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SpaceIL lunar lander mission - 2019
algorithm
post Apr 11 2019, 07:29 PM
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Controlled landing unssucessful, main engine failure, fantastic effort from a non govenmental enterprise.


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algorithm
post Apr 11 2019, 07:42 PM
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Final telemetry


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Hungry4info
post Apr 11 2019, 08:02 PM
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From this tweet.

QUOTE
Just received from SpaceIL communication team what appears to be the last image #Beresheet spacecraft managed to beam to earth before it crashed on the moons surface


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-- Hungry4info (Sirius_Alpha)
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Thorsten Denk
post Apr 11 2019, 09:25 PM
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Just wondering if Phil Stooke will identify the craters... smile.gif

Thorsten
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marsbug
post Apr 11 2019, 10:05 PM
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Well done to them - as I understand it this was far more a mission about promoting STEM education, PR, and inspiring people than it was about science. They've achieved 99% of what they hoped for just by making it into lunar orbit, so well done - even a hard lunar landing is a huge achievement.

That said, I'm seriously hoping that 'inspiring people' part means we can look forward to some new (hopefully not 150 meters/sec) private landing attempts in the not too distant future......


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Explorer1
post Apr 11 2019, 10:14 PM
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Yeah, Phil will definitely identify the craters!
That IMU issue and premature engine cutoff reminds me of Schiaparelli's impact (in trajectory if not in exact cause). Hopefully LRO can take a look during this lunar day or the next.

My hats off to the team; an incredible achievement, and apparently they still win the million dollars for the X-Prize contest (no other team even got to launch!)
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Thorsten Denk
post Apr 11 2019, 10:32 PM
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The crater should be Hypatia A.
looking North East into Mare Tranquilitatis.
Still over 1000km from the landing point.
(Credits for identification go to @Henning81 from the German astronomie.de)

Thorsten


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Phil Stooke
post Apr 11 2019, 11:41 PM
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Here's the first image, reprojected a bit to help identify it ...

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The crater near the limb is Burg in Lacus Mortis, 45 north, 28 east.

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That's a bit off the landing longitude. Was it from a previous orbit?

Phil


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Phil Stooke
post Apr 11 2019, 11:49 PM
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And the second. As was said already, it's Hypatia at 4 south, 22 east. Looking northeast from one of the four side-mounted cameras which would have taken the surface panorama.

Attached Image


Attached Image


Far south of the landing site, so although just released, presumably it must be from an earlier orbit.

Phil



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JRehling
post Apr 12 2019, 01:26 AM
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I have to say, it somewhat alarmed me to see that photo and identify it as the spur of highlands south of the Apollo 11 landing site. It's the feature I use as a finder to zero in on that location. I'm sure I don't know the entire Moon that well, but that's one spot that I do.
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John Whitehead
post Apr 12 2019, 05:59 AM
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On April 5, Space News reported that the lander fired its main engine for six minutes, slowing the spacecraft by about 1,000 kilometers per hour.

https://spacenews.com/spaceil-lander-enters-lunar-orbit/

These numbers work out to 0.77 meters per second squared acceleration, which is less than half of lunar surface gravity. Landing from a low lunar orbit needs about half of the spacecraft to be propellant, so after burning that off, the deceleration capability would still be less than lunar surface gravity. So if the reported numbers correctly represent full thrust from the main engine, there would not have been enough thrust to land.

Does anyone know the correct numbers for the orbit insertion burn last week, or is it true that there simply was not enough thrust?

Otherwise, what did I miss in my calculation? A million meters per hour in 6 minutes is 278 m/s in 360 s, or 0.77 m/s^2.
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Xerxes
post Apr 12 2019, 02:17 PM
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QUOTE (John Whitehead @ Apr 12 2019, 12:59 AM) *
Otherwise, what did I miss in my calculation? A million meters per hour in 6 minutes is 278 m/s in 360 s, or 0.77 m/s^2.


I'm not sure you missed anything. According to the Wikipedia entry, Beresheet has a dry mass of 150kg and a Leros 2b engine capable of 407N thrust. If we assume it's near-dry at landing, that gives it 2.7 m/s^2 acceleration, which should be fine for a lunar landing.

The fueled mass is more like 585kg, of which I think they'd used about 100kg of fuel at that point, which works out to 0.90 m/s^2, perhaps within the uncertainty of our napkin-based calculations. Presumably, the rest of the fuel is used up lowering the apolune and during the descent maneuver, though I haven't been able to find any clear description of the engine firing for those maneuvers.
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Paolo
post Apr 13 2019, 06:46 AM
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any idea whether the expected magnetometer data to be collected during orbits and descent have been obtained?
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Phil Stooke
post Apr 13 2019, 06:43 PM
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News today:

Leonard David reports LRO's LOLA laser will attempt to get a reflection from the ball-shaped reflector, if it survived the crash.

http://www.leonarddavid.com/did-nasa-exper...el-moon-lander/

No word yet on if any magnetometer results were transmitted.

Kahn will begin a Beresheet 2 mission right away. Flight in 2 or 3 years.

https://www.timesofisrael.com/spaceil-chief...ag-on-the-moon/


Phil


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GoneToPlaid
post Apr 14 2019, 03:48 AM
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QUOTE (Hungry4info @ Apr 11 2019, 01:02 PM) *
From this tweet.


LIVE BROADCAST URL:

https://www.youtube.com/watch?v=HMdUcchBYRA

This undated image was shown at 18:35 in the recorded live broadcast. Phil and Thorsten have correctly identified the lunar location as Hypatia A.

The Beresheet selfie photo was shown at 31:33 during the live broadcast. Further work shows that it could not have been taken during the descent.

Following is a listing of the events which I observed while reviewing the live broadcast video.

All times, below, are video recording time stamps.

18:35 A photo taken at an unknown time and lunar location is shown during the live broadcast.

Up until the following video time stamps, neither the telemetry indicator nor the horizontal velocity value is green. Altitude and vertical velocity are shown in yellow.

23:03 Telemetry indicator turns green. Sub State is Orientation.

25:04 Sub State changes to Braking.

25:20 "We are past the point of no return."

25:26 The Point of No Return indicator turns black.

25:52 Vertical velocity display turns green.

28:16 Telemetry indicator is no longer green.

28:20 Telemetry indicator momentarily turns green, then is no longer green.

29.37 Distance is shown as 210 km.

29:50 Distance changes to 385 km.

30:03 Distance changes to 370 km.

30:40 Telemetry indicator is green.

30:51 Distance is 314 km.

31:33 Beresheet selfie is shown. Altitude approx 22 km??? Telemetry is green.

31:50 Telemetry indicator is no longer green.

31:55 to 32:29 "[inaudible] kill it." "[More inaudible mission chatter] busy."

32:48 Telemetry screen is shown. Telemetry indicator is light yellow. Altitude is 14095 m. Horizontal velocity is 955.5 m/s. Vertical velocity is 24.8 m/s. Main engine is on. Horizontal velocity is light yellow. Other parameters are green, except for the telemetry indicator.

32:49 All engines are on.

32:51 All engines are off.

32:55 Main engine is on.

32:57 All engines are on.

32:59 Main engine is on. Distance is 183.8 km.

33:01 - 33:03 "IMUstein not okay."

33:02 All engines are on.

33:05 Main engine is on.

33:07 All engines are on.

33:09 Main engine is on.

33:11 All engines are on.

33:13 Main engine is on.

33:16 All engines are on.

33:20 Telemetry indicator turns green. All engines are off. All displays remain static (no change).

33:32 Telemetry indicator is no longer green. All engines are off. All displays remain static (no change).

34:24 Telemetry indicator turns green. All engines are off, yet supposedly turn on. Vertical acceleration on the Z axis is fixed at 0.6. "We currently have a problem in one of our inertial measurement units." Vertical velocity starts to steadily increase. Altitude continues to steadily decrease. Vertical acceleration on the Z axis becomes fixed at 0.6. Main engine probably is not on.

Telemetry indicator intermittently turns green and then turns light yellow, up until the following video time stamp.

34:56 Telemetry indicator is no longer green. Although all engines are shown as on, vertical velocity continues to increase. Vertical acceleration on the Z axis remains fixed at 0.6. Main engine probably is not on.

36:25 - 36:33 "We seem to have a problem with our main engine. We are resetting the spacecraft to try to enable the engine."

36:40 Telemetry indicator is green. All engines appear to be on, yet Z axis acceleration remains fixed at 0.6 m/s. Altitude is 678 meters. Horizontal and vertical velocities are 948.1 m/s and 130.1 m/s respectively.

36:44 Last telemetry data. Telemetry indicator is green. All engines appear to be on. Z axis acceleration changes to 0.7 m/s. Final altitude is 149 meters. Final horizontal and vertical velocities are 946.7 and 134.3 m/s respectively. Main engine does not appear to be functioning properly.
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