Dawn at Ceres

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  • #1517

    Dawn is closing in on Ceres. Final approach operations began this week. This is what it can currently see at the end of December 2014.

    Really more of a mini-Ceres than anything, but I think it’ll be renewed for a full Ceres once we get to see more of it. 😉 What’s that really reflective bit on the right hand side?

    #7461
    ubikuberalles
    ubikuberalles
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    Looks like the Death Star to me.

    #7462

    Check. it. out. [LINK]

    This animation of the dwarf planet Ceres was made by combining images taken by NASA’s Dawn spacecraft on January 25, 2015. The spacecraft’s framing camera took these images, at a distance of about 147,000 miles (237,000 kilometers) from Ceres, and they represent the highest-resolution views to date of the dwarf planet.

    Are we there yet? Are we there yet?

    #7463

    We’re there… but we’re also in safe mode. The hell, Space Robots? [LINK]

    NASA’s Dawn spacecraft is healthy and stable, after experiencing an anomaly in the system that controls its orientation. It is still in its second mapping orbit 2,700 miles (4,400 kilometers) above dwarf planet Ceres.

    On June 30, shortly after turning on its ion engine to begin the gradual spiral down to the next mapping orbit, its protective software detected the anomaly. Dawn responded as designed by stopping all activities (including thrusting), reconfiguring its systems to safe mode and transmitting a radio signal to request further instructions. On July 1 and 2, engineers made configuration changes needed to return the spacecraft to its normal operating mode. The spacecraft is out of safe mode, using the main antenna to communicate with Earth.

    Dawn will remain at its current orbital altitude until the operations team has completed an analysis of what occurred and has updated the flight plan.

    Because of the versatility of Dawn’s ion propulsion system and the flexibility of the mission’s plan for exploring Ceres, there is no special “window” for starting or completing the spiral to the third mapping orbit. The plans for the third and fourth mapping orbits can be shifted to new dates without significant changes in objectives or productivity.

    #7464

    Dawn is back in business. The problem appears to be a steering mechanism on one of its ion engines. [LINK]

    NASA’s Dawn spacecraft is using its ion propulsion system to descend to its third mapping orbit at Ceres, and all systems are operating well. The spiral maneuvering over the next five weeks will take the spacecraft to an altitude of about 900 miles (less than 1,500 kilometers) above the dwarf planet.

    The spacecraft experienced a discrepancy in its expected orientation on June 30, triggering a safe mode. Engineers traced this anomaly to the mechanical gimbal system that swivels ion engine #3 to help control the spacecraft’s orientation during ion-thrusting. Dawn has three ion engines and uses only one at a time.

    Dawn’s engineering team switched to ion engine #2, which is mounted on a different gimbal, and conducted tests with it from July 14 to 16. They have confirmed that the spacecraft is ready to continue with the exploration of Ceres.

    So Dawn has triple ion engines. So if it was a fighter, it would be a……

    #7465

    Utterly fascinating tweet from the NASA Exploration Science Forum today:

    @asrivkin
    Russell: Can see haze in crater with bright spots at some local times. Bright spots “indicate Ceres is active today.”

    Wow. What is this? Volcanic/cryovolcanic outgassing? Solid ice sublimating to vapor (seems most likely to me, but due to what process?)? Local mineral deposit reacting to atmosphere with sunlight exposure? Fascinating stuff. Get closer, Dawn…

    #7466

    And they’re actually…salt?!?

    Salt.

    That being said, there’s a possibility that this salt is somehow being erupted onto the surface of Ceres.

    Stay tuned for the next exciting episode of saltcano.

    #7467

    Want to see ALL of Dawn’s Ceres imagery, and not just the “released” stuff?

    Your tax dollars put it there, go have a look. Some are overexposed; a few are not quite focused, and a few are empty (when they were looking for possible “mini-moons” orbiting Ceres that would present a navigational hazard to an orbiting space probe). Others are beautiful and I can’t fathom why they weren’t judged “best in show” and shown to the public.

    These images are the ones from the approach and early orbit phase.

    #7468

    This is astounding. Dawn may get a previously unplanned third stop at a target to be determined! [LINK]

    With enough fuel for at least another year of operations, NASA asked the Dawn team to submit a proposal for an extended mission.

    Green declined to elaborate on an earlier discussion about options for Dawn, including sending the probe to visit another body in the main asteroid belt.

    “They have had a variety of things they’ve discussed, and because it’s a proposal I’m not at liberty to talk about it. But once again, an exciting mission,” Green said.

    #7469
    Steve W
    Steve W
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    But what happens to be nearby (within the reach of a year’s travel at low propulsion at least) they can examine? Pallas is at least near(ish), according to the map I just looked up.

    #7470

    Don’t forget, Dawn would probably use its ion propulsion system for the boost from one body to the next. The maneuvering thrusters are traditional chemical rocket nozzles used primarily for fine tuning once it arrives in orbit of wherever they decide to go.

    #7471

    The Dawn team needs a decision from NASA in about a week and a half. No pressure. [LINK]

    Dawn’s next move depends on a decision due from NASA Headquarters in the coming days.

    “We are awaiting a response any day now, I hope, because we’re on a very tight timeline to leave Ceres by July 12 in order not to expend more hydrazine at Ceres because, at some point, we’ll rapidly run out of the ability to leave Ceres and go anywhere else,” Raymond said.

    Jim Green, head of NASA’s planetary science division at NASA Headquarters, said Wednesday that agency officials will decide the fate of Dawn this week or next week.

    “We are very sensitive to that,” Green said of the July 12 deadline. “That hasn’t lost our attention.”

    Dawn is one of nine planetary science missions, including the New Horizons probe that flew past Pluto in July 2015, up for extensions this year. Other projects awaiting a decision from NASA leadership include the Curiosity and Opportunity Mars rovers, the Mars Odyssey and Mars Reconnaissance Orbiter missions, and the Lunar Reconnaissance Orbiter.

    New Horizons is aiming for a flyby of a distant Kuiper Belt Object beyond Pluto on Jan. 1, 2019. The probe has already steered on to a path toward its new target, but like Dawn, its future hangs in the balance of NASA’s looming decision.

    The space agency convened a broad of senior planetary scientists to review mission extension proposals submitted by each project’s science team, and Green said the panel has delivered their recommendations to NASA, which must match the independent review results with budget constraints.

    C’mon, NASA, send that thing on to the Planet of the Apes.

    Because then it can be Dawn…of the Planet…of the Apes.

    #7472

    And the verdict is… [LINK]

    • Dawn stays put for the rest of its operational lifetime until its Ceres finale
    • Curiosity and Opportunity keep roving Mars, while MRO, MAVEN and Mars Odyssey keep orbiting overhead
    • New Horizons continues on to MU69
    • Lunar Reconnaissance Orbiter keeps being loony in lunar orbit

    But even these approvals are “contingent on available resources” (i.e. $$$).

    The fact that this approval process is an annual thing just blows my mind. It’s a working resource, it’s already there, it’s not like we’re having to run resupply missions. Keep using it until it stops talking back to us.

    #7473

    Wow! The water volcanoes of Ceres! [LINK]

    A lonely 3-mile-high (5-kilometer-high) mountain on Ceres is likely volcanic in origin, and the dwarf planet may have a weak, temporary atmosphere. These are just two of many new insights about Ceres from NASA’s Dawn mission published this week in six papers in the journal Science.

    “Dawn has revealed that Ceres is a diverse world that clearly had geological activity in its recent past,” said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles.

    A surprising finding emerged in the paper led by Russell: Dawn may have detected a weak, temporary atmosphere. Dawn’s gamma ray and neutron (GRaND) detector observed evidence that Ceres had accelerated electrons from the solar wind to very high energies over a period of about six days. In theory, the interaction between the solar wind’s energetic particles and atmospheric molecules could explain the GRaND observations.

    A temporary atmosphere would be consistent with the water vapor the Herschel Space Observatory detected at Ceres in 2012-2013. The electrons that GRaND detected could have been produced by the solar wind hitting the water molecules that Herschel observed, but scientists are also looking into alternative explanations.

    Ahuna Mons is a volcanic dome unlike any seen elsewhere in the solar system, according to a new analysis led by Ottaviano Ruesch of NASA’s Goddard Space Flight Center, Greenbelt, Maryland, and the Universities Space Research Association. Ruesch and colleagues studied formation models of volcanic domes, 3-D terrain maps and images from Dawn, as well as analogous geological features elsewhere in our solar system. This led to the conclusion that the lonely mountain is likely volcanic in nature. Specifically, it would be a cryovolcano — a volcano that erupts a liquid made of volatiles such as water, instead of silicates. “This is the only known example of a cryovolcano that potentially formed from a salty mud mix, and that formed in the geologically recent past,” Ruesch said.

    Quite a place, that Ceres.

    #7474

    Dawn has broken. [LINK]

    While preparing for this observation, one of Dawn’s two remaining reaction wheels stopped functioning on April 23. By electrically changing the speed at which these gyroscope-like devices spin, Dawn controls its orientation in the zero-gravity, frictionless conditions of space.

    The team discovered the situation during a scheduled communications session on April 24, diagnosed the problem, and returned the spacecraft to its standard flight configuration, still with hydrazine control, on April 25. The failure occurred after Dawn completed its five-hour segment of ion thrusting on April 22 to adjust its orbit, but before the shorter maneuver scheduled for April 23-24. The orbit will still allow Dawn to perform its opposition measurements. The reaction wheel’s malfunctioning will not significantly impact the rest of the extended mission at Ceres.

    I suppose they can’t all be Voyager 1. 🙁

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