Author Topic: Beresheet, SpaceIL Israeli Moon mission  (Read 127688 times)

Online Comga

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Re: Spaceil Israeli Moon mission
« Reply #60 on: 02/26/2019 05:14 pm »
There [are] some pluses to taking slow route to moon. Plenty of time to find bugs and sort them out before critical landing.
But a downside is multiple trips through the radiation belts.
We don't have any evidence that the most recent glitch is even related to radiation, but computer resets are a common result of radiation effects like single event upsets.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline GregTheGrumpy

Re: Spaceil Israeli Moon mission
« Reply #61 on: 02/27/2019 12:05 am »
I've warned you before, Chris Bergin, there's a mission thread for this and updates on the above nature should be posted here:

https://forum.nasaspaceflight.com/index.php?topic=47217.0

Honestly, some people! ;)

(Sorry about posting in the wrong place :))


But you could reasonably say that it was, in fact, an Update.  It just wasn't a picture and you weren't discussing it.  Just providing a fact content.  Is this wrong thinking on my part somehow?

Offline Phil Stooke

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Re: Spaceil Israeli Moon mission
« Reply #62 on: 02/27/2019 12:57 am »
"But a downside is multiple trips through the radiation belts."

Yes, but very dependent on the inclination (in this case, 27 degrees).  If SMART-1 could survive it anything else should be OK.

Offline Blackstar

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Re: Spaceil Israeli Moon mission
« Reply #63 on: 02/27/2019 02:25 am »
If SMART-1 could survive it anything else should be OK.

Presumably SMART-1 went through radiation testing before the mission. That's probably not the case for this mission.

I've been seeing some discussion among American space radiation experts who think that the reported computer problem was probably a radiation event, a Single Event Effect:

https://radhome.gsfc.nasa.gov/radhome/see.htm

« Last Edit: 02/27/2019 02:31 am by Blackstar »

Offline mcgyver

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Re: Spaceil Israeli Moon mission
« Reply #64 on: 02/27/2019 08:29 am »
If SMART-1 could survive it anything else should be OK.

Presumably SMART-1 went through radiation testing before the mission. That's probably not the case for this mission.

I've been seeing some discussion among American space radiation experts who think that the reported computer problem was probably a radiation event, a Single Event Effect:

https://radhome.gsfc.nasa.gov/radhome/see.htm
Space newbies...  ???
« Last Edit: 02/27/2019 06:40 pm by mcgyver »

Offline lamid

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Re: Spaceil Israeli Moon mission
« Reply #65 on: 02/27/2019 12:44 pm »
If I understand correctly raw data of this file, Beresheet is going to "upgrade" its orbit this night, raising apogee from 74000 to 120000 km:
25/02/2019 9.54 -  74140km
26/02/2019 20.49 - 121232km

Next raisings:
10/3: 276000 km
25/3: 391000 km

Source: http://live.spaceil.com/

yes, it is geocentric orbital state vectors: date   x   y   z   vx   vy   vz

and last version
Apo 25.2.19 10:33 75331 km
Peri 25.2.19 22:05 6974.7 km
Apo 26.2.19 21:06 123397 km
http://live.spaceil.com has text: the telemetry data is updated every 24 hour
I do not know how old they are
and therefore whether they are current.

Edit
these are out-of-date data as if the ignition had gone right.
« Last Edit: 02/27/2019 01:04 pm by lamid »

Offline mcgyver

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Re: Spaceil Israeli Moon mission
« Reply #66 on: 02/27/2019 01:06 pm »

yes, it is geocentric orbital state vectors: date   x   y   z   vx   vy   vz
I thought that... but then I found negative values...  ???
Are they centered on Earth distance from Sun rather than on Earth center?

Offline lamid

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Re: Spaceil Israeli Moon mission
« Reply #67 on: 02/27/2019 01:17 pm »
yes, has negative values
GEOCENTRIC, Earth is the center of coordinates.

Beeresht2.png  + Moon trajectory
Coordinate systm: Earth Mean Equator and Equinox of Reference Epoch

Beresheet3.png 4.apr 2019 12:00 Monn and probe position  (that's bad, somewhere I'm mistaken (UTC and Israel Time?))
« Last Edit: 02/28/2019 08:16 am by lamid »

Offline koraldon

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Re: Spaceil Israeli Moon mission
« Reply #68 on: 02/27/2019 03:47 pm »
If SMART-1 could survive it anything else should be OK.

Presumably SMART-1 went through radiation testing before the mission. That's probably not the case for this mission.

I've been seeing some discussion among American space radiation experts who think that the reported computer problem was probably a radiation event, a Single Event Effect:

https://radhome.gsfc.nasa.gov/radhome/see.htm

Out of curiosity, where can one read that discussion?
Thanks

Offline mcgyver

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Re: Spaceil Israeli Moon mission
« Reply #69 on: 02/27/2019 04:58 pm »
yes, has negative values
GEOCENTRIC, Earth is the center of coordinates.

Beeresht2.png  + Moon trajectory
Coordinate systm: Earth Mean Equator and Equinox of Reference Epoch
Thanks, I didn't think of plotting y vs x, I plotted "something" vs time.  ::)

Online Comga

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Re: Spaceil Israeli Moon mission
« Reply #70 on: 02/27/2019 06:45 pm »
If SMART-1 could survive it anything else should be OK.

Presumably SMART-1 went through radiation testing before the mission. That's probably not the case for this mission.

I've been seeing some discussion among American space radiation experts who think that the reported computer problem was probably a radiation event, a Single Event Effect:

https://radhome.gsfc.nasa.gov/radhome/see.htm

No spacecraft or instrument I have worked on has been "radiation tested", exposed to protons, gamma rays, electrons, etc.,  as a whole.  Generally components, and occasionally subsystems like circuit boards, are tested like that.  I have even sent components and material samples to some of the labs listed in the GSFC link, and another in Colorado Springs, CO.  I bet the Israelis have their own facilities for some of this testing.

The linked page has a further link to a list of components, whose types have been tested by GSFC and found tolerant to radiation.  It is assumed that IAI referred to this and similar lists to choose acceptable parts.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline mcgyver

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Re: Spaceil Israeli Moon mission
« Reply #71 on: 02/27/2019 07:35 pm »
If SMART-1 could survive it anything else should be OK.

Presumably SMART-1 went through radiation testing before the mission. That's probably not the case for this mission.

I've been seeing some discussion among American space radiation experts who think that the reported computer problem was probably a radiation event, a Single Event Effect:

https://radhome.gsfc.nasa.gov/radhome/see.htm

No spacecraft or instrument I have worked on has been "radiation tested", exposed to protons, gamma rays, electrons, etc.,  as a whole.  Generally components, and occasionally subsystems like circuit boards, are tested like that.  I have even sent components and material samples to some of the labs listed in the GSFC link, and another in Colorado Springs, CO.  I bet the Israelis have their own facilities for some of this testing.

The linked page has a further link to a list of components, whose types have been tested by GSFC and found tolerant to radiation.  It is assumed that IAI referred to this and similar lists to choose acceptable parts.


There are two different steps in this process:
1) Components manufacturer tests their components against radiation and provide radiation test reports
2) Spacecraft manufacturers purchase radiation hardened components as per mission requirements, BUT they also perform simulation of EACH component behaviour in mission environment and calculate the probability of failure during mission time. If they have enough money...


Online ccdengr

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Re: Spaceil Israeli Moon mission
« Reply #72 on: 02/27/2019 10:58 pm »
The linked page has a further link to a list of components, whose types have been tested by GSFC and found tolerant to radiation.
It's unlikely that a cost-constrained mission would be able to use such parts exclusively.  Using soft parts with some kind of imperfect error mitigation is pretty common in cost-constrained Newspace missions.  Murphy's Law always applies for when an error might show up; at least SpaceIL correctly aborted instead of losing the mission.  We'll see if/how they will recover.

Offline Lar

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Re: Spaceil Israeli Moon mission
« Reply #73 on: 02/28/2019 04:24 am »
When is the next burn? I am assuming they can't miss two in a row, no?
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline Blackstar

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Re: Spaceil Israeli Moon mission
« Reply #74 on: 02/28/2019 04:39 am »

No spacecraft or instrument I have worked on has been "radiation tested", exposed to protons, gamma rays, electrons, etc.,  as a whole.  Generally components, and occasionally subsystems like circuit boards,

I meant the components.


Offline Blackstar

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Re: Spaceil Israeli Moon mission
« Reply #75 on: 02/28/2019 04:52 am »
There are two different steps in this process:
1) Components manufacturer tests their components against radiation and provide radiation test reports
2) Spacecraft manufacturers purchase radiation hardened components as per mission requirements, BUT they also perform simulation of EACH component behaviour in mission environment and calculate the probability of failure during mission time. If they have enough money...

Yeah, all that costs money. On a cost-constrained mission, they just may not be able to do it.

I ran a DoE/USAF/NASA-funded study in 2017 on the US infrastructure for testing components. There's a push to use commercial electronic parts in space for lower cost missions like cubesats. One of the more interesting aspects of this work is that automobile electronics perform quite well. When you think about it, they're designed for a broad range of temperatures (arctic to desert), humidity, vibration, and longevity. And in fact, some automobile electronics are radiation hardened. So they're decent options for spaceflight, assuming that they can actually do the mission. Many other consumer electronic parts like those designed for household appliances and even cellphones are actually poor options for spaceflight. Quite often they are either designed sloppily, or they're not really intended to have longevity, but to be disposed of when the next generation comes along, like cellphones. They don't do well in space, although they can be cheap, and if you're launching 100 cubesats and you're willing to lose 5% of them because of radiation, then maybe that's a decent trade.

Offline Bogeyman

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Re: Spaceil Israeli Moon mission
« Reply #76 on: 02/28/2019 05:49 am »
When is the next burn? I am assuming they can't miss two in a row, no?
I've been asking this myself. The pity is that SpaceIL doesn't seem to be very big in providing information. Their twitter account is full with questions being unanswered. I just hope they can do something during next perigee...

Offline mcgyver

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Re: Spaceil Israeli Moon mission
« Reply #77 on: 02/28/2019 07:16 am »
There are two different steps in this process:
1) Components manufacturer tests their components against radiation and provide radiation test reports
2) Spacecraft manufacturers purchase radiation hardened components as per mission requirements, BUT they also perform simulation of EACH component behaviour in mission environment and calculate the probability of failure during mission time. If they have enough money...

Yeah, all that costs money. On a cost-constrained mission, they just may not be able to do it.

I ran a DoE/USAF/NASA-funded study in 2017 on the US infrastructure for testing components. There's a push to use commercial electronic parts in space for lower cost missions like cubesats. One of the more interesting aspects of this work is that automobile electronics perform quite well. When you think about it, they're designed for a broad range of temperatures (arctic to desert), humidity, vibration, and longevity.
yes they perform well in any environmental situation... on Earth. On Earth you have (almost) no radiation. But the first thing you discover when you put in space an Earth-designed circuit is that there are "mysterious malfunctions in electronics".
They were mysterious in '60s, now we call them Single Event Effects: Upset, Burn-out, Latch-up, Gate Rupture, whatelse...




Offline Bogeyman

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Re: Spaceil Israeli Moon mission
« Reply #78 on: 02/28/2019 07:51 am »
I hope my question is not all too stupid: Wouldn't it be possible to encapsulate circuit boards etc. properly to resist radiation? Like put a lead case around it? Or is the radiation just too strong and then the whole probe would become extremely heavy?

Offline mcgyver

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Re: Spaceil Israeli Moon mission
« Reply #79 on: 02/28/2019 10:10 am »
I hope my question is not all too stupid: Wouldn't it be possible to encapsulate circuit boards etc. properly to resist radiation? Like put a lead case around it? Or is the radiation just too strong and then the whole probe would become extremely heavy?
There are specific softwares which calculate how much alluminum/kovar/steel you should put around a component to prevent it from "burning up" in space (total ionising dose calculations).
You can't instead shield against Single Event Effects, you must rely on component hardness and take into account the failure probability along mission duration; if too many effects are foreseen for the period, you can or select a different component, or setup HW redundancy or SW corrective actions which allow continuing the mission without that component, or with degraded performance from it. But stronger components cost more, redundancy costs more.
With just 100 M$ you can just send an iPhone on the Moon... ;)
Do 100M$ include launch costs?!?




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