Share this project

Done

Share this project

Done
A nano-satellite that lets you take Earth images and "tweet" from space, then inflates a visible balloon, and de-orbits cleanly.
A nano-satellite that lets you take Earth images and "tweet" from space, then inflates a visible balloon, and de-orbits cleanly.
2,711 backers pledged $116,890 to help bring this project to life.

Looking Back, Looking Forward

48 likes

This is the final update to the SkyCube project. I'd like to begin by thanking everyone who's followed and supported SkyCube over the past 2 years.  You made possible some amazing accomplishments.  You proved that an amateur team can build, manifest, and orbit a functioning spacecraft on a shoestring budget.  You were pioneers in a DIY space movement that - over the past few years - has blossomed into a multi-million-dollar industry.

FINAL MISSION STATUS

At this point, SkyCube's 90-day mission is now complete. Our definitive contacts with SkyCube on March 27th were our last communications with the satellite. Since then, we tried many different command sequences to cut the solar panel restraints, reboot the satellite, and inflate its balloon. These did not generate any apparent response. On July 8th, we stopped attempting further communication. Our efforts since then have concentrated on determining the cause of these results.

SkyCube deployment from ISS, 28 Feb 2014.  SkyCube is the middle satellite in the "train."
SkyCube deployment from ISS, 28 Feb 2014. SkyCube is the middle satellite in the "train."

Interestingly, of the five CubeSats deployed from ISS on February 28th, SkyCube is the last remaining in orbit. It's expected to stay there several months longer; the other four CubeSats in our deployment have all decayed and reentered Earth's atmosphere. We feel this is conclusive proof that SkyCube's solar panels did not open on day 1. If they had, the SkyCube would have had more surface area than any other satellite in the deployment, hence the most drag, and fastest orbit decay.

CubeSats in SkyCube's deployment
CubeSats in SkyCube's deployment

A solar panel non-deployment would explain our other communication problems. SkyCube's radio antennas were tucked inside the solar panels for launch. They could not have extended if the solar panels never released. Antennas folded inside solar panels would explain why SkyCube's transmissions were so weak and sporadic. On March 30th, we tested radio communication with SkyCube's twin in packed configuration, and found that its signal was weakened by about the same amount (10 - 12 dB) as the difference between the expected and observed signal strength in the packets that were actually received on March 27th.

Solar panel non-deployment would also explain why the balloon did not inflate: the tie lines restraining the solar panels were deliberately reinforced, to prevent the lid from opening in case of premature balloon inflation. If the tie lines were not cut loose, the balloon could not have punched through the lid.

SkyCube in packed configuration.
SkyCube in packed configuration.

ONE MYSTERY REMAINS

Our final remaining unanswered question is this: the solar panel deployment mechanism was tested repeatedly on the ground, so why did it fail in space? None of the proposed theories are very satisfying:

  • Burnwires cut nylon more slowly in vaccuum.  We didn't test the solar panel deployment in a vacuum chamber before launch.  But we did test the (identical) balloon inflator burnwire mechanism in vaccuum before launch, and re-tested the burnwire mechanism in vacuum in March 2014.  These tests showed burnwires cutting nylon in 3 - 5 seconds, with no noticeable difference between the time to cut them in air.
  • Battery charge was not sufficient to power the burn wires.  In testing, we learned that a battery charge below 7.25 volts was not sufficient to power the burn wires.  But we programmed the satellite to wait until battery charge was above this level before attempting the deployment.  When signal was actually receieved from the satellite, the battery voltage was over 8V.
  • Burnwires broke due to vibration on launch.  If burnwires came loose or disconnected, applying current would have no effect.  However, burnwires survived all pre-launch vibration tests without incident; and all 4 burnwires would have to have broken in this way.
  • Burnwires worked perfectly, but hinges were mechanically stuck.  Again, we did not observe this in testing, and all four independent solar panels would have to have gotten stuck the same way to explain a complete failure.

The truth is that we may never know the answer. Rather, we view this as a lesson learned: if this is your first satellite, design it without moving parts that are required to deploy for mission success.

WHAT WE ACCOMPLISHED

Given the solar panel deployment problem, it's even more remarkable that we did actually hear from our satellite on orbit. The contacts on March 27th proved that the satellite's electronics had been working normally for at least a month. The batteries were fully charged; the solar cells and power system worked as designed.

This also means that all of your names were actually transmitted by the satellite as "tweets" (albeit quietly, through folded antennas) during the mission's first week. Those tweets are still streaming out across the universe on 915 MHz at the speed of light.

Our ground station operators at Saber Astro and elsewhere also deserve special mention. During the difficult post-deployment period, after the first suggestive transmissions were received, they patiently kept listening while 3 weeks of silence followed. Through the silence, they repeatedly pinged each of the five candidate objects for a response. Without their persistence, that response would have never been caught.

THE BIG PICTURE

Over the 2+ years since this project began, CubeSats have made enormous progress in general. When SkyCube's kickstarter launched in July 2012, they were an academic curiosity. When SkyCube's kickstarter began, the greatest number launched in any year was fifteen (in 2010). So far in 2014, more than sixty CubeSats have been launched. On our own launch, 33 CubeSates were carried into orbit. Of those, 28 were commercial earth-imaging satellites, operated by Planet Labs in San Francisco. In July, NanoSatisfi - whose ArduSat kickstarter preceded ours - announced its transformation into Spire, a global asset-tracking service using CubeSats. The same month, Spaceflight Services announced a new commercial small satellite communication service.

Movement really is happening. Significant venture capital is flowing into the field. Communication challenges are being addressed. Access to space really is getting easier. Our timing may have been a bit eariy. Our results may have been different if we'd started now instead of 2 years ago. We were pioneers in the movement, and performed a tremendous amount of work on an incredibly small budget. Hearing from SkyCube on orbit - at all! - was a more successful result than the majority of first-time CubeSats achieve. And we have a lot of very hard working and talented people to thank for that.

Finally, we have all of you to thank. Although this particular chapter may be closing, the larger story of the New Space movement is far from over. We encourage you to take advantage of our lessons learned, to take on new challenges of your own, and to view what we all accomplished not as falling short of some specific goals, but as a groundbreaking achievement in the democratization of space exploration.

You have our gratitude for making it possible.

-Tim on behalf of Team SkyCube

Comments

Only backers can post comments. Log In
    1. Brent Sieling
      Superbacker
      on September 28, 2014

      I hope this is not the "final" update. The true final update should be information on the next Kickstarter to retool and launch number 2 when you are ready. Please keep us informed when that might happen, so we can back it then!

    2. Tim DeBenedictis Creator on September 16, 2014

      Thanks to everyone for the strong words of support. First: for everyone who's requested a high-resolution version of the image above, here's a ZIP file containing that image, plus six more that make up a "digital scrapbook" of the project:

      http://www.southernstars.com/skycube/images/SkyCubeImages.zip

      Glenn - you asked some good questions. Yes, we did build two satellites, and yes, Nanoracks offered to fly #2 at no charge in case #1 were destroyed in a launch vehicle failure. However, the launch succeeded, and since we don't fully understand the causes of our solar panel non-deployment, it doesn't make sense to launch #2 without some re-engineering. There's also the issue that this project ran significantly over budget, so additional fundraising would have to happen for a second launch.

      And your second question, I can happily say, is based on a false assumption. The team here unanimously wants another stab at this. It's simply a question of when, how, and how much it'll cost.

      Tom, since you know personally how much effort and energy went into this project, I'll offer you a similar answer: "when we're good and ready." And that means both from a technical and financial point of view.

      Marco - we needed deployable solar panels because the high-bandwisth radio used about 3W of power - the amount generated by 2U worth of solar panel area - but we only raised funds to launch a 1U-sized satellite. You're obviously correct - now! - that tying the radio antenna deployment system to the solar panel deployment system was a mistake. We never caught it in testing, but we'd certainly do it differently next time.

      Stephen - it's hard to predict exactly where/when SkyCube will re-enter. It depends a lot on random, unpredictable solar activity which affects the density of the upper atmosphere. My personal guess is that SkyCube will re-enter sometime in the next 3 to 6 months. And if you happen to be in the right place at the right time, I'd expect the re-entry to be visible as a bright, slow-moving "meteor". I hope you're there when it happens!

      Thanks again to everyone for the amazing words of support. It's what keeps us going.

      -Tim

    3. Glenn Kelly on September 16, 2014

      I will never regret having backed the attempt; but, I am curious. I thought during this whole process a second satellite was being built and held in reserve in case of a failure or was that just a launch failure?

      The second question is why are we giving up instead of continuing with the pursuit?

    4. Thomas Hubbard on September 16, 2014

      what a ride! I would do it all over again!
      So.... when are we doing it again :)

    5. Missing avatar

      virginia DeBenedictis on September 15, 2014

      Well, well done, Tim and Team Skycube. I think of the following words: "Reach for the swift winged dream, flying higher than it ought, though you but touch its gleam. For, once the wings are caught, and the feathers brought to land, they are ashes in the hand." Like any great human endeavor, Skycube began with a dream. But the Skycube dream-- (and any subsequent progeny)--flies on. It has been an honor for us all to have been a part of the dream. Thank you.

    6. Missing avatar

      Bas on September 15, 2014

      Hi Tim & co,
      Thank you all for letting me be part of this adventure. As Bill Salina posted, the things you did achieve were very, very impressive.
      The idea of posting a hi-res picture of the deployment that others mentioned is a very good one, because it will remind you and us all of what you did achieve. I mean, look at that picture! You actually had a home built sattelite deployed from the ISS! As Sherlock Holmes would have said: "I would not have missed it for worlds."

    7. Jeff Richards
      Superbacker
      on September 15, 2014

      Very proud to have been part of this. While it's (relatively) easy at this point to use hindsight to pick out potential ways things could have been done differently, that's what exploration is all about: finding ways to make things work in the future. Congratulations on all the many accomplishments of this mission, and here's to future success!

    8. Missing avatar

      Marco on September 15, 2014

      Hi Tim. Thank you very much for your precise and sincere update.
      I'm really sorry that the project did not work out as excepted until the end, but space is hard. I hope you can also figure out better why it did not work, I mean, to be able to replicate the problem here on earth.
      Still, the project was cool and I hope there will be some sort of follow up.

      A lesson learned is surely that you should not have put an extra layer (i.e. an extra failure point) before the antenna deployment. By the way, why did you need to deploy the solar panels? Where the solar panels on the sides not enough?

      Best of luck for all your future works!

    9. Missing avatar

      James Oglethorpe on September 14, 2014

      It has been a source of great pleasure and pride to be a small part of this endeavor, something I was invested in made it to the ISS and space! The T-Shirt was a success too, even a TSA official at IAD said: that's really cool. I now wear it frequently on the streets of Kathmandu. It was a great pleasure and shows also that space is a very difficult environment to work in. You all did a wonderful thing and and I was proud to be a part of SkyCube.

    10. Mauricio Fonseca Beltran on September 14, 2014

      Thanks Tim and thanks to all Skycube members for this exciting experience.
      Life goes on !

    11. Missing avatar

      Bill Salina on September 14, 2014

      Thanks Tim and the entire SkyCube Team! Ok, so we didn't to take control of it and beam back photos and our messages. The team still accomplished 99% of what the mission was about - namely: design, fabrication, and testing the spacecraft, getting it flight certified and a place on a launch manifest, prepping it for launch, and actually getting it deployed from the ISS. Even more amazing considering the shoe-string budget. After all the crazy hoops you guys had to jump through to make this happen, my only question is, when do we go again? Seriously, it would be a shame to waste the knowledge learned from this and not build upon it. When you are ready, count me in! Thanks! - Bill

    12. Stephen Racicot on September 14, 2014

      Thank you Tim and Skycube Team!
      I don't regret backing this project, it's been fun being part of this space experience! Do you have any estimate when and where Skycube will make a burn-up re-entry and would it be visible? I guess without the re-entry ballon it would probably be insignificant, but I thought I would ask? :-)

    13. Charlie
      Superbacker
      on September 14, 2014

      Best of luck in the future and please keep us informed. I'm happy to have supported this project even though I'm disappointed I never got to send: "Attention inhabitants of the Third Planet: prepare for hyperspace demolition. Capt VP Jeltz, commencing: 5, 4, 3..."

    14. Beagle on September 14, 2014

      I like the photo of deployment idea, we'd all have something to show and keep.

    15. Missing avatar

      Steven Richardson on September 14, 2014

      While disappointed (though not as much as you), I do not regret supporting this project. Best of luck in your future projects and I'd consider pledging again to a similar project in the future.

    16. Zak Zebrowski on September 14, 2014

      Very happy to have helped with this project. Best of luck in future adventures.

    17. Missing avatar

      Greg Lynn on September 14, 2014

      Could we get access to a high rez print of the photo in this message showing the deployment? My thanks and appreciation for giving it your best, it is part art and part engineering still, so many variables in play. Regards, Greg Lynn