Lucy, Discovery Mission 13 - a grand tour of the Jupiter Trojans Options

[Floyd]

I also watched the launch this morning--it is always breathtaking. I understand the huge solar panels unfolded properly.

[Tom Tamlyn]

The best general media article I’ve run across concerning the Lucy Mission is this one in the New York Times. (I assume it’s paywalled, although the NYT is a little more generous with free articles than it was.)

https://www.nytimes.com/article/nasa-lucy-t...-asteroids.html

The article is nicely written, features some particularly good graphics, and most importantly, feels more comprehensive than is typical for the twenty-first century NYT science section.

This was a mild surprise. I’m a life-long reader and admirer of the New York Times science desk. However, since the MER rover missions renewed and intensified my interest in planetary science in 2004, I’ve frequently felt that the NYT’s fine writers were not allowed enough ink to do do justice to planetary missions. I began to rely much more on specialist journals and online sources, especially Emily Lakdawalla, and particularly during her time at the Planetary Society, and of course this forum.

The article's author, David W. Brown, is a freelancer who has apparently just published a book on the Europa Clipper mission with the following title:

THE MISSION, or: How a Disciple of Carl Sagan, an Ex-Motocross Racer, a Texas Tea Party Congressman, the World's Worst Typewriter Saleswoman, California Mountain People, and an Anonymous NASA Functionary Went to War with Mars, Survived an Insurgency at Saturn, Traded Blows with Washington, and Stole a Ride on an Alabama Moon Rocket to Send a Space Robot to Jupiter in Search of the Second Garden of Eden at the Bottom of an Alien Ocean Inside of an Ice World Called Europa (A True Story)

I'm not a fan of goofy long book titles that don't include useful search terms in the first few words, or in this case, anywhere at all, but on the strength of Brown's article about Lucy, I'm going to read his book.

[Explorer1]

I posted a minor review of the audiobook in the Europa Clipper thread: http://www.unmannedspaceflight.com/index.p...st&p=251818
He's a good writer, though naturally he can only write about non-confidential subject matter, so he is limited to some degree.

[stevesliva]

Re: NYT: this reads like a Science Tuesday section front page, and that's where I'd expect to see it in print.

[JTN]

Hmmm. Since this Atlas launch will be without any SRBs, a couple of shock diamonds might be just barely visible in the far end of the exhaust of the rocket.

I think this tweet (direct image link) might show such.

Also, the Spaceflight Now article has "A tiny diamond buried deep inside the L’TES spectrometer acts as a beam splitter".

[Decepticon]

https://spacenews.com/nasa-investigating-is...cy-solar-array/

[Explorer1]

They're optimistic that it's not a major issue: RCS thrusters worked already, main change has been a delay in deploying the instrument platform:

https://spaceflightnow.com/2021/10/18/nasa-...lar-array-snag/
EDIT: More details, directly from the team:
https://blogs.nasa.gov/lucy/2021/10/19/nasa...s-solar-arrays/

[Hungry4info]

Lucy update. We're now in cruise mode, with the instrument platform deployed. They're going to turn the spacecraft to various attitudes to try to use the current measurement from the stuck array to determine how far it deployed to better inform how to fix it. https://scitechdaily.com/nasa-issues-update...ay-problem/amp/

[Explorer1]

https://blogs.nasa.gov/lucy/2021/10/27/lucy...in-cruise-mode/
Next attempt to fully deploy no earlier than November 16th. Instrument checkout going on as planned, some minor manouvers have been completed.
Array is 75 - 95 % deployed, team estimates.

[lcs]

Something similar happened on Galileo. Possible explanation?

https://www.mdpi.com/2075-4442/9/8/72?type=...e&version=2

[stevesliva]

The mechanisms are different, and Galileo was in storage for too many years.

The status report above mentions a 'lanyard'. There is a timelapse video from a deployment test here: https://www.youtube.com/watch?v=6vjK9vGEw5Q

My guess is that the lanyard they mention is seen here. It starts pulling around the fulcrum at the center of the array, and then pulls across the screen, and then is off screen.

[Explorer1]

Lucy was never in storage for an extended period due to delays. I'm sure they're thinking over every possibility. Although we all hope the array finishes deploying, I have been thinking that if this isn't fixed by the time of the Earth flyby next year, the low altitude combined with the size of the arrays, might make it possible to resolve the stuck array directly with Earth-based imagery?

[mcaplinger]

...possible to resolve the stuck array directly with Earth-based imagery?

See https://www.jpl.nasa.gov/nmp/st8/tech_paper...20NGU%20ST8.pdf for some information about how Ultraflex arrays work (BTW, ST8 never flew as far as I know). I don't know what kinds of position information or other telemetry (e.g., motor current) they get during deployment. What's been said suggests that all they get is a single binary flag showing full latching, but I doubt that's true.

It's not at all obvious to me if images, especially ground-based, would be of any use whatsoever to fixing the problem. The TTCAM cameras could in theory produce out-of-focus images of the spacecraft, but I don't know if their placement and platform articulation would allow anything useful of the panel (links to a paper on those cameras upthread.)

There's a lengthy, mostly off-topic discussion of this at https://forum.nasaspaceflight.com/index.php?topic=46685.0 if you're into that kind of thing.

[JRehling]

An object 300 km from a telescope on the ground might enable imagery with resolution as good as about 10 cm per pixel… but that assumes a lot, including good weather at the sub-spacecraft point, which is completely beyond anyone's control or ability to predict, as well as two geometric factors that are knowable in advance, but not known to me: Will the spacecraft be near closest approach over land vs. the 70% of Earth that is water, and will the spacecraft be in sunlight at the time of closest approach, but not lost in daylight? This all sounds well below 50% probability, but not impossible.

[mcaplinger]

An object 300 km from a telescope on the ground might enable imagery with resolution as good as about 10 cm per pixel…

Color me skeptical that this is 1) possible or 2) useful, but feel free to check out the geometry -- the best trajectory info so far is https://naif.jpl.nasa.gov/pub/naif/LUCY/ker...-TCM36-P_v2.bsp