Author Topic: SNC Dream Chaser DISCUSSION Thread  (Read 655054 times)

Offline clongton

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #60 on: 08/05/2012 11:52 AM »
Sorry if this have been discussed before but there are to many pages to go through to see if it have been discussed before.

Easy solution: View the entire thread in printable format, then "print" it to a .pdf file. That gives you the ability to search the entire file, which "could" be a couple hundred pages (this one os only 5 pages), for key words. That would take you directly to the the posted comments relevant to what you want to know. It's a shame to not read them all though; one misses *so* much when they skip the reading.
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I started my career on the Saturn-V F-1A engine

Offline Calphor

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #61 on: 08/05/2012 05:09 PM »
Sorry if this have been discussed before but there are to many pages to go through to see if it have been discussed before.

Since DC will stay docked to the ISS for ~6 months its heat-shield will be exposed to MMOD strikes. Is this a concern for NASA? When the shuttle was docked ISS was flying 'backwards' to offer some protection to the shuttles heat-shield but this won't be possible for DC and it will be in front of the ISS and therefore fully exposed to MMOD strikes.

Would a bullet proof shield, possible made out of Kevlar, placeable by the robotic arm be useful?

It would need to be something more akin to a Whipple Shield than a straight Kevlar-type systems, but it could be feasible. Approach velocities are extreme (>3 km/s) and Whipple-type systems are much more mass efficient at those velocities. The only problem is that is one more large system to maintain and deploy on orbit.

Online Robotbeat

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #62 on: 08/05/2012 10:19 PM »
Sorry if this have been discussed before but there are to many pages to go through to see if it have been discussed before.

Easy solution: View the entire thread in printable format, then "print" it to a .pdf file. That gives you the ability to search the entire file, which "could" be a couple hundred pages (this one os only 5 pages), for key words. That would take you directly to the the posted comments relevant to what you want to know. It's a shame to not read them all though; one misses *so* much when they skip the reading.
Don't need to actually print it to a PDF. When you click "print" in the forum, you can just use your browser's built-in search function (i.e. Ctrl-F).
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline vt_hokie

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #63 on: 08/07/2012 03:35 AM »
Aren't those aft thrusters exposed to some of the highest heating during reentry?

Offline Ronsmytheiii

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #64 on: 08/08/2012 01:45 AM »
Since DC will stay docked to the ISS for ~6 months its heat-shield will be exposed to MMOD strikes. Is this a concern for NASA? When the shuttle was docked ISS was flying 'backwards' to offer some protection to the shuttles heat-shield but this won't be possible for DC and it will be in front of the ISS and therefore fully exposed to MMOD strikes.

The X-37 flight lasted about a year each and were fine in regards to MMOD, I would be more concerned with the cabin windows than the heat shield as on PMA-2 DC will have a minimal cross section of the lower heat shield in the velocity bar.
And this is a good reminder that just because one of your fellow space enthusiasts occasionally voices doubts about the SpaceX schedule announcements or is cautious about believing SpaceX has licked a problem before actually seeing proof that's true, it doesn't mean they hate SpaceX.

Offline Go4TLI

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #65 on: 08/08/2012 01:57 AM »
Since DC will stay docked to the ISS for ~6 months its heat-shield will be exposed to MMOD strikes. Is this a concern for NASA? When the shuttle was docked ISS was flying 'backwards' to offer some protection to the shuttles heat-shield but this won't be possible for DC and it will be in front of the ISS and therefore fully exposed to MMOD strikes.

The X-37 flight lasted about a year each and were fine in regards to MMOD, I would be more concerned with the cabin windows than the heat shield as on PMA-2 DC will have a minimal cross section of the lower heat shield in the velocity bar.

In addition all MMOD does not come in from the same vector.  There is also the OBSS still on ISS if one suspects something.

Online Robotbeat

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #66 on: 08/08/2012 07:44 PM »
What's the angular distribution of MMOD?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline yg1968

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #67 on: 08/24/2012 02:36 PM »
One thing I have been wondering about is what will happen to DC if it doesn't get chosen by NASA for the next round in 2014.

I believe that SNC has plans for DC outside of NASA. But I wonder what those plans are and if Richard Branson would be involved with them. A while ago, Branson had stated that he wanted to get involved in orbital crewed flights but so far that involvement has been fairly limited. I sort of wonder if he is waiting for the right moment to get more involved in DC.
« Last Edit: 08/24/2012 02:43 PM by yg1968 »

Offline zt

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #68 on: 08/24/2012 03:25 PM »
Richard Branson doesn't have the funds.

Offline yg1968

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #69 on: 08/24/2012 04:25 PM »
Richard Branson doesn't have the funds.

His net worth is $4.2B which is a lot more than Elon. But I don't think that he will get into a venture unless there is a reasonable expectation of profit from it.
« Last Edit: 08/24/2012 04:28 PM by yg1968 »

Offline dcporter

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #70 on: 08/25/2012 01:02 AM »
His net worth is $4.2B which is a lot more than Elon. But I don't think that he will get into a venture unless there is a reasonable expectation of profit from it.

Elon only gets into things when success is an option, so, that's basically the same...

Offline yg1968

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #71 on: 08/25/2012 01:13 AM »
I agree. I just wonder if success is an option without a NASA contract.

Offline QuantumG

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #72 on: 08/25/2012 02:12 AM »
Elon only gets into things when success is an option, so, that's basically the same...

Which makes me wonder if you really want or need a government agency to "get into things" when success isn't an option.

What's this got to do with SNC again?
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline yg1968

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #73 on: 08/25/2012 02:54 AM »
He was responding to my post about Richard Branson and DC.

Online docmordrid

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #74 on: 08/25/2012 07:39 AM »
If Branson could design a business plan with Tier 1 suborbital flights on SS2 and the advanced Tier 2 orbital flights on DC for both joyriders an serious experimenters (including universities) then NASA funding isn't a concern.
DM

Offline zerm

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #75 on: 08/25/2012 04:09 PM »
Reading the posts about landing at any airport with a 7,000+ foot runway got me wondering. Very few airporths support glideslopes greater than 3 degrees, DC will likely fly a 19 to 23 degree approach. I'm wondering if that can be electronically compensated with by way of a GPS glideslope. Any avionics heads out there who would like to chime in on this?

Offline clongton

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #76 on: 08/25/2012 07:58 PM »
Reading the posts about landing at any airport with a 7,000+ foot runway got me wondering. Very few airporths support glideslopes greater than 3 degrees, DC will likely fly a 19 to 23 degree approach. I'm wondering if that can be electronically compensated with by way of a GPS glideslope. Any avionics heads out there who would like to chime in on this?

Any idea how many airports with 7,000 foot runways there are that would fall under DC cross range limits?
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Rocket Science

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #77 on: 08/30/2012 03:45 PM »
Reading the posts about landing at any airport with a 7,000+ foot runway got me wondering. Very few airporths support glideslopes greater than 3 degrees, DC will likely fly a 19 to 23 degree approach. I'm wondering if that can be electronically compensated with by way of a GPS glideslope. Any avionics heads out there who would like to chime in on this?

Any idea how many airports with 7,000 foot runways there are that would fall under DC cross range limits?
Here is a Global list for runway data Chuck, U.S. alone (2,438 to 3,047 m: 235 ) lots of choices. ;)

https://www.cia.gov/library/publications/the-world-factbook/fields/2030.html
« Last Edit: 08/30/2012 03:52 PM by Rocket Science »
"The laws of physics are unforgiving"
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Offline clongton

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #78 on: 08/31/2012 01:33 AM »
Any idea how many airports with 7,000 foot runways there are that would fall under DC cross range limits?
Here is a Global list for runway data Chuck, U.S. alone (2,438 to 3,047 m: 235 ) lots of choices. ;)

https://www.cia.gov/library/publications/the-world-factbook/fields/2030.html

Thanks
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Comga

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #79 on: 08/31/2012 05:11 AM »
What's the angular distribution of MMOD?

Predominantly from behind and the sides.  Stuff coming in from the front is going slower, so has a lower perigee, so has experienced more atmospheric drag and is likely to be scrubbed out of orbit relatively quickly.  That's one reason the ISS orbit is not higher, I believe.

Ditto on things coming in from below.  They have seen more drag.  (However, there was a strike on the Cupola.)
Same altitude orbits in different inclinations approach from the sides.
Stuff in elliptical orbits with higher apogees comes in from behind.

The front of the ISS is probably a relatively safe place, particularly if the VV doesn't stick out like the Shuttle did.

Someone must have quantitative data.  Look online for orbital debris quarterly reports from NASA.
« Last Edit: 08/31/2012 05:15 AM by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

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