Interstellar Off Grid

SurfpathSurfpath Solar Expert Posts: 439 ✭✭✭
As a break from the ordinary, I think it’d be fun to speculate on the off grid capabilities of the newly landed Philae probe on comet 67P. Now that the probe has settled down somewhat.

Obviously it’s a different situation in space. Here are some interesting facts:

From the Makers: “The solar cells in Rosetta's solar panels are based on a completely new technology, so-called Low-intensity Low Temperature Cells. Thanks to them, Rosetta is the first space mission to journey beyond the main asteroid belt relying solely on solar cells for power generation. Previous deep-space missions used nuclear RTGs (Radio isotope thermal generators). The new solar cells allow Rosetta to operate over 800 million kilometres from the Sun, where levels of sunlight are only 4% those on Earth” After touchdown, the initial battery lifetime of the lander is expected to be about 64 hours. ..Solar illumination conditions and the amount of dust settling on the lander’s solar panels will determine the length of the long term science phase".

From an online publication written by a NASA Engineer: “Philae must function on a small amount of stored energy upon arrival: 1000 Watt-Hours (equivalent of a 100 watt bulb running for 10 hours). Once that power is drained, it will produce a maximum of 8 watts of electricity from Solar panels to be stored in a 130 Watt-Hour battery [aside: is this balanced??:confused:]… Without any assurance that they would land fortuitously and produce more power, the Philae designers provided a high capacity battery that is charged, one time only, by the primary spacecraft solar arrays (64 sq meters) before the descent to the comet. With an initial science command sequence on-board Philae and the battery power stored from Rosetta, Philae will not waste any time to begin analysis — not unlike a forensic analysis — to do a “dissection” of a comet. Thereafter, they utilize the smaller battery which will take at least 16 hours to recharge but will permit Philae to study 67P/Churyumov-Gerasimenko for potentially months".

“The lander could get too cold when the solar arrays stop providing enough energy, because the comet's average surface temperature (now) is -70 °C (Wikipedia)”

The first photo of Philae’s landing has been published (attached) and it doesn’t look so good for insolation. Philae drifted perhaps 2KM from the proposed landing site and is apparently in more rocky shaded terrain. Hope those panels are not in one series.

Anyway, fun morning cwaffee talk.
Attachment not found.
Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.

Comments

  • CALLDCALLD Solar Expert Posts: 230 ✭✭
    Re: Interstellar Off Grid

    With only 8 watts I suppose making a cup of coffee would be out of the question....
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Interstellar Off Grid

    I'll wait for Starbucks to open their kiosk....:roll:
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • BB.BB. Super Moderators, Administrators Posts: 32,008 admin
    Re: Interstellar Off Grid

    Maybe I should move this thread to under the Mobile/RV/Marine forum?

    -Bill :p
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • SurfpathSurfpath Solar Expert Posts: 439 ✭✭✭
    Re: Interstellar Off Grid
    BB. wrote: »
    Maybe I should move this thread to under the Mobile/RV/Marine forum?

    -Bill :p
    Actually, I think they now wish the probe was a mobile rover so it could relocate to a sunnier location. Little chance it'll be able to recharge where it's at. So the clock is ticking.

    As it gets closer to the sun in December it may awaken, but perhaps the batteries will be sulphinated by then (again they probably have some newfangled technology that prevents this...). Sounds like us off gridders should benefit from this here space exploration R & D.
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
  • zonebluezoneblue Solar Expert Posts: 1,218 ✭✭✭✭
    Re: Interstellar Off Grid

    What kind of batterys are they? And even more curious why is the device reporting -70C temps, that seems kind of warm for deep space.

    Edit: they appear to be some kind of lithium cells, made by Saft, that can withstand -40/-85C. 1000Wh for the main "primary" battery, and a second 140Wh cell. I get the impression only the smaller battery is solar recharged, and the bigger battery must be a non rechargeable primary lithium, with very high energy density, which means its been sitting for a decade without losing capacity.

    See
    http://www.dlr.de/rd/Portaldata/28/Resources/dokumente/rx/Philae_Lander_FactSheets.pdf
    http://www.power-eetimes.com/en/News/full-news.html?id=222908522&news_id=222908522&cmp_id=7
    http://www.saftbatteries.com/
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • CALLDCALLD Solar Expert Posts: 230 ✭✭
    Re: Interstellar Off Grid
    zoneblue wrote: »
    What kind of batterys are they?

    All I can say is by Off Grid scale these batteries have a bit of a sense of humour (they are not very serious). As Bill said, maybe this thread should be moved to the Mobile/RV/Marine forum? As impressive as space technology is this can at best be seen as a micro-off grid system - more comparable to those "solar garden light jar thingy's"...
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Interstellar Off Grid
    Surfpath wrote: »
    Actually, I think they now wish the probe was a mobile rover so it could relocate to a sunnier location. Little chance it'll be able to recharge where it's at. So the clock is ticking.

    As it gets closer to the sun in December it may awaken, but perhaps the batteries will be sulphinated by then (again they probably have some newfangled technology that prevents this...). Sounds like us off gridders should benefit from this here space exploration R & D.
    I sincerely doubt that they are using lead-acid batteries.
    SMA SB 3000, old BP panels.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Interstellar Off Grid
    Surfpath wrote: »
    Actually, I think they now wish the probe was a mobile rover so it could relocate to a sunnier location. Little chance it'll be able to recharge where it's at. So the clock is ticking.
    Since the harpoons designed to anchor the lander to the surface did not fire, they have the option of using the descent engine to try to move into the sun.
    A bit tricky controlling where they end up, since the first rebound bounce upon landing without the harpoons lasted two hours.
    SMA SB 3000, old BP panels.
  • SurfpathSurfpath Solar Expert Posts: 439 ✭✭✭
    Re: Interstellar Off Grid

    Looks like the lander had a 24v battery bank. Latest news is that it is now depleted.
    Attachment not found.
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Interstellar Off Grid

    I don't care how much they beg; I am not going on a service call to fix that one! :D
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