posted 03-29-2010 08:54 AM               

This was defined as the period towards the end of the descent when there was no way of aborting the flight in the event of a mishap. Lasting for about ten seconds, it was that time when the combination of low altitude and high rate of descent made it impossible for the ascent engine to overcome the downward inertia of the LM.

posted 03-30-2010 07:37 AM               

"Below the 200-foot level, you are in the dead man’s curve," says Cernan. "Past that point, if the descent engine quit burning for any reason, you would fall to the surface and crash before you could manually abort."

At an altitude of 15 metres they entered what was referred to as the deadman zone. In this zone, if anything had gone wrong if for example, the engine had failed it would probably have been too late to do anything about it before they crashed on the moon. There were no fail-safe abort systems available until after the landing.

posted 03-30-2010 03:42 PM               

This from 'Chariots for Apollo' would seem to suggest that the two things were different -

Tindall's group also found guidance system faults that might result in unwanted excursions. Flight controllers would have to help the crew decide whether to go on or return to the command module. But returning to the mother ship would be tricky, Tindall said. Dispersions had to be severely contained to prevent the crew from flying a "dead man" curve - an aimless trip across the lunar sky far out of range of the command module's rescue capability.

posted 05-22-2010 10:00 PM            

Normally, when flying an aircraft, to fly slower you need less power. However, while in certain parts of the flight envelope, particularly in a landing configuration, you actually need MORE power to fly slower.

This counter-intuitive situation is caused by the need for additional power to overcome the increasing drag associated with the high angle of attack needed to generate enough lift at low speeds.

It is sometimes called the "back of the Power Curve", but I've also heard that part of the Power Curve referred to as the "Deadman's Curve". The reason being, that while adding power allows you to slow down, you also get closer to the critcal angle of attack at which the wing will stall. If you feel yourself getting into a near stall situation, you usually get some relief from adding power, which will increase airspeed, but not in this situation. You may already be using all or almost all of your avaialable power to fly so slowly, so ther's nothing more to help you. The only solution is to lower the nose of the aircraft to lower the angle of attack. Unfortunatly, this tends to lead to a loss of altitude in this high drag configuration.

In conventional flight, the most likely times to flirt with the "Deadman's Curve" are on take off and landing. So lowering the nose tends to lead to contact with Mother Earth.

posted 11-13-2012 02:22 PM               

Having reviewed the procedures for a normal lift-off from the moon's surface which include the helium tanks valves being opened to pressurize the oxidiser and propellant etc etc, this would appear to take some time and hence an abort would not be immediate?

posted 01-12-2014 09:58 AM               

quote:

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Originally posted by MadSci:
Welcome to the Deadman's Curve.

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