Lucy spacecraft to the Jupiter Trojan asteroids

[lpetrich]

 Lucy (spacecraft) - The First Mission to Jupiter's Trojan Asteroids - Lucy Mission

Earlier today, as I write this, the Lucy spacecraft was launched on its way to the Jupiter Trojan asteroids. Over its 12-year mission, it will fly by 8 asteroids in 6 asteroid systems, two of them binary systems.

Like the Juno spacecraft, which has been orbiting Jupiter for 5 years, it is powered by solar panels -- big ones, two disks 6 meters / 20 feet in diameter. These were successfully deployed.

The spacecraft has these cameras:

• L'Ralph - panchromatic and color visible imager (0.4-0.85 μm) and infrared spectroscopic mapper (1-3.6 μm). -- like New Horizons Ralph
• L'LORRI - high-resolution visible imager. -- like New Horizons LORRI
• L'TES - thermal infrared spectrometer (6-75 μm). -- like OSIRIS-REx OTES

From radio tracking, it will be possible to measure the spacecraft's targets' masses from the targets' gravitational pulls on the spacecraft.

An optical element in L'TES is made of lab-grown diamond, making the spacecraft "Lucy in the Sky with a Diamond".

 

[lpetrich]

How NASA's Lucy Mission Will Visit More Asteroids Than Any Other Spacecraft. - YouTube

The spacecraft will get a gravity assist from the Earth by flying by first next year, and then three years from now. It will then be going fast enough to go into the outer Solar System.

Along the way, it will be doing a flyby of a small main-belt asteroid, 52246 Donaldjohanson.

Over 2027 and 2028, the spacecraft will fly by five asteroids in four systems in the "Greek camp" of asteroids, at Lagrange point L4, 60d ahead of Jupiter in its orbit.

It will then return to the Earth on 2030 for another gravity-assist flyby, and will fly by two asteroids in one system in the "Trojan camp" of asteroids, at Lagrange point L5, 60d behind Jupiter in its orbit.

Several asteroids at these Lagrange points are named after heroes of the Trojan War, the Greek camp being of attackers of Troy and the Trojan camp being of defenders of Troy. There is an out-of-place one at each Lagrange point, however.


The Trojan War comes down to us in Greek mythology, notably in the Iliad and the Odyssey. Its author is traditionally someone named Homer, but we don't know much about him, if there was a historical Homer. This lack of knowledge was evident in antiquity, when people in several cities claimed their residences as his birthplace.

The Iliad has some anachronisms in it, like bronze armor and boar's-tusk helmets. Both have been found in Mycenaean Greek archeological sites (roughly 1500 - 1200 BCE), but both had gone out of style by the time it was written down, around 700 BCE. Some ruins at Hissarlik, Turkey, are where the Iliad described Troy as being, so we can be confident that Troy was a real place. But for the most part, telling fact from fiction in the Iliad is a difficult and contentious issue.

 

[lpetrich]

The Lagrange points are places where an object can orbit in constant relative position relative to two other objects.

The first three are: L3 - (more massive) - L1 - (less massive) - L2

The last two are: L4 (60d ahead) and L5 (60d behind) both in the orbit of the less massive body relative to the more massive body.

Orbits at L1, L2, and L3 are all unstable, and L4 and L5 are stable only if (smaller mass) / (larger mass) <~ 1/25 for those two.

That condition is satisfied by the Sun-Jupiter system, since Jupiter is a bit less than 1/1000 as massive as the Sun.

-

 Lucy (Australopithecus) is a specimen of the human-predecessor species Australopithecus afarensis from 3.2 million years ago, in the late Pliocene, not much before the start of the Pleistocene ice ages. The Earth looks very much like what it looks like today, and most of its inhabitants were very familiar-looking.

The Lucy specimen is an early australopithecine and is dated to about 3.2 million years ago. The skeleton presents a small skull akin to that of non-hominin apes, plus evidence of a walking-gait that was bipedal and upright, akin to that of humans (and other hominins); this combination supports the view of human evolution that bipedalism preceded increase in brain size.[4][5] A 2016 study proposes that Australopithecus afarensis was also to a large extent tree-dwelling, though the extent of this is debated.[6][7]

...
Lucy was 1.1 m (3 ft 7 in) tall,[18] weighed 29 kg (64 lb), and (after reconstruction) looked somewhat like a chimpanzee. The creature had a small brain like a chimpanzee, but the pelvis and leg bones were almost identical in function to those of modern humans, showing with certainty that Lucy's species were hominins that had stood upright and had walked erect.[19]

 

[lpetrich]

 Lucy in the Sky with Diamonds

"Lucy in the Sky with Diamonds" is a song by the English rock band the Beatles from their 1967 album Sgt. Pepper's Lonely Hearts Club Band. It was written primarily by John Lennon and credited to the Lennon–McCartney songwriting partnership.[2] Lennon's son Julian inspired the song with a nursery school drawing that he called "Lucy – in the sky with diamonds". Shortly before the album's release, speculation arose that the first letter of each of the title nouns intentionally spelled "LSD", the initialism commonly used for the hallucinogenic drug lysergic acid diethylamide.[3] Lennon repeatedly denied that he had intended it as a drug song.[3][4] He attributed the song's fantastical imagery to his reading of Lewis Carroll's Alice in Wonderland books.[3]

The Lucy Plaque - Lucy Mission

The first spacecraft to leave the Solar System carried with them messages from Earth for any intelligent life that may one day encounter them. The Lucy Mission continues this tradition, but the plaque it carries as a time capsule is not for unknown aliens, but for our own descendants. After the mission is over, the Lucy spacecraft will remain on a stable orbit—travelling between the Earth and the Trojan asteroids for hundreds of thousands, if not millions, of years. It is not hard to imagine that some day in the distant future our descendants may retrieve the Lucy spacecraft as a relic of the early days of humanity’s exploration of the Solar System.

Therefore the spacecraft carries a plaque as a time capsule, including messages from prominent thinkers of our time and a diagram showing the positions of the planets on the date of Lucy’s launch.

Of the sentiments in it, I like this one from Albert Einstein:

The important thing is not to stop questioning. Curiosity has its own reason for existence. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery each day. Never lose a holy curiosity. Try not to become a man of success, but rather try to become a man of value. He is considered successful in our day who gets more out of life than he puts in. But a man of value will give more than he receives.

 

[lpetrich]

Of spacecraft missions to minor planets, three are active:

 New Horizons now at about 50 AU from the Sun.

 Hayabusa2 successfully delivered the samples that it collected from the asteroid 162173 Ryugu. It went into orbit around the asteroid in mid-2018 and surveyed it for the next year and a half, deploying landers and rovers and collecting samples. It then went into an orbit with a flyby of the Earth and it released a capsule that contained its samples. That capsule successfully landed, and the spacecraft stayed in orbit around the sun. It will fly by some asteroids in coming years.

 OSIRIS-REx is returning the samples that it collected from the asteroid 101955 Bennu. It went into orbit at the end of 2018, surveyed the asteroid, landed on it late in 2020, collected up some samples of it, returned to orbit, and departed for Earth on May of this year. Its sample capsule should arrive at the Earth in September 2023, and the spacecraft should continue to another asteroid, currently 99942 Apophis, one with an orbit that gets it dangerously close to the Earth.

-

 Double Asteroid Redirection Test - DART for short - is scheduled to launch on 24 November 2021. It will impact asteroid 65803 Didymos a year later, as a test of a planetary-defense concept.

 Psyche (spacecraft) and  Janus (spacecraft) will be launched together in August 2022.

Psyche will fly by Mars nearly a year later for a gravity assist, and it will go into orbit around asteroid 16 Psyche early in 2026. This asteroid is largely metallic, likely the largest asteroid with that composition.

Janus is two spacecraft, one for (175706) 1996 FG3 and one for (35107) 1991 VH, both binary asteroids. They will both do a gravity-assist flyby of the Earth in 2023, and fly by their targets in 2026.

 Near-Earth Asteroid Scout is one of 13 cubesats that will be launched atop the first Space Launch System rocket to launch, likely next year. It will deploy a solar sail, then do gravity-assist flybys of the Moon to escape into heliocentric orbit. Once there, it will fly by some asteroid, currently 1991 VG.

-

There are several missions in various stages of planning and proposal, but I won't go into those.

 

[none]

Good.
Simple Minds -"Dont You Forget About Me"... which leads to so what...

 

[Harry Bosch]

Of spacecraft missions to minor planets, three are active:

 New Horizons now at about 50 AU from the Sun.

 Hayabusa2 successfully delivered the samples that it collected from the asteroid 162173 Ryugu. It went into orbit around the asteroid in mid-2018 and surveyed it for the next year and a half, deploying landers and rovers and collecting samples. It then went into an orbit with a flyby of the Earth and it released a capsule that contained its samples. That capsule successfully landed, and the spacecraft stayed in orbit around the sun. It will fly by some asteroids in coming years.

 OSIRIS-REx is returning the samples that it collected from the asteroid 101955 Bennu. It went into orbit at the end of 2018, surveyed the asteroid, landed on it late in 2020, collected up some samples of it, returned to orbit, and departed for Earth on May of this year. Its sample capsule should arrive at the Earth in September 2023, and the spacecraft should continue to another asteroid, currently 99942 Apophis, one with an orbit that gets it dangerously close to the Earth.

-

 Double Asteroid Redirection Test - DART for short - is scheduled to launch on 24 November 2021. It will impact asteroid 65803 Didymos a year later, as a test of a planetary-defense concept.

 Psyche (spacecraft) and  Janus (spacecraft) will be launched together in August 2022.

Psyche will fly by Mars nearly a year later for a gravity assist, and it will go into orbit around asteroid 16 Psyche early in 2026. This asteroid is largely metallic, likely the largest asteroid with that composition.

Janus is two spacecraft, one for (175706) 1996 FG3 and one for (35107) 1991 VH, both binary asteroids. They will both do a gravity-assist flyby of the Earth in 2023, and fly by their targets in 2026.

 Near-Earth Asteroid Scout is one of 13 cubesats that will be launched atop the first Space Launch System rocket to launch, likely next year. It will deploy a solar sail, then do gravity-assist flybys of the Moon to escape into heliocentric orbit. Once there, it will fly by some asteroid, currently 1991 VG.

-

There are several missions in various stages of planning and proposal, but I won't go into those.

Yes, I feel lucky to be living today in a great time of adventure and exploration. I just hope that I am alive when we find the first evidence of ETs!

 

[lpetrich]

Lucy Mission - blog at nasa.gov

Of the two solar panels, one is fully deployed and latched in place and the other one is partially deployed, though it seems to be nearly fully deployed. Lucy's operators have decided to make the spacecraft deploy its instrument pointing platform, a step that was successful. They are now trying to get an estimate of the state of the partially-deployed panel.

 

[none]

Humans are awesome, except those bad ones.

 

[lpetrich]

NASA’s Lucy Mission Suspending Further Solar Array Deployment Activities – Lucy Mission - January 19, 2023

NASA’s Lucy mission team has decided to suspend further solar array deployment activities. The team determined that operating the mission with the solar array in the current unlatched state carries an acceptable level of risk and further deployment activities are unlikely to be beneficial at this time. The spacecraft continues to make progress along its planned trajectory.

Shortly after the spacecraft’s Oct. 2021 launch, the mission team realized that one of Lucy’s two solar arrays had not properly unfurled and latched. A series of activities in 2022 succeeded in further deploying the array, placing it into a tensioned, but unlatched, state. Using engineering models calibrated by spacecraft data, the team estimates that the solar array is over 98% deployed, and it is strong enough to withstand the stresses of Lucy’s 12-year mission. The team’s confidence in the stability of the solar array was affirmed by its behavior during the close flyby of the Earth on Oct. 16, 2022, when the spacecraft flew within 243 miles (392 km) of the Earth, through the Earth’s upper atmosphere. The solar array is producing the expected level of power at the present solar range and is expected to have enough capability to perform the baseline mission with margin.

The spacecraft's operators don't see much point in trying much further, especially when the spacecraft will be out in the asteroid belt and much colder than near the Earth's orbit.

 

[lpetrich]

NASA’s Lucy Spacecraft Adjusts Course for Asteroid Flyby in November – Lucy Mission - May 18, 2023

On May 9, NASA’s Lucy spacecraft carried out a trajectory correction maneuver to set the spacecraft on course for its close encounter with the small main belt asteroid Dinkinesh. The maneuver changed the velocity of the spacecraft by only about 7.7 mph (3.4 m/s).

Even though the spacecraft is currently travelling at approximately 43,000 mph (19.4 km/s), this small nudge is enough to move the spacecraft nearly 40,000 miles (65,000 km) closer to the asteroid during the planned encounter on Nov. 1, 2023. The spacecraft will fly a mere 265 miles (425 km) from the small, half-mile- (sub-km)-sized asteroid, while travelling at a relative speed of 10,000 mph (4.5 km/s).

 152830 Dinkinesh

152830 Dinkinesh (provisional designation 1999 VD57) is a small, stony main-belt asteroid about 760 meters (2,500 feet) in diameter. It was discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) survey at Socorro, New Mexico on 4 November 1999. This asteroid is the first flyby target of NASA's Lucy mission, which will approach 425 km (264 mi) from the asteroid on 1 November 2023.[8] Dinkinesh will be the smallest main-belt asteroid explored by spacecraft yet.[9] The asteroid has an elongated shape and rotates slowly with a period of 52.67 hours.[4][5]

The spacecraft will fly by the Earth again on 13 December 2024, then fly by another main-belt asteroid on 20 April 2025, then do 4 flybys of Trojan asteroids over 2027-2029, then do another flyby of the Earth on 26 December 2030, then do another flyby of a Trojan asteroid in 2033.

 

[lpetrich]

The Lucy Plaque - Lucy Mission - "Therefore the spacecraft carries a plaque as a time capsule, including messages from prominent thinkers of our time and a diagram showing the positions of the planets on the date of Lucy’s launch."

Though it might also have included the beginning of Homer's Iliad. From the translations at The Iliad - Wikisource, the free online library, I compose this translation:

Sing, goddess, of the destructive wrath of Achilles son of Peleus, wrath which sent countless miseries to the Greeks, wrath which threw many brave souls of heroes into Hades, making their bodies meals for dogs and vultures. Thus the will of Zeus was done, from the time when the son of Atreus, king of men, and great Achilles, had a falling out with each other.

 

[lpetrich]

I might revise that bit to "Sing, goddess, sing of the destructive wrath..." I repeated "wrath" to make it easier to follow, and I added "sing" there for that reason.

Last month, Lucy flew by an asteroid on its way out to the Trojan asteroids. It was  152830 Dinkinesh provisionally named 1999 VD57 when it was discovered. NASA’s Lucy Asteroid Target Gets a Name - NASA

The first asteroid to be visited by NASA’s Lucy mission now has a name. The International Astronomical Union has approved the name (152830) Dinkinesh for the tiny main belt asteroid that the Lucy spacecraft will encounter on November 1, 2023. “Dinkinesh”, or ድንቅነሽ in Amharic, is the Ethiopian name for the human-ancestor fossil, also known as Lucy, which was found in that country and currently curated there. Dinkinesh means “you are marvelous” in Amharic.

NASA’s Lucy Spacecraft Discovers 2nd Asteroid During Dinkinesh Flyby - NASA

In the weeks prior to the spacecraft’s encounter with Dinkinesh, the Lucy team had wondered if Dinkinesh might be a binary system, given how Lucy’s instruments were seeing the asteroid’s brightness changing with time. The first images from the encounter removed all doubt. Dinkinesh is a close binary. From a preliminary analysis of the first available images, the team estimates that the larger body is approximately 0.5 miles (790 m) at its widest, while the smaller is about 0.15 miles (220 m) in size.

This encounter primarily served as an in-flight test of the spacecraft, specifically focusing on testing the system that allows Lucy to autonomously track an asteroid as it flies past at 10,000 mph, referred to as the terminal tracking system.

“This is an awesome series of images. They indicate that the terminal tracking system worked as intended, even when the universe presented us with a more difficult target than we expected,” said Tom Kennedy, guidance and navigation engineer at Lockheed Martin in Littleton, Colorado. “It’s one thing to simulate, test, and practice. It’s another thing entirely to see it actually happen.”

From Wikipedia,

During the flyby, the Lucy spacecraft discovered that Dinkinesh has a natural satellite 220 m (720 ft) in diameter.[3] The satellite is named Selam (full designation Dinkinesh I Selam), after the fossil remains of a three-year-old Australopithecus afarensis female hominin (the same species as the Lucy fossil) found in Dikika, Ethiopia in 2000.[32]: 5  Selam means "peace" in the Amharic language (ሰላም) and it was proposed by Raphael Marschall.[33] The name was approved by the International Astronomical Union's WGSBN on 27 November 2023.[33][32]: 5 

NASA’s Lucy Surprises Again, Observes 1st-ever Contact Binary Orbiting Asteroid - NASA Science

In the first downlinked images of Dinkinesh and its satellite, which were taken at closest approach, the two lobes of the contact binary happened to lie one behind the other from Lucy's point of view. Only when the team downlinked additional images, captured in the minutes around the encounter, was the true nature of this object revealed.

“Contact binaries seem to be fairly common in the solar system,” said John Spencer, Lucy deputy project scientist, of the Boulder, Colorado, branch of the San-Antonio-based Southwest Research Institute. “We haven’t seen many up-close, and we’ve never seen one orbiting another asteroid. We’d been puzzling over odd variations in Dinkinesh’s brightness that we saw on approach, which gave us a hint that Dinkinesh might have a moon of some sort, but we never suspected anything so bizarre!”

I haven't found any details of that asteroid moon's orbit, however, though from measuring one of the pictures, that orbit's size is at least 3 kilometers.