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LightSail Wakes Up After Silent Spell and Tries To Spread Solar Sails
An anonymous reader writes: After a second outage LightSail's controllers have re-established contact with the experimental spacecraft, and plan to begin the process for unfurling its photo voltaic sails. LightSail is a solar sail propelled test spacecraft that was launched on May 20. Two days later, it went offline because of a software glitch. "It's exciting," said William Sanford Nye, the [Planetary] society's chief executive, who is better known as Bill Nye the Science Guy. "It's anxious. It's anxiety producing."
It's easy to criticize a low budget spacecraft. "They shouldn't have had a log file overflow". "They should have tested panel deployment under realistic conditions". That covered 99% of the comments in the previous slashdot thread about this thing.
And some of those criticisms are valid, make no mistake... but I'm inclined to cut them a little slack. This is a citizen-funded spacecraft developed on a shoe-string budget with a tiny team, caught up in schedules not of their own making. The first attempt is for them to learn from, and learning they are. Not everything has gone perfectly! But they have several of these planned, and the lessons they learn from the first will be applied to the following ones.
I think it is mildly incredible that within the next year or two, we might see a fucking Kickstarted spacecraft leave low earth orbit using a solar sail.
Sheesh. Nothing PV about them. (There are separate PV panels which provide power, but they are completely unrelated to the sail.)
It sounds like as soon as the sails unfurl, the satellite will re-enter Earth's atmosphere because of high altitude drag.
You realize that is intentional, yes? They are limited by being a small secondary payload on a launch funded and primarily meant for another purpose. They are launching a subsequent sail next year that is designed to leave LEO rather than re-enter, as this one was planned to do all along.
Yes, they should not have had the log file problem, but this is their first ever spacecraft, designed on fuck-all budget as far as such things go. Please point us all to the web page(s) for YOUR operational spacecraft, so that we can see how the really good people do it. I'm sure we could all learn from your perfection.
"4. Not placing the satellite high enough"
While I agree with your other points this one is likely out of their control. Cubesats due to their lack of backups, limited quality control and no attitude/orbit control systems are almost always put into low orbits that will degrade on their own within a year or so. And given this satellites obvious faults its probably not such a bad policy. There is enough junk in orbit as is without us throwing droves of dead cubesats into the mix.
And yet, they have a workaround for the csv problem, the reset did happen (and they were fairly sure it would), the batteries are now charged and the sail is deploying, and they expected it to re-enter fairly soon after deployment.
This is the test mission and it's quite successful in spite of problems. All with limited experience and a shoestring budget. They have learned a lot in the process, all of which will contribute to the success of the real thing which will fly soon.
Rumor has it the LightSail team installed software they downloaded from SourceForge, the bundled adware blew the stack and caused outages. Next time they'll know not to download anything from SourceForge.
The LightSail kickstarter crowdfunding campaign is still active. Moneys donated at this point will help fund a publicity campaign.
https://www.kickstarter.com/projects/theplanetarysociety/lightsail-a-revolutionary-solar-sailing-spacecraft
Jason Davis' blog has mission updates:
http://www.planetary.org/blogs/jason-davis/
This is a test mission. Still a historic achievement for solar sailing, though. The real LightSail mission will launch in 2016.
Wait, lemmegetthisstraight - it's somehow a "major embarrassment" to have put a spacecraft in orbit, which is sending back photos, was funded by space enthusiasts out of their own pockets, and has now achieved the nearly all of its intended objectives?
Because they have now had a successful sail deployment, which was what this thing was supposed to do. The only remaining thing is to send back a picture of the deployed sail. Despite the glitches, it has done everything they wanted from it, including acting as a test to shake out problems for the next one.
If only anything I've ever done in MY life could be such as "major embarrassment"...
This was a test flight on a shoestring budget. This thing was never going to sail anywhere. The whole idea was to see if the power management and sail deployment could be accomplished in a CubeSat footprint. Re-entry was planned to occur soon after sail deployment and it's not a surprise or a disappointment. Not bad for a Kickstarter.
Left MS Windows for Linux Mint and never looked back!
Vote for Bernie in 2016!
but clearly he doesn't know what it takes to put together a team that knows how to design a satellite.
The problem was if he put together a team that did know how to design a satellite he never would have managed to do it within the required budget. Let's not forget how much they were trying to accomplish, with how little, and despite all their problems lets also not forget how far they've managed to come.
Well, I'm not a space guy, just worked with avionics, but I would have started with a RTOS instead of Linux. Hint hint.
It is/was like a normal corporate or any other project then? Low on budget and with other project parameters (skill of a crew, time etc) also constrained. I'd say with all that they went ok. It was after all only a test flight. The main mission being scheduled for 2016.
Yes it has: http://www.planetary.org/blogs...
Don't be apathetic. Procrastinate!
Sometimes one needs Real Engineering(tm). This is an engineering test. To get to the point where Real Science(c) can get done.
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
It is/was like a normal corporate or any other project then?
No. It wasn't.
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
Adding more people to a project does not necessarily increase the chances for success. And, since the Planetary Society has a lot of educational outreach, I'm guessing that they included a lot of relative novices that learned a *hell* of a lot from the successes, but even more from the failures.
Anyways, I include this Planetary Society blurb because I believe this is one of the pathways to the solar system.
"Through this proof-of-concept mission, we will use CubeSats to open new paths beyond Earth and, one day, potentially to other planets with an inexpensive, inexhaustible means of propulsion: photons, solar energy in its purest form."
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
An RTOS is an obvious advantage. I wonder what the disadvantages of it were, as I assume they would have considered this. Expense? Resources? Experience? All of the above?
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
None of the problems they have had would have been solved by an RTOS, but it would have added cost. Sometimes an RTOS is really necessary, sometimes usually getting things done on time is good enough. Since the LightSail doesn't even have engines which may need to be fired with precision, RTOS wasn't really called for.
FYI, there are RTOS variants of linux. They aren't mutually exclusive.
Bill! Bill Nye! Is this you? Big fan!
They seem to have done reasonably well for such a low budget not to mention a launch schedule dictated from outside their project (when you're getting a free ride, you leave when the driver is ready). One hint is that the reset after a hardware upset actually restored the craft to functionality after crashing on a software error.
Latest data says the sail is deployed:
http://spaceflightnow.com/2015...
That would be the case if the primary purpose of this mission was scientific or engineering related. But it really seems mostly publicity-related. After all, the people running the Planetary Society do not believe in private space exploration; they are mainly just advocating more funding for NASA. A cynic might say that if they produce a mission that barely limps along, that's the best outcome for their goals: it gets people involved while at the same time "demonstrating" the need for large amounts of government funding.
I don't know what inspired you, but the idea of space travel by solar sails is much older than that. I used to enjoy Clarke, but as I have gotten older, have found him too much of a statist for my taste.
I am a happy backer. I have no regrets and will continue to fund them to some extent.
"So long and thanks for all the fish."
I agree with you for point 1 and 2.
But for the point 3, it looks like they actually designed the power supply to keep the batteries charged. They just have reach a level where the safe power mode has been activated, disabling all non essential function from the spacecraft. (it's a design choice to consider TM/TC as critical or not, I would say that it should stay on, but it can be discussed) Note that reaching a charge level that low could be linked to the fact that they have lost for several days the contact due to 1 and 2, which has delayed the SA deployment. (I haven't look in detail the design of the satellite, but usually a satellite get less power when the solar array are not deployed)
And for the point 4, it's a "design" choice. They have looked for a cheap launch to test a first version of their satellite, and found that one.
You forget, they had an absolute drop dead date. They could either fly and fix any remaining problems during the mission, or they could scrub.
You realize that Bill Nye was one of the Engineers who designed the Boeing 747 right ? His credentials as an engineer were pretty damn well established before he ever hosted a children's show.
And clearly he has experience working in teams doing massive engineering projects on hugely complicated designs.
What he may not have much experience with is those teams working on a budget slightly less than the one you get from the sperm bank.
Unicode killed the ASCII-art *
Likely their teams experience with a real-time platform and I strongly suspect additional cost of compatible equipment. I would bet an arm that the dev community for drivers in Linux is exponentially larger then that of any RTOS on the market.
Damn amateurs... Any decent coder would have made sure there's no buffer overflow that would jam system... I'm little surprised they dint catch CSV file overflow in testing phase in lab..
Because no pro coder has ever overflowed a buffer. Hell, MS built a business model on shipping defective code.
Oh, I'm sorry sir, I thought you were referring to me, Mr. Wensleydale.
So Christ exchanged emails with the Anti-Christ?
APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?
While it is not technically "tacking," gravity provides the counter force that allows a spacecraft to steer with a lightsail.
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RTOS is not needed, nor is it practical.
The only thing they really missed out on design-wise was having a hardware watchdog reboot it faster than it would have otherwise done.
I've been building those into remotely deployed systems for 35+ years. The top of a mountain may not be LEO but not having to helicopter out to hit a reset button because you can't drive out through 15-foot deep snowdrifts saves a few thousand dollars the first time you get a lockup.
"They could either fly and fix any remaining problems during the mission, or they could scrub."
This is the essence of flying any space probe where you're a hitchhiker. It's why Beagle didn't quite complete its mission and it's why what was left of the original Solar mission ended up being dug out out of a south american swamp by the french foreign legion (there's a piece of that sitting in a glass case not far from me).
All in all they did well. They'll do better next time and that is the essence of cubesats (learning from your mistakes).
"The problem was if he put together a team that did know how to design a satellite he never would have managed to do it within the required budget"
People who "know how to build satellites" would never fit what they know how to build into a cubesat even if they were free. Believe me, I've watched them trying.
Actually, from what I understand it's the resistance of the keel that lets a sailing ship tack into the wind. The keel is long and thin seen from the front and wide and flat seen from the side - so in one sense it is water resistance, but its resistance of sideways motion vs. front to back motion. A flat bottomed rowboat can't tack even if you add sails - no keel. Learned that from Peabody and Sherman a few centuries ago.