Astrobotic PM-1 mission, CLPS mission with NASA and commercial payloads |
Astrobotic PM-1 mission, CLPS mission with NASA and commercial payloads |
Feb 4 2022, 03:12 AM
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#1
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
I am starting a new thread for this mission which should fly this year.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Feb 4 2022, 09:52 AM
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#2
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
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 |
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Dec 6 2022, 09:25 PM
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#3
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
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 -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 7 2022, 08:09 PM
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#4
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Senior Member Group: Members Posts: 2998 Joined: 30-October 04 Member No.: 105 |
Have we got any sites outlining or detailing the mission or the equipment?
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Dec 7 2022, 08:55 PM
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#5
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
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.] -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Feb 2 2023, 10:44 PM
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#6
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
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 -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Jul 7 2023, 08:16 PM
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#7
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
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 -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 25 2023, 01:53 PM
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#8
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
Launch is now foreseen for Christmas Eve (24-dec)!
https://spacenews.com/ula-sets-christmas-ev...vulcan-centaur/ Thorsten |
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Nov 29 2023, 11:01 PM
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#9
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
https://www.nasa.gov/wp-content/uploads/202...ess-kit-508.pdf
Press kit for the Astrobotic Peregrine Mission 1 launch. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 3 2023, 11:06 AM
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#10
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Member Group: Members Posts: 349 Joined: 20-June 07 From: Slovenia Member No.: 2461 |
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). |
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Dec 3 2023, 05:57 PM
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#11
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
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 -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 3 2023, 11:21 PM
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#12
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Member Group: Members Posts: 349 Joined: 20-June 07 From: Slovenia Member No.: 2461 |
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. |
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Dec 4 2023, 03:59 AM
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#13
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
Ah, yes, so long since I did that, I only remembered the second figure.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 5 2023, 10:26 AM
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#14
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
According to this TwiX
https://twitter.com/SpaceflightNow/status/1...942846130606349 landing will be on January 25. Thorsten |
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Dec 10 2023, 06:28 PM
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#15
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
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 |
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Dec 19 2023, 05:08 PM
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#16
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
-------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 19 2023, 08:06 PM
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#17
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
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. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jan 2 2024, 08:27 PM
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#18
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
https://twitter.com/ulalaunch/status/1742233436457169366
Launch next Monday Jan 8th at 07:18 UTC. Thorsten |
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Jan 8 2024, 08:21 AM
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#19
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Successful launch & TLI, spacecraft AOS just occurred.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Jan 8 2024, 04:15 PM
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#20
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Jan 8 2024, 04:53 PM
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#21
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
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 -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jan 8 2024, 06:35 PM
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#22
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
-------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jan 8 2024, 09:49 PM
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#23
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Member Group: Members Posts: 900 Joined: 15-June 09 From: Lisbon, Portugal Member No.: 4824 |
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 |
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Jan 8 2024, 10:14 PM
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#24
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
Landing almost certainly off the table. 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? |
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Jan 8 2024, 10:31 PM
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#25
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Senior Member Group: Members Posts: 2085 Joined: 13-February 10 From: Ontario Member No.: 5221 |
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....
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Jan 9 2024, 08:05 AM
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#26
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
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 |
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Jan 9 2024, 04:41 PM
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#27
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
Anything known about what caused this propellant leak? 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. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jan 9 2024, 06:55 PM
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#28
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
snip 1) damage during launch vibration (hopefully unlikely since the spacecraft was vibe-tested) snip 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. |
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Jan 9 2024, 07:27 PM
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#29
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
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. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jan 9 2024, 10:29 PM
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#30
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IMG to PNG GOD Group: Moderator Posts: 2250 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
From the latest update from Astrobotics:
QUOTE ...There is no indication that the propulsion anomaly occurred as as result of the launch.
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Jan 9 2024, 11:01 PM
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#31
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
...3) pressure regulator failure leading to overpressurization. Astrobotic is now saying QUOTE Astrobotic’s current hypothesis about the Peregrine spacecraft’s propulsion anomaly is that a valve between the helium pressurant and the oxidizer failed to reseal after actuation during initialization. This led to a rush of high pressure helium that spiked the pressure in the oxidizer tank beyond its operating limit and subsequently ruptured the tank. 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.) -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jan 10 2024, 05:45 PM
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#32
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Senior Member Group: Members Posts: 2085 Joined: 13-February 10 From: Ontario Member No.: 5221 |
https://www.astrobotic.com/update-10-for-pe...ne-mission-one/
QUOTE Peregrine has been operational in space for 55 hours. We are at an approximate distance of 192,000 miles from Earth, which is 80% of the way to lunar distance. Although we are approaching lunar distance, the Moon won’t be there. We remain on our nominal trajectory for the mission, which includes a phasing loop around Earth. This loop goes out to lunar distance, swings back around the Earth, and then cruises out to meet the Moon. This trajectory reaches the Moon in about 15 days post-launch.
Peregrine continues to leak propellant but remains operationally stable and continues to gather valuable data. We estimate that we will run out of propellant in about 35 hours, an improvement on yesterday’s update. The team is working around the clock to generate options to extend the spacecraft’s life. |
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Jan 11 2024, 07:32 AM
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#33
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
https://twitter.com/tony873004/status/1745274757417931128
This tweet (or whatever you call it these days) predicts a lunar impact on the second apogee. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Jan 11 2024, 08:35 AM
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#34
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
> This tweet (or whatever you call it these days)
I call it "TwiX" Thorsten |
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Jan 11 2024, 06:44 PM
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#35
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Member Group: Members Posts: 401 Joined: 5-January 07 From: Manchester England Member No.: 1563 |
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>
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Jan 12 2024, 04:22 AM
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#36
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Senior Member Group: Members Posts: 2085 Joined: 13-February 10 From: Ontario Member No.: 5221 |
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... |
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Jan 12 2024, 09:31 AM
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#37
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
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 |
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Jan 12 2024, 02:34 PM
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#38
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
QUOTE 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.) 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. QUOTE I wonder if they still have enough control to do minor trajectory corrections. 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? |
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Jan 12 2024, 03:08 PM
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#39
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Senior Member Group: Members Posts: 2085 Joined: 13-February 10 From: Ontario Member No.: 5221 |
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? |
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Jan 12 2024, 03:39 PM
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#40
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
Well, there's no functioning seismometers on the moon at the moment to benefit, so that's a bit of an issue. 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? |
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Jan 12 2024, 06:43 PM
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#41
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Solar System Cartographer Group: Members Posts: 10160 Joined: 5-April 05 From: Canada Member No.: 227 |
Scott Tilley has an impact prediction:
https://twitter.com/coastal8049/status/1745668952754389197 The current estimated location is near Luna 13 in Oceanus Procellarum. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Jan 12 2024, 07:56 PM
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#42
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Senior Member Group: Members Posts: 2085 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Some (marginally) better news.
QUOTE Peregrine has now been operational in space for more than 4 days. The spacecraft remains stable and operational, and is currently in a planned loss-of-signal period for about another hour and a half. The leak rate on Peregrine has continued to slow, and the spacecraft is estimated to now have 52 hours of propellant remaining. Our engineers continue to work on solutions to extend life expectancy and there is growing optimism that Peregrine could survive much longer than the current estimate. 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.... |
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Jan 13 2024, 09:14 PM
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#43
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Member Group: Members Posts: 219 Joined: 14-November 11 From: Washington, DC Member No.: 6237 |
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.
And of course, between the time I started plotting and when I post this, now they're projecting to hit the Earth. Ah well. |
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Jan 13 2024, 09:26 PM
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#44
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Member Group: Members Posts: 219 Joined: 14-November 11 From: Washington, DC Member No.: 6237 |
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 |
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Jan 14 2024, 01:16 AM
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#45
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
eventually have caught up and overall each improvement was been greater than the proportional loss during the time between updates 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? |
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Jan 14 2024, 05:58 PM
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#46
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
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. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jan 14 2024, 06:09 PM
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#47
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Member Group: Members Posts: 611 Joined: 23-February 07 From: Occasionally in Columbia, MD Member No.: 1764 |
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.) 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..... |
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Jan 15 2024, 12:30 PM
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#48
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
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 |
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Jan 19 2024, 08:57 AM
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#49
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Member Group: Members Posts: 123 Joined: 3-September 12 From: Almeria, SE Spain Member No.: 6632 |
"Peregrine appears to have reentered [Jan 18] around 2059 UTC as predicted"
https://twitter.com/planet4589/status/1748110238664802317 Thorsten |
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Jan 20 2024, 08:07 PM
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#50
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Senior Member Group: Members Posts: 2085 Joined: 13-February 10 From: Ontario Member No.: 5221 |
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/ |
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Jan 29 2024, 04:58 AM
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#51
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Newbie Group: Members Posts: 1 Joined: 17-January 24 Member No.: 9314 |
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..... Isn’t it usual to use a pyrotechnic valve to isolate the He tank? Solenoid valves present the risk of valve bounce during periods of very high vibration during the launch; the valve stem lifts off the seat. The pyrovalve provides a hermetic seal until the charge is ignited, so it ensures zero leakage during the launch phase and is only fired when that is complete. I know that the thrusters on the mission have no previous flight heritage; I’m wondering whether other fluid-flow components in the propulsion system also lack heritage. Ed |
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Jan 29 2024, 06:54 AM
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#52
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Senior Member Group: Members Posts: 2516 Joined: 13-September 05 Member No.: 497 |
Isn’t it usual to use a pyrotechnic valve to isolate the He tank? Solenoid valves present the risk of valve bounce during periods of very high vibration during the launch; the valve stem lifts off the seat. The pyrovalve provides a hermetic seal until the charge is ignited, so it ensures zero leakage during the launch phase and is only fired when that is complete. Of course. The Peregrine leak only started after the Triton Space pyrovalves were fired. They apparently worked fine and the issue was downstream. QUOTE I know that the thrusters on the mission have no previous flight heritage; I’m wondering whether other fluid-flow components in the propulsion system also lack heritage. Possibly not, but heritage only goes so far. The components on Cassini and Juno had tons of heritage, but that didn't keep them from misbehaving. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Lo-Fi Version | Time is now: 13th May 2024 - 03:30 AM |
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