Tag Archives: Lucy

A Jupiter Trojan asteroid spouts a tail

The ATLAS telescope has discovered the first Jupiter Trojan asteroid to spout a tail like a comet.

Early in June 2019, ATLAS reported what seemed to be a faint asteroid near the orbit of Jupiter. The Minor Planet Center designated the new discovery as 2019 LD2. Inspection of ATLAS images taken on June 10 by collaborators Alan Fitzsimmons and David Young at Queen’s University Belfast revealed its probable cometary nature. Follow-up observations by the University of Hawaiʻi’s J.D. Armstrong and his student Sidney Moss on June 11 and 13 using the Las Cumbres Observatory (LCO) global telescope network confirmed the cometary nature of this body.

Later, in July 2019, new ATLAS images caught 2019 LD2 again – now truly looking like a comet, with a faint tail made of dust or gas. The asteroid passed behind the Sun and was not observable from the Earth in late 2019 and early 2020, but upon its reappearance in the night sky in April of 2020, routine ATLAS observations confirmed that it still looks like a comet. These observations showed that 2019 LD2 has probably been continuously active for almost a year.

While ATLAS has discovered more than 40 comets, what makes this object extraordinary is its orbit. The early indication that it was an asteroid near Jupiter’s orbit have now been confirmed through precise measurements from many different observatories. In fact, 2019 LD2 is a special kind of asteroid called a Jupiter Trojan – and no object of this type has ever before been seen to spew out dust and gas like a comet.

There are a number of mysteries here. First, why should it have suddenly become active, since its orbit is relatively circular (similar to Jupiter’s)? Second, it had been assumed that the Jupiter Trojans had been in their orbits for a long time and had long ago vented any ice on their surfaces. This discovery proves that assumption false. It suggests that either this asteroid is a comet that was recently captured, or that things can happen on these asteroids to bring some buried volatiles up to the surface, where they can then vent.

Above all, this asteroid shows that it is dangerous to assume all Jupiter Trojan asteroids are the same. I guarantee when we finally get a close look at a bunch, when the Lucy mission arrives beginning in 2027, the variety will be quite spectacular.

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Probe to visit 8 asteroids, not 7

Scientists developing the Lucy mission to visit seven Trojan asteroids that share an orbit with Jupiter have found an eighth satellite they will also be able to visit.

This first-ever mission to the Trojans was already going to break records by visiting seven asteroids during a single mission. Now, using data from the Hubble Space Telescope (HST), the Lucy team discovered that the first Trojan target, Eurybates, has a satellite. This discovery provides an additional object for Lucy to study.

“If I had to bet that one of our destinations had a satellite, it would have been this one,” said SwRI’s Hal Levison, principal investigator of the mission. “Eurybates is considered the largest remnant of a giant collision that occurred billions of years ago. Simulations show that asteroid collisions like the one that made Eurybates and its family often produce small satellites.”

The mission is targeting a 2021 launch date.

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SpaceX drops protest against NASA launch decision

SpaceX has decided to withdraw its protest against NASA’s decision to choose ULA as the launch vehicle for its Lucy asteroid mission.

The company did not provide any reason for the withdrawal. I suspect Musk decided that it was doing SpaceX harm both publicly and privately. Publicly it threatened the launch date of Lucy, which might cause a significant and fatal delay to the mission. That did not make SpaceX look good to the general public.

Privately, I suspect that the protest was hurting SpaceX with NASA officials. They almost certainly did not say so directly, but I am certain they were able to make this clear in any number of ways. This, combined with the agency’s new willingness to consider commercial rockets, like the Falcon Heavy, for its lunar plans, probably convinced SpaceX that it was doing itself more harm than good with the protest.

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ULA gets launch contract for Lucy asteroid mission

Capitalism in space: NASA has awarded ULA a $145 million contract to launch the Lucy asteroid mission on its Atlas 5 rocket.

The price is high for such a launch in today’s market, and is even higher than the cost of some recent military launches, which routinely tack on extra requirements that cause the price to rise. I wonder why. Is it because NASA doesn’t care how much it spends? Or is there a political component here, providing a contract to a company that is having trouble winning contracts in the private sector because their price is too high?

It could be that the mission requires things from the launch that add to the cost. The press release mentions that it “includes the launch service and other mission related costs” but does not specify what they are.

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NASA approves two new asteroid missions

NASA has approved two new unmanned missions aimed at studying the asteroids.

Lucy will take a close look at six Trojan asteroids orbiting near Jupiter, after first visiting a main belt asteroid.

Lucy, a robotic spacecraft, is scheduled to launch in October 2021. It’s slated to arrive at its first destination, a main belt asteroid, in 2025. From 2027 to 2033, Lucy will explore six Jupiter Trojan asteroids. These asteroids are trapped by Jupiter’s gravity in two swarms that share the planet’s orbit, one leading and one trailing Jupiter in its 12-year circuit around the sun. The Trojans are thought to be relics of a much earlier era in the history of the solar system, and may have formed far beyond Jupiter’s current orbit.

Psyche will visit 16 Psyche, an unusual metal-rich asteroid made up mostly of iron and nickel.

While Psyche will use an ion engine, allowing it great freedom and even the potential to go elsewhere, like Dawn, when its primary mission is complete, I have not been able to determine whether Lucy will use conventional chemical altitude thrusters or an ion-type engine.

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