Soviet Luna Missions Options

[Toma B]

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[John Whitehead]

Regarding the Luna 16, 20, and 24 sample returns, does anyone have solid verifiable information about the mass or physical size of the upper part that launched off the moon? I have seen conflicting information that the earth entry capsule (the sphere at the top) was anywhere between 1 foot and 3 feet in diameter. Anything more accurate and verifiable would be much appreciated. Has anyone been to the NPO Lavochkin Museum where the sample return capsules are (or were) on display?

Below is some information about how the Luna ascent vehicles worked:

It was functionally very simple engineering, tailored to the particular physical situation. The moon's small size (compared to Mars) permitted a direct return. Not going into lunar orbit meant no circularization (orbit insertion) burn, and the fact that the target (earth) was gravitationally large and nearby meant no midcourse corrections either. No need for any engine restarts or staging. A single propulsive burn from the 1-stage ascent vehicle was simply timed (both moment of launch relative to the calendar, and burn duration).

Guidance consisted of flying a vertical trajectory off the moon. The vernier engines were controlled by a local vertical sensor, a pendulum! Site selection was limited to the east side of the moon, where a vertical ascent reduced the geocentric velocity compared to the moon's, so it was effectively just a deorbit burn with respect to the earth. Velocity would have been less than lunar escape velocity, since the earth was sitting there pulling it home. The return stage had a transmitter that could be switched on and off by commands from earth, and the resulting signals received on earth were used to predict the landing point accurately enough to go out and find it.

All this is explained in a paper by Boris Girshovich, presented at the National Space Society's 26th International Space Development Conference, Dallas Texas 2007May25-28. See isdc.nss.org/2007/index.html.

Also I found an online paper in the Electronic Journal of the Astronomical Society of the Atlantic, Vol. 7, Nr. 1, Jan 1996, by Andrew J. LePage. He points out that the return capusle was essentially just falling almost straight toward earth, and notes that they had to land near 56 degrees east longitude on the moon, in order to make the simplified return scheme work. The ascent vehicle is said to be 520 kg total, roughly 300 kg of which would have to be expended propellant. The sample return capsule is described as 40 kg total and 50 cm in diameter, which suggests that the "3 feet" diameter noted by the Girshovich paper is a typo.

John W.

[kenny]

The capsule was certainly not 3 feet in diameter. The overall width of the full craft including legs was about 3.3m diameter, and from images you can gauge the small size of the capsule. Here it is said to be 25 cm dimater, which seems about right to me...

Luna missions details

[stevesliva]

The vernier engines were controlled by a local vertical sensor, a pendulum!

I know mechanical means sound archaic, but similar concepts are used in MEMS devices these days... like in the Wii video game controller. Ok, it's really an 'accelerometer' but as long as you're accelerating away from the moon, same difference. Just think on the pendulum being a few dozen microns in area.

[John Whitehead]

The overall width of the full craft including legs was about 3.3m diameter, and from images you can gauge the small size of the capsule.

Good point, 3.3 m is the diameter to fit in the Proton launch vehicle fairing. Scaling from 3 different images & diagrams with a ruler suggests to me that the earth entry capsule was in the range 40 to 50 cm diameter. This is consistent with the paper by Andrew LePage (see my Nov14 posting), which includes the most details that I've seen. His mass and dimensional data are in agreement, based on scaling the ascent propellant tanks which works out to about 300 kg ascent propellant for a 520-kg vehicle. But it would be nice to also find such a detailed paper authored by a Russian!

John W.

[peter59]

I checked today the old broken link, and met me a nice surprise.
Lunokhod 2 Panoramas
I wish you all a pleasant evening.

Crater Le Monnier viewed from Apollo

[Paolo]

Lunokhod 2 Panoramas

[SFJCody]

I wonder what prompted this release?

[elakdawalla]

I checked today the old broken link, and met me a nice surprise.
Lunokhod 2 Panoramas
I wish you all a pleasant evening.

Way cool. I sucked them all down to my hard drive in case the link should go bad again

Does anybody have any recommendations on how to take the bend out of these images?

[Phil Stooke]

They have been talking about this for years. When I was in Russia I heard stories of finding the tapes in the State archives and carring them back on public transit to the institute. Then the tape reader would only operate in the winter, it got too hot in the summer (I think it was that way round). And they also spoke of setting up the equivalent of a PDS node to distribute their old data. Lack of funding delayed it for years. Maybe this is the start of it.

Warning: at least some, probably all, raw Lunokhod panoramas are reversed left to right. If you try to match topographic features you have to flip them.

Phil

[centsworth_II]

I wonder what prompted this release?

Maybe this:
(clicked "main" on the panorama page, then "news")

The 50-th Vernadsky/Brown Microsymposium on Comparative Planetology

Under sponsorship of Russian Foundation of Basic Research
October 12-14, 2009, Moscow Russia

Organized by Vernadsky Institute and Brown University

[4th rock from th...]

What a nice surprise! I can't wait to try to match the panoramas to the traverse maps ;-) It would also be nice to see them on Google Moon.

The only thing I don't like is that the images are water marked. That will make further processing difficult.

[marswiggle]

Panoramas 12 and 13 in that link (click page 3) seem to form an almost perfect stereo pair. Both are centered at the lander, and so after some basic adjustments I was able to produce this stereo pair of it in 40% of the original size, for crossed-eyes viewing.

Attached thumbnail(s)

 

[Hungry4info]

Way cool. I sucked them all down to my hard drive in case the link should go bad again

Yep. Same here.

Does anybody have any recommendations on how to take the bend out of these images?

Photoshop has a tool that will do that.

[ngunn]

That is fantastic, marswiggle, thanks a million. Would it be worth doing the left-right flip Phil mentioned to make that 3D even more like the real thing? (I may try that if I can find out how.)