Artemis 1 Cubesats, Ride-Along Robots Options

[Phil Stooke]

A new thread for a miniature (cubesat) moon lander. OMOTENASHI (a convoluted acronym which is also a Japanese word for 'selfless hospitality) is one of ten cubesats to be launched with Artemis 1, possibly as early as Monday, 29 August 2022 (two days away as i write rhis).

The lander has received little attention because it is really just a technology demonstrator of a method for getting very small objects safely to he lunar surface. Basically, let it come zooming in at 2 km/sec, slam the brakes on with a retro firing just above the surface and then let it fall to a hard but survivable landing. It's not totally dissimilar to the Soviet Union's Luna 9. Luna 13 landing method. Originally it included an airbag but that will not be used now.

This landing demo does no science on the surface, though part of it will will collect some radiation data during approach. The only sign of a successful landing will be radio transmissions for a brief period.

LRO may see evidence of the impact of the cruise module (which is not braked), though it will be small. The landing target is on the nearside limb south of Orientale at roughly 45 south, 75 west (285 east).

Phil

[Phil Stooke]

https://www.jaxa.jp/projects/files/youtube/..._20220826_2.pdf

This document gives the most up to date information (in Japanese). Older reports describe a very low angle approach, but now it will be a steep angle, about 80 degrees. Studies of its trajectory around 2017 all suggested a landing near Mare Crisium but the new trajectory requires a landing near Mare Orientale. The last slide shows the area - a large red ellipse for general (non-date-specific) trajectories and a green circle for launch on 29 August. The change comes from a need to avoid a long period in shadow during approach.

This map shows where that green ellipse is (change of shape caused by map projection). The two larger ellipses are different versions of the general ellipse.

Phil

[Phil Stooke]

A launch on 29 August would have given a landing in darkness. The delay may result in a landing in daylight. Daylight would probably mean more transmission time on the surface, according to documents I have seen, as the battery would be better able to cope. I will post anything I get on site changes.

Here's a link to some amateur radio information.

https://www.isas.jaxa.jp/home/omotenashi/JHRCweb/jhrc.html

and another to a useful document. The second mission will also be of interest.

www.unoosa.org/documents/pdf/psa/activities/2017/SouthAfrica/slides/Presentation21.pdf


Phil

[Phil Stooke]

OMOTENASHI is in space... that's the good news part of this. The bad part is that it is not doing well, tumbling and not communicating, with limited time to correct the problem.

Some other cubesats flown with Artemis 1 are OK, some are not, and they do not correlate with whether or not they were recharged before launch. As I said earlier, Artemis may be outside our area of coverage for UMSF, but the lunar cubesats are presumably OK and we may get some interesting things - impact flashes on the lunar farside from EQUULEUS, infrared observations during a low flyby from LunIR, ice mapping from LunaH-Map, possibly some lunar images from ArgoMoon.

Phil

[Phil Stooke]

OMOTENASHI has now officially lost its opportunity to land and is passing into heliocentric orbit. Attempts to revive it may continue so radiation data can be obtained.

Its companion cubesat, EQUULEUS, successfully entered a very elongated Earth orbit (currently about 80000 km by 650000 km) from which it will maneuver into an EM-L2 halo orbit. It may provide impact flash images of the far side.

Phil

[Phil Stooke]

EQUULEUS has now taken an image of the farside morning terminator:

https://twitter.com/EQUULEUS_ja/status/1595260514695024640

The crater right in the middle is the 68 km diameter Kostinskiy at 14 north, 119 east.

Phil

[Phil Stooke]

Since OMOTENASHI has failed (and I doubt it can be revived, certainly not for a lunar mission) I will use this thread for news of the other cubesats. I have been avoiding the Artemis 1 mission and imaging from Orion because they are part of a crewed mission project, which we don't cover, but the cubesats seem to be reasonable for us here. Orion has cameras which have taken nice images of the Moon,and you can see some of them on the Artemis threads (discusson and update) at NASASPACEFLIGHT.COM.

Here I will post this map showing image coverage (ignoring global views) from Orion, EQUUELEUS and ArgoMoon, the latter two being a Japanese cubesat and an Italian cubesat. Argomoon was built by the same people who did the Liceacubes for DART. The EQUULEUS images were taken with the DELPHINUS camera which is intended to take images of the unlit part of the far side to look for impact flashes.

Phil

[Antdoghalo]

NEA Scout doesn't seem to have made it. Was hoping scout could map another pile of space boulders. Cubesats are probably safe UMSF territory as they are like Galileo or Magellan, piggybacking on inhabited spaceflight.

[nprev]

Ride-along cubesats for planetary exploration launching with crewed missions are absolutely allowed to be discussed here. Topic title changed to reflect this.

[Phil Stooke]

Here are the three images from EQUULEUS (courtesy of JAXA and the mission) fitted together. They overlap very slightly, though a graphic posted by JAXA suggests they don't. EQUULEUS is is a big orbit around the Earth from which it will transition to an orbit around the L2 point above the far side. One of its tasks there is to image the unlit part of the far side to look for impact flashes, something which is routinely done from Earth for our side of the Moon.



And the two ArgoMoon images which overlap considerably, courtesy of the Italian Space Agency. ArgoMoon is in a large elongated orbit about Earth which will encounter the Moon from time to time, giving more imaging opportunities. The long crater chains were originally named after Soviet space research facilities when discovered in Zond 3 images.



Phil

[StargazeInWonder]

Beautiful stuff. The rays in the upper right corner of that ArgoMoon pictures have unusually sharp edges. Interesting to contemplate the circumstances that led to that.

[Phil Stooke]

Looking at that Argomoon image, and some of the media postings about it...

e.g. this:

https://www.facebook.com/ArgotecSpace/posts/584682640324135/

They say the prominent crater with bright rays (and a sector missing rays) is Jackson. It's not - this crater is Ohm. Jackson is similar at a glance but much further east..

StargazeInWonder: if that missing sector is what you are referring to, it is probably caused by the impact being oblique rather than near-vertical. The projectile approached along the central part of the dark sector and ejected material principally downrange and sideways.

Phil

[Phil Stooke]

Image coverage update, showing nearside views from the Orion navigation cameras. See images here (moon images scattered among other mission images):

https://www.flickr.com/photos/nasa2explore/

And this image in particular:

https://www.flickr.com/photos/nasa2explore/52549239085/

must be one of the most spectacular views of the Moon I have ever seen. Aristarchus Plateau on the terminator.

Phil

[Phil Stooke]

The cubesat missions are not over yet. Both EQUULEUS and ArgoMoon are in roughly month-long orbits which will re-encounter the Moon. I have seen two different plans for ArgoMoon, one with 7 lunar flybys (quite high altitude) over 6 months, the other with 2 very high flybys and a third at 5000 km which will permit nice imaging. That last one is in about 6 months, followed by escape to heliocentric orbit. EQUULEUS is in a similar orbit but it will gradually adjust its orbit via many flybys to end up in an L2 halo orbit. It should take more images too.

Phil

[Phil Stooke]

EQUULEUS lives! And recently imaged Comet ZTF:

https://twitter.com/EQUULEUS_en/status/1627864630419931137

Phil