Author Topic: Atlas V 501- AFSPC-05 (X-37B OTV-4) - May 20, 2015 to May 7, 2017 - UPDATES  (Read 118571 times)

Offline zubenelgenubi

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #240 on: 05/27/2015 08:28 PM »
Just because LightSail-A shut down, does that mean it failed?

If they can't get the satellite to reboot, then yes.  The photon sail had not yet been deployed.

If they cannot reboot the satellite, or they revive the satellite, but the sail deploy fails:
"LightSail is capable of remaining in orbit about six months in its CubeSat form." (from Mr. Davis' blog post)
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Offline kevin-rf

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #241 on: 05/27/2015 09:02 PM »
Right, but this requires the computer to be able to interpret the uplinked commands - which if it is frozen, it will not.  Not including a hardware watchdog timer is a poor design decision.

Based on what you said up-thread it sounds like this system does not have a watchdog, or a watchdog enabled by default.

That said, it is also possible to screwup the implementation of a watchdog. If done wrong, it could be updating the watchdog while still stuck...
« Last Edit: 05/27/2015 09:03 PM by kevin-rf »
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Offline kevinof

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #242 on: 05/27/2015 09:12 PM »
Right, but this requires the computer to be able to interpret the uplinked commands - which if it is frozen, it will not.  Not including a hardware watchdog timer is a poor design decision.

Based on what you said up-thread it sounds like this system does not have a watchdog, or a watchdog enabled by default.

That said, it is also possible to screwup the implementation of a watchdog. If done wrong, it could be updating the watchdog while still stuck...

From what I understand there is no watchdog timer in the system.

Offline Andrewwski

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #243 on: 05/28/2015 12:01 AM »
The board they are using does not have a built-in watchdog.  They would have had to implement an external one.  I haven't seen one mentioned in any of the articles, so it does not seem that they have one.
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Offline king1999

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #244 on: 05/28/2015 04:16 AM »
Raise your hand for how many times you tested something, had it pass SQA, get released to the wild, and then found the SQA test didn't cover everything and had to issue a fast patch. I would raise my hand, but I don't have enough ;)
Yes, they need to assume that this kind of human errors would happen and have something built-in to handle it. A simple hardware watchdog would do well. This kind of bugs are very common even in space. Mars Rover had to deal with it.
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« Last Edit: 05/28/2015 04:18 AM by king1999 »

Offline Ben the Space Brit

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #245 on: 05/28/2015 01:02 PM »
Solar sails seem to be functioning under something of a curse, don't they? I'm aware of three vehicles so far.

One was Japanese and didn't work, one was American and never flew because the contractor's internal organisational issues led to its cancellation, now LightSail-1's apparent brain-death.

How long will they keep monitoring the vehicle for a reboot? It would be a shame if they give up after a month and then, a month later, the vehicle restarts, deploys and soars off with no-one the wiser!
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Offline kevin-rf

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #246 on: 05/28/2015 01:53 PM »
Solar sails seem to be functioning under something of a curse, don't they? I'm aware of three vehicles so far.

One was Japanese and didn't work, one was American and never flew because the contractor's internal organisational issues led to its cancellation, now LightSail-1's apparent brain-death.

How long will they keep monitoring the vehicle for a reboot? It would be a shame if they give up after a month and then, a month later, the vehicle restarts, deploys and soars off with no-one the wiser!

You missed NASA's NanoSail-D and NanoSail-D2. The first was lost in a falcon 1 launch failure, the other was launched on a Minotaur-4 in 2010.

http://space.skyrocket.de/doc_sdat/nanosail-d.htm
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Offline Star One

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #247 on: 05/28/2015 02:29 PM »
Article on the X-37B's unusual low orbit and inclination. Interesting speculation in the comments ELF propulsion anyone.:) Perhaps that's why there was no photos of it before launch.

http://spaceflightnow.com/2015/05/27/x-37b-spaceplanes-orbit-discovered/

Offline kevin-rf

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #248 on: 05/28/2015 03:04 PM »
194 by 202 mile orbit (312 X 325 km) inclined 38 degrees, should lead to some really fast passes for those far enough south.

I just checked heavens above and for me it will never be higher than 30 degrees. Might have to take trip down to DC for viewing...
« Last Edit: 05/28/2015 03:12 PM by kevin-rf »
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Offline zubenelgenubi

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #249 on: 05/28/2015 03:42 PM »
Solar sails seem to be functioning under something of a curse, don't they? I'm aware of three vehicles so far.

One was Japanese and didn't work, one was American and never flew because the contractor's internal organisational issues led to its cancellation, now LightSail-1's apparent brain-death.

How long will they keep monitoring the vehicle for a reboot? It would be a shame if they give up after a month and then, a month later, the vehicle restarts, deploys and soars off with no-one the wiser!

You missed NASA's NanoSail-D and NanoSail-D2. The first was lost in a falcon 1 launch failure, the other was launched on a Minotaur-4 in 2010.

http://space.skyrocket.de/doc_sdat/nanosail-d.htm

The Planetary Society lost their previous solar sail experimental satellite in June 2005 in a launch failure--a Volna-O rocket launched from a Russian submarine.

http://space.skyrocket.de/doc_sdat/cosmos-1.htm
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Offline eeergo

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #250 on: 05/28/2015 05:38 PM »

One was Japanese and didn't work, [...]

IKAROS (launched with Akatsuki) did work, and so successfully they're still in contact with it after solar opposition!

http://global.jaxa.jp/projects/sat/ikaros/
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Offline Kansan52

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #251 on: 05/28/2015 06:00 PM »

IKAROS (launched with Akatsuki) did work, and so successfully they're still in contact with it after solar opposition!

http://global.jaxa.jp/projects/sat/ikaros/

Did not know that. Excellent news.

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #252 on: 05/31/2015 05:42 AM »
Well the luck is there! LightSail's computer has re-booted 8 hours ago!  ;D

http://www.planetary.org/blogs/jason-davis/2015/20150530-lightsail-phones-home.html
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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #253 on: 06/01/2015 12:05 AM »
Well the luck is there! LightSail's computer has re-booted 8 hours ago!  ;D

http://www.planetary.org/blogs/jason-davis/2015/20150530-lightsail-phones-home.html

Let's hope the computer stays on.
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Online hop

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #254 on: 06/01/2015 02:00 AM »
Let's hope the computer stays on.
Looks like they have a plan for that:
Form Jason Davis https://twitter.com/jasonrdavis/status/605130192638451712
Quote
102 LightSail packets received since yesterday. Team attempting software patch; rebooted manually to keep troublesome beacon.csv in check.
« Last Edit: 06/01/2015 02:08 AM by hop »

Offline a_langwich

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #255 on: 06/04/2015 03:15 PM »
http://www.planetary.org/blogs/jason-davis/2015/20150603-ls-panel-deploy-update.html

-- solar panels commanded to deploy
--- subsequently temps dropped, consistent with exposure to space, but voltage levels have not risen as expected
--- possibly camera heaters + power used to deploy solar panels depleted batteries and will recover

Battery voltage is at 3.9 V, team would like to see 4.2 V before solar sail deployment.  This will be monitored during comm passes Thursday June 4.  If the voltages recover, the team would like to command sail deployment Friday June 5.


Online DaveS

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #256 on: 06/04/2015 09:45 PM »
LightSail has fallen silent once again, no signals detected at all during the ground station passes today: https://twitter.com/jasonrdavis/status/606559935086759939

Early thinking is battery protection mode: https://twitter.com/jasonrdavis/status/606486955191189504
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Offline Kaputnik

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #257 on: 06/06/2015 10:48 PM »
Lightsail is back online after a suspected battery problem.
Sail deployment is scheduled for tomorrow:

http://www.planetary.org/blogs/jason-davis/2015/20150506-lightsail-wakes-second-time-1.html
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Online DaveS

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Re: LIVE: Atlas V 501- AFSPC-05 (X-37B) - May 20, 2015
« Reply #258 on: 06/07/2015 05:52 PM »
All is GO for LightSail deploy at 2:02 pm EDT: https://twitter.com/jasonrdavis/status/607581131299356672

Teams on console ready for deployment: https://twitter.com/jasonrdavis/status/607605030078652416
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-USA engineer about the rollback of Discovery prior to the STS-114 Return To Flight mission

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