Tianwen-1 At Mars |
Tianwen-1 At Mars |
Mar 26 2021, 11:23 AM
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#31
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Member Group: Members Posts: 185 Joined: 4-January 19 Member No.: 8523 |
New Photos from medium-res camera. Detail of mars tiny limb.
https://mobile.twitter.com/AJ_FI/status/1375401463682306051 -------------------- "The Earth is a very small stage in a vast cosmic arena"
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Apr 4 2021, 10:59 AM
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#32
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Member Group: Members Posts: 349 Joined: 20-June 07 From: Slovenia Member No.: 2461 |
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Apr 4 2021, 11:01 AM
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#33
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Member Group: Members Posts: 349 Joined: 20-June 07 From: Slovenia Member No.: 2461 |
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Apr 4 2021, 09:37 PM
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#34
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
Very nice maps! Once we are safely down I will start a map thread and these can be the first posts.
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 PDF: 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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Apr 5 2021, 03:40 AM
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#35
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Member Group: Members Posts: 122 Joined: 19-June 07 Member No.: 2455 |
A close-up of the central area. Once the mapping thread for the mission is established the maps can be moved there. Wow, that's a gutsy first landing given how tough it is just to set down safely on a Martian surface with almost no obstacles and they are aiming for a spot adjacent to a rather scary looking crater. Wouldn't take much during that 7 minutes or so of "terror" timing to be off by a significant amount. I wonder how much hover and maneuver time they have built into the lander to be able to spot and avoid large obstacles at the last minute. |
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Apr 5 2021, 10:27 AM
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#36
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Member Group: Members Posts: 241 Joined: 13-October 09 From: Olympus Mons Member No.: 4972 |
There are also a lot of pseudocones and lava wrinkles/channels in the landing ellipse too.
-------------------- "Thats no moon... IT'S A TRAP!"
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Apr 5 2021, 02:56 PM
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#37
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Member Group: Members Posts: 706 Joined: 3-December 04 From: Boulder, Colorado, USA Member No.: 117 |
Given the size of the landing ellipse, there's very little chance of landing next to that crater right in the center of the ellipse. I suspect it's just coincidence that the ellipse center is on the rim of that crater.
John |
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Apr 5 2021, 03:18 PM
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#38
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
Yeah - the landing ellipse is almost certainly larger than that entire image.
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Apr 5 2021, 08:46 PM
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#39
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Member Group: Members Posts: 349 Joined: 20-June 07 From: Slovenia Member No.: 2461 |
I guess there are many uncertainties, but this map is a start, based on limited data available.
Landing ellipse could certainly be bigger, I got 100x40 km from Twitter source, so far from 100% reliable. Couldn't find this information in any Chinese source to confirm it's really true. The landing coordinates precision (24,748N, 110,318E) by itself carries about 100 meters imprecision in any direction. CTX camera images are also not absolutely referenced, although I did check different images to confirm that the coordinates really work out to be at crater's rim. On the other hand the two high resolution images published so far do show area at the center of the map, so they could be working towards landing near the center of the ellipse. And thank you Phil. It is always nice to get encouraged by the best. |
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Apr 19 2021, 04:45 PM
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#40
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Member Group: Members Posts: 559 Joined: 1-May 06 From: Scotland (Ecosse, Escocia) Member No.: 759 |
Apollo 12 in 1969 was trying to land close to the dead Surveyor 3 craft, which was located inside a sizeable lunar crater with internal slopes which could not be landed on safely. So the Commander asked the navigation team to target him directly at Surveyor, on the basis that, due to landing errors, this was the best way to AVOID hitting Surveyor or descending inside its crater! The same rationale might apply here -- aim for the place that you least want to arrive at, in the sure knowledge that actually getting there is extremely unlikely!
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Apr 19 2021, 07:07 PM
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#41
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Member Group: Members Posts: 559 Joined: 1-May 06 From: Scotland (Ecosse, Escocia) Member No.: 759 |
Apollo 12 in 1969 was trying to land close to the dead Surveyor 3 craft, which was located inside a sizeable crater with internal slopes which could not be landed on safely. So the commander asked the navigation team to targeted him directly at Surveyor, on the basis that, due to landing errors, this was the best way to AVOID hitting Surveyor or decending inside its crater! The same rationale might apply here -- aim for the place that you least want to arrive at, in the sure knowledge that actually getting there is extremely ulikely!
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Apr 20 2021, 07:32 PM
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#42
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Member Group: Members Posts: 155 Joined: 8-February 04 From: Phoenix, AZ USA Member No.: 9 |
Apollo 12 in 1969 was trying to land close to the dead Surveyor 3 craft, which was located inside a sizeable crater with internal slopes which could not be landed on safely. So the commander asked the navigation team to targeted him directly at Surveyor, on the basis that, due to landing errors, this was the best way to AVOID hitting Surveyor or decending inside its crater! The same rationale might apply here -- aim for the place that you least want to arrive at, in the sure knowledge that actually getting there is extremely ulikely! This phenomena played a role in the plot of the novel Gravity’s Rainbow by Thomas Pynchon, wherein the German V-2 engineers would observe the impacts of ballistic rocket tests from the center of the targeted bullseye. -------------------- Tim Demko
BioLink site |
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May 10 2021, 02:31 PM
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#43
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Member Group: Members Posts: 185 Joined: 4-January 19 Member No.: 8523 |
We are entering the week distance window of the estimated landing date (17/may), from 10/may till 24/may.
As expected no info, but if they continue with the estimated dates, soon they will try the landing. https://www.uol.com.br/splash/noticias/afp/...-afp-7-dias.htm AFP international news for 7 days, land probably before May 15. "China's Tianwen-1 mission getting set to try and land Zhurong rover on Mars" https://www.abc.net.au/news/science/2021-05...nding/100101552 -------------------- "The Earth is a very small stage in a vast cosmic arena"
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May 12 2021, 10:11 AM
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#44
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Member Group: Members Posts: 149 Joined: 18-June 08 Member No.: 4216 |
I don't think the entry module will be "detaching from an orbiter 70 kilometres above the surface", that's already in the atmosphere!
Instead it would be detaching from the orbiter somewhere along the orbit, the question is then how to change the entry module orbit to intersect the atmosphere. For Viking, the entry module carried its own propulsion system for this purpose. |
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May 12 2021, 10:33 AM
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#45
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Member Group: Members Posts: 185 Joined: 4-January 19 Member No.: 8523 |
Indeed not less than 200km at periapsis. Timing for Zhurong to start its landing maneuver, in UTC, by Edgar Kaiser, based on the orbiter periapsis and time over the landing guessed coordinates on Utopia Planitia:
Mars in sight over China 2021.05.10 20:33:02 SKIPPED 2021.05.12 21:47:53 SKIPPED Mars off sight over China 2021.05.14 23:02:44 DATE OF LANDING, BY SOURCE QUOTING CAST (by Cosmic_Penguin) 2021.05.17 00:17:35 2021.05.19 01:32:26 Mars in sight over China 2021.05.21 02:47:17 In sight with Jiamusi Antenna: https://en.wikipedia.org/wiki/Chinese_Deep_Space_Network 2021.05.23 04:02:08 2021.05.25 05:16:59 Last periapsis on May: 27/05/2021 06:31 29/05/2021 07:46 Date of Landing, by a source quoting CAST: https://twitter.com/Cosmic_Penguin/status/1...701561030123521 More from Edgar Kaiser, that sugests we could have an atempt at today window: "Tianwen-1 showed quite some ground station activity along yesterday's approach to apoapsis. Tonight, at 21:47:53 UTC it will pass periapsis again." Based on Mars position in the sky on the periapsis dates, chinese would have best comunication with the Tianwe-1 only today, bad sight on 14, 17 and 19th, so it apears that today could be the last window till may 21th. https://twitter.com/df2mz/status/1392384013986410504 Orbital Period is 49h 14m 51s https://twitter.com/df2mz/status/1391876766294331395 Good Thread following the landing from kaynouky https://twitter.com/Kaynouky/status/1392051005664239619 -------------------- "The Earth is a very small stage in a vast cosmic arena"
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