Surveyor 2 retro rocket firing

My reading of the Surveyor 2 timeline

http://ntrs.nasa.gov/archive/nasa/ca...1968009188.pdf

is that one of the three vernier engines failed, resulting in the
spacecraft spinning out of control.

As it was spinning out of control, they tried various things to jolt
the non-working engine into operation. As battery power was depleted
they tried but failed to deploy the solar array. I see some sense in
trying these actions.

But what I don't get, is at 45H2M, they sent an emergency command to
fire the retro engine, and two seconds later radio contact is lost.
Why fire the retro engine at this point, wouldn't that guarantee no
moon landing? Was this firing of the retro engine a truly last gasp
effort at fixing... something, anything? The lunar equivalent of
dumping most of your fuel before crashing into a pristine area? :-).

Tim.

Tim Shoppa wrote:
But what I don't get, is at 45H2M, they sent an emergency command to
fire the retro engine, and two seconds later radio contact is lost.
Why fire the retro engine at this point, wouldn't that guarantee no
moon landing? Was this firing of the retro engine a truly last gasp
effort at fixing... something, anything? The lunar equivalent of
dumping most of your fuel before crashing into a pristine area? :-).


Well, the main solid-fueled retro generated a considerable amount of
thrust, so maybe they though it might shake the vernier engine into action.

Pat

"Tim Shoppa" wrote in message
...
My reading of the Surveyor 2 timeline


http://ntrs.nasa.gov/archive/nasa/ca...1968009188.pdf

is that one of the three vernier engines failed, resulting in the
spacecraft spinning out of control.

As it was spinning out of control, they tried various things to jolt
the non-working engine into operation. As battery power was depleted
they tried but failed to deploy the solar array. I see some sense in
trying these actions.

But what I don't get, is at 45H2M, they sent an emergency command to
fire the retro engine, and two seconds later radio contact is lost.
Why fire the retro engine at this point, wouldn't that guarantee no
moon landing? Was this firing of the retro engine a truly last gasp
effort at fixing... something, anything? The lunar equivalent of
dumping most of your fuel before crashing into a pristine area? :-).

Tim.


On page 1-1 (1.0 Scope and Purpose) it says:

"Communication with the spacecraft was lost approximately 45 hours after
launch when the main retro engine was fired to obtain additional engineering
data."

Obviously at that point the controllers knew the mission was lost and turned
it into an engineering test of the "wonder what would happen" variety.

John