Word today that the MMRTG has been installed on the rover, so seems like a good time to start the launch thread. Launch currently scheduled for 30 Jul, 2-hr window opening at 1150 GMT.

GO PERSEVERANCE!!!

I'll try and catch the launch but it will be a pain since it's at sunrise. Eclipse glasses should hopefully help with that for the 7:50 AM EST launch.
Here is the Google Earth placemark if anyone is interested. I like how there's an upside down "Mickey Mouse" crater to the northwest.
Let the UAE/China/US Mars races commence!!!

Flight Readiness Review cleared today.

Glad they apparently fixed the oxygen sensor launch rocket issue I recall from a couple of weeks ago.

She's on the pad.

T-0 now planned for 30 Jul/1150 GMT. Live coverage with text updates available at Spaceflight Now.

Greetings, I'm soliciting suggestions for additional twitter accounts to follow for the Perseverance launch tomorrow.

My own twitter list for planetary science, which I haven't updated in years, is set out below.

Also, I have a question about good-luck peanuts. It's my understanding that these are generally considered mandatory for events like landings and orbital insertions following a cruise. I don't recall hearing so much about them for launches.

I've got some peanuts ready for tomorrow in any event, but then, I'm very fond of peanuts. I'd be curious to hear other views.

******** Twitter List for Planetary Science *******
Emily Lakdawalla @elakdawalla

Dr./Prof. Sarah Hörst @PlanetDr

Shannon Stirone @shannonmstirone

James Tuttle Keane @jtuttlekeane

Doug Ellison @doug_ellison

Dr Pamela L Gay @starstryder

Nadia Drake @nadiamdrake

Elizabeth Tasker @girlandkat

Alexandra Witze @alexwitze

Planetary Society @exploreplanets

Scott Maxwell@marsroverdriver

Kimberly Maxwell @marssciencegrad

Dr. Julie Rathbun @LokiVolcano

Morgan Cable @starsarecalling

Katie Stack Morgan @kstackmorgan

Dr. Sarah Milkovich @milkysa

Stephanie [Stephanie L. Schierholz] @schierholz


ADMIN: Topic merged into launch & cruise thread. Also, as I understand it, peanuts are only appropriate for landings in accordance with the start of the custom with Ranger 7.

[Edited to reformat list items as single lines]

Not clear, though I don't pretend to understand the specifics of the JPL usage. https://solarsystem.nasa.gov/news/10022/lucky-peanuts/

I'm pretty sure they can't actually hurt, though.

12 minutes to launch. Small 4.3 earthquake rattled some of the Team in California. Luckily no ill effects from the terrestrial temblor and the countdown goes on. Luckily Mars doesn't appear to be as geologically active.

In parking orbit. So far so good.

That was a good launch. Good thing it was today or else terrestrial weather may have put off launch until 2022.

Engine cutoff! Spacecraft separation upcoming!

EDIT: SEP confirmed! Mars, here we come!

Go Perseverance!!

AOS! (Acquisition of Signal)
It's showing up on the DSN Now page too.

DSN stills shows signal (Carrier wave only): press conference starting now.

From Shannon Stirone @shannonmstirone:





https://twitter.com/shannonmstirone/status/...862886710743041

I assume that this is a problem with every launch, and that sometimes DSN solves it it a couple of minutes, other times it takes longer.

At the press conference, they said it seems to have been solved and they have good telemetry!
Presumably it is not worth the trouble to use another Earth-based array for such a brief period, in terms of complexity?

Emily Lakdawalla has noted that she has not yet been able to get detailed information about Perseverance’s additional EDL cameras.

https://twitter.com/elakdawalla/status/1288650896495144960

Matt Wallace just said that the new EDL cameras are ruggedized versions of standard 1080p cameras, and that they will capture, among other things, images of the parachute filling and of the descent engines blasting. He also mentioned that JPL was goaded into increasing the number of EDL cameras from watching beautiful videos of boosters separating from launch vehicles.

There's a paper about them all for the upcoming M2020 Space Science Reviews issue. I've seen some stuff in the media about them: https://www.businessinsider.com.au/nasa-mar...ng-video-2020-7

At 39 bits/sec. DSN Now shows uplink from Canberra DSS-34, they are probably trying to get the rate up to some normal value.

I have no source of information better than anyone else's.

That's a big stress gone. Launches always terrify me. I'll never forget checking the papers to see how Mariner 8 fared, and the Montreal Gazette wrote: MARTIANS SAFE AS ROCKET GOES ASTRAY. That totally ruined my day!

Been wondering when that issue was going to come out. Those special issues for missions have been my go to place for instrument descriptions for, I think, decades now.

The MSL special issue didn't come out until a month or so after MSL landed, and I wouldn't expect anything faster with this one.

A thorough explanation of everything that happened: https://blogs.nasa.gov/mars2020/2020/07/30/...and-on-its-way/

Tl;dr: Conservative safe mode parameters and an excessively strong signal; all is well now. (DSN shows 10 kb/s download rate!)

Can anyone point me to a solar system simulator that shows the relative positions of Tianwen, Hope and Perserverance? I found Perserverance on NASA’s Eyes not the other two. Tried googling around but no luck. Would be much appreciated!

I'm not sure if this is the right thread to bring this up, but one question I have is what is the maximum weight that Perseverance can store in its sample return containers?

Per this page, each sample is max 15g & there are a max of 30 samples, so 450g...just shy of 1 pound in imperial units (454g).

As far as Eyes, been some time since I been on there. Likely that it just tracks US spacecraft. If I recall correctly setting up & maintaining the models is not a trivial effort, plus it relies on near-real time state data which is probably not readily available to NASA for most non-US planetary missions.

Per the Perseverance press kit, the rover carries 43 sample tubes, 5 of which are reserved as witness tubes.

I've read that the team designing the Mars assent vehicle (MAV) is finding it challenging to close a design that could return all the tubes. If memory serves me right (that's less and less reliable these days :<), the number returned might be as low as low 20s to 30ish. (Published presentations are vague on this as the MAV design matures.)

JPL Horizons had some early optically-derived elements for Tianwen-1 but I expect those will rapidly become inaccurate. Hope is being tracked by the DSN but I don't know who is doing their navigation [edit: KinetX is doing it] or if any information is being publicly shared. So any simulation would be fairly schematic.

[Oops, spoke too soon, Hope is on Horizons at EMM (spacecraft ID -62)]

Thanks very much - I did not know about Horizons - unfortunately I don’t know enough about orbital mechanics to use the data, but provides good motivation to learn!

An update from NASA's website:

Ingenuity recharges its batteries while in flight

Does anyone know how Ingenuity will avoid having its landing legs land on a large rock and tilting it over? From what I understand, it doesn't have a hazard detection system. I'm guessing it will somehow know where it lifted off from and return there after the flight?

Thanks

Pages 16 and 17 of this 2018 paper give a good description of the plan:

With tip-prevention by careful reconnaissance to plan avoidance of such features in the flight plan seems effective enough given the other risks, in the NASA article it also states "If Ingenuity survives the cold Martian nights during its preflight checkout, the team will proceed with testing" a choice of words that didn't exactly fill me with confidence, but from the paper linked by Explorer1 shows in page 15-16 section 'H' seems the batteries should have more than adequate capacity to provide the 21Wh needed to keep above -15C at night, but does anyone know if the CO2 insulation was ever replaced by aerogel?

TCM-1 was supposed to be today, but I heard it was delayed according to Reddit due to the accuracy of the launch. I haven't heard anything official from JPL or NASA though.

TCM-1 was completed today:



https://twitter.com/NASAPersevere/status/1294450300095471616

Perseverance is now fewer than 100 days away from landing on Mars.

In addition to an EDL microphone recording of the heating system, one of the hazcams took some images during the cruise of some insulation and a cable:

https://www.jpl.nasa.gov/news/news.php?feature=7789

I am wondering about the lighting though: is that sunlight coming through the aeroshell, or something internal?

I thought these cruise shots were illuminated by an LED, but I could be wrong.

P

This may be of interest re: sound propagation in the Mars atmosphere
http://www-mars.lmd.jussieu.fr/granada2017...granada2017.pdf

There's no LED illumination out the back of the rover. That illumination is coming through gaps in the backshell

Obviously this isn't true, but I would have thought that gaps would allow super heated gasses to enter the backshell during entry.

It's perhaps surprising, but there is a vent hole in the backshell - you have to let the air escape during launch to avoid a pressure differential that could cause structural failure. The same hole (the ~30cm dark circle you can see on backshell images, but there is some sort of wire mesh/filter, so the effective area is only 600cm2 or so) allows the aeroshell to repressurize during entry/descent, but this is slower. Attention is paid to avoid sensitive items being exposed to that repressurization flow, but it is relatively slow (effectively it just sips at the wake, it isnt exposed to the dynamic pressure on the heat shield).

I managed to put together some info on this sort of venting in a recent paper (email me if you can't access)
https://arc.aiaa.org/doi/abs/10.2514/1.A34861

New interactive Jezero geologic map at https://planetarymapping.wr.usgs.gov/interactive/sim3464

Following on from that is a new paper in Space Science Reviews:

https://link.springer.com/article/10.1007/s11214-020-00739-x

If you have access to it. It's a description of this map and the geology of the site.

There is a supplementary file here (a c. 18 MB TIF file):

https://static-content.springer.com/esm/art..._MOESM2_ESM.tif

which I think is open access (correct me if I'm wrong), and this gives the names of the nearly 200 quadrangles used for mapping the site. I really wanted to have this for Curiosity, but it was never released, as far as I know.

Phil

New EDL video: https://images.nasa.gov/details-JPL-2020122...%20w%20SFX.html

My obligatory link to a comic on my office door: https://i.pinimg.com/originals/e0/32/a0/e03...c0a1fbc5f1f.jpg (Overlook the technical errors in the first two panels, it's still funny.)

Great video, and superb obligatory comic.

Phil, wonderful stuff - does the paper provide a scale for this map, specifically the size of each of these quadrangles, also it would be good to know how to attribute it (I dont have access to the paper)
TIA

Hi Paul - this abstract from LPSC earlier this year:

https://www.hou.usra.edu/meetings/lpsc2020/pdf/2254.pdf

says the quadrangles are 1200 m by 1200 m.

This is the paper citation:


Stack, K.M., Williams, N.R., Calef, F., Sun, V.Z., Williford, K.H., Farley, K.A., Eide, S., Flannery, D., Hughes, C., Jacob, S.R. and Kah, L.C., 2020. Photogeologic map of the perseverance rover field site in Jezero Crater constructed by the Mars 2020 Science Team. Space Science Reviews, 216(8), pp.1-47.

Phil

Many, many thanks Phil, much appreciated.

A lot of mountain regions from near my place including Pyrénées, Ordesa Y Monte Perdido, Pico de Europa...