[X] My Assistant

[atomoid]

i had made a stereo of that SOL18 set, but due to the crazy parallax wasn't compelled to post it, so i revisited it increasing the gamma, cropping and optimizing for the area beneath the deck so it comes out a little better to get a feel for the gouge mark depths, so seems worth posting in response, really get the sense a lot of regolith must have been blasted up against the lander body, so it seems no wonder that some managed to work its way behind the lens cap. unfortunately the footpad is itself obscured by the nozzle in one of the pair.


Regarding translation, its easiest to simply insert the below string in front of any URL you want to translate (in this case FR to EN):

CODE

https://translate.google.com/translate?sl=fr&tl=en&u=

[nogal]

Here is a translation. Though I used Google for speed it then needs review and adjustments. It is a good and useful tool but still not good enough. I also attach a file with the translated text. The original page is here

Congratulations to the SEIS team!
Fernando
 SEIS_deployment.txt ( 6.78K ) Number of downloads: 176



The second landing of SEIS seismometer

Posted on December 19, 2018.

The seismometer SEIS has just been successfully deposited on the surface of Mars by the probe InSight

NASA has successfully deposited the seismometer of the probe InSight on Mars. This is the first time in the history of space conquest that an instrument is deployed by a robotic arm on the surface of another planet. The success of this critical step for the rest of the mission is the result of years of unceasing technical efforts by the American, French and European teams.

Photo 1 Legend: SEIS seismometer capture by the robotic arm grapple during sol 20 (© NASA / JPL)

The complex sequence of instructions commanding the deployment was sent yesterday (December 18, 2018 at 5:11 pm in California) to the red planet. At that moment, the probe InSight began its 22nd day of operations on the surface of Mars (it was then 5 o'clock in the morning on Elysium Planitia). For thermal considerations, the deployment was planned for the same day, but in the evening. On December 19, 2018, when the Sun had just disappeared behind the Martian horizon at 6:40 pm local time (while simultaneously rising in California on Los Angeles), InSight's arm went into action to place the 9,5 kg of the SEIS seismometer on the ground. For this high-risk operation, the instrument was completely powered off. Many tests have been previously done on Earth to validate the orders, the landing site having been faithfully reproduced for the occasion.

The automatic sequence actually started on Mars at 17:00 with the subsequent firing of the three frangibolts that kept SEIS securely attached to the probe deck. To carry out the deployment of the seismometer itself, the engineers had decided to wait a little, so that the IDA robot arm was cold enough: the latter is actually more efficient at low temperatures. Activation of the deployment sequence was therefore scheduled for 18:30, or ten minutes before the sunset on Mars.

To place SEIS on the ground, the robotic arm has performed a fairly complex series of movements. After lifting the 25 centimeter instrument vertically, the arm moved back to pull the cable off the deck, the latter being held by several velcro fasteners. He then made a 180° rotation on itself, before going forward again to continue tearing the velcro. The arm then stretched as far as possible to the south to remove the part of the cord attached to the outside of the TSB (the cylindrical case where the SEIS cable is wound), again with a velcro patch. This step inevitably induces a somewhat intimidating swing of SEIS at the end of the grapple. For the last part of the sequence, the arm goes back slightly towards the lander, then, thanks to arc movements, it gently places SEIS on the ground. The sequence did not provide for the opening of the grapple. This stage, which will mark the definitive release of the instrument, is planned in the coming days.

Photo 2 Legend: Image from the ICC camera showing SEIS seismometer on the ground just before sunset (© NASA / JPL)

The duration of the deployment sequence itself is quite short: only 10 minutes. The need to acquire images via the ICC camera (located under the deck) and the IDC camera (mounted on the arm), however, took the duration of the operation to about 20 minutes, spread over 45 minutes. The time at which the SEIS seismometer planted its three feet in the sand is estimated at 7:05 (in California), which is 18:54 Martian time.

In view of the night planning chosen for the deployment, the first Martian orbiter capable of relaying to Earth the data confirming the emplacement of SEIS on the ground could be in position only on 19 December in the evening (ie the beginning of the morning of sol 23 on Mars). A first X-band transmission around 6:00 pm had already given the deployment team a number of subtle indications that operations were running smoothly. But it was not until the overflight by Mars Odyssey at 9:00 pm (California time) that the images, absolutely beautiful, finally appeared on the screens of the control room at JPL. Between sending orders to the red planet and receiving the first telemetry data, the engineers had, thus, to wait 24 hours. A long wait punctuated with doubt and worry, given the complexity of the maneuver involved and the interests a stake.

The area where SEIS now rests is directly in front of the robotic arm (to ensure that the umbilical cord connecting the instrument to the undercarriage rests flat on the ground), and as far away as possible (1,65 meters) from the probe, so as to minimize disturbances. The speed with which the engineers and geologists chose this placement site is related to the appropriateness of the area where the probe landed on November 26th. With a very small slope (only 2 to 3 degrees of inclination) and a striking absence of pebbles, almost all of the terrain located south of the lander and within reach of the robotic arm was suitable for the deployment of the seismometer.

Photo 3 Legend: The SEIS seismometer of the InSight probe, as seen by the robotic arm's IDC camera, after its deployment during sol 22 (© NASA / JPL).

Operations are however far from being completed for SEIS. Many critical steps must now take place in the coming weeks before scientists can start tracking down Martian quakes. Engineers will actually first have to align the seismometer with the horizontal, thanks to the motorized leveling cradle. Once this step is completed, sensors for the very wide band (VBB), inactive for the moment, contrary to the short period sensors SP, will be refocused and calibrated. The totality of the data transmitted by the six seismic sensors will then be used to characterize the noise level of the emplacement site (which should be as low as possible), as well as the level of disturbances induced by the cable connecting the instrument to the lander.

When performance is deemed acceptable, the cable in the TSB unwinder will be fully unwound. If the engineers notice that the cable is injecting too much noise into the instrument the pyrotechnic opening of the service loop (LSA) will be performed. Depending on the result of this step, the cable may possibly be re-positioned using a hook located on a pinning mass. The final placement, over the instrument, of the imposing WTS wind and thermal protection shield can then take place.

As we can see, on Earth and on the Red Planet, engineers and scientists still have a lot of work to do before the first Mars geophysical station is fully operational. But the emplacement of the first seismometer on Mars is already a great success, that the members of the team will celebrate with according dignity, probably by allowing themselves a few days of rest for the Christmas holidays!

Pasadena, 19 December 2018 (update of the paragraphs concerning arm movements and subsequent operations on 20 and 21 December)

[Phil Stooke]

Serpens: "I suspect that rather than sinking the landing pads were covered by regolith excavated by the thrusters."

I think that's a very good point!

Phil

[climber]

I cannot find it again but I red, may be somewhere in french, that 2 feet sank and not the 3rd so the vehicule is tilted 4 degres in the arm side direction. Could be consistent with Phil’s thoughts then.

[climber]

I will try to run some traduction but not sure my english is good enough
Will be during 3 months or so, then I’ll have 2 years to recover anyway

[propguy]

Nice view of the thrusters and how firing change the color of their throats.

Actually, the discoloration was from acceptance testing hotfire on Earth. The thrusters are fired in a mostly evacuated test chamber, but it still has residual atmosphere, thus the Inconel chambers oxidize when they get hot. That is pretty much how they looked when they launched (since there is little or no O2 in the atmosphere of Mars).

[kungpostyle]

Actually, the discoloration was from acceptance testing hotfire on Earth. The thrusters are fired in a mostly evacuated test chamber, but it still has residual atmosphere, thus the Inconel chambers oxidize when they get hot. That is pretty much how they looked when they launched (since there is little or no O2 in the atmosphere of Mars).

Thanks propguy, I was wondering about that.

[MahFL]

The grapple has let go of SEIS.

[climber]

Into the wild

[paraisosdelsiste...]

The arm is moving away from SEIS... (animated GIF attached)

[elakdawalla]

It is, and also inspecting the tether.

[James Sorenson]

The first plumb bob on another planet if I'm not mistaken.

[Paolo]

what is the white thing about halfway along the tether?

[Pikaia]

what is the white thing about halfway along the tether?

It's the tether field joint, that connects the part of the tether located inside the circular Tether Storage Box (TSB) to the part located outside the TSB (called octopus), with SEIS at the end. Before deployment, the field joint is attached with velcro to the TSB (see here : https://mars.nasa.gov/system/resources/deta...IA22952-web.jpg ). When deployment occurs, the white sock ensures that the robotic arm load is not applied to the connectors.

[ronatu]

Yes, and still vibrations were made of the solar panels flapping that were detected by the instrument on the lander. Parachutes have been seen in the past blowing over in the wind. A thin and light flex cable almost surely can still move and resonate in the wind.

ForceOn1m^2=(airdensity*windspeed^2)/2*g

The highest atmospheric density on Mars is equal to the density found 35 km above the Earth's surface.
The strongest Martian storms top out at about 60 miles per hour
g=3.8 m/s2