Science News
LUCI1 MOS failure – Resolved
Posted Mar 28, 2022
The LUCI1 1.5/2.0 Longslit mask experienced a MOS mask failure moving from turnout to FPU. During this failure the mask rotator failed to move and the mask stuck in an intermediate state. This MOS error could be caused by loose screws on the mask frame, or the “OPEN” position has shifted. Investigations are ongoing. LUCI1 is out of service until this is resolved.
UT20220331 – The motor currents were adjusted and the unit put back in service with no restrictions
MODS2 Cassette Mechanism Damage – Partially Resolved
Posted Mar 01, 2022
During operations last night there was a MODS slitmask fault error:
2022-03-01T06:08:37.819582 M2.IE>MC2 ERROR: SLITMASK SLITMASK=FAULT Mechanism out-of-position, in-position sensor not asserted. Reset SLITMASK to recover
Visual inspection of the mask loading port showed damage to the upper part of the cassette mechanism. The proximity sensor had been broken and the mounting plate bent, the grabber shows signs of damage and also the cassette shows some mis-alignment.
Repairs are underway and a full inspection is being performed. MODS2 is out of service until further notice.
UT20220303 – The mask cassette was repaired and inspected. The cassette is operational at half capacity until a full intervention is completed during summer shutdown 2022
UT20220321 – A sensor gap for the grabber was adjusted. No restrictions on elevation for use.
LUCI1 AO Patrol Field Change
Posted Feb 21, 2022
The LUCI1 AO Patrol field is pending remeasurement after a recent intervention. The field has slightly changed. Users should avoid selecting stars too close to the edge of the field as they appear in the OT as there is not guarantee they will match the physical limits of the AO bayside stages. An updated version of the OT is pending to reflect this change.
MODS2 Ne Lamp Failing to fire – Resolved
Posted Feb 17, 2022
The MODS Neon Lamp is failing to fire consistently. It appears to be the result of a bad power supply. A new power supply has been obtained and is awaiting installation. (Update on 3-Mar-2022: The power supplies and Ne lamps on both MODS were replaced and this has resolved the problem.)
Near-Earth Asteroid Might be a Lost Fragment of the Moon
Posted Nov 11, 2021
A team of UArizona-led researchers think that the near-Earth asteroid Kamo`oalewa might actually be a miniature moon.
A near-Earth asteroid named Kamo`oalewa could be a fragment of our moon, according to a new paper published in Nature Communications Earth and Environment by a team of astronomers led by the University of Arizona.
Kamo`oalewa is a quasi-satellite – a subcategory of near-Earth asteroids that orbit the sun but remain relatively close to Earth. Little is known about these objects because they are faint and difficult to observe. Kamo`oalewa was discovered by the PanSTARRS telescope in Hawaii in 2016, and the name – found in a Hawaiian creation chant – alludes to an offspring that travels on its own. The asteroid is roughly the size of a Ferris wheel – between 150 and 190 feet in diameter – and gets as close as about 9 million miles from Earth.
Due to its orbit, Kamo`oalewa can only be observed from Earth for a few weeks every April. Its relatively small size means that it can only be seen with one of the largest telescopes on Earth. Using the UArizona-managed Large Binocular Telescope on Mount Graham in southern Arizona, a team of astronomers led by planetary sciences graduate student Ben Sharkey found that Kamo`oalewa’s pattern of reflected light, called a spectrum, matches lunar rocks from NASA’s Apollo missions, suggesting it originated from the moon.
The team can’t yet be sure how it may have broken loose. The reason, in part, is because there are no other known asteroids with lunar origins.
“I looked through every near-Earth asteroid spectrum we had access to, and nothing matched,” said Sharkey, the paper’s lead author.
The debate over Kamo`oalewa’s origins between Sharkey and his adviser, UArizona associate professor Vishnu Reddy, led to another three years of hunting for a plausible explanation.
“We doubted ourselves to death,” said Reddy, a co-author who started the project in 2016. After missing the chance to observe it in April 2020 due to a COVID-19 shutdown of the telescope, the team found the final piece of the puzzle in 2021.
“This spring, we got much needed follow-up observations and went, ‘Wow it is real,'” Sharkey said. “It’s easier to explain with the moon than other ideas.”
Kamo`oalewa’s orbit is another clue to its lunar origins. Its orbit is similar to the Earth’s, but with the slightest tilt. Its orbit is also not typical of near-Earth asteroids, according to study co-author Renu Malhotra, a UArizona planetary sciences professor who led the orbit analysis portion of the study.
“It is very unlikely that a garden-variety near-Earth asteroid would spontaneously move into a quasi-satellite orbit like Kamo`oalewa’s,” she said. “It will not remain in this particular orbit for very long, only about 300 years in the future, and we estimate that it arrived in this orbit about 500 years ago,” Malhotra said. Her lab is working on a paper to further investigate the asteroid’s origins.
An artist impression of Earth quasi-satellite Kamo`oalewa near the Earth-Moon system. Astronomers using the Large Binocular Telescope have shown that it might be a lost fragment of the moon.
Credit: Addy Graham/University of Arizona
Kamo`oalewa is about 4 million times fainter than the faintest star the human eye can see in a dark sky.
“These challenging observations were enabled by the immense light gathering power, of the twin 8.4-meter telescopes of the Large Binocular Telescope,” said study co-author Al Conrad, a staff scientist with the telescope.
The study also included data from the Lowell Discovery Telescope in Flagstaff, Arizona. Other co-authors on the paper include Olga Kuhn, Christian Veillet, Barry Rothberg and David Thompson from the Large Binocular Telescope; Audrey Thirouin from Lowell Observatory and Juan Sanchez from the Planetary Science Institute in Tucson. The research was funded by NASA’s Near-Earth Object Observations Program.
MODS1 Cassette Mechanism Damage – Partially Resolved
Posted Oct 26, 2021
During Operations on October 12th, there was a MODS slitmask fault moving a mask in the lower part of the cabinet. Further inspection revealed the mask cassette was damaged during the failure. The cassette, mechanisms, and mask frames underwent inspections and repairs and MODS1 was returned to service. The MOS cassette is available at half capacity until a more extensive intervention can be performed in summer shutdown 2022.
