Author Topic: SpaceX: Advanced Launch Abort System (LAS)  (Read 107003 times)

Offline space nut

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #15 on: 04/28/2011 07:16 PM »
If one was to pre-position supplies and return modules (moon,Mars Moon, Mars, Etc.) and have ready made Bigelow habs , I would assume yes we
can go to Mars in 10 to 15 years.

This is what we need,

What NASA needs is lunar , mars landing modules and EDS, Tugs,Fuel depot
and put back the moon and mars plan that was taken away.
Need the Plan !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I love the Direct plan and SDHLV but yes it can wait some, but only
some to enable a healthy list of providers.
« Last Edit: 04/28/2011 07:29 PM by space nut »
Why is there air ?

Offline simonbp

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #16 on: 04/28/2011 07:58 PM »
OK, B$ detector going off big time on the Mars landing aspect. The only way to make that work is with a parachute to get you subsonic first, and then turn on the engines (rockets cannot fire into a supersonic flow). Not impossible, but ends up with a completely redesigned vehicle. Plus (of course), you still need to get back up, which means a entirely separate vehicle. And there's no way you're landing on the Moon with it without a crasher stage to brake from LLO.
« Last Edit: 04/28/2011 07:58 PM by simonbp »

Online Robotbeat

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #17 on: 04/28/2011 08:02 PM »
OK, B$ detector going off big time on the Mars landing aspect. The only way to make that work is with a parachute to get you subsonic first, and then turn on the engines (rockets cannot fire into a supersonic flow)....
That's not true at all. Rockets can, in fact, fire into a supersonic flow. For supersonic retropropulsion with just a single engine, there is a marked reduction in drag, but for canted side-mounted rocket engines like this, there wouldn't be a reduction in drag.
« Last Edit: 04/28/2011 08:40 PM by Robotbeat »
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Offline hop

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #18 on: 04/28/2011 08:36 PM »
Quote
The SpaceX design also provides crew with emergency escape capability throughout the entire flight, whereas the Space Shuttle has no escape system and even the Apollo moon program allowed escape only during the first few minutes of flight.
This is misleading. Apollo only had the *escape tower* for the first few minutes of flight, because after that escape was possible without the tower. Same applies to Soyuz (and in that case, crew lives have been saved by this)

Sigh. SpaceX is doing genuinely cool things, and doing them well. Do they really need to spin half truths like this ?

Offline ugordan

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #19 on: 04/28/2011 08:43 PM »
because after that escape was possible without the tower.

If that center J-2 on Apollo 13 ripped out from its mount and torpedoed through the entire S-II stage (as some speculated could have happened had it not shut down first), I wonder if the gentle SPS acceleration would have done the trick.

Offline neilh

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #20 on: 04/28/2011 08:46 PM »
OK, B$ detector going off big time on the Mars landing aspect. The only way to make that work is with a parachute to get you subsonic first, and then turn on the engines (rockets cannot fire into a supersonic flow)....
That's not true at all. Rockets can, in fact, fire into a supersonic flow. For supersonic retropropulsion with just a single engine, there is a marked reduction in drag, but for canted side-mounted rocket engines like this, there wouldn't be a reduction in drag.

Indeed, supersonic retropropulsion is actually one of the main research areas of Robert Braun, the NASA Chief Technologist.

http://www.ssdl.gatech.edu/papers/conferencePapers/AIAA-2009-5613.pdf
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Offline hop

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #21 on: 04/28/2011 08:56 PM »
If that center J-2 on Apollo 13 ripped out from its mount and torpedoed through the entire S-II stage (as some speculated could have happened had it not shut down first), I wonder if the gentle SPS acceleration would have done the trick.
Right, escape being possible doesn't mean it's guaranteed to save you in every scenario. This is true whether you have high power escape motors or not.

I'm not saying that SpaceX system couldn't be better than what Apollo had, I'm just disappointed by the needless conflation of an *escape tower* with an *escape system*. SpaceX should know better.

Offline ugordan

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #22 on: 04/28/2011 09:03 PM »
Right, escape being possible doesn't mean it's guaranteed to save you in every scenario. This is true whether you have high power escape motors or not.

I agree and I'm not saying having a LAS would necessarily have worked in that case, either.

Quote
I'm not saying that SpaceX system couldn't be better than what Apollo had, I'm just disappointed by the needless conflation of an *escape tower* with an *escape system*. SpaceX should know better.

Maybe there's a fine distinction between "escape" and "abort" to be made? SPS could have aborted away from let's say a gracefully shut down stage, but it probably wouldn't have worked that well if the vehicle executed a RUD.

In the end, this is all spin and I don't personally get too excited over it.

Online 2552

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #23 on: 04/28/2011 09:06 PM »
Looks like the vision is for Martian powered landing. What really interests me is at 1:18 you get a view of a Spacex "space barge" holding cargo and another Dragon spacecraft for accent. Are those engines underneath the Dragon for the martian accent phase?

Screencap (cropped) from the 720p HD version at 1:17, taken in fullscreen mode.


Online Downix

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #24 on: 04/28/2011 09:08 PM »
because after that escape was possible without the tower.

If that center J-2 on Apollo 13 ripped out from its mount and torpedoed through the entire S-II stage (as some speculated could have happened had it not shut down first), I wonder if the gentle SPS acceleration would have done the trick.
Gentle?  The AJ-10-137 was overpowered for it's job as SPS, by 200% according to estimates, and wasn't used at full power during the Apollo flights.  The reason why is due to it's design beginnings were on the original Moon-direct landing Apollo, and was carried over when the mission profile was changed to LOR. (it would have enabled the SM+CM to lift off from the Moon, leaving the S-IVB on the surface of the moon)  While it would not yank it away as fast as the tower would, once out of the atmosphere it would get the crew away from an emergency.

You know, looking this up answered another question I'd had since the ESAS study came out, what the LR-85 mentioned as a possible US engine for Ares was. 
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Online 2552

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #25 on: 04/28/2011 09:11 PM »
Attached is the SpaceX press kit.

And the actual press kit... http://www.spacex.com/downloads/20110428-spacex-sts134.pdf

Link doesn't seem to work, goes to a 404 for me. Can someone attach it here?

Offline ugordan

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #26 on: 04/28/2011 09:14 PM »
Gentle? 

Gentle compared to the LES acceleration. Not when used as normal main propulsion.

Link doesn't seem to work, goes to a 404 for me. Can someone attach it here?

Hmm. Still works for me. Have you tried copying the URL text manually into the address bar?

Offline Cog_in_the_machine

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #27 on: 04/28/2011 09:15 PM »
Here.
^^ Warning! Contains opinions. ^^ 

Online 2552

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #28 on: 04/28/2011 09:18 PM »
Gentle? 

Gentle compared to the LES acceleration. Not when used as normal main propulsion.

Link doesn't seem to work, goes to a 404 for me. Can someone attach it here?

Hmm. Still works for me. Have you tried copying the URL text manually into the address bar?

Yes, didn't work. Maybe SpaceX took it down but it's still in your browser cache, so the link still "works" for you?

Here.

Thanks.
« Last Edit: 04/28/2011 09:18 PM by 2552 »

Offline ugordan

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Re: SpaceX: Advanced Launch Abort System (LAS)
« Reply #29 on: 04/28/2011 09:21 PM »
Maybe SpaceX took it down but it's still in your browser cache, so the link still "works" for you?

Nope, the PDF definitely downloads every time plus I tried it in another browser where it wasn't cached. Curious.

Oh, well.

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