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Author
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Topic: Return To Launch Site (RTLS) aborts
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Fra Mauro
Member Posts: 1587
From: Bethpage, N.Y.
Registered: Jul 2002
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posted 08-25-2006 05:29 PM
   
Having read about Return To Launch Site (RTLS) abort simulations, I get the feeling that the probability of crew survival in this scenario is low. |
ea757grrl
Member Posts: 729
From: South Carolina
Registered: Jul 2006
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posted 08-25-2006 10:14 PM
I recall one astronaut describing a successful RTLS as "two miracles, followed by an Act of God." |
goldbera
Member Posts: 25
From: Melbourne, FL
Registered: Jul 2006
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posted 08-28-2006 11:15 AM
I heard a rumor long ago that John Young was the only astronaut to ever successfully perform a RTLS abort (in the simulator, of course). True? Not true? |
nasamad
Member Posts: 2121
From: Essex, UK
Registered: Jul 2001
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posted 08-28-2006 12:34 PM
I don't know about Young performing a RTLS abort in the sim, but I have heard he could get it to perform an aileron roll! No doubt he experimented with a RTLS as well. |
OV-105
Member Posts: 816
From: Ridgecrest, CA
Registered: Sep 2000
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posted 08-28-2006 03:58 PM
If I remember right there was talk of testing the RTLS on one of the OFT flights. I don't think the plan was to do it on STS-1, maybe STS-3 or STS-4. I think the idea was shot down before they could pick a flight to do it on. Talk about a short mission maybe 10 minutes. By the way is this article on line? |
Tom
Member Posts: 1597
From: New York
Registered: Nov 2000
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posted 08-28-2006 04:43 PM
Mission time for an RTLS is supposedly 25 minutes. |
lewarren
Member Posts: 269
From: Houston, TX, USA
Registered: Aug 2001
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posted 08-28-2006 05:58 PM
All launch abort modes are practiced by all crews, many, many times over. This includes RTLS. |
Paul78zephyr
Member Posts: 675
From: Hudson, MA
Registered: Jul 2005
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posted 01-24-2009 10:54 AM
At what point in the launch - T+? - is an RTLS even possible? |
mjanovec
Member Posts: 3811
From: Midwest, USA
Registered: Jul 2005
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posted 01-24-2009 01:13 PM
quote:
Originally posted by Paul78zephyr:
At what point in the launch - T+? - is an RTLS even possible?
It's an option roughly between 2 minutes and 4 minutes into the flight. It cannot be initiated until the SRBs have burned out and have been jettisoned. And it cannot happen roughly 4 minutes or later into the launch, because the shuttle will be too far downrange to return to KSC. You will notice they call out "negative return" at this point in the launch sequence. From that point on after negative return, the abort options usually involve a transoceanic abort landing, abort-once-around (a non-stable orbit of the earth, with landing after a single orbit), or abort-to-abort (usually to a lower-than-planned orbiter altitude). Each point in the launch when these options become available are usually called out, so listen for them next time you view a launch. |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
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posted 01-24-2009 01:57 PM
For STS-126 negative-RTLS was +03:52. You can see abort boundaries at the bottom of the above link. Essentially, an engine loss during SRB flight would require them to wait until burnout to press ahead with RTLS. |
webhamster
Member Posts: 106
From: Ottawa, Canada
Registered: Jul 2008
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posted 01-26-2009 09:42 PM
quote:
Originally posted by OV-105:
If I remember right there was talk of testing the RTLS on one of the OFT flights. I don't think the plan was to do it on STS-1, maybe STS-3 or STS-4.
According to an interview with Young in Popular Mechanics an early planning option for STS-1 was an RTLS. He said "I said no. I said let's not practice Russian roulette, because you may have a loaded gun there. So we didn't." |
ASCAN1984
Member Posts: 1049
From: County Down, Nothern Ireland
Registered: Feb 2002
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posted 09-22-2009 12:24 PM
What exactly is involved in an RTLS abort and why is it the least likely to succeed of the abort modes?Editor's note: Threads merged. |
Bob M
Member Posts: 1745
From: Atlanta-area, GA USA
Registered: Aug 2000
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posted 09-22-2009 12:27 PM
This is what John Young, before STS-1, thought was involved with an RTLS abort and famously stated "RTLS requires continuous miracles interspersed by acts of God to be successful." Perhaps that was his response after NASA actually proposed that STS-1 carry out a planned RTLS to see if the thing would actually work! |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 09-24-2009 02:37 AM
The main thing about an RTLS abort that makes it risky is while the shuttle is traveling down range, it essentially has to do a pitch manuever (about 5 degrees per second, until it is flying tail first) to kill its forward momentum and then begin to gain some momentum back to return to KSC for a safe landing. Altitude that the abort is typically initiated would be above 200,000 feet with the flip manuever occurring above 300,000 feet (presumeably when the air is thin enough that flipping the orbiter around won't have the back end getting roasted by the exhaust plumes from the remaining SSMEs due to air drag).The second half involves energy management as the pitched around orbiter with the ET uses up the remaining fuel and drops the external tank to initiate a (hopefully) normal approach back to KSC for landing. Of course, whether the shuttle makes it back to the launch site will entirely depend on whether it gained back enough velocity on the turnaround since if it ended up short, somebody is going to be taking a swim in the Atlantic (and shuttles don't have good ditching characteristics AT ALL). The shuttle flight crews have simulated RTLS aborts plenty of time as part of their training. But if you ask them, I don't think any shuttle commander or pilot is eager to want to try it for real. |
garymilgrom
Member Posts: 1966
From: Atlanta, GA
Registered: Feb 2007
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posted 09-24-2009 07:19 AM
I agree this would be a difficult maneuver but I also think there is a high degree of confidence it could be flown. Each mission has simulated this many times and there have been 100's of missions, so if something was fundamentally wrong surely it would have turned up by now. I certainly hope it's never needed, but I think the skill of the astronauts and thoroughness of NASA's training would likley mean a successful outcome. |
kr4mula
Member Posts: 642
From: Cinci, OH
Registered: Mar 2006
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posted 09-25-2009 11:17 AM
I think there may have even been a "Young Gram" about the RTLS issue at one point. I don't have access to those anymore, so I can't confirm, but I'm pretty sure I saw it in print somewhere. |
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