LightSail / Planetary Society build a $2.5M+ satellite with no watchdog timer - Page 1
Forum section: electronics / general

author: LabSpokane
author_rank: Super Contributor
timestamp: May 28, 2015, 06:22:25 pm
content: http://sail.planetary.org/missioncontrolhttp://sail.planetary.org/story-part-1.htmlIn short, Bill Nye is attempting to wear the mantle of Carl Sagan by realizing Sagan's vision of a spacecraft propelled by light pressure. It is a program that has resulted in a spending spree that would even make NASA blush. Over $4M in donations have been expended thus far on two, 3U Cube Sats. One cube sat is currently drifting about the earth incommunicado, CPU locked up due an easily reproducible software error. Apparently, in the melee to spend millions on cube sats (the raw kits cost maybe $10K each), they forgot to include an external watchdog timer. In fact, the Planetary Society seems blissfully unaware of such a device's existence. From:http://www.planetary.org/blogs/jason-davis/2015/20150526-software-glitch-pauses-ls-test.html?referrer=http://t.co/iEqtb4yZvLQuoteThe Planetary Society's current plan is to await a perfectly-timed cosmic ray to reset the CPU, then fix the bad firmware that should have been tested on Earth (had the Planetary Society had the foresight to perform systems tests prior to launch).Cube Sats are not cheap, but they don't cost millions each either. Launch costs are listed between $50K and 100K USD - which I'm assuming is for a 1U. If there are reaction wheels, sun and or star trackers, etc., that adds to the cost as well. And of course engineers and techs cost money, but $5.5M is a staggering sum for what are largely existing plaftorms with an add-on "pop-up" sail.Now, thanks to the miracle of crowd-funding, you too can help the Planetary Society spread the word about questionable engineering and test practices by giving them more cash to blow via Kickstarter:https://www.kickstarter.com/projects/theplanetarysociety/lightsail-a-revolutionary-solar-sailing-spacecraft

author: bills
author_rank: Frequent Contributor
timestamp: May 28, 2015, 09:12:51 pm
content: I informed them about your idea of a external watchdog timer, maybe they will learn something.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 29, 2015, 11:07:23 am
content: I alluded to the file overflow problem, which should have easily been detected. I'm talking about an external watchdog doing a system reset including the radio, not the watchdog internal to the micro. Regardless of the specifics, I'm shocked at the level of spending versus the obvious lack of testing and design.This has been a huge drain on the finances of the Planetary Society. I thought the $4M might have been an exaggeration, but nope. A perusal of the annual reports shows they really did spend it, or at least allocated it to that accounting bucket.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: May 29, 2015, 12:02:09 pm
content: Quote from: LabSpokane on May 29, 2015, 11:07:23 amThat's bloody cheap for three missions, and believe it or not they may have decided not to include something like an external watchdog timer due to the weight, every gram counts on launches. And it could have been worse, they could have mixed up inches and centimeter, but I guess no one spending millions would ever do that :p

author: andersm
author_rank: Super Contributor
timestamp: May 29, 2015, 01:05:16 pm
content: In one of the comments on the blog post, it was mentioned that the system board was designed by a company called Tyvak. Assuming it isthis one, there is an external hardware watchdog present. That would mean it is either not used, or it is never triggered due to some design flaw in how the software tasks are monitored.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 29, 2015, 02:56:05 pm
content: Quote from: Mechanical Menace on May 29, 2015, 12:02:09 pmCheap for big space for sure. For microsats, not so much. AMSAT (who probably has launched more microsats than any other single entity) estimates launch costs at $100K USD/kg. So, I could see a $250K launch bill x 3. Maybe tracking station time is more expensive than I think it is. But over $5M for three microsats really seems expensive.For reference, a 16 pin DIP package is approximately 0.001661 kg. So, we're talking about a sub-$300 decision with solder and support components. Not cheap, but reasonable insurance in light of the launch costs.Regardless, testing adds no weight at all.The good part of all this is that it has me reading up on microsats and might get inspired to get my HAM license and join AMSAT. Those folks really have cost-effective space nailed down.

author: m98
author_rank: Frequent Contributor
timestamp: May 29, 2015, 03:11:54 pm
content: Quote from: Mechanical Menace on May 29, 2015, 12:02:09 pmA simple watchdog timer IC as CSP weights somewhere in the milligram region, launch costs are not nearly calculated that tight.

author: LabSpokane
author_rank: Super Contributor
timestamp: May 29, 2015, 03:15:05 pm
content: Quote from: andersm on May 29, 2015, 01:05:16 pmInteresting. Here's the price sheet:http://static1.squarespace.com/static/50e0b24de4b03955129ee278/t/53dfc347e4b07b43013d5d20/1407173447631/BB14-70_Tyvak-IntrepidDatasheet4.pdfI'm coming up with $56,500 for a fully-optioned out 3U system with integration. So, $169,500 for 3 satellites in basic hardware costs + the sail system + launch costs + ground control.Basic mass is 1.2kg, call it 2kg with the sail, so $200,000 each in launch costs. I'm up to $870,000.So, let's round up and call this program a $1.5M program for three satellites, launch costs, ground costs, NRE and extra hardware for the sails.Where's the other $3M+? What have I left out?

author: bills
author_rank: Frequent Contributor
timestamp: June 09, 2015, 11:50:47 pm
content: It's working again. It appears a cosmic particle rebooted it???http://www.planetary.org/blogs/jason-davis/2015/20150607-lightsail-deployment-initiatied.html

author: LabSpokane
author_rank: Super Contributor
timestamp: June 10, 2015, 03:02:39 am
content: Quote from: bills on June 09, 2015, 11:50:47 pmThe Planetary Planetary Society has a curious definition of "success:" bad firmware undiscovered due to not allowing the unit to operate for over 40 hours prior to launch (who does that!?), a bad power system, and a partial sail deployment. I'd be ok with "we've got some work to do," but to do a victory lap after screwing the pooch so badly is just absurd.

author: Len
author_rank: Frequent Contributor
timestamp: June 10, 2015, 03:31:25 am
content: Quote from: LabSpokane on June 10, 2015, 03:02:39 amStandard procedure, re-define "success" after the mission. Look at NASA's press release about the failed LDSD test the other day:http://www.nasa.gov/press-release/nasas-ldsd-project-completes-second-experimental-test-flightFor the second time, the parachute ripped when it was deployed. But now they say that's what they wanted to happen:QuoteYeah, right.

author: Howardlong
author_rank: Super Contributor
timestamp: June 10, 2015, 04:37:39 pm
content: Quote from: LabSpokane on May 29, 2015, 03:15:05 pmI suspect because a good deal of the development was farmed out commercially, but will ask those in the know.AMSAT organisations, of which I am an active member and am involved directly in many past and present spacecraft development projects, both successful and a few not quite so much, are predominantly run and developed by volunteers. We do sometimes use third party off the shelf parts such as deployable antennas and power supplies where we sometimes find we lack sufficient resource, but from a pure R&D and testing perspective it's pretty much all volunteer work.

author: LabSpokane
author_rank: Super Contributor
timestamp: June 10, 2015, 05:30:03 pm
content: Quote from: Howardlong on June 10, 2015, 04:37:39 pmI think it's these folks:http://www.eclipticenterprises.com/

author: Rasz
author_rank: Super Contributor
timestamp: June 29, 2015, 06:00:56 am
content: Quote from: LabSpokane on May 29, 2015, 03:15:05 pmmiddlemen, telephone sanitizers gotta eat

author: Stonent
author_rank: Super Contributor
timestamp: June 29, 2015, 07:38:37 am
content: Quote from: Rasz on June 29, 2015, 06:00:56 am