Launch of worlds largest model rocket (Saturn V)

[WxDude]

ECAL (east coast abort landing) sites

Halifax International Airport, Nova Scotia

Ok,

Not saying I want it to happen, but how cool (and equally freaky) would it be to be waiting
at the airport for your flight and seeing the shuttle land on the runway?

[Dr Mordrid]

SRB's cannot be shut down, so an 'early' jettisoning is a rather dangerous affair since where they'll end up in an emergency situation is anyone's guess - their separation thrusters may fail, the control systems for the shaped charges on the struts may not work etc. etc.

No good options in that time frame at all, which is why I called it a death trap - once those things light the options are very limited in the absense of a launch abort system (LAS) for the crew capsule.

Orion and Dragon at least have LAS's for crew flights which can get the crew and ship out of Dodge on the triple-quick from before T=0 to long after, giving them more than a good chance in trade for some sore bones for a week or so; an 8+ G ride vs 3-4 G for a regular launch.

ECAL (east coast abort landing) sites

Eastern seaboard

1. Myrtle Beach, South Carolina (high inclination orbit only)
2. Marine Corps Air Station Cherry Point, North Carolina (high inclination orbit only)
3. Naval Air Station Oceana, Virginia Beach, Virginia (high inclination orbit only)
4. Dover Air Force Base, Delaware (high inclination orbit only)
5. Otis Air National Guard Base, Massachusetts (high inclination orbit only)
6. Pease Air National Guard Base, New Hampshire (high inclination orbit only)
7. Naval Air Station Bermuda (low or mid inclination orbit only

Canada (all high inclination orbit only)

1. Gander, Newfoundland
2. Goose Bay, Newfoundland
3. Halifax International Airport, Nova Scotia
4. St. John's, Newfoundland
5. Stephenville, Newfoundland

[Nowhere]

...PS It would certainly become unstable with the loss of an SRB though...

Well, actually that is what happened to Challenger, sort of; but more of a massive structural failure kind, not in the same sense of losing an engine which I was thinking about - after all there's no way of shutting down an SRB even if you want to.

BTW Doc, I wonder - safe jettisoning of SRBs before time, when their trust lowers substantially, was deemed impossible, right?

PS. I believe there are also options for abort in New England / eastern coast of Canada during high inclination (ISS) launches?

[Dr Mordrid]

Just so we have it all out there for the other forum readers;

Shuttle abort modes

1. Redundant Set Launch Sequencer (RSLS) Abort

The main engines are ignited roughly 6.6 seconds before liftoff. From that point to ignition of the Solid Rocket Boosters at T+0.00 seconds, the main engines can be shut down. This has happened five times: STS-41-D, STS-51-F, STS-51, STS-55 and STS-68.

This has always occurred under computer (not human) control after sensors uncover a problem before the SRB's ignite at T+0.00. The SRB's cannot be turned off once ignited and once they are the shuttle is committed to launch.

2. Inflight Crew Escape System

The crew would make the escape decision at an altitude of ~60,000 feet and make an input to the autopilot enabling this mode.

When the orbiter descends to ~30,000 feet its airspeed must be ~200 knots (230 mph) or it's a no-go. At ~25,000 feet a crew member in the middeck (the "jump master") pulls a T-handle which starts a controlled depressurization before the side hatch is jettisoned.

At ~25,000 feet the autopilot changes the orbiter's angle of attack to 15 degrees, which must remain nearly constant for approximately 3 minutes until the orbiter reaches ~2,000 feet. During this time the jump master deploys the escape pole and the crew exits.

This is an awful lot to go right in a presumably deteriorating situaton and presumes no damage to the orbiters flight systems or control surfaces and a successful tank separation, so its real-world effectiveness is IMO highly debateable.

3. Return To Launch Site (RTLS)

The Shuttle continues downrange until the solid rocket boosters are jettisoned. It pitches around with the SSME's retro-firing and the tank attached, which continues until downrange velocity is killed and the vehicle is headed back towards KSC. Then it jettisons the tank and glides to a landing on the Shuttle runway.

4. Transoceanic Abort Landing (TAL)

TAL is used between T+2:30 - T+ 8:30 (MECO - main engine cutoff) and involves landing at a location in Africa or western Europe (Portugual, Spain, Ireland, Iceland, the UK & a few others) about 30 minutes after launch. This occurs when velocity, altitude and distance downrange do not allow RTLS. It's also used when a less time-critical failure doesn't require the faster, but more stressful, RTLS abort.

5. Abort Once Around (AOA)

Abort Once Around (AOA) is used when the shuttle can't reach a stable orbit but has sufficient velocity to circle the earth once and land.

6. Abort to Orbit (ATO)

Abort to Orbit (ATO) is available when the intended orbit isn't attainable but a lower, stable orbit is possible. This actually happened on STS-51-F (Challenger).

[cjolley]

Interesting points.

...
But that's beside the point...Shuttle wasn't designed with ejected cabin in mind, doing which is hard, and redesigning any craft for it even harder.
...

It was "in mind." It was rejected because of weight consideration, if I remember correctly.


PS It would certainly become unstable with the loss of an SRB though...

[Nowhere]

Actually, I would agree with Doc - "could" is about correct.

There wasn't really any explosion during Challanger disaster at all, that might had flung high speed shrapnel around - what looked like explosion was basically just burning of fuel dumped from badly damaged fuel tank...behind it; what tore the stack apart (and into pieces) was aerodynamic force.

By that time ejected cabin would be probably far enough "sideways" so debris wouldn't be a big problem - small would decelerate rapidly, large one would stay out of the trajectory of the cabin due to inertia...and would decelerate quicker anyways, beeing probably much less aerodynamic - and this essentially happened, on some photos you can see the cabin "flying alone".

But that's beside the point...Shuttle wasn't designed with ejected cabin in mind, doing which is hard, and redesigning any craft for it even harder.

My point, Doc, was that Shuttle doesn't become unstable after losing just one engine. Then you dump external fuel tank in the apogee of your trajectory, and if there is no suitable landing site - bring the orbiter down to stable flight at relatively low speed and altitude and bail out on parachutes. For me that's also absolutelly valid abort mode.

[cjolley]

...The cabin ejection system could have saved the Challenger crew.

Do you mean might?
There was an awful lot of high speed debris flying around up there.

[Dr Mordrid]

Those 'other landing places' are in Spain etc., plus as noted if they don't get to a decent altitude neither chutes or glide does them a lick of good. What you need is a powered cabin ejection system (crew capsule ejects & comes down on mulitple chutes) which, along with ejection seats, didn't make the cut. The cabin ejection system could have saved the Challenger crew.

[Nowhere]

They can also bail out (plus there are other landing places)

[Dr Mordrid]

Well...no. Failure of one of the Shuttle engines (not counting the SRBs) is (supposedly) survibeable.

Only if it gets high enough to separate from the tank with enough velocity to glide to the KSC runway, and that's by no means certain.

[Nowhere]

Well...no. Failure of one of the Shuttle engines (not counting the SRBs) is (supposedly) survibeable.

PS. Drunk posting is haaaaard

[Dr Mordrid]

It's not about completing the mission, it's about safe abort modes. Shuttle can do it, so I'd say it IS engine-out tolerant.

Tell that to the Challenger crew families. Any kind of failure where they don't have time to separate the orbiter and glide to the emergency strip and the crew is dead, even if they and the shuttles internal capsule survive an explosion like Challenger's did. No 'chutes, no escape thrusters etc. etc. so it's a 300 mph dive into the drink from 50,000 feet or more. That doesn't even take into account the thermal protection system and foam isssues.

Thing's a death trap, which is why it's standing down.

[Nowhere]

It's not about completing the mission, it's about safe abort modes. Shuttle can do it, so I'd say it IS engine-out tolerant.

OTOH rocket in this image has a problem with overall layout, it would have to at least shut down one more engine, opposite to the one which fails, to remain stable. And react quickly, not to be ripped apart. And the still...only half of the engines running would give much lower safety margin.

[Dr Mordrid]

Almost all rockets are. No American rocket since the Saturn V has been engine-out tolerant, and it could only lose one engine. For most all others one engine goes out and it's end of mission - at least nothing until SpaceX's Falcon 9. It can lose up to 2 of its 9 first stage engines and still continue to orbit by burning the rest longer and extending the second stage burn. Engine-out was one of its primary design goals, right along with stage reusability (first stage is for sure and they're working hard on a reusable second stage).

[Nowhere]

This configuration seems highly intolerant of single engine failures...