12/26/2022 – Ephemeris – Some space firsts this year

This is Ephemeris for Monday, December 26th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:08, and it will rise tomorrow at 8:19. The Moon, halfway from new to first quarter, will set at 9:10 this evening.

I hope we all survived the holiday season so far. We now have one more to go, New Year’s Eve. The Moon will pass the planet Saturn later this morning. By this evening, Saturn will be to the right of the Moon in the southwestern sky. Now that we’re ending the year, we can look back at some space firsts. The James Webb Space Telescope was launched last Christmas. It became operational late spring of this year and presented its first 5 spectacular images in July. The DART spacecraft, also launched last year, collided with the small asteroid Dimorphos, orbiting the larger Didymos in a 12-hour orbit produced an amazing effect on its orbit. And late this year Artemis I finally launched, making a nearly flawless orbit of the Moon with its Orion space capsule, and returned.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.

Addendum

The Moon and Saturn at 6:30 pm tonight, December 26, 2022. Note that the Moon is shown at twice its apparent size to better show its phase. Created using Stellarium.

The James Webb Space Telescope teaser deep field image from President Biden’s July 11th presentation. Credit: NASA, ESA, CSA, JWST, STScI.

DART images of both Didymos, the big one, and Dimorphos, on approach. Dimorphos is the target. Credit NASA / JHAPL.

Two images from the LiciaCube satellite launched from the DART spacecraft 15 days before the impact, and trailing it to record the collision with its wide and narrow angle imagers. Dimorphos does appear to be a rubble pile asteroid from its appearance and the amount of ejecta caused by the impact. The ejecta adds to the effect of the spacecraft’s kinetic energy by pushing away from the asteroid by Newton’s third law of motion.
Credit Italian Space Agency.

Earthset from Artemis I’s Orion spacecraft, as it moves around to the far side of the Moon. Click on the image to enlarge it. Credit: NASA.

12/02/2022 – Ephemeris – Astronomical events tonight and tomorrow in Traverse City

This is Ephemeris for Friday, December 2nd. Today the Sun will be up for 9 hours and 2 minutes, setting at 5:03, and it will rise tomorrow at 8:02. The Moon, 2 days past first quarter, will set at 3:07 tomorrow morning.

We have a big astronomy and space weekend starting tonight at 8 pm I’ll be giving a talk about the Star of Bethlehem at Northwestern Michigan College’s Rogers Observatory located south of Traverse City on Birmley Road, with observing at 9 pm, clouds permitting. This is part of the December meeting of the Grand Traverse Astronomical Society. Tomorrow is NASA Family Day at the Dennos Museum Center. There are fun activities at 1 pm, making comets and exploring the phases of the Moon. At 2 pm, Dr. Jerry Dobek from NMC and the GTAS will be giving a talk at the Milliken Auditorium. Museum admission is waived for the event, which is to celebrate the Museum’s having a NASA Kiosk through the end of the month.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.

11/14/2022 – Ephemeris – Psyche spacecraft to launch to its namesake asteroid next October after a 14-month delay

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This is Ephemeris for Monday, November 14th. Today the Sun will be up for 9 hours and 37 minutes, setting at 5:15, and it will rise tomorrow at 7:39. The Moon, 2 days before last quarter, will rise at 10:07 this evening.

The launch of the Psyche spacecraft to the asteroid of the same name this past August was canceled due to problems with the spacecraft itself, not the SpaceX Falcon Heavy rocket. NASA thinks they have a handle on the problem and are now wanting to launch in October of next year. If they launched this year, they could have gotten a gravity assist by passing close to Mars on their way to the asteroid belt, where the asteroid Psyche resides. Next year’s launch will not have a Mars flyby and take 2 more years to reach Psyche, a total of 6 years, arriving in 2029. The long flight time is because of the attempt to orbit Psyche rather than just flying by the asteroid. To handle such a maneuver, the spacecraft will also use ion thrusters like the Dawn spacecraft did last decade, which orbited both the asteroids Vesta and Ceres.   Psyche is a special metal rich asteroid that may have been the core of a protoplanet.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

An artist’s rendition of the Psyche spacecraft at the asteroid Psyche. Credit: NASA.

10/13/2022 – Ephemeris – CAPSTONE satellite stabilized again

This is Ephemeris for Thursday, October 13th. Today the Sun will be up for 11 hours and 5 minutes, setting at 7:01, and it will rise tomorrow at 7:57. The Moon, half way from full to last quarter, will rise at 8:59 this evening.

The CubeSat named CAPSTONE, was launched June 28th to prove out the near rectilinear halo orbit of the Moon that the Lunar Gateway Space Station and Orion Capsule will be located in on missions to the south pole of the Moon. CubeSats are built on a 10 by 10 centimeter or 4 by 4 inch cube. They are relatively inexpensive. CAPSTONE is a 12 unit CubeSat arranged 4 by 3 cubes with a solar panel/antenna attached to one side. Back on September 8th it made a course correction which caused it to tumble. It took almost a month, until last Friday to regain control of the satellite and stop the tumbling. Apparently a stuck propellant valve was the problem. CAPSTONE should enter this halo orbit of the Moon on November 13th.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Artist’s impression of the CAPSTONE spacecraft at perilune, the closest point in its orbit, over the north pole of the Moon.

CAPSTONE low-energy trajectory to the Moon. TCM are trajectory Correction Maneuvers (Thruster firings). Click on the image to enlarge it. Credit: Advanced Space, builder of the CAPSTONE CubeSat.

NASA CAPSTONE pathfinder for gateway orbit to prove out the near rectilinear halo orbit for the Lunar Gateway.

10/06/2022 – Ephemeris – Artemis I rescheduled

This is Ephemeris for Thursday, October 6th. Today the Sun will be up for 11 hours and 27 minutes, setting at 7:14, and it will rise tomorrow at 7:48. The Moon, 3 days before full, will set at 4:52 tomorrow morning.

Artemis 1 was going to launch on September 27th, But Hurricane Ian had other plans, so the rocket was trundled back to the Vertical Assembly Building. There, a battery or components of the auto destruct mechanism had to be swapped out before they attempted to launch again. All rockets launched from the US are required to be equipped with a destruct package to blow up the rocket if it veers off course, to not endanger lives on the ground. There are other tweaks, including charging or replacing batteries in all the CubeSats that are on board. The next possible launch period runs from November 12th to the 27th, with four blackout dates within that period. The weather should be better, being the tail end of hurricane season.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Artemis I November launch calendar. Dates in green are possible launch dates. I’m not sure, but red dates are also forbidden because the Orion Capsule will experience more than 90 minutes in shadow at a time. It’s powered by solar panels. Light green dates allow a long mission of 1 1/2 orbits of the Moon in the distant retrograde orbit (DRO). The dark green dates can only have 1/2 a DRO. Source: NASA.

10/04/2022 – Ephemeris – DART does its job, now we wait and watch.

This is Ephemeris for Tuesday, October 4th. Today the Sun will be up for 11 hours and 33 minutes, setting at 7:17, and it will rise tomorrow at 7:45. The Moon, 2 days past first quarter, will set at 2:14 tomorrow morning.

Last week Monday night NASA’s DART spacecraft successfully smashed into the tiny asteroid Dimorphos, which was slowly orbiting an asteroid named Didymos five times its size, and nearly a half mile in size. Dimorphos is too small and too close to Didymos to be seen in optical telescopes. Even the DART spacecraft’s telescope could only spot it in the last hour before the collision. Astronomers have found that they can see asteroid shapes and moonlets by radar. One technique was to send out radar pulses out from the Arecibo Observatory in Puerto Rico and receive them back with the Green Bank Telescope in West Virginia. Now that Arecibo has been destroyed, astronomers transmit from Goldstone, California.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Dimorphos collision from as seen from Hubble and JWST. The colors aren’t true. Credit: NASA, ESA, CSA, Jian-Yang Li, Cristina Thomas, Ian Wong, Joseph DePasquale, Alyssa Pagan. From CNET web site.

10/02/2022 – Ephemeris Extra – NASA goes on the offensive

DART images of both Didymos, the big one, and Dimorphos, on approach. Credit NASA / JHAPL

This is a slightly revised version of my article in the Stellar Sentinel, the newsletter of the Grand Traverse Astronomical Society. Educators may receive a free PDF copy of this monthly publication via email, which covers astronomical topics and events visible from Northwest Lower Michigan. Send your request, stating your affiliation, to info@gtastro.org.

The score is: Asteroids-billions, NASA-1. It’s a bit unfair, since asteroids have been hitting the Earth for 4.567 billion years or so, and NASA has been around for 64 years before DART spacecraft collided with the asteroid Dimorphos. Hey, this was their first attempt at a small asteroid. As far as the 21st century destructive asteroid score is 1 to NASA’s 1, as far as I know.
That strike was in Chelyabinsk, Russia. That was February 15, 2013. We were all waiting on another asteroid making a close pass of the Earth, when the Chelyabinsk meteoroid exploded 14 miles above the city. Over a thousand people were injured by the blast wave. They saw the bright flash and rushed to the windows to see what it was. Then the blast wave hit, shattering the windows, causing glass cuts for over a thousand people. One building’s wall collapsed, and a fragment fell into a lake outside of town.
NASA’s record in attempting to hit a planetary object dates back to the early 1960s and the nine Pioneer missions to crash a probe on the Moon, sending back pictures all the way down. Back in the early 60s, just hitting a 2,100-mile (3380 kilometer) wide object a quarter of a million miles away was a dicey prospect. It’s one thing to miss the Moon on one side or the other, but to not have enough oomph to even make it all the way is downright embarrassing. NASA did much better by the end of the decade with the Apollo manned landings and bombarding the Moon with used space vehicles for seismic studies of its interior.
NASA actually collided a spacecraft into a comet. That was July 4, 2005, when the impactor part of the Deep Impact spacecraft hit Comet Tempel 1’s nucleus, attempting to study part of its subsurface. The non-impactor part was later renamed EPOXI and went on to fly by the dog-bone shaped Hartley 2 comet nucleus. Another reused comet explorer spacecraft Stardust after collecting cometary dust from Comet Wild 2 (pronounced Vilt 2), and possible interstellar dust penetrating the solar system, and after dropping the sample re-entry capsule back on Earth it ended in solar orbit. Later it was repurposed as the Stardust-NexT mission and flew by Tempel 1 six years later to study the crater the Deep Impact Impactor made in the comet.
To study the effect of a collision of a spacecraft from the Earth despite the fact that Dimorphos cannot be seen is a trick. However, the pair is an eclipsing binary from our point of view, so the brightness of the unresolved pair changes as they eclipse each other.
Before the collision, Dimorphos had an 11.9 hour orbit of Didymos. Dimorphos is a fifth the size of Didymos orbiting it at three times the primary’s radius. If the orbit is near circular, Dimorphos’ orbital velocity is only 0.39 mph (0.63 kph). It should be relatively easy to see a tiny change in Dimorphos’ orbital period.

Last frame Dimorphos fit in from DART. Credit NASA / JHAPL.

Two images from the LiciaCube satellite launched from the DART spacecraft 15 days before the impact, and trailing it to record the collision with its wide and narrow angle imagers. Dimorphos does appear to be a rubble pile asteroid from its appearance and the amount of ejecta caused by the impact. The ejecta adds to the effect of the spacecraft’s kinetic energy by pushing away from the asteroid by Newton’s third law of motion. Credit: Italian Space Agency.

A frame from a time-lapse video taken from the ATLAS Project’s South African observatory of the unresolved Didymos – Dimorphos pair and the expanding ejecta cloud. The asteroid pair developed a dust tail like a comet for a while.
ATLAS is an acronym for a rather apocalyptic title “Asteroid Terrestrial-impact Last Alert System”. Developed by the University of Hawai’i and funded by NASA. It has two telescopes in Hawai’i, one in Chile, and one in South Africa. Credit: NASA/UH.

Days later, Dimorphos was exhibiting a thin dust tail, like a comet.

Now we wait on Earth’s observatories to observe of the period of Dimorphos’ orbit. It should decrease the orbital time.

09/26/2022 – Ephemeris – The DART spacecraft will attempt to deflect an asteroid tonight, Artemis I launch postponed

This is Ephemeris for Monday, September 26th. Today the Sun will be up for 11 hours and 57 minutes, setting at 7:32, and it will rise tomorrow at 7:35. The Moon, 1 day past new, will set at 8:07 this evening.

Tonight at 7:14 pm EDT (23:14 UTC), NASA’s DART spacecraft will collide with the tiny asteroid Dimorphos, which is orbiting the somewhat larger asteroid Didymos. They are potentially hazardous asteroids. The idea is to see what effect the collision has on the orbit of Dimorphos as it orbits Didymos at four tenths of a mile an hour. Trailing DART is an Italian CubeSat LiciaCube (pronounced LEE-cha-cube), which was launched from DART more 15 days ago to witness the collision. DART is an acronym for Double Asteroid Redirection Test, part of the Planetary Defense Program. Earth based radio and optical telescopes will assess if and how much the collision alters the orbit of Dimorphos. LICIAcube will return images of the collision, crater and the other side of Dimorphos. NASA will air it live on their channels.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Unlike the Artemis I launch, this event cannot be postponed. It will either hit Dimorphos at 7:14 pm or miss forever.

Graphic on NASA’s DART mission to crash a small spacecraft into a mini-asteroid to change its trajectory as a test for any potentially dangerous asteroids in the future. Click on the image to enlarge it. Credit: AFP / AFP (Agence France-Presse)

A Note from EarthSky.org:

If you want to watch the event live, coverage begins at 6 p.m. EDT (22 UTC) on September 26, 2022, on NASA’s website. You can also watch it via Facebook, Twitter and YouTube.

Artemis I news

The Artemis I launch, scheduled for Tuesday, September 27, has been postponed due to the threat from tropical storm Ian.

09/13/2022 – Ephemeris – SpaceX Crew-5 flight to the ISS will be commanded by first Native American female astronaut

This is Ephemeris for Tuesday, September 13th. Today the Sun will be up for 12 hours and 37 minutes, setting at 7:57, and it will rise tomorrow at 7:20. The Moon, 3 days past full, will rise at 9:38 this evening.

On or around October 3rd a SpaceX Crew Dragon capsule will be launched to the International Space Station with an international crew of four with the first female Native American astronaut Nicole Mann as commander, pilot Josh Cassada, both NASA astronauts, Japanese astronaut Koichi Wakata, and Russian cosmonaut Anna Kikina. Nicole Mann, a member of the Round Valley Indian Tribes of northern California, is also the first female commander of a Commercial Crew spacecraft. She was originally assigned to the Boeing CST-100 Starliner, but was transferred to the SpaceX Dragon due to the prolonged problems with the former vehicle. Crew 5 will be a part of Expeditions 67 and 68 on the International Space Station.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

SpaceX Crew-5 Official Crew Portrait – Left to right: Anna Kikina, Josh Cassada, Nicole Mann and Koichi Wakata.

09/12/2022 – Ephemeris – The Dart Mission hits its asteroid in two weeks

This is Bob Moler with Ephemeris for Monday, September 12th. Today the Sun will be up for 12 hours and 40 minutes, setting at 7:59, and it will rise tomorrow at 7:19. The Moon, 2 days past full, will rise at 9:16 this evening.

Two weeks from today, a small satellite will smash into a small asteroid ion an attempt to change its orbit. The spacecraft and the name of the NASA mission is DART (Double Asteroid Redirection Test). At 7:14 pm Monday, September 26th, the DART spacecraft will crash into a tiny 525-foot diameter asteroid that’s orbiting a larger asteroid. The target is Dimorphos that is orbiting Didymos. Dimorphos is orbiting Didymos at the slow pace of four tenths of a mile an hour, taking 11.9 hours to orbit it once. The DART spacecraft hit should change that a bit. A cube sat, launched by DART, should witness the event. Radio telescopes using radar should see any effect on the velocity of Dimorphos, to see if it worked.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Schematic of the DART mission shows the impact on the moonlet of asteroid (65803) Didymos. Post-impact observations from Earth-based optical telescopes and planetary radar would, in turn, measure the change in the moonlet’s orbit about the parent body. The DART spacecraft is not to scale with the asteroids. Click on the image to enlarge it. Credits: NASA/Johns Hopkins Applied Physics Lab.

Dart and asteroids to scale with terrestrial landmarks. Click on the image to enlarge it. Credit: NASA/JHUAPL