Beresheet moon lander crashes...

[bsudbrink]

Too bad...

https://arstechnica.com/science/2019/04/a-private-spacecraft-from-israel-will-attempt-a-moon-landing-thursday/

[electromotive]

That’s unfortunate. Maybe the new Chinese lunar rover will fare better. Still impressive that they came as close as they did to a successful mission.

[hamster_nz]

What a shame it didn't land 

You know you've played too many Space Sim games when you are watching the telemetry in the live stream and say.... "That doesn't add up... not much slowing down...  I hope that it gets really light as they burn off the remaining 90 kgs of fuel... how can you get through that fuel quick enough?  Oh.... THAT does not look good..."

(oh, and Falcon Heavy launch in a couple of hours)

PS. Was it just me or did the live stream cut? Or did it just go bad really fast when they rebooted the system?

[bsudbrink]

I don't speak Hebrew, but I thought I heard something that sounded like "telemetry loss" a couple of times towards the end.

[electromotive]

I don't speak Hebrew, but I thought I heard something that sounded like "telemetry loss" a couple of times towards the end.

"We seem to have a problem with our main engine."
"We are resetting the spacecraft to try to enable the engine"
"We have the main engine back on."
*telemetry cuts out*
*emergency call-out to JPL*
"The main engine is back on, but we've lost communication with the spacecraft."
*noun and verb code call-outs*
"We've lost it. We've lost it."

[Brumby]

Sounds like a delay from the reboot.

I keep imagining a message like this: "Performing update 1 of 3.  Do not turn off your computer".

[tsman]

The BBC article talked to the engine manufacturer. They're saying the difficulty is from using the same engine for propulsion to the moon and also descent. A certain amount of CYA is going to be involved in the explanation since it was their engine that didn't start up properly...

Before the landing, Rob Westcott, senior propulsion engineer at Nammo, said "We've never used an engine in this kind of application before".

He said the big challenge would be "the fact that the engine is going to have to be switched on and get very hot, then switched off for a short period of time when all that heat is remaining in its thermal mass, and then fired up again, very accurately and very precisely such that it slows the craft down and lands very softly on the surface on the Moon."

[schmitt trigger]

And at a cost of $100 million, it was done on a shoestring, as space expenditures go for.

Even if it crashed, it still qualifies as a landing, although a pretty rough one.

[electromotive]

Sounds like a delay from the reboot.

I keep imagining a message like this: "Performing update 1 of 3.  Do not turn off your computer".

The noun / verb call out had me wondering that as well. It's as if the engine re-initialized, but then didn't know which procedure it was supposed to complete afterward. By that point, impact would have been just seconds away.

[CatalinaWOW]

According to the article they think it got rid of ~98% of its approach speed.  Unfortunately this isn't horseshoes, so close doesn't count.  Even 99% would probably not have been survivable.

[Rick Law]

According to the article they think it got rid of ~98% of its approach speed.  Unfortunately this isn't horseshoes, so close doesn't count.  Even 99% would probably not have been survivable.

Well, may be it is not counted as a "landing" but "hitting" the moon is still an impressive accomplishment.  Granted, it is a lot easier to get that close with today's technology than in 1968 (the first human lunar orbiting), but given the distance involve, reaching just the vicinity of the moon is not easy.

Approx distance to moon ~ quarter million miles
Approx diameter of the moon ~ 2100 miles

Let just be generous and let the target be 2500 miles, that is a bull's eye of 2500 miles @ 250,000 miles away, moving target, with changing wind condition along the way.   (wind as in gravity, strength and direction changing all along the way from earth to moon.)

Very impressive given it is just their first try.

I think the discussion in Israel probably is: "I know we are on a budget, but next time we probably shouldn't source our stuff from AliExpress...  I really wonder about that MCU with the sanded off label that we used for our rocket controller board...  But you know, it was so cheap it was almost like free... "

[PA0PBZ]

Height: 0.149 Km
Desc. Rate: 134.3 m/s
Ground speed: 946.7 m/s
Not a lot you can do? 

[Lord of nothing]

Well there Drones are still an sucess and kill tousend of innocent People.
Israeli Technique is made for war and not for peace. 
And Yes I still buy there stuff because it work for the intend use. 

[electromotive]

Height: 0.149 Km
Desc. Rate: 134.3 m/s
Ground speed: 946.7 m/s
Not a lot you can do? 

I'll convert some of the values for non-metric users as well.
Height: 488.84 ft
Desc. Rate: 440.62 ft/s (300.42 mph or 483.48 kmh)
Ground speed: 3105.97 ft/s  (2117.71 mph or 3408.12 kmh)

Based on that telemetry data, the lander crashed 1.094 seconds later, after traveling a further 3,445.877 ft. (1.05 km) horizontal distance.

[Rerouter]

Scott manly did a good rundown, basically the lander was in complete freefall, though it was reporting that it was burning fuel, which left me confused unless it was just a calculated value based on burn time.

Equally the reset happened essentially at the point where no matter what they did, they did not have enough delta-V to get out of the situation.

[Brumby]

They weren't doing too bad with the vertical velocity.

Just think - if they were able to get the vertical velocity down a little bit more, they could have established a record for the closest lunar fly-by.  That would be a seat-of-the-pants ride .... 50m above the lunar surface at over 3,000 km/h.

[jonovid]

given the push into artificial intelligence this is a bit unexpected.
maybe stick to Temple building & land acquisitions back on earth!

[stj]

it does show one very important thing,
they arent short of money and SHOULD NOT be parrasitically sucking money out of the u.s. and germany every year.

[rdl]

It was under powered and to reach the Moon they had to make multiple burns right at periapse to maximize efficiency instead of just one long TLI burn. I'm guessing all those engine restarts contributed to the failure.

[amyk]

So I guess the classic saying now becomes "Does a Beresheet on the moon?"

[stj]

So I guess the classic saying now becomes "Does a Beresheet on the moon?"

israeli ones sheet everywhere.
 

[igendel]

Thanks to all here who actually addressed the lander story and didn't feel they had to throw in their personal biases against Israel.

The crash was a huge disappointment here, because this mission had tons of publicity - especially since the launch in February - and everyone was all worked up. Personally, even though I know Hebrew very well and I'm familiar with at least some of the jargon, I couldn't figure out what exactly went wrong. The media accounts so far are pretty much useless.

The landing process was supposed to be fully automatic, to land safely even with no communications at all. It's clear that the main engine did not fire as expected, so the lander didn't slow down in the critical phase of descent, but the telemetry was far more confusing than that. First it showed some problem with one of the Inertial Measurement Units, then there was a communications blackout, and then it appeared as though the engine was firing while the acceleration data indicated it definitely wasn't.

I can only assume it would take a deep technical dive to sort this out, and unfortunately that kind of data is not available publicly (yet?). The good news is that we're going to try again 

[Psi]

At-least they're not trying to claim that the moon was out of position.   

[schmitt trigger]

Space is hard. And the fact that a non-government enterprise was able to make it to the Moon, is an achievement on its own. I am sure that next time they will succeed.

I had also feared that this thread would become political ugly pretty quickly. But as I have mentioned previously, this forum is quite polite and civilized. The comments here have been quite tame compared to what I have read elsewhere.

[rdl]

I'm all for space exploration and don't really care much who does it. This failure was definitely disappointing. I hope their next attempt is successful.