Origin of what became Pioneer P-3, P-30, P-31 Options

[Jay Gallentine]

Hi Folks,

Trying to iron out the origins of STL's Pioneer P-3, P-30, and P-31 flights beginning 1959.

Paolo Ulivi's 'Lunar Exploration' mentions they began life as a series of Venus probes, but the successes of Luna prompted a conversion to ships for lunar exploration instead.

Does anyone happen to have any more detail on the original plans for Venus, who or what entity pushed for the change, and how, exactly the ships changed as a result?

Was this in fact a NASA venture, or one controlled more by the Air Force?

Thanks much!
Jay Gallentine

jay at firingroom dot com

[Paolo]

That is a nice question, and it's nice for you to mention my book
Unfortunately the literature on these flights is extremely scarce. I hope that someone one these days will do for these missions the same kind of historical work that Marcus Gideon is doing for the early Pioneer 0 to 2 orbiters. If you haven't seen it I suggest to give a look at Marcus' article "Pioneering Space" in the latest issue (14:2) of Quest

[Jay Gallentine]

Hello Paolo, yes indeed, your book has been well-thumbed and properly acknowledged!

I've done some deeper web digging, but can't find anything much more.

What, specifically, is the source of your information as to 'four STL-built probes to the Moon and Venus'?

Just curious!

Thanks much,
Jay Gallentine

[Paolo]

What, specifically, is the source of your information as to 'four STL-built probes to the Moon and Venus'?

My main reference for that should have been "Thor Able and Atlas Able" (JBIS, 37, 1984, 224)
I have at hand the article "The forgotten mission of Pioneer 5" by Joel Powell (Spaceflight, May 2005, 189). It states: "The original plan for Pioneer 5 [...] the tiny spacecraft would have been rocketed to Venus as a fly-by probe in tandem with a Venus orbiter to be launched on an Atlas-Able rocket in June 1959. [...] NASA planners decided to re-target the Venus orbiter to Earth's Moon."
See also "Atlas Able IVB" entry in Siddiqi's "Deep Space Chronicle" http://history.nasa.gov/monograph24/Table%...%20Contents.pdf

[tasp]

There is a thread here at UMSF on that.

I will attempt to locate.

[tasp]

Check out this thread:

Mariner Mars 1964, Mariners 3 and 4 to Mars: imaging plans?

[Jay Gallentine]

Well, that's a very helpful link! Thank you very much!

I've also received a nice e-mail from Bruce Moomaw promising to forward the story, but it looks like he's posted it already and I might be able to save him the trouble.

In the interim I did manage to locate vague references to the program in Homer Newell's book 'Beyond the Atmosphere' as well as John E. Naugle's 'First Among Equals'.

I think I share Don Mitchell's desire to see more pictures of these!

Thanks to all for their help.

Jay Gallentine
STILL trying to frantically revise the book manuscript... due in eight weeks... tick tock tick tock....

[GregM]

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[Art LeBrun]

INLINE QUOTING REMOVED

Since the 5 lunar probes were assigned at the same time it would be inaccurate to write that Pioneers
3 and 4 were "scaled back" to achieve success. The realistic goals were all the Army Juno II could
hope to do - ever. Ironically the Juno II failed in 5 out of 8 earth orbital attempts later on. Excellent
review of the Atlas-Able lunar Pioneer vs the "Venus probe".

[Paolo]

Check out this amazing site on the Atlas-Able probes as well as Pioneer 0-2 and Pioneer 5!!
http://www.sdfo.org/stl/

[Liss]

Well, I'm still curious with the story of STL probes to Venus and Moon of 1959. Maybe it'd be useful to move here some postings from http://www.unmannedspaceflight.com/index.php?showtopic=945 . I'll first quote a message:

The scheme was more complex than that. It did involve launching Pioneer 5 toward Venus in early June 1959, but without a midcourse correction motor no one thought it would get anywhere close. HOWEVER: it also involved simultaneously launching the very first of the much bigger Atlas-Able Pioneer orbiters to Venus -- and since that had two restartable hydrazine motors sticking out of its poles, the plan really would been to make an honest effort to put it into Venus orbit. Aviation Week had several short items on it in 1959 -- and the NY Times of (I believe) May 1, 1959 made the plan's last-minute cancellation its front-page headline. (It was cancelled on the grounds that "the science payload could not be gotten ready in time", by which NASA may have meant the entire spacecraft.)

A second Pioneer orbiter was to be built simultaneously to be put into lunar orbit later...

Anyway, after the cancellation of that plan, the goal of the smaller Pioneer 5 remained to be put into a solar orbit with its perihelion at Venus' orbit -- and after sitting on the pad through delay after delay during the last half of 1959, it finally got off the ground in March 1960 and became the only genuine success of the early Pioneers (although its perihelion ended up considerably outside Venus' orbit, and its power supply failed at a range of 22.5 million miles instead of the 50 million hoped for).

The plan to launch a single Atlas-Able orbiter to the Moon remained; and after its planned October launch was scrubbed when the booster blew up during a September static test, NASA grabbed the Atlas planned for the cancelled second Mercury "Big Joe" test and launched it in late November -- only to end up with the infamous "turkey shoot" in which the shroud came off due to inadequate venting of internal air pressure, and the air blast then tore off the probe and third stage and crippled the second stage. No doubt this would have been its fate had it been launched to Venus in June.

Since this meant that there was still one spare Pioneer orbiter, Eisenhower gave permission to try to launch it to the Moon in late 1960 -- and to build a third copy for one last attempt if the second one failed. Unfortunately, both the second AND third tries also failed ignominously (due to failures of the second stage, which by then was usually working pretty reliably on Thor-Able).

So I understand this as follows:
(1) Four different spacecraft were in design and productiion at STL in the spring of 1959: a HEO probe, a Venus flyby probe, a Venus orbiter and a Moon orbiter.
(2) The HEO probe was launched as Explorer VI (S-2) in August 1959, and the Venus orbiter was launched as Pioneer V (P-2) to a fake Venus target in March 1960.
(3) Three attempts of Moon orbiter launches were made in Nov 1959, Sep and Dec 1960, using the two probes remained and a third built from scratch.

So the principal question is: we know that a P-3 probe was lost in the Nov 1959 launch failure. But which orbiter was intended for launch to Moon in Oct 1959 and failed in Nov 1959, the initial Moon one -- or the converted Venus orbital probe? Was P-1 the designation of another probe, not launched in 1959? What was the difference in design between the two? For example, did they have the hydrazine tank of the same size and volume? And the last large question: with a constant rotation axis pointing, how would the probes achive the mid-course corrections and the orbit insertion?

Here are smaller scale questions as well.

Both Explorer VI and Pioneer V were based on a common almost spherical body with four vanes. What was the 'equatorial' diameter of the body, 26 or 29 inches -- publications tend to quote both figures? What was the size of Explorer VI vanes -- 18x18 inches or larger? (It is obvious that Pioneer V used a shortened version of Explorer VI vanes with only 600 cells per side instead of 1000.) Is it safe to say that one panel of Explorer VI could produce 15 W if it is known that one module of cells (2x50 cells from the two sides of a panel) would produce 0.75 W? And who built the photo cells?

Well, sources say that the 1960 P-30/P-31 spacecraft used 24x24 inch panels of 1100 cells per side, and a 100 cells module could produce 1.3 W. Is it safe to say that the cells were larger in size, or more efficient, or both? Did a spacecraft exist with 1200 cells per side, 9600 in total? What about the P-3 probe solar cells?

[gwiz]

Both Explorer VI and Pioneer V were based on a common almost spherical body with four vanes. What was the 'equatorial' diameter of the body, 26 or 29 inches -- publications tend to quote both figures?

The NASA Explorer 6 final report (SP-54) quotes a length of 26 in. and a diameter of 29 in. Since the satellite is manifestly longer than its diameter, could these figures be reversed, explaining the confusion?