what an ending that would be!!

  • Florian Vollnhals says:

    If ESA parks Rosetta on Tschuri without damaging it, they could try to contact it on the next orbit when it is closer to the sun again? If it were parked near Philae to relay its transmission, could they both be used as a "science outpost" during summer on Tschuri?

    • Kasuha says:

      When landed on the comet, Rosetta will no longer be able to point its antenna at Earth.

  • anjin says:

    congrats ! !! Rosetta team - It's a blast !



  • Haring says:

    Triple hurrah for the Rosetta Team!!!
    And what a wonderful news for the science, for us and for that damned couple of guys (Rosetta&Philae)!

  • Does the phrase, "Once the orbiter lands on the surface, however, it is highly unlikely to be able to continue operations and relay data back to Earth..." a nice way a saying that Rosetta will crash on the surface, probably get broken up, and in any case won't be able to point its antenna toward Earth?

    • Gerald says:

      Rosetta's antenna needs to be pointed accurately to Earth to communicate. For this the star trackers need to know the position of stars. So after landing Rosetta would/will be in a non-nominal state. Besides this the comet rotates, such that the attitude of the spacecraft will be changing all the time, as well as the available power due to changing illumination. The power would even be low with optimal solar panel illumination, due to the increasing distance to the Sun.

  • Laurence says:

    Wow! Was the landing attempt of Rosetta onto the comet surface a pre-planned goal? I am awestruck and happy that this might be attempted as the last 'great act' in a series of great acts! It reminds me of my surprise when I found out that the NEAR spacecraft made a last-minute decision to land on Asteroid Eros! You folks at ESA are amazing. Just amazing. This is all so overwhelmingly wonderful, and the communication has been SO good, especially the wonderful updates from Emily and Claudia. GO ROSETTA! GO PHILAE!

  • masanori says:

    WHY NOT. That's all.

    But to all those who have been involved in this mission: Congratulations & Well-deserved!!

  • Bill Harris says:

    Setting a completed-mission spacecraft down on the surface is one way of ensuring that it won't create problems for future missions to 67P.

    And look at it as a nifty monument....


  • Kamal says:

    Do we have an assessment of how long this second life of Philae is expected to last? More specifically, do we now expect it to survive perihelion and (all things considered) have a fair chance of being active until September 2016? If so, one could try a finale borrowed from Deep Impact: to crash Rosetta near Philae and make Philae measure what happens after the impact.

    • J.H. says:

      I'm pretty sure that Philae can't send data to Earth Kamal, only Rosetta can, so once Rosetta crashed we'd never know what Philae measured or filmed...

    • Gerald says:

      At some point near the end of 2015, Philae won't get sufficient illumination from the Sun to establish contact with Rosetta, unless they succeed with a very hazardous jump out of the shadow. In the latter rather unikely case Philae might be able to continue work a few additional months, but not until September 2016.
      If one would try to crash Rosetta, we would lose contact, since Rosetta is the relais station for Philae. And the impact would be slow, with few effects to the comet. Some surface material would be displaced.

      One crazy thing I could imagine would be a landing, followed by a lift-off. Rosetta's thrusters may be able to clean some of the cometary surface from dust / regolith, allowing for some more in-situ analysis of the surface, and maybe of the resulting regolith cloud.

      • Ramcomet says:

        Excellent idea, Gerald.
        Was thinking similarly of a super close flyby with thrusters blasting some dust off. But navigating delay from Earth and all, would probably be best to (extremely) soft land as you suggest, and lift off again.
        Measure and photograph results... Then repeat if possible! (Although not built as a lander, especially vulnerable is the dish antennae and solar panels getting damaged)
        But who knows, Rosetta' number of slo-mo setdowns could match Philae's multiple "landings", wouldn't that be something!

      • Harvey says:

        Nice idea, but I think the probability of pulling that off without fatal damage to Rosetta is vanishingly small.
        Too many vital fragile things sticking out all over, and it would have to do it autonomously.
        An apposite analogy about snowballs and he'll comes to mind 🙂

    • Ove Kjeldgaard says:

      I see at least two problems with crashing Rosetta into the comet - beyond that it would be a sad ending..
      There are problems getting enough speed on the vessel, Rosetta's thrusters is mainly to control the direction and the thrusters will be almost empty at the time.
      But the worst obstacle to the project is that Philae itself can not communicate with Earth, but requires Rosetta as a link station. Philae have neither radio power enough to send to Earth, or a high efficiency antenna to receive messages from Earth.

      • Ramcomet says:


        Yes, acknowledge the two problems, but thinking in terms of more of a "nudge landing". Could land well under 1/2 kph!

        Possibly, not likely, but wait and see: Rosetta could lift off again with very little power from 67P's weak gravity and point antennae to Earth. Transmitting both crafts final findings.

        Another problem is it looks like landing on any side is going to damage some antennae or camera, but that could be Rosetta team's choice. And they might run simulations.

        As Gerald said, crazy, but the whole mission was built on " crazy ", which turned into " amazing "!

        Still incredibly fascinating!!!

  • Ramcomet says:

    Wonderful, stunning news! Congratulations ESA, Rosetta and Philae! In awe.

  • Americo says:

    If Rosetta has enough energy, it could be used to escape the gravity of the comet and return to Earth, it could be years in an orbit like any other satellite of the earth, and maybe someday, with technology and resources enough it could be recovered ... It would be a museum artifact!.

    • AJ says:

      Judging by what was said in the article about worries of lack of fuel by the end of the mission, there's no way there'll be enough in the tank to make the long journey back to Earth - it took 10 years to navigate to the comet so sadly there won't be any chance of bringing the probe home.

    • SKK says:

      .. back home to Museum !?

  • Vivek Dadu says:

    Is it not possible that the rosetta lands on surface and philae keeps on recording data even when it goes far away from Sun considering that their may be another sun which this comet may encounter. If such happens, the mission will again have sufficient power to carryout further tests. This phenomena may work (expected) till the time this comet reach back to our solar system.

  • Kamal says:

    Suppose we find a bright comet, say with potential origins from the Oort cloud, scheduled to reach perihelion inside the Earth's orbit a year from now. (I am thinking of Ison.)
    It would be worthwhile sending a quick, cheap, throwaway mission which will reach the comet nucleus and try to get into orbit around it. At some point as it gets closer to the Sun the spacecraft might get destroyed. But it might give us a lot of valuable data (especially in comparison to 67p). Have we learnt enough from the Rosetta mission to be able to have such a strategy planned out? Or is this just infeasible at the velocity that the comet will be travelling in the vicinity of 1 AU?

  • Ramcomet says:

    Say a prayer folks, Philae may not be out of the woods. Check out DLR Portal's latest news, "Contact with Philae Still Irregular and Unstable"
    Please read to the end, especially the last four paragraphs.
    Tomorrow, when Rosetta is stationed @ 165 km, may bring better news. Hope so!

  • Craig Willford says:

    After the soft landing, I expect Philae and Rosetta to become part of the rubble pile that will someday be left after all the water has jetted or sublimated off the comet. Since the rubble pile will remain a hazard to navigation to future travelers, the two spacecraft might as well be part of it, instead of being in addition to it (if left in orbit). I applaud the decision to put it down.

    Congratulations to the whole team and thank you for providing such stimulating images and data!

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