Help - Search - Members - Calendar
Full Version: ExoMars
Unmanned Spaceflight.com > Mars & Missions > Past and Future > ExoMars Program
Pages: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
hendric
The landing site altitude is about 1400-1600m higher up than Curiosity, with a bit of variation across the ellipse. I did some math with https://www.grc.nasa.gov/WWW/K-12/airplane/atmosmrm.html and that means about 10% less air density.

Maybe there are lower descent speed requirements on their landing site acquisition?
vikingmars
Thanks for the link to the ESA page : I discovered this EDL procedure which seems quite 'baroque' to me also, with all those parachutes sequences embedded in one another.
Many failure points are at risk and I would have liked Jim Martin (Viking Program Manager) to give us his opinion on the subject.
Then... let's go back to the basics ...which are still to be considered as a technological feat even 43 years after the successful landings of the two Viking spacecrafts !
Click to view attachment
JRehling
This reminds me of the fluid dynamics issues that complicated the Wright Brothers' development of the first propellers used in HTA aviation. "We had thought we could adopt the theory from marine engineers, and then by using our tables of air pressures, instead of the tables of water pressures used in their calculations, that we could estimate in advance the performance of the propellers we could use." That proved to be incorrect, and they had to begin with no useful specific from marine propellers. "It is hard to find even a point from which to make a start; for nothing about a propeller, or the medium in which it acts, stands still for a moment." They ended up testing 200 different wing designs in wind tunnels and then used what they learned about wings to design their propellers.

Fluid dynamics is not good old Newtonian predictable physics.

I have leapt out of a plane once, and one of the things they taught me during training was how to perform a little maneuver that decreases the probability that the chute fails to open, something that can occur if it unfortunately inhabits a small wind-less pocket behind the parachutist's back and never catches the winds that open it. (The aforementioned physical maneuver and a backup parachute are hedges against that possibility.)
Explorer1
Some very helpful details in this article:

https://spacenews.com/esa-turns-to-nasa-to-...arachute-tests/

tl; dr: NASA stepping in to help, more tests to be done in December in Oregon. Also this pertinent detail that answered our questions about why there are 4 'chutes:

QUOTE
The unprecedented size and complexity of the parachute system is related to the lander, being provided by Roscosmos. A more powerful retropropulsive system on the lander could have allowed the mission to require only one main chute, Spoto says.
bobik
You have to ask, why they don't ask their direct partner in the program the Russians for help? Russia has great know-how in parachute technology. An 2017 interview (in Russian) with the CEO of the leading Russian parachute developer suggests that the sanctions imposed on Russia render cooperation difficult. Very unfortunate indeed!
nogal
An update on the progress of the ExoMars parachute can be found at

http://www.esa.int/Science_Exploration/Hum...achute_progress

The article also includes an update on the overall mission progress.
Fernando
Explorer1
Looks like some progress has been made in ground tests with the JPL assistance; the high-altitude tests are coming soon too: http://www.esa.int/Science_Exploration/Hum...Mars_parachutes

Of course, the true test will be on the red planet....
Quetzalcoatl
Bonjour à tous,

The problem of parachutes to land on the red planet the European rover Rosalind Franklin and its surface platform Kazachok built by Russia will most likely result in the postponement of the Exomars mission to the next (but farther) launch window, in about two years.

The European and Russian space agencies are to meet on 12 March to make a final decision on this subject.

Until then, it was expected that the launch would take place in July this year from the cosmodrome in Baikonur, Kazakhstan. But the problems found during parachute deployment tests will certainly not be solved in time.

An ESA spokesperson said:

"An operational review of the project took place between ESA and Roscosmos at the end of January. A preliminary assessment was sent on 3 February to the heads of space agencies, Jan Wörner of ESA and Dmitry Rogozin of Roscosmos."

"Programme leaders were asked to submit an updated plan and schedule covering all remaining activities necessary for the authorisation to launch. This plan will be reviewed by the two heads of agencies who will meet on 12 March to jointly agree on next steps."

With this deadline, we are waiting for a public announcement on a possible confirmation of a launch in July or, more probably, of a two-year postponement at the next window favorable for a launch towards March.

The modifications on the parachute system that have been undertaken since the discovery of the problems must be validated, with the help of the JPL, by a last test at high altitude which was initially planned during February. Unfortunately, a change in NASA’s schedule would have postponed this indispensable test in March. huh.gif

In its space section, the BBC informs us of another complication concerning especially the rover Rosalind Franklin.

Thales Alenia Space reportedly discovered a defect in the hinges of the solar panels of the rover. The problem was found on the rover test model and on the flight model during the thermal and vacuum tests. The glue that was holding the hinges in place took off. Engineers are working to solve this problem. It is planned to replace the glue with bolts. The margins for the maximum payload are such that it’s not really going to be a problem.

In two weeks we should be fixed the fate of this launch in July 2020 ...
Phil Stooke
Many thanks for giving us these details. Sad - but much appreciated. And remember MSL was delayed 2 years, and many other missions have been before. You have to do it right!

Phil

climber
Merci serpent à plume, espérons que ça ne deviendra pas un serpent de mer.
Sorry guys, no way to put this in English...
Quetzalcoatl
Thank you, Phil, smile.gif

Adiu Climby, tongue.gif

"High-altitude parachute testing is now scheduled for the end of March," an ESA spokesperson told Spacenews.
The delay occurred despite six ground tests demonstrating successful parachute extraction, a phase where damage had been caused in previous high altitude tests.
However, the Exomars mission could be postponed even before these new tests are carried out. Heads of ESA and Roscosmos are expected to meet next week to discuss next steps following the mission progress report.

Extract from the source :

https://spacenews.com/exomars-parachute-tes...n-faces-review/
atomoid
QUOTE (climber @ Mar 3 2020, 03:41 AM) *
Merci serpent à plume, espérons que ça ne deviendra pas un serpent de mer.
Sorry guys, no way to put this in English...

well it was worth a try anyway... Thank you feathered snake, let's hope it doesn't become a sea snake.
Quetzalcoatl
Well done atomoid. smile.gif

QUOTE (Phil Stooke @ Mar 3 2020, 03:59 AM) *
... And remember MSL was delayed 2 years, and many other missions have been before. You have to do it right!

Phil


You’re absolutely right, Phil, a postponement is not a cancellation. The success of this mission represents a crucial step for European and Russian space exploration, the people know full well what is at stake.

I would have been particularly interested to see SEIS (the Insight seismometer) work in association with SEM (the Russian seismometer installed on the Kazachok platform). For the latter, although I am currently unable to find his technical specifications, I am quite convinced that simultaneous event recordings by the two instruments would bring a real benefit to the analyses of the data.

It is also possible that if the launch of Exomars is postponed for two years, a possible extension of Insight’s mission will allow my wish to be fulfilled.

In addition, I am convinced that the ability to work two machines at the same time on the surface of Mars would not stop at the only example I give, we can also think of the search for methane in the atmosphere and other similar things, when we know that surface and orbital measurements are sometimes very dissonant...

climber
Jan Wöerner, ESA director, announce ExoMars launch has been delayed. Official ESA com to be issued.
Quetzalcoatl
In addition to the announcement of this news by climber:

http://www.esa.int/Newsroom/Press_Releases..._Planet_in_2022

Cautious, predictable but frustrating.
PaulH51
ExoMars rover upgrades and parachute tests... (detailed ESA News release) Link
Roby72
QUOTE (PaulH51 @ May 15 2020, 12:10 PM) *
ExoMars rover upgrades and parachute tests... (detailed ESA News release) Link


ExoMars parachute is more than double the diameter of Curiositys - is there a table of other planetary mission parachutes (Viking, Huygens, Galileo-Probe, ...) to compare them easily ?
Tom Dahl
The Viking decelerator (parachute) was 53 feet in diameter, for what that's worth.
rlorenz
QUOTE (Roby72 @ May 15 2020, 04:20 PM) *
ExoMars parachute is more than double the diameter of Curiositys - is there a table of other planetary mission parachutes (Viking, Huygens, Galileo-Probe, ...) to compare them easily ?


"Planetary Landers and Entry Probes" by Ball et al. (Cambridge University Press) has a whole chapter on descent through atmospheres, including this table (part)
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2020 Invision Power Services, Inc.