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#280 by zaitcev on 23 Oct, 2014 19:46
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There is no "freedom" in Wallops and a very limited mission subset that it can do. Only ISS resupply and some sun synchronous, no GSO comsat and limited planetary and no DOD.
Meanwhile Russians are getting ready to launch to GSO with Angara from Plesetsk. Don't tell me Wallops is further north. -
#281 by Jim on 23 Oct, 2014 20:02
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Meanwhile Russians are getting ready to launch to GSO with Angara from Plesetsk. Don't tell me Wallops is further north.
Angara has multiple configurations and was sized to do GSO from Plesetsk. Antares is too small to do current comsats. -
#282 by arachnitect on 23 Oct, 2014 20:07
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Meanwhile Russians are getting ready to launch to GSO with Angara from Plesetsk. Don't tell me Wallops is further north.
Angara has multiple configurations and was sized to do GSO from Plesetsk. Antares is too small to do current comsats.
Would moving to CCAFS really change that? -
#283 by russianhalo117 on 23 Oct, 2014 20:15
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Yes and No as depend on the Launch azimuth and result inclination. That is one reason why Antares flights to ISS are going via Wallops. Higher Energy transfer to the 51.6 inclination on a descending node towards the equator results in more payload lifted for them than a 51.6 ascending node from CCAFS like shuttle and F9. My guess is Cuba is in the way for a 51.6 descending node from CCAFS. Please correct me if I'm wrong.
Meanwhile Russians are getting ready to launch to GSO with Angara from Plesetsk. Don't tell me Wallops is further north.
Angara has multiple configurations and was sized to do GSO from Plesetsk. Antares is too small to do current comsats.
Would moving to CCAFS really change that? -
#284 by kevin-rf on 23 Oct, 2014 22:53
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Built by who? Orbital builds small comsats. Just pointing out if they had the correct upperstage, they could launch some of the GSO satellites they build.
Angara has multiple configurations and was sized to do GSO from Plesetsk. Antares is too small to do current comsats. -
#285 by Lobo on 23 Oct, 2014 23:11
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Meanwhile Russians are getting ready to launch to GSO with Angara from Plesetsk. Don't tell me Wallops is further north.
Angara has multiple configurations and was sized to do GSO from Plesetsk. Antares is too small to do current comsats.
Would moving to CCAFS really change that?
Would replacing the Castor 30XL with a hydrolox upper stage change that? Or would it still need to go to CCAFS?
And can Wallops be modified to accomodate USAF/DoD requirements about vertical payload integration and changout? Or are they completely locked in to their current horizontal pad flow? -
#286 by rayleighscatter on 23 Oct, 2014 23:26
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USAF/DoD specifically requires CCAFS or Vandenberg (military bases). I'm not even certain if KSC would qualify for those launches (Jim?).
And can Wallops be modified to accomodate USAF/DoD requirements about vertical payload integration and changout? Or are they completely locked in to their current horizontal pad flow? -
#287 by Comga on 24 Oct, 2014 05:41
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snip
My guess is Cuba is in the way for a 51.6 descending node from CCAFS. Please correct me if I'm wrong.
No. It's the Bahamas and other islands in the Caribbean.
edit: Oops -
#288 by baldusi on 24 Oct, 2014 15:16
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Yes and No as depend on the Launch azimuth and result inclination. That is one reason why Antares flights to ISS are going via Wallops. Higher Energy transfer to the 51.6 inclination on a descending node towards the equator results in more payload lifted for them than a 51.6 ascending node from CCAFS like shuttle and F9. [...]
Could you explain me why? I had it understood that the only advantage of latitude (assuming it is less than the orbit's inclination) is the Earth's rotation. Which is a vector with the exact direction of the rotation. Thus, the rocket needs to add the difference.
For example, let's say that orbital speed is 7,500m/s, and inclination is 51.6deg, then the (lat,long) component vector is (4,659m/s, 5,878m/s) for a northward orbit and (4,659m/s, -5,878m/s) of a southward on. So, launching southward or northward should be the same.
Due to the rotation of the Earth, your launch site supplies a (cos(lat)*radius m/s,0m/s) of energy. But you obviously then have to add atmospheric and gravity losses. Thus, if you execute no dogleg, launching from KSC (407m/s help) should actually give better performance than Wallops (365m/s). You'd get better performance from Wallops as you go orbits with higher inclinations than 87 deg or so, since you'd have to actually cancel the Earth rotation supplied by KSC.
But that's how I understand it, and that's clearly a simplistic model. Can you help me understand why southern azimuth give better performance, and also why closer latitude to orbit inclination gives better performance than closer to equator? I'm quite intrigued.
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#289 by Lobo on 24 Oct, 2014 16:34
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USAF/DoD specifically requires CCAFS or Vandenberg (military bases). I'm not even certain if KSC would qualify for those launches (Jim?).
And can Wallops be modified to accomodate USAF/DoD requirements about vertical payload integration and changout? Or are they completely locked in to their current horizontal pad flow?
It did when military payloads were launched on the Shuttle. That was the whole reason for the RSS and the ability to install and changout payloads at the pad vertically, as I understand. So the USAF would help pay for STS. -
#290 by Jim on 24 Oct, 2014 18:15
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USAF/DoD specifically requires CCAFS or Vandenberg (military bases). I'm not even certain if KSC would qualify for those launches (Jim?).
The reason is that the ground infrastructure for processing the payloads already exists at the Cape and VAFB.
KSC would qualify because it is close enough to the Cape. -
#291 by simonbp on 24 Oct, 2014 19:42
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And Shuttle did obviously launch classified payloads from KSC/LC-39.
A commercial launch contract for Antares would be very big news. -
#292 by arachnitect on 26 Oct, 2014 20:30
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What is the seemingly half assembled (half disassembled?) structure north of the Pad 0A tank farm? In older photos (of 0A being converted for Antares) it has a roof and siding.
image from here: https://www.flickr.com/photos/nasahqphoto/15608404916/
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#293 by rayleighscatter on 26 Oct, 2014 21:35
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http://www.rubbusa.com/project-wallops-flight-facility-wallops-island-va-military-project
http://www.nasa.gov/centers/langley/images/content/366324main_MLAS_904.jpg
It's a fabric covered building set on tracks. It was built to support the MLAS (Max Launch Abort System). -
#294 by yg1968 on 27 Oct, 2014 13:17
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Quote from: Twitter
Orbital Sciences: We settled our antitrust lawsuit w/ Russian RD-180 engine seller RD Amross & are negotiating an RD-180 access deal w/ ULA.
https://twitter.com/pbdes/status/526721347993759744 -
#295 by arachnitect on 27 Oct, 2014 14:02
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Quote from: Twitter
Orbital Sciences: We settled our antitrust lawsuit w/ Russian RD-180 engine seller RD Amross & are negotiating an RD-180 access deal w/ ULA.
https://twitter.com/pbdes/status/526721347993759744
Very interesting. -
#296 by Lars-J on 27 Oct, 2014 15:16
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Quote from: Twitter
Orbital Sciences: We settled our antitrust lawsuit w/ Russian RD-180 engine seller RD Amross & are negotiating an RD-180 access deal w/ ULA.
https://twitter.com/pbdes/status/526721347993759744
Here is another tweet: https://twitter.com/pbdes/status/526721627988697089QuotePeter B. de Selding @pbdes
Orbital Sciences: If our negs w/ ULA for access to Russian RD-180 engine fail, we can refile our antitrust lawsuit against ULA.
I guess that settles the engine debate. They have decided to use to RD-180, and will re-file lawsuits if necessary to get it. -
#297 by baldusi on 27 Oct, 2014 15:58
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It's actually the only logical choice. No other equally performing engine is available. And actually it is the only Russian engine with an export license. It was hard to do it on 1998/7, doing it now for the RD-193 or RD-181 would be close to impossible.
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#298 by Antares on 29 Oct, 2014 03:19
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Those NK's must have been reading Twitter and got mad.
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#299 by Ben the Space Brit on 29 Oct, 2014 08:26
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Assuming (and that is all it is so far) that the ORB-CRS-3 anomaly is ultimately due to an engine failure this gives NK-33 a failure rate of 1-in-4, as of now, including the two test stand failures. Am I correct?
(Asked not to bash but because I genuinely want the information)