CM/SM observed from the lunar surface?

[Clive Tester]

Hi all,
Was the orbiting CM/SM ever seen from the moon’s surface during the Apollo moon landings?

[Drbuzz0]

Hi all,
Was the orbiting CM/SM ever seen from the moon’s surface during the Apollo moon landings?

well they did have direct radio communications between the LM and CSM when it was within line of sight. Does that count? I don't know how much they would have used that though. There was a contingency for a failure of the S-band system on the LM where the CSM would have to act as a relay for earth communication via the VHF system.

[samkent]

I would expect the CM/SM to be a bright dot moving across the sky more so than on Earth.

[Larry Jacks]

That would depend on the relative angles of the sun, moonwalkers, and the SM/CM stack. Given the right conditions, it certainly should've been visible. Far smaller satellites are visible to the naked eye here on Earth. I just don't know if they ever saw it. Their glare shields on the helments might've been too dark, or they might not have been able to look at the right angles due to restricted mobility of the spacesuits.

[ugordan]

Keep in mind it wasn't as trivial to see everything up in the sky as you might imagine. I heard Charlie Duke say he could not see the Earth from the surface as it was too high up and he couldn't lean back as much and the top of the helmet blocked the view otherwise. Most of the times the astros were too busy to look up anyway.

I would think the CSM would otherwise be readily apparent as a starlike point moving across the sky.

[samkent]

That’s shame about the suit restrictions. But wasn’t the CM orbiting about 60 miles up? That’s one third the distance we would have on Earth. Plus with no atmosphere the view would have been spectacular excluding the helmet.

[Clive Tester]

It still amazes me to think that men once walked on the moon. Every time I look at the moon, I think how amazing it was. Really showed what a nation could achieve. Many people I know are old enough to remember the time when having a conversation like this would have been inconceivable.

[Parallax M86]

It still amazes me to think that men once walked on the moon. Every time I look at the moon, I think how amazing it was. Really showed what a nation could achieve. Many people I know are old enough to remember the time when having a conversation like this would have been inconceivable.

Not to get political but I think it's because this country used to have ambition. To be fair so did the Soviets.

I think the problem now is that since we've been there America has kind of lost that spark. Other nations haven't been there so they're more "hungry", if you will, to go places than we are. They want it more badly. Maybe international competition is what our country needs. A kick in the pants from a competitor is part of what drove us to do so many great things during the first 3/4 of the 20th century.

[Parallax M86]

Hi all,
Was the orbiting CM/SM ever seen from the moon’s surface during the Apollo moon landings?

I'm not sure if the LM astronauts could but I've seen it portrayed before on film. If they could it would have appeared as a rapidly moving small dot in the sky. Almost like a relatively slow-moving shooting star. I know the CM/SM pilot could look down at the landing site and see the LM with a sextant. I don't think he could see the astronauts though.

[Clive Tester]

Not to get political but I think it's because this country used to have ambition. To be fair so did the Soviets.

I think the problem now is that since we've been there America has kind of lost that spark. Other nations haven't been there so they're more "hungry", if you will, to go places than we are. They want it more badly. Maybe international competition is what our country needs. A kick in the pants from a competitor is part of what drove us to do so many great things during the first 3/4 of the 20th century.

I agree. I think as well, that Apollo was conceived of a very unique time in world history. There was the competition between ideological opposites, coupled with the emerging technology of rocketry and precision engineering and electronics associated with military aviation. Maybe now that technology has been around for so long, there is not quite the desire for nations to show their developmental progress in this way. I think that it is possible that mankind will not return to the moon for centuries. I feel very privileged indeed, to have been around when men walked on the moon.

[Clive Tester]

If the helium pressure was lost on the LM, could pressure from the PLSS be used to start the ascent engine?

[Larry Jacks]

If the helium pressure was lost on the LM, could pressure from the PLSS be used to start the ascent engine?

I don't think so. It isn't just a matter of starting the ascent engine but of keeping it firing all the way to orbit. If you lost helium pressure in the ascent propellant tanks, you probably wouldn't have enough helium available to pressurize the tanks to the proper level (greater than ascent engine chamber pressure) and maintain that pressure as the propellants are consumed. If the propellant tank pressure drops, so does the thrust produced by the engine.

[Craigboy]

I agree. I think as well, that Apollo was conceived of a very unique time in world history. There was the competition between ideological opposites, coupled with the emerging technology of rocketry and precision engineering and electronics associated with military aviation. Maybe now that technology has been around for so long, there is not quite the desire for nations to show their developmental progress in this way. I think that it is possible that mankind will not return to the moon for centuries. I feel very privileged indeed, to have been around when men walked on the moon.

I think it's very unlikely that man will not return to the moon for centuries. I was going to say within the next 50 years, but than I thought about apollo...

[Clive Tester]

If the helium pressure was lost on the LM, could pressure from the PLSS be used to start the ascent engine?

I don't think so. It isn't just a matter of starting the ascent engine but of keeping it firing all the way to orbit. If you lost helium pressure in the ascent propellant tanks, you probably wouldn't have enough helium available to pressurize the tanks to the proper level (greater than ascent engine chamber pressure) and maintain that pressure as the propellants are consumed. If the propellant tank pressure drops, so does the thrust produced by the engine.

Thanks Larry

[Clive Tester]

Thanks all, for your input.

I have been watching Shadow of the Moon. Best documentary I have seen on the Apollo era. Very poignant to look at it, with the knowledge of the current position on going back to the moon.