UMSF space history photo of the month Options

[Phil Stooke]

Re: the Pioneer 5 image.

That's quite a Clean Room they've got going there. Just finished milking the cows by the look of it.

Phil

[imipak]

That's quite a Clean Room they've got going there. Just finished milking the cows by the look of it.

I love the dustbin in the background of the Pioneer 2 image (post #2). In a parallel universe where NASA was British, the engineers are smoking pipes... I suppose the ashtray must be just out of shot.

[Guest_PhilCo126_*]

Thanks for pointing out the typo, Apollo 12 indeed: NASA SP-184 & SP-284
http://ares.jsc.nasa.gov/HumanExplore/Expl...Part1/Surv3.htm

[dvandorn]

Surveyor descended on its little 'vernier' thrusters, after braking on a big rocket module mounted under the frame. The rocket and tankage were dropped as the verniers came on, and must lie near each landing site. None were seen in Surveyor images, or by the Apollo 12 crew. But if a Google Lunar X Prize rover were to visit a Surveyor site it might have a chance to search for it.

As highly as I regard your work, Phil, this statement is a teeny-tiny bit misleading. Surveyor's main descent engine was a solid rocket motor; it consisted of little more than a basketball-sized sphere, which held the solid fuel, and a nozzle. After burnout, which occurred about a km over the surface and at a speed of about 100 mph, Surveyor free-fell for a few seconds and then the verniers started up, at which point the descent motor was dropped. The combination of the vernier ignition and descent motor jettison gave maximum separation velocity between lander and motor.

I guess I just would never consider the sphere that held the solid fuel "tankage," just as I would never consider the length of a Shuttle SRB a tank. With solid fuel motors, the device that holds the fuel is more often called a casing than a tank...

I'd change the statement to "the burned-out descent motor casing and its nozzle were dropped," with this kind of technology.

I also have to correct another possible mis-speak -- Philco says "Surveyor 1 made the first soft landing on the Moon in June 1966." In point of fact, it made the first lunar soft landing in the Surveyor program. The first "soft" landing (in which an instrument package survived and sent back images and data from the surface) was, of course, made by Luna 9 several months prior to Surveyor 1's achievement.

-the other Doug

[Guest_PhilCo126_*]

Doug, the 58 cm diameter spheroidal probe Luna 9 "landed" on the Moon in February 1966 and this capsule weighted 100 kg.
It sat ontop the 1440 kg main bus and was ejected up & sideways by springs, the main bus impacted onto the lunar surface... is there somewhere an official definiton of "soft" landing?
Next month's photo = Mariner 4

[Phil Stooke]

Quite right, Doug. I had only just got out of bed. Don't tell my wife the first thing I did was check UMSF.

Phil

[dvandorn]

Doug, the 58 cm diameter spheroidal probe Luna 9 "landed" on the Moon in February 1966 and this capsule weighted 100 kg.
It sat ontop the 1440 kg main bus and was ejected up & sideways by springs, the main bus impacted onto the lunar surface... is there somewhere an official definiton of "soft" landing?
Next month's photo = Mariner 4

Well -- Pathfinder was dropped onto Mars from about 100 meters and bounced up half a km on its first bounce, and they called that a soft landing...

There was an attempt to define such things as the Mars airbag systems, the early Luna landers (which also used airbags) and the attempted-but-never-successful balsawood-packed Ranger surface instrument packages as "hard survivable landers," but the concept never took solid hold. Any system that delivers a reasonably complex instrument package to the surface of a planet seems to be considered a soft landing system, these days. (I would argue that penetrators are in a special class of their own, neither soft landers nor padded/bagged/protected survivable landers.)

-the other Doug

[djellison]

Well -- Pathfinder was dropped onto Mars from about 100 meters and bounced up half a km on its first bounce, and they called that a soft landing...

The bridle was cut 21.5 m above the ground and impacted at a velocity of 16 m/s (14 m/s vertical and 12 m/s horizontal). It bounced about 12 m.

(paraphrased from http://burro.astr.cwru.edu/stu/advanced/20...pathfinder.html )

Doug

[dvandorn]

Really? I clearly recall a much higher bounce estimate at the time of the landing, and a somewhat higher release point...

Perhaps they refined their estimates after the first reports that were reported at the time of the landing.

-the other Doug

[DDAVIS]

Surveyor 7 (January 1968) was a scientific mission and its TV registered 2 lasers aimed at the spacecraft from observatories in California & Arizona.
I have seen a reproduction of that photo, but the 'laser' specks on the night side of Earth appeared to be retouched onto the photo in the version I saw. Is there an original image of this experiment in existance showing their actual brightnesses?

Don

[edstrick]

There used to be a distinction between hard and soft landing and it's certainly valid. A "hard lander" is one that does a controlled crash landing and survives. Even at low speed, like the Venera 7 and 8 landing spheres. A "Soft lander" is one that does not need all-sides protection during landing.. it lands on footpads, like Surveyors, Apollo, Viking, Venera 9 through Vega 2, Hayabusa, NEAR, Huygens, and Phoenix. It's more than just a "landing you can walk away from". Not trivial.

Luna 9 was the first successful landing on the moon. It got the real prize for being first. Surveyor 1 was the first soft landing, a technical quibble, but not a trivial one.

[tedstryk]

There used to be a distinction between hard and soft landing and it's certainly valid. A "hard lander" is one that does a controlled crash landing and survives. Even at low speed, like the Venera 7 and 8 landing spheres. A "Soft lander" is one that does not need all-sides protection during landing.. it lands on footpads, like Surveyors, Apollo, Viking, Venera 9 through Vega 2, Hayabusa, NEAR, Huygens, and Phoenix. It's more than just a "landing you can walk away from". Not trivial.

Luna 9 was the first successful landing on the moon. It got the real prize for being first. Surveyor 1 was the first soft landing, a technical quibble, but not a trivial one.

I don't think it is fair to make this distinction with Venus landers in the same way one does with the moon. I mean, the PVO day probe wasn't intended to land and lasted an hour. Also, Venera 8 was a much softer landing that Venera 7, which hit much harder than it was supposed to do to technical problems that would have killed a lander anywhere else. Landing on Venus is definitely not easy, but it is probably the easiest place to slow down, ignoring Titan for the moment.

Back to the moon, part of the reason that landers like Luna 9 and 13 are often dubbed "soft" landers is because the term "hard lander" is often (mis?) applied to missions such as the Rangers and Luna 2.

[Phil Stooke]

I don't think there should be any distinction, because in principle any combination of methods is possible (was MER hard or soft - ouch!) The only thing that counts is if you survive and transmit afterwards.

Phil

[NGC3314]

The Surveyor bacterium story is not generaly accepted today. The people who did the work reported that they probably contaminated it. I think one of them wrote in to the Planetary Report about it years ago.

Surveyor descended on its little 'vernier' thrusters, after braking on a big rocket module mounted under the frame. The rocket and tankage were dropped as the verniers came on, and must lie near each landing site. None were seen in Surveyor images, or by the Apollo 12 crew. But if a Google Lunar X Prize rover were to visit a Surveyor site it might have a chance to search for it.

Phil

Thanks for that tidbit! Never knew that about Surveyor. And I thought designs for crewed landers (on both sides of the moon race) using such "crasher stages" were unnecessarily risky... But then now we find out that Luna 9 used air bags, so I should cease being surprised about anything from UMSF history. Anybody else hear about the tests carried out during the Salyut program to work out the best way for recoating telescope mirrors in orbit?

[NGC3314]

Surveyor 7 (January 1968) was a scientific mission and its TV registered 2 lasers aimed at the spacecraft from observatories in California & Arizona.
I have seen a reproduction of that photo, but the 'laser' specks on the night side of Earth appeared to be retouched onto the photo in the version I saw. Is there an original image of this experiment in existance showing their actual brightnesses?

Don

The only printed version I can remember seeing was in "Exploring Space with a Camera" (scanned image here. They don't look retouched in my copy, just that the rendering left gaps between scan lines - is this where you saw it?