ExoMars

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Profile JakeTheDog
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Message 1825364 - Posted: 19 Oct 2016, 9:36:12 UTC
Last modified: 19 Oct 2016, 9:48:25 UTC

the TGO satellite raised its periapsis after separation with the Schiaparelli lander, and it sounds like it will not aerobrake for orbital insertion. it will perform a 2 hour burn to arrive at a highly elliptical orbit.

TGO will aerobrake for 11 months through November 2017. i can't find information if the solar panels stay in place during each pass. seems like it's very light aerobraking, which is why it will take 11 months.

i cant find information on what the lander's periapsis before entry is. some blogs make it sound like a "collision course," which doesn't seem correct. the closest info i could find is that it will "hit the atmosphere" at an altitude of 120km, which is just stating the altitude of the Karman Line of Mars.

all the EDL and orbital stuff made me start playing Kerbal Space Program again this weekend.

need to set my alarm to wake up early in several hours to see these updates live. hopefully ESA will have success at EDL, will be historic moment for them. well, maybe Beagle 2 technically was successful EDL. solar panels didn't deploy afterwards.
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Message 1825411 - Posted: 19 Oct 2016, 15:21:52 UTC
Last modified: 19 Oct 2016, 15:27:59 UTC

Schiaparelli has landed.
It is not yet clear if the landing was successful.
During the mission, a Swedish instrument is for the first time to be used on Mars.
A press conference is scheduled for 20 October at 08:00 GMT / 10:00 CEST, when a mission status update is expected, along with the first images from the Schiaparelli descent camera.
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rob smithProject Donor
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Message 1825555 - Posted: 20 Oct 2016, 5:21:41 UTC

The tone of recent news is that the lander has "bought the real estate" :-(

http://www.bbc.co.uk/news/science_and_environment
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Profile JakeTheDog
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Message 1825583 - Posted: 20 Oct 2016, 8:26:47 UTC
Last modified: 20 Oct 2016, 8:30:52 UTC

Dang, the Q and A with reporters, they all want to know if the lander is intact, and the answers don't seem very good, but can't make a conclusion, yet. Sounds like the thrusters fired shorter than expected. Maybe it fell from a higher height than intended. At least they got data on the aerobraking and the drogue chute.

My guesses are maybe the thrusters fired too late, or ended too early. Or the velocity at the timed firing was too high, meaning the aerobrake and drogue didn't slow the probe enough.

EDL/EDM issue is going to be the focus of the public. Should also remember the orbiter is doing well. EDL data received is also valuable. However, I feel like this casts a shadow on EDL for ExoMars 2020.
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Message 1825590 - Posted: 20 Oct 2016, 9:23:13 UTC

I remember a video game on the TI99/4A home computer. You had to land on the Moon with a fixed amount of fuel but the entry height and speed could vary. If you fired the rocket too high you would exhaust the fuel and then fall down. If you waited too much for firing you would crash and be greeted with jeerings. You had to be very quick in deciding what to do.
Tullio
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Message 1825592 - Posted: 20 Oct 2016, 10:00:04 UTC - in response to Message 1825590.  

That arcade game was in the lobby of the local swimming pool near me infuriating game .

Just read this about the Mars probe on the BBc News website

Telemetry data recovered from the probe during its descent indicates that its parachute was jettisoned too early


Here's a link to the story

http://www.bbc.co.uk/news/science-environment-37715202
Life is what you make of it :-)

When i'm good i'm very good , but when i'm bad i'm shi#eloads better ;-) In't I " buttercups " p.m.s.l at authoritie !!;-)
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Message 1825635 - Posted: 20 Oct 2016, 14:06:10 UTC

It seems that the rockets fired for only three seconds instead of thirty seconds. Then bum!
Tullio
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Message 1825640 - Posted: 20 Oct 2016, 14:56:12 UTC

The European Space Agency (Esa) has not yet conceded that the lander crashed but the mood is not positive.
Schiaparelli Mars probe's parachute 'jettisoned too early'
http://www.bbc.com/news/science-environment-37715202
But the Trace Gas Orbiter TGO is still working.
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Message 1825653 - Posted: 20 Oct 2016, 16:10:16 UTC

USA JPL has landed on Mars 2 Vikings, two rovers, Spirit and Opportunity, which is still working after 12 years, another rover, Curiosity, which is slowly climbing Mount Sharp (Aeolis Mons). Clearly JPL is still in a class by itself.
Tullio
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Message 1825678 - Posted: 20 Oct 2016, 18:31:38 UTC

Just goes to show that landing on Mars is not an easy task.
Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.
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Message 1825692 - Posted: 20 Oct 2016, 19:23:46 UTC - in response to Message 1825653.  

USA JPL has landed on Mars 2 Vikings, two rovers, Spirit and Opportunity, which is still working after 12 years, another rover, Curiosity, which is slowly climbing Mount Sharp (Aeolis Mons). Clearly JPL is still in a class by itself.
Tullio

Another rover Sojourner, Phoenix lander.

If you want to explore Mars, the road goes through La CaƱana.
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Message 1825732 - Posted: 20 Oct 2016, 21:54:57 UTC

I think the thrusters were supposed to burn for about 1 minute at landing, so the actual burn of a few seconds was too short. The parachute was jettisoned at the wrong time, but I dont think it was explained in detail yet whether it was too early or late, or at an unexpected altitude.

My theory is the parachute was let go too early and maybe the thrusters were programmed to fire at a specific height rather than a specific speed, so the speed was too high at the time of firing. But I would've thought the lander would measure both speed and height to calculate when to do a suicide burn.
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Profile Gary CharpentierCrowdfunding Project Donor
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Message 1825795 - Posted: 21 Oct 2016, 4:38:48 UTC - in response to Message 1825732.  

I think the thrusters were supposed to burn for about 1 minute at landing, so the actual burn of a few seconds was too short. The parachute was jettisoned at the wrong time, but I dont think it was explained in detail yet whether it was too early or late, or at an unexpected altitude.

My theory is the parachute was let go too early and maybe the thrusters were programmed to fire at a specific height rather than a specific speed, so the speed was too high at the time of firing. But I would've thought the lander would measure both speed and height to calculate when to do a suicide burn.

It would. Either Radar or Laser altimeter. Of course if it failed, that could explain the entire oops in the landing sequence. (Or someone confusing inches and meters ...)
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Message 1825813 - Posted: 21 Oct 2016, 6:34:41 UTC
Last modified: 21 Oct 2016, 6:35:50 UTC

It went,

SPLAT!!!

Cheers.
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Message 1825964 - Posted: 21 Oct 2016, 21:10:00 UTC

http://www.space.com/34472-exomars-mars-lander-crash-site-photos.html
Schiaparelli lander appears to have crashed, according to photographs from NASA's MRO satellite. ESA to continue analyzing data to figure out sequence of events. The TGO satellite portion of the mission will continue as planned.
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Message 1826724 - Posted: 26 Oct 2016, 0:38:19 UTC - in response to Message 1825964.  

http://www.nature.com/news/computing-glitch-may-have-doomed-mars-lander-1.20861

Some articles today saying the parachute and heat shield were detached too early and too high. Then the thrusters turned off too early. Some of the instruments for the ground were turned on early, as well. Theory is that the probe thought it was lower than it really was, and then thought it had landed. Root problem may be a software or sensor issue.
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Message 1826859 - Posted: 26 Oct 2016, 23:53:40 UTC
Last modified: 26 Oct 2016, 23:54:26 UTC

What they needed was a flight simulator like the one I had on the home computer TI99/4A, which simulated a landing on the Moon under variable conditions, and ended mostly in crashes greeted with jeering sounds.
Tullio
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Message 1827151 - Posted: 28 Oct 2016, 11:36:40 UTC

A high-resolution image taken by a NASA Mars orbiter this week reveals further details of the area where the ExoMars Schiaparelli module ended up following its descent on 19 October.
http://www.esa.int/Our_Activities/Space_Science/ExoMars/Detailed_images_of_Schiaparelli_and_its_descent_hardware_on_Mars
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Message 1832280 - Posted: 24 Nov 2016, 23:28:10 UTC
Last modified: 24 Nov 2016, 23:28:17 UTC

http://exploration.esa.int/mars/58590-schiaparelli-landing-investigation-makes-progress/

Looks like ESA has discovered the likely problem for the lander's crash. Not sure if it's hardware or software, but one of the sensors that measures rotation gave bad data for 1 second, making the calculation of the altitude to be a negative number. Which led the lander to start the final landing phase when it was still 3.7 km above the surface.
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Message 1832288 - Posted: 25 Nov 2016, 0:22:41 UTC

The Italian Space Agency has made a rather critical review of the Schiaparelli affair. Its software was developed by a Romanian software house founded by a man graduated in theology and no hardware test of the Schiaparelli landing procedure was made, for economy reasons.
Tullio
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Message boards : Science (non-SETI) : ExoMars


 
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