a 135-images Mastcam-Z survey documenting the Bright Angel outcrops

by the Mars rover Perseverance
June 12, 2024 (Sol 1177)
Credit images: NASA/JPL-Caltech/ASU

#Perseverance #Mars #Sol1177 #BrightAngel #outcrop #outcrops #geology #rover #PerseveranceRover #science #STEM #NeretvaVallis #Neretva #Valley #NASA #JPL #Caltec #ASU #space #Astrodon

Hey, Press! Let's talk about your reporting of very early engineering science.
This is a prime example, because the (German) press article is basically a translation of the Caltec press release which lacks a couple of very important pieces of information.
⚠️ An btw, this is also a critique towards #Caltec who in their press release do not link any scientific publication, which is generally pretty misleading to start with.

But what is known? A relatively quick search does like this:

1️⃣ Type "MAPLE" and "SSPD-1" into Google Scholar and find just a few publications. What does this tell you as a journalist? This is early tech, not very mature and many, many open questions. This puts the introducing sentence into perspective.

2️⃣ Check out the ones from renowned journals, like IEEE MTT rather than some (potentially pretty small) conferences. Not much to find here, btw. except maybe [2] and [3]. Also, check for exhaustive Arxiv articles that match publications in renowned journals if you don't have access to them [1].

That's it. You'll read a few more pages, but you can speed up your reading by starting with the "Conclusion" section of each article (yeah, weird to start from the end, right?).

So, what info is missing and/or misleading?

From this long piece uploaded to Arxiv [1], you can find that:

🅰️ The end-to-end efficiency of this proposed system is a mere 7-14%. And that assumes previously published top-results, not the expected efficiencies after technical realisation which tend to be no quite top-efficiency. Just a reminder: Cheap ground-based PV achieves ~22% peak at the moment. Grid rectifiers ~80% give or take. And that's right into the grid, no some 100 km RF transmission through the atmosphere...
🅱️ That the around-the-clock solar power claim is shaky to say the least: Earth tends to block the sun on its night side and so it does in space (i.e. for a satellite). Efficiency drops under oblique angles (both PV and RF antenna). And there is one more catch: The assumed efficiencies seem to include a double sided antenna/PV including RF transparent PV and PV transparent RF (or else: even less efficiency). Well, you can flip the craft and avoid that, but again: fuel.

So, phrases like
"Space solar power provides a way to tap into the practically unlimited supply of solar energy in outer space, where the energy is constantly available without being subjected to the cycles of day and night, seasons, and cloud cover—potentially yielding eight times more power than solar panels at any location on Earth's surface."
tend to boil down significantly:

Seasons and cloud cover are things we can circumvent by the very, very conventional technology of: cables.

Nights can be bridged by several technologies under investigation of decades (hydropower, molten salt storage, or again: long cables).

I'm not saying they shouldn't do research on this or that the published work is bad. It's just a very long way to maturity outside the lab (or a demonstrator on a test satellite). Getting on an actual flight and testing in orbit is quite impressive. But it's only that: an impressive engineering feat.

What it's not proven to be: economically or commercially viable.

But the bottom line is: Just copying university press releases (or translating them to the local language) is a bit lazy for journalism.

[1] https://arxiv.org/abs/2206.08373
[2] https://ieeexplore.ieee.org/document/8547403
[3] https://ieeexplore.ieee.org/abstract/document/9926883
QT: https://social.heise.de/@heiseonline/110490774491533237