[amsat-bb] Listen for LightSail - transmissions stopped
bryce.salmi at gmail.com
Wed May 27 11:07:11 UTC 2015
This is a good example of "let the engineering unit run over the weekend"
On Wed, May 27, 2015 at 03:49 Robert McGwier <rwmcgwier at gmail.com> wrote:
> The reboot will work but only if it erases beacon.csv otherwise it will
> crash on the first telemetry packet.
> On Tue, May 26, 2015 at 6:00 PM, JoAnne Maenpaa <k9jkm at comcast.net> wrote:
> > Just read on-line at http://planet.ly/0gVop (Planetary Society) that the
> > LightSail satellite stopped transmitting. The team is attempting a
> > The telemetry data is sent on a downlink of 437.435 MHz, AX.25, 9600 bps
> > FSK.
> > Excerpt from their page ...
> > As of late Friday afternoon, LightSail was continuing to operate
> > The spacecraft's ground stations at Cal Poly San Luis Obispo and Georgia
> > Tech were receiving data on each pass. Power and temperature readings
> > trending stably, and the spacecraft was in good health.
> > But inside the spacecraft's Linux-based flight software, a problem was
> > brewing. Every 15 seconds, LightSail transmits a telemetry beacon packet.
> > The software controlling the main system board writes corresponding
> > information to a file called beacon.csv. If you're not familiar with CSV
> > files, you can think of them as simplified spreadsheets-in fact, most can
> > be
> > opened with Microsoft Excel.
> > As more beacons are transmitted, the file grows in size. When it reaches
> > megabytes-roughly the size of ten compressed music files-it can crash the
> > flight system. The manufacturer of the avionics board corrected this
> > in later software revisions. But alas, LightSail's software version
> > include the update.
> > Late Friday, the LightSail team received a heads-up warning them of the
> > vulnerability. A fix was quickly devised to prevent the spacecraft from
> > crashing, and it was scheduled to be uploaded during the next ground
> > station
> > pass. But before that happened, LightSail's automated chirps fell silent.
> > The last data packet received from the spacecraft was May 22 at 21:31 UTC
> > (5:31 p.m. EDT).
> > A LightSail map tracking application is at:
> > http://sail.planetary.org/missioncontrol
> > --
> > 73 de JoAnne K9JKM
> > k9jkm at amsat.org
> > AMSAT VP User Services
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> Bob McGwier
> Co-Founder and Technical Director, Federated Wireless, LLC
> Research Professor Virginia Tech
> Senior Member IEEE, Facebook: N4HYBob, ARS: N4HY
> Faculty Advisor Virginia Tech Amateur Radio Assn. (K4KDJ)
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
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