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#20
by
2552
on 08 Apr, 2011 00:49
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#21
by
simonbp
on 08 Apr, 2011 00:56
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#22
by
Robotbeat
on 08 Apr, 2011 00:59
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Several, several threads in the SpaceX section are now better resolved because of Shotwell (Falcon 1e heavy, Falcon 1(e) status, reusability, Falcon Heavy payload to escape, etc, etc).
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#23
by
savuporo
on 08 Apr, 2011 01:03
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Thanks for reporting from there. ( suprisingly Twitter is pretty quiet about SA )
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#24
by
e of pi
on 08 Apr, 2011 01:09
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Forgive a newbie to payload planning, but what destinations do those C3 values correspond to?
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#25
by
robertross
on 08 Apr, 2011 02:06
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Gwynne Shotwell, President of SpaceX
(lots here)
Indeed!!
Here's a few that stand out for me (on SpaceX)
FH core almost (but not quite) full when boosters separate.
NASA wants a fresh Dragons for CRS (because of costing uncertainties), so DragonLab will all be reflights.
Might have redundant engines on second stage in future!
Interested in electric propulsion.
10-15 years until first Mars mission. 
Thanks for the notes simon. Very much appreciated!
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#26
by
Comga
on 08 Apr, 2011 02:09
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Forgive a newbie to payload planning, but what destinations do those C3 values correspond to?
C3 is the square of the excess velocity over that needed to escape, in this case Earth. Squared corresponds to energy. (E=1/2*mv^2) Lots of hits with Google for "C3 escape velocity". There is a relatively fixed C3 for efficient transfers between planets. Bigger numbers means going faster. A C3 of 90 (cm^2/cec^2) is pretty darn good. The New Horizons mission to Pluto and the Kuiper Belt left with C3=163 km^2/sec^2, the fastest ever. (IIRC)
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#27
by
simonbp
on 08 Apr, 2011 02:13
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On the fresh Dragons point, was apparently the case that they had no idea what it would cost to refurb them when the CRS contracts were written, so NASA just specified new ones to allow for fixed contracts. The recovered Dragon is actually in better shape than they predicted, so the spacecraft costs for DragonLab are going to be pretty low.
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#28
by
robertross
on 08 Apr, 2011 02:15
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On the fresh Dragons point, was apparently the case that they had no idea what it would cost to refurb them when the CRS contracts were written, so NASA just specified new ones to allow for fixed contracts. The recovered Dragon is actually in better shape than they predicted, so the spacecraft costs for DragonLab are going to be pretty low.
A great bonus for sure!
(of course if it were my company, I would dedicate those vehicles to students/schools for reasearch purposes)
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#29
by
simonbp
on 08 Apr, 2011 02:15
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A C3 of 90 (cm^2/cec^2) is pretty darn good.
Shotwell said that was for a "very specific application", which I assume is either Uranus or Neptune (and probably Uranus given the Decadal survey).
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#30
by
simonbp
on 08 Apr, 2011 04:00
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James Reuther on NASA Space Technology Roadmaps
(Very much a bureaucratic NASA HQ talk)
$1 Billion requested in FY2012 for Space Technology; slightly more than in 2010 Authorization. Large amount of funding is for grad student fellowships (~500) to work at NASA centers. Franklin and Edison small sat development programs for technology development. Technology was 10% of budget during Apollo, 2% in last year. Try to have strict budgets and accountable milestones. Vet technologies with National Academes study to develop roadmaps; started study in December and finished next January. Nuclear surface fission still in development, and NTR and NEP still in play. Mission directorates do not fund low TRL, so this fills the gap.
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#31
by
simonbp
on 08 Apr, 2011 04:30
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George Herbert on An In-Situ Resources Manufacturing Proof-Of-Concept
Direct metal laser sintering, 3d rapid fab method for in-space construction with ground up asteroidal metals. Can't do with materials that vapor deposit, like Al. Next step is actually to try it; need metallic meteorite iron.
Change tracks to using neutron flux from a bomb to deflect an asteroid. Asking for a redacted version of classified report...
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#32
by
Halidon
on 08 Apr, 2011 04:54
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Change tracks to using neutron flux from a bomb to deflect an asteroid. Asking for a redacted version of classified report...
Really? What medium to transmit the pulse?
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#33
by
simonbp
on 08 Apr, 2011 05:00
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Gary Hudson on t/Space's CCDEV2 proposal
Scaled Composites, ULA, Dynetics among partners. "XV" Kistler-style reentry vehicle and "OM" docking/power/etc service module. OM can be left as a free-flyer (like Shenzhou mission module). 20,000 lb in total. Patent on integral liquid abort system. LV agnostic. Designed to be lowest-cost solution. Cargo revenue on CRS flight pays for crew. XV plus drop tank doesn't need second stage on Atlas, Falcon or Taurus II (OMS provides last 1 km/s of dv). All avionics on simple mission on XV. Really poo-poos using anything fancy to "load" crew onto XV. GOX and GCH4 propulsion. Capture parachute Corona-style with a Skycrane. Same interior diameter as CRJ regional jet. Up to 12 crew in lifeboat mode. No chance for CCDEV because no skin in the game.
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#34
by
simonbp
on 08 Apr, 2011 05:01
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Change tracks to using neutron flux from a bomb to deflect an asteroid. Asking for a redacted version of classified report...
Really? What medium to transmit the pulse?
Vacuum. The neutrons ablate a layer of rock which expands off, carries momentum, and acts as an effective rocket.
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#35
by
Halidon
on 08 Apr, 2011 05:09
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Hell of an event.
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#36
by
simonbp
on 08 Apr, 2011 05:11
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Gerry Nordley on Tethers Unlimited
Solar arrays for cubesats and other bus work. Terminator Tape deorbit module: deploy a conductive tape to cause EM drag to deorbit nanosat. Different version for orbit raising with EM tether. Nanosat IMU, release mechanism
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#37
by
simonbp
on 08 Apr, 2011 05:32
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Alex Bruccoleri on Propellant Density Effects on Hydrogen Thermal Rockets
Use a microwave phased array fired from the ground to heat LH2 and use it as a thermal rocket. But does the low density of LH2 make it worth it? Answer is no, LOX/RP-1 is better per volume, unless much better pumps, etc. Also, range of phased arrays just 100 km, which implies >20g acceleration! Use NH3 instead (much higher density)?
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#38
by
simonbp
on 08 Apr, 2011 05:40
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And that's it for day one of three; much more tomorrow, including our own Jon Goff.
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#39
by
ugordan
on 08 Apr, 2011 08:30
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A C3 of 90 (cm^2/cec^2) is pretty darn good.
Shotwell said that was for a "very specific application", which I assume is either Uranus or Neptune (and probably Uranus given the Decadal survey).
Unless it involves a Jupiter flyby, 90 (km/s)^2 doesn't look enough for Uranus. Injection energies to Jupiter apparently range from 75-85, depending on if you have good winds that day.
