Hi all,

Before February 18th I will be trying to get an article about Perseverance into one of the major newspapers of Denmark. I had an article in "Politiken" about the SpaceX Starship just before its December flight test.

Would you know of a good resource with a timeline of all EDL events? - I have been struggling a bit to find a source for all events with the precise Earth time as well as the expected altitude and speed at the time of the event. I'm sure the data is out there, but would like it from an authoritative source.

Thanks!

- Mercure

The EDL timeline is not precisely known in advance but can vary by as much as a minute or two at least.

https://mars.nasa.gov/mars2020/timeline/lan...escent-landing/ is as good as we know. Predicted landing time is Feb. 18, 2021, at approximately 12:30 p.m. PST (that's 20:30 UT.)

Thanks mcaplinger!

There was a Mars Sample Return sample caching workshop today with very interesting details about how Perseverance will go about its task of collecting and caching samples for later return. Here are the presentation slides:


https://drive.google.com/file/d/1fj5ZPFuieC...Dq2OQlq9v6TxN3/


https://drive.google.com/file/d/1nRoqv5vK_K...GpDb0tGYUnXlvo/


https://drive.google.com/file/d/1u19Svop3Ka3buHUyaemk2p2-7a1L-ZOC/ ://https://drive.google.com/file/d/1u1...k2p2-7a1L-ZOC/


Phil

Thanks so much Phil for the useful links.
I have already prepared a PPT presentation for our large Perseverance landing public event next February we (Planetary Society + Societe Astronomique de France/SAF) are organizing in Paris at our National Science Museum (Cite des Sciences).
It integrates the sample-return mission that follows the Perseverance mission.
=>> Now, thanks to you, I have a very good update to show about the latest sampling-cache strategy

NASA's Eyes show Mars is now a barely resolved circle from the distance of Percy. Just a week away!!!
https://eyes.nasa.gov/apps/orrery/#/sc_pers...-02-11T15:51:36

I thought the sample tubes were dropped as each one was filled . Learnt something new...

Not a great idea because they want to minimize the time it takes for the 'fetch' rover to pick up the cache. If the tubes are set down all along the traverse the fetch rover has to drive the whole traverse length to get them and then get back to the return vehicle. With the two cache system they decide which cache is best (almost certainly the second one) and go for that, land as close as possible and do a quick trip to collect it. In fact the only real reason for the first cache is insurance against a catastrophic failure of the rover before the second cache can be set down.

Phil

It's only as I read those excellent documents about the sampling plan that I absorb for the first time that, if all goes well, the scientific results from this mission will be far beyond what the instruments on Perseverance measure. This first occurred to me when I thought about absolute age dating, not from one rock or another, but from several rocks in the stratigraphy, and suddenly we'll have a specific, detailed timeline of Mars's early evolution.

We need a lot of successes to occur before this knowledge will be in hand, but it's awe-inspiring to consider the leap in understanding that this mission sequence is attempting.

I have a question about the current landing target. In two recent EDL animations (Eyes and the one about 3 minutes long), the landing is much nearer the delta face, maybe only several hundred meters away, instead of the earlier point near a 400 m crater more than a km away to the S. I'm answering some questions on YT threads and do not want to provide bad information. Thanks.

I think it is just a generic point near the centre of the ellipse. The real landing will deviate somewhat in both entry point and trajectory through the atmosphere, as well as the direction onboard navigation takes it when firing the thrusters. Definitely smart enough not to land on a giant slope!

P.S. my own question for anyone in the know: any plans on MRO attempting imaging like MSL, or does the bent-pipe relay attitude preclude it this time around?
I could really use a new avatar....

PlanetFest 21 happened this weekend (run by the Planetary Society) and there was an amazing talk by Rob Manning of the details of the landing. The ellipse (which this time is really a circle) they could come down in is about the size of Manhattan but the expectations are that the lander would emerge in powered descent somewhere near the center of it which is somewhat near the delta but below it in the crater. The onboard navigation system is designed to locate the closest safe spot to where it figures out it is and aim for that. He said that they determined there were safe spots to be found at all parts of the ellipse within close proximity. Eventually that talk will be posted to the Planetary Society's Youtube page so watch for it. The engineering he described is amazing.

He also said that MRO will be tasked with not only going after a shot of the lander on the parachute but also during the actual powered landing as well if they can get lucky.

At the L-30 briefing they said yes - infact, they're going to try and do it a little later during EDL - so you'll have the powered descent vehicle flying below the parachute and backshell.

Fingers crossed.

I was curious:
Click to view attachment

Can someone give any more detailed insight on how exactly does the TRN work ? Are they aiming for a safe spot at the center of the landing ellipse, or any safe spot ?

It has a catalog of multiple safe spots within the ellipse and guides toward the closest one based on imaging. See https://www.jpl.nasa.gov/news/a-neil-armstr...mars-2020-rover and https://trs.jpl.nasa.gov/handle/2014/46186

Thank you for the links, now I have a good understanding.

Less than 2M miles to go now....

Less than 1M miles to go now.

I know MRO will be able to act as a relay for Perseverance during landing. Will Mars Odyssey or MAVEN be available as well?

I think TGO is recording during the landing, later other orbiters are making passes, there are 5 orbiters that can relay rover data.

MRO will be doing bent-pipe realtime relay ( which is a new feature on MRO thanks to a software update )
MAVEN will be doing canister mode recording for later return to Earth.

See pages 23 and 43 of the Landing Press Kit
https://www.jpl.nasa.gov/news/press_kits/ma...g_press_kit.pdf

Does anyone know of a Jezero map using the same coordinates as this landing zone map that was presented today:
Click to view attachment
Knowing the origin of those coords we could probably translate into lat,long...

That's not a map of the surface - that's a map of a plan through deep space. The spacecraft actively flies its way through entry to target the center of the ellipse. You can't translate that entry mapping image onto a surface map.

Right - it's showing where the entry target point is on a plane perpendicular to the approach vector.

Phil

I see; thanks.

EDIT:---Wrong Topic---