I am starting a new thread for this mission which should fly this year.

Phil

Peregrine will be the payload of the maiden flight of ULA's Vulcan rocket.
So the date will depend on when the rocket is ready (assuming the lander is completed first).


Thorsten

https://twitter.com/SpcPlcyOnline/status/1600228326198677534

This tweet shows the PM1 mission landing site near the Gruithuisen domes. It had been targeted at Lacus Mortis since the GLXP days, over a decade ago. Interesting!

The lander is now in the final testing phase before shipping to the launch site. That is a few months away yet, probably. Spacecraft and launcher have been trading places as the pacing item for this mission for years. Right now it looks like the launcher is pretty much ready, but it's never certain to the outside world.

Phil

Have we got any sites outlining or detailing the mission or the equipment?

Not a lot of info AFAIK. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/...on?id=PEREGRN-1 and https://nssdc.gsfc.nasa.gov/nmc/spacecraft/...aftId=PEREGRN-1 has a summary of the spacecraft and instruments. I presume the lander itself has some kind of camera but the payload doesn't appear to.

[edit: https://www.astrobotic.com/lunar-delivery/manifest/ has some information about non-NASA payloads. Note that it still gives Lacus Mortis as the landing site.]

https://blogs.nasa.gov/clps/2023/02/02/new-...robotic-flight/

The new site is made official in this NASA CLPS blog post. Not specifically identified, however, but it's on the mare near the domes, not on top of a dome as the future CLPS lander will be.

It has been named "Sinus Viscositatis" (Sticky bay) probably in reference to the viscous lavas which built the nearby domes.

https://astrogeology.usgs.gov/news/nomencla...us-viscositatis

Phil

This is the landing site for Astrobotic PM1 in Sinus Viscositatis. The site was specified in a Planetary Science Advisory Committee presentation recently.

Presentation: https://www.lpi.usra.edu/pac/presentations/...earns-Noble.pdf

Phil

Click to view attachment

Launch is now foreseen for Christmas Eve (24-dec)!
https://spacenews.com/ula-sets-christmas-ev...vulcan-centaur/

Thorsten

https://www.nasa.gov/wp-content/uploads/202...ess-kit-508.pdf

Press kit for the Astrobotic Peregrine Mission 1 launch.

Phil

Click to view attachment

My version of Phil's landing map above, color coded with elevation. There is about 3000 m difference in height between highest and lowest points in the selected area.
The region was also studied in Apollo era, green landing ellipses showing sites selected on the base of Lunar Orbiter 5 photography (of course nothing ever landed there in the end).

Great map, thanks. I had only seen some of the smaller Apollo sites in the past. Where did you find these? I would love to see the source.

Phil

Thank you Phil. The source might be very familiar to you since is you who wrote the book.
Figures 149 & 162 with a bit of artistic license. Smaller ellipses are really r=1.5 km circles at this latitude, the three real ellipses are standard Apollo ellipses 7.9 x 5.3 km.
For the context here is the area in question framed by Lunar Orbiter site V-45.1 photo footprint.

Click to view attachment

Ah, yes, so long since I did that, I only remembered the second figure.

Phil

According to this TwiX
https://twitter.com/SpaceflightNow/status/1...942846130606349
landing will be on January 25.

Thorsten

According to this TwiX from Tory Bruno
https://twitter.com/torybruno/status/1733907494030688486
the launch is postponed to the 08 of January.
This means no triple landing mid January.

Thorsten

https://twitter.com/astrobotic/status/1737123176336048282

Landing on February 23rd!

Phil

Fingers crossed. But FWIW, I am certainly not holding my breath for this launch, which seems likely to slip even more, for Vulcan-related reasons if nothing else.

I also think it's amusing that the photo in the tweet makes it look like Peregrine only barely fits in the fairing, when in reality it is lost in all of that volume.

https://twitter.com/ulalaunch/status/1742233436457169366

Launch next Monday Jan 8th at 07:18 UTC.

Thorsten

Successful launch & TLI, spacecraft AOS just occurred.

Agh. Serious anomaly. Hopefully it will be resolved, and right soon.

Sounds like a stuck thruster or bad prop system leak. Fingers crossed but it is not sounding good at all.

https://twitter.com/astrobotic/status/1744389634568724791

Landing almost certainly off the table.

Click to view attachment

Astrobotic has been publishing news reports on the Peregrine-1 status.

Report #5 has the following image:




Here is the link to the news page https://www.astrobotic.com/category/press/


______________________________________________________
Fernando

Curious, not a snarky question, but what sort of TLI are they on, and where do they end up (making the unwarranted assumption that they can even get star tracker telemetry while outgassing) Any idea whether "Landing diagram" plots out to be a lunar splat, Earth atmosphere burnup, or stuck in a chaotic orbit?

Glad to see that they're still getting data, understand that it's heart dropping outcome for the PI & post docs, but perhaps then can get some telescope time / citizen science for 'rapid unscheduled spectroscopy' from the ejecta of a lunar splat or atmospheric reentry?

The Vulcan took it to TLI, but they were planning on several other burns to refine. Whether they pass the Moon and at least conduct some science (like a few of the Artemis cubesats) and where it will go afterward is still unknown....

Update #6:
"An ongoing propellant leak [...]"
"[...] in a stable sun pointing state for approximately 40 more hours, [...]"
https://twitter.com/astrobotic/status/1744543629392134194

Anything known about what caused this propellant leak?

Thorsten

I haven't heard anything, and there is not much public detail about Peregrine's propulsion system. But it started right after the system was pressurized and was large enough to disturb blankets. I can think of three root causes: 1) damage during launch vibration (hopefully unlikely since the spacecraft was vibe-tested); 2) propellant migration causing a small explosion that blew a hole in the plumbing; 3) pressure regulator failure leading to overpressurization. Assuming https://www.nasa.gov/stmd-game-changing-dev...in-space-talos/ describes what they ended up flying, the main engines were MON-25/MMH biprops but how the attitude-control thrusters (presumably monoprops) were tied in, I have not seen.

I wonder if there might be an unexpected resonance- e.g. when the SpaceX Falcon Heavy launches from Kennedy Space Center, the Vehicle Assembly Building 'squeals' because it randomly has a resonant frequency with the Merlin engine exhaust.
Sorta makes sense that the first actual lift off a brand-new rocket is when you actually find out about the sounds and launchpad acoustics.

Normally all of that is determined by analysis and then the testing is done with a lot of extra margin to cover all uncertainties. https://blogs.sw.siemens.com/simcenter/spac...oustic-testing/

And it's not like Vulcan is that different than Atlas in that regard.

What is a little odd is that Peregrine was supposed to be launched with two prototype Kuiper satellites, but after all of the delays, those were launched separately. There didn't seem to be any place to put them on the Centaur, but it seems implausible that they changed the configuration enough to impact Peregrine unfavorably.

If Astrobotic decides this was a vibe-induced failure, I'm sure there will be some finger-pointing.

From the latest update from Astrobotics:

Astrobotic is now saying



This seems odd to me, since usually such a valve would open just once and then a downstream regulator would maintain system pressure at the desired safe level. But it sounds like they tried to avoid needing a regulator by just burping the valve open briefly (in hindsight maybe not such a good idea.)

https://www.astrobotic.com/update-10-for-pe...ne-mission-one/

https://twitter.com/tony873004/status/1745274757417931128

This tweet (or whatever you call it these days) predicts a lunar impact on the second apogee.

Phil

> This tweet (or whatever you call it these days)
I call it "TwiX"
Thorsten

Jeff Foust reports that nine of the payloads are powered, and data is being collected - relating to how they operate in the space environment, not regarding the Moon, obviously - but that's still valuable for the payload teams. Article here: <a href="https://spacenews.com/astrobotic-gets-payloads-working-on-ailing-peregrine-lander/" target="_blank">https://spacenews.com/astrobotic-gets-paylo...regrine-lander/</a>

Great to see transparency from Astrobotic; Update #13 shows even another rover is functional.

They must all be glad that the other systems seem to be working perfectly, even though it's a pity the best they will be is impact probes (if that is in fact the trajectory). Would be an interesting target for LRO and yet another mark (or marks) on Phil's maps...

I wonder if they still have enough control to do minor trajectory corrections.
Because in this case, maybe they could "choose" if the probe impacts the Moon, falls back on Earth, remains in a high orbit around Earth, or enters into orbit around the Sun.
I'm also not sure which one of these options would be the most desirable. (Thinking in particular what should happen to the ash they have on board.)

Thorsten

That valve trouble sounds similar to Apollo 6, which was damaged due to valves opening and causing \'pogo\' shockwaves / water hammer effects in the piping.


I wonder if the rover\'s battery capacity could be tapped to extend the mission\'s data collection, ala Apollo 13?

If there rover battery is isolated, then try and deploy the rover, perhaps the existing spin could launch the rover into a slightly different trajectory?
You wouldn\'t change the distance much, but perhaps get enough separation to generate \'stereo impacts\' for seismic monitoring?

PostScript- looks like the lander is exposed to space and could be let loose?

Well, there's no functioning seismometers on the moon at the moment to benefit, so that's a bit of an issue.
I do agree that the payloads that can be released, may as well be. There is nothing to lose, is there?

Yep, that's a problem.
Hmm, I thought somebody had gotten seismic data in recent years using the old Apollo laser retroflector array (LRA)... or perhaps I'm misremembering, and it was just modern re-analysis of old Apollo data.

But, "if you knew the impact time in advance, could the existing array of Apollo laser retroreflectors be used to obtain usable seismic data, extracted from the jitter of the laser signal?" seems like an interesting nerdy question, (or homework for a graduate physics course).
But to GET that level of precision on impact time, you'd have to get precise measurements of Peregrine's trajectory. Probably, the range & orbit can be roughly calculated based on loss of signal going behind the moon / reacquisition of signal upon emergence?
Fortunately, IIRC Peregrine does have a next-gen laser retroreflector mounted on its deck, so perhaps it would be possible to use the retroreflector to get more precise distance and angle measurements over time? Then use that prediction of impact time to turn on ranging lasers and see if the Apollo LRA shows any jiggle.

Who knows, perhaps the Psyche laser communication cat-video could be reused to paint the lunar LRA during predicted impact? (Quick review) as a rough guess, a 267 megabit per second laser signal SEEMS like it should contain enough information to identify signal jitter caused by from siesmic events shaking the LRA?

Scott Tilley has an impact prediction:

https://twitter.com/coastal8049/status/1745668952754389197

The current estimated location is near Luna 13 in Oceanus Procellarum.

Phil

Some (marginally) better news.

EDIT Dec 13:

Lunar distance achieved, teleconference with NASA set for Thursday.
Some more optimism about extending the life of the lander, and certainly a major milestone just to get this far. I am reminded of Philae's many difficulties 10(!) years ago, and the sudden imposition of a time limit. If the various payloads can be tested as much as possible regardless of the impossibility of soft landing, that is still quite an achievement. Perhaps the rovers can be released, even if it's futile....

Been thinking about ways to visualize the evolving fuel situation, and whether it was converging towards anything or otherwise showing trends. I thought of two ways.

• First version plots the projected zero-fuel time vs the update time, alongside a reference "out of time" line (where y=x). Some linear trendlines indicate that initially they weren't improving faster than the leak. But eventually have caught up and overall each improvement was been greater than the proportional loss during the time between updates (dy/dx > 1). But that should probably be interpreted in light of a presumably ~exponential decay...
• Second illustration tries to show that a little more directly. At each update timestamp I draw a line* to zero after the stated number of hours. Initial "fuel" value at time of anomaly report (update #1) arbitrarily set to 100, projecting backwards using slope from following update (#6, which was the first one with a time estimate). *N.B: may make more sense to think of y-axis like log(remaining fuel)? Not sure if that distinction makes a difference anymore...

And of course, between the time I started plotting and when I post this, now they're projecting to hit the Earth. Ah well.
Click to view attachment Click to view attachment

In case anyone cares to not re-do the tabulation, here's the values I used.

CODE

Update #, Update Timestamp, Stated Remaining Hrs, Est Zero Fuel Time
14    2024-01-12 11:52    52    2024-01-14 15:52
13    2024-01-11 19:01    48    2024-01-13 19:01
11    2024-01-10 18:35    36    2024-01-12 06:35
10    2024-01-10 10:56    35    2024-01-11 21:56
7     2024-01-09 12:17    40    2024-01-11 04:17
6     2024-01-08 21:16    40    2024-01-10 13:16
1     2024-01-08 09:37    n/a

Well, I'd suspect that a stuck valve works both ways. Which suggests that there is now a helium & NO/NO4 froth filling the oxidizer and pressurant tanks. Which might not be so bad, having some liquid in the pressure tank might have helped to close the wonky valve.

The analogy I think of is just cracking open a warm 2 litre bottle of soda- you get an initial blast of carbonated water, but that quickly subsides and what mostly escapes the opening (here the cracked tank) is the gas, not so much the liquid.

Perhaps the trick here would be figuring out a way for 'ullage thrust' to push the "flat soda" oxidizer (and fuel) into the engine for a burn attempt?

Without a schematic of the propulsion system, it's really difficult to intuit what may be happening. Having done a little digging, apparently even the ACS thrusters are biprop (MMH doesn't work as a monopropellant, the spacecraft I'm familiar with that used dual-mode monoprop/biprop used pure hydrazine.)

Normally the large pressure gradient between the helium tank and the rest of the system would prevent any migration back into the helium tank, but if the pressure is equalized then all bets are off. Systems that aren't so mass-constrained have one-way check valves to keep migration from happening anyway (see Figure 1 in https://www.researchgate.net/publication/23...ion_Performance ) but it seems that Peregrine cut out anything that wasn't absolutely required.

Cassini operated this way. I mean, it wasnt designed to operate this way (see my Haynes Cassini-Huygens Owners Workshop Manual) - it had a regulator, but somehow the regulator stuck open with a high leak rate - not enough to pop the propellant tank right away, thankfully, so the operators were able to close the upstream latch valve (which turned out to have a rather lower leak rate than specc'd, fortunately) and burped it later to maintain the ullage pressure as the fuel depleted. Sounds like Peregrine jumped to that approach - higher risk, but simpler/lighter

Biprops are hard to get right - a lot of failures/anomalies attributable to this piece of the system - Mars Observer, Akatsuki, Cassini, JUNO.....

Latest update, very detailed and interesting:
https://www.astrobotic.com/update-17-for-pe...ne-mission-one/

The probe will burn up deliberately in Earth's atmosphere on Thursday evening (UTC) over the Great Barrier Reef.
https://twitter.com/tony873004/status/1746288506509684988

Thorsten

"Peregrine appears to have reentered [Jan 18] around 2059 UTC as predicted"
https://twitter.com/planet4589/status/1748110238664802317

Thorsten

Some poignant video footage has been released, separation of the lander from the upper stage, and the Iris rover spinning its wheels in the vacuum. The CMU students can take heart in their rover working to the moon and back, even if they couldn't land.
https://www.astrobotic.com/final-update-for...ne-mission-one/