Ah, the nostalgia! One of my favorite programs - a briefly lit flame 1959-early 1961 snuffed out by the JFK Apollo decision...Nestles right in between the use of Surveyor for 3 lunar orbit and 4 lunar surface missions, with 15 Prospector shots on Saturn C-2 by the end of 1970 and Apollo lunar landings sometime after that. First Prospector was to have flown on the last of seven C-2 development flights, 2-3 per year thereafter.
But what was the Surveyor orbiter supposed to be? Where do I find info on that?
Quote from: Blackstar on 03/30/2012 06:35 pmBut what was the Surveyor orbiter supposed to be? Where do I find info on that?Lunar Orbiter. After the series of Ranger failures, it was taken away from JPL (so they could focus on getting Ranger and Surveyor lander to work) and given to NASA Ames. Lunar Orbiter project histories (if they exist) might be a good start to look.
I don't think that's right. I don't think that Lunar Orbiter is an extension of Surveyor. I think that it started as a new program, with the specific goal of gathering high resolution imagery in support of Apollo. Surveyor orbiter would have been a science spacecraft, not primarily imagery. I'll look in Cargill Hall's book.
...NASA canceled JPL's mapper and instead ordered the Langley Research Center to develop a lightweight orbiter to ride Atlas-Agena.
Quote from: Blackstar on 03/30/2012 09:53 pmI don't think that's right. I don't think that Lunar Orbiter is an extension of Surveyor. I think that it started as a new program, with the specific goal of gathering high resolution imagery in support of Apollo. Surveyor orbiter would have been a science spacecraft, not primarily imagery. I'll look in Cargill Hall's book.From David Harland's Exploring the Moon (p. 7):Quote...NASA canceled JPL's mapper and instead ordered the Langley Research Center to develop a lightweight orbiter to ride Atlas-Agena.Which does make it sound like a separate program scaled for Atlas-Centaur. In that case, the JPL library might be your best bet, though there's a lot they haven't digitized yet...
Pedantry alert: The lightweight orbiter studies were always sized for Agena. Surveyor was tied to Centaur.
I also seem to remember (Nicks' book?) that there were quite a few people at NASA that weren't too impressed with JPL, particularly after the problems with Ranger. There seems to have been a feeling that the lab was over-promising/under-delivering and perhaps being just a bit too optimistic. Combine that with the Centaur development problems and...
These days JPL has become much more powerful, and NASA doesn't have much influence when JPL projects run way over budget. They just have to take it.
Quote from: Blackstar on 04/01/2012 02:40 amThese days JPL has become much more powerful, and NASA doesn't have much influence when JPL projects run way over budget. They just have to take it.Or just avoid giving JPL too much control to begin with for low-cost missions, such as Phoenix.
there was a good historical paper on Prospector in the JBIS in 1995: D.L. Burnham "Mobile Explorers and Beasts of Burden: A History of NASA's Prospector and Lunar Logistic Vehicle Projects", vol 48, pp 213-228
A couple of pennies-worth from notes assembled at JPL far too many years ago to recall:
The only trouble was none of us had strong enough position, loud enough voice or leveraged clout to get that message heard! Except I do recall Carl Sagan listening very hard and mentioning this approach on the Hill.
And the Moon in all of this - what's that...?
Interesting. The text indicates that it was a current design under study. Obviously it was canceled. I would have to go digging, but I vaguely remember that the cost and timeline for Surveyor Orbiter was too much and so NASA called for a simpler and more straightforward orbiter that would not have instruments only an imager for high quality imagery in support of Apollo. Of course, the gold is all in the details--for instance, what exactly made Surveyor Orbiter so expensive and time-consuming? My guess is that the camera was not big enough and could not be bigger considering the other planned instruments. So NASA called for a design that put all the emphasis on the camera system.
Also, ISTR something about Lunar Orbiter being at a considerable advantage in that it was capable of being launched to the Moon on an Atlas-Agena, while Surveyor Orbiter (like the Surveyor Lander) required an Atlas-Centaur. I don't recall if that more to do with Agena availability or Centaur reliability at the time of the mission planning, though.
I think you're right about it being all about the camera system. The above design for a Surveyor Orbiter had a TV camera system, while Lunar Orbiter employed a film system with onboard photographic development and electronic (though not digital) read-out. Apollo planners at the time were requiring high-resolution imagery of the proposed Apollo landing sites ASAP, and IIRC the output of the television system would not have been good enough.
Quote from: the_other_Doug on 03/21/2015 03:09 amI think you're right about it being all about the camera system. The above design for a Surveyor Orbiter had a TV camera system, while Lunar Orbiter employed a film system with onboard photographic development and electronic (though not digital) read-out. Apollo planners at the time were requiring high-resolution imagery of the proposed Apollo landing sites ASAP, and IIRC the output of the television system would not have been good enough.It would be interesting to understand how the engineering requirements for Apollo translated into design requirements for Lunar Orbiter and Surveyor. For instance, what exactly did they need from a camera in terms of resolution, precision, and amount of territory covered? And why did they think they needed that?As I understand it, one of the problems with TV systems is that even if the resolution is okay their precision is poor--the distance between any two evenly-space spots on the image will not necessarily be the same. So it gets harder to rely upon that if you're feeding it into a set of calculations.
Exactly -- the spatial resolution, I believe it's called, was poor in the television imaging systems of the time, even if pixel resolution could be made to be good. And while I don't have the official Apollo imaging requirements at hand, I do know that good stereo coverage of each potential landing site was required. And not just within the landing ellipse -- they wanted good stereo imaging for the terrain overflown during the final stages of the descent trajectory, as well.This was at least partly so they could model the terrain for the benefit of the guidance computer -- if (as was the case for Site 2, Tranquility Base) there was a general slope of the terrain resulting in a significant difference in mean surface elevation from landing radar lock-on to landing, it helped for the guidance computer to know that. Site 2 had a general westward-trending downward slope of about four degrees throughout the final miles of the descent trajectory, and the guidance computer used a rough correction subroutine that took this into account.I'm pretty certain that the TV imaging systems of the time just weren't capable of providing stereo strips good enough to provide the terrain information required by Apollo planners. And since microgravity film development and electronic read-out had already been developed for reconnaissance satellites and the technology was available, that's what they ended up using.
Surveyor.