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#200
by
renclod
on 13 Aug, 2011 18:08
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from MLAS thread:
The [CST-100] abort motors also are the orbital maneuvering, propulsion and de-orbit system.
Citation, please ?
edit:
"orbital maneuvering" = propulsion system
"de-orbit" = propulsion system
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#201
by
Namechange User
on 13 Aug, 2011 18:13
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No need for a citation, it's not accurate
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#202
by
docmordrid
on 13 Aug, 2011 18:29
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They state re-use of the abort fuel to reboost ISS but not specifically the Bantam thrusters, though I would imagine the attitude control thrusters wouldn't be up to the task.
http://www.parabolicarc.com/2011/03/15/boeing-tests-pusher-abort-system-cst100-vehicle/>
“The successful engine test series was Boeing’s last major milestone under our current Commercial Crew Development Space Act Agreement with NASA. It validates our technical approach for a pusher launch abort system,” said Keith Reiley, deputy program manager, Commercial Crew programs, Boeing. Â ”With this system, we can use the abort fuel to re-boost the space station orbit, which is an added benefit to NASA and Bigelow Aerospace. Â This is a significant step in our plan to provide safe, reliable and affordable crew and passenger transportation to the International Space Station and other low-Earth orbit destinations.”
>
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#203
by
renclod
on 13 Aug, 2011 18:49
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...
though I would imagine the attitude control thrusters wouldn't be up to the task. ...
Why not ?
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#204
by
docmordrid
on 13 Aug, 2011 19:35
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I had presumed too small, but after researching it I see Soyuz uses its attitude thrusters so....
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#205
by
Downix
on 13 Aug, 2011 20:34
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...
though I would imagine the attitude control thrusters wouldn't be up to the task. ...
Why not ?
The CST-100 is using an evolved form of the thrusters from Gemini, according to Rocketdyne:
www.space.com/9024-boeing-moves-commercial-space-capsule.html120kgf is not terribly much for reboost, even if you could use all 24. Especially when there are four much more powerful and efficient engines right there.
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#206
by
hop
on 13 Aug, 2011 21:10
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120kgf is not terribly much for reboost, even if you could use all 24. Especially when there are four much more powerful and efficient engines right there.
Progress reboosts are generally done with the RCS engines, which are significantly lower thrust.
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#207
by
Downix
on 13 Aug, 2011 21:21
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120kgf is not terribly much for reboost, even if you could use all 24. Especially when there are four much more powerful and efficient engines right there.
Progress reboosts are generally done with the RCS engines, which are significantly lower thrust.
The Progress' engines are model KDU-80, and have 6* the thrust.
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#208
by
hop
on 13 Aug, 2011 21:56
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The Progress' engines are model KDU-80, and have 6* the thrust.
As I said, Progress reboosts are frequently done with the smaller RCS thrusters.
For example
http://forum.nasaspaceflight.com/index.php?topic=22789.msg765151#msg765151Reboost Update:
The 2nd one-burn ISS reboost (of 2) was performed today at 12:16 AM GMT using Progress M-11M/43P DPO rendezvous & docking thrusters, with attitude control handover to RS MCS (Motion Control System) at 10:30 AM GMT and return to US CMGs (Control Moment Gyroscopes) at 1:10 PM GMT. Due to the thruster malfunction during 43P docking, only 4 thrusters were used (instead of the usual 8 ). Burn duration: 29m 32s. Actual Delta-V was 1.97 m/s (6.46 ft/s) vs. predicted 1.95/6.60
Now will you *please* take the time to familiarize yourself with the facts before making blanket statements ?
edit:
note DPO thrusters are on the order of 10kgf
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#209
by
Downix
on 13 Aug, 2011 22:59
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The Progress' engines are model KDU-80, and have 6* the thrust.
As I said, Progress reboosts are frequently done with the smaller RCS thrusters.
For example http://forum.nasaspaceflight.com/index.php?topic=22789.msg765151#msg765151
Reboost Update:
The 2nd one-burn ISS reboost (of 2) was performed today at 12:16 AM GMT using Progress M-11M/43P DPO rendezvous & docking thrusters, with attitude control handover to RS MCS (Motion Control System) at 10:30 AM GMT and return to US CMGs (Control Moment Gyroscopes) at 1:10 PM GMT. Due to the thruster malfunction during 43P docking, only 4 thrusters were used (instead of the usual 8 ). Burn duration: 29m 32s. Actual Delta-V was 1.97 m/s (6.46 ft/s) vs. predicted 1.95/6.60
Now will you *please* take the time to familiarize yourself with the facts before making blanket statements ?
edit:
note DPO thrusters are on the order of 10kgf
Yes, please do. The DPO system has four models of thruster, 12 of 2.3kg, 14 of 13.2 kgf and two of the forementioned model. You just made a blanket statement on these thrusters which is not true. According to the reboost manual, the reboost uses two KDU-80 and up to six of the 13.6 kgf.
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#210
by
Ronsmytheiii
on 13 Aug, 2011 23:24
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Progress thruster discussion has nothing to do with the Atlas V announcement for CST-100. Please get back on topic.
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#211
by
Robotbeat
on 14 Aug, 2011 18:10
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...
The CST-100's abort thrusters are most likely LESS efficient. They won't be used for ISS reboost.
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#212
by
Downix
on 14 Aug, 2011 18:21
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...
The CST-100's abort thrusters are most likely LESS efficient. They won't be used for ISS reboost.
~340 isp is pretty efficient to me for a kerolox engine.
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#213
by
Lars_J
on 14 Aug, 2011 22:52
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The CST-100's abort thrusters are most likely LESS efficient. They won't be used for ISS reboost.
Efficiency doesn't matter much in this case. If a spacecraft is docked at ISS in a reboost-friendly position (fore and aft), and has extra propellant to spare - of course it makes sense to use it for reboost.
After all, Progress and Shuttle were certainly not the most efficient way to reboost the station - but they are/were available, and so you use what you have.
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#214
by
SgtPoivre
on 15 Aug, 2011 10:09
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After all, Progress and Shuttle were certainly not the most efficient way to reboost the station - but they are/were available, and so you use what you have.
As far as I remember the Shuttle could not reboost the ISS (and I can't see how it could have done it given its docking location). Well maybe in the early stages of the assembly of the ISS...
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#215
by
AnalogMan
on 15 Aug, 2011 11:23
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After all, Progress and Shuttle were certainly not the most efficient way to reboost the station - but they are/were available, and so you use what you have.
As far as I remember the Shuttle could not reboost the ISS (and I can't see how it could have done it given its docking location). Well maybe in the early stages of the assembly of the ISS...
I'm afraid your memory may be failing you
The last reboost of the ISS by a shuttle was as recently as the STS-134 mission. This used the vernier RCS thrusters and gave a ΔV = +0.57 m/s resulting in a mean altitude increase of 1.04 km.
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#216
by
SgtPoivre
on 15 Aug, 2011 12:38
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ΔV = +0.57 m/s resulting in a mean altitude increase of 1.04 km.
Call that a reboost!!
But thanks for the information I learned something today
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#217
by
erioladastra
on 20 Aug, 2011 00:49
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...
The CST-100's abort thrusters are most likely LESS efficient. They won't be used for ISS reboost.
Abort engines won't be used but the RCS will be available, if the ISS program wants the delta V.
The last reboost of the ISS by a shuttle was as recently as the STS-134 mission. This used the vernier RCS thrusters and gave a ΔV = +0.57 m/s resulting in a mean altitude increase of 1.04 km.