The last major update to the NTRS (between 28/30 of May) bought up some interesting documents from 1969 which seem to be the earliest set of plans for what later became Viking.

What caught my attention was a series of documents discussing a 'Hard-Lander' probe for the 1973 launch opportunity. Sadly the documents are too large for me to read at the moment (I'm restricted to dial up) but I was wondering if anyone here would be able to fill me in on just what was planned?

Edit: I've decided to add a direct link to one of the documents in question, it's the summary report. For those on dial-up expect a long wait it's 36mb in size. ('Mars Hard Lander: Summary Final Report (1968)')

I want to point out two important things...

1. A hard lander in 1973 means it had to be sophisticated enough to carry out communication sessions directly with the Earth or to be simple and use a relay satellite instead.

2. The launch window in 1973 was not a good one. The best scenario - launch a simple communication orbiter (no camera, no scientific payload) + a small hard lander with very few scientific instruments.

It's hard to justify such a mission, both financially and scientifically.

IIRC, in the mid 60s, a Saturn 5 launched Mars surface lab was considered, probably an even earlier incarnation of Viking. Considering 2 Titan IIICs would be ball parkish to a Saturn 5, might be one of the more closely realized end results NASA ever achieved when compared to the original concept.

This study and another similar study dealing with a soft-lander mars probe for the 1973 launch opportunity seem to be the immediate response to the cancellation of Voyager-Mars (eg the Saturn V based mission).

Interestingly a Titan-Centaur was the preferred launch vehicle for this version. (I'll be visiting a net cafe tomorrow to pull down the soft lander material tomorrow.

I've attached a picture of the proposed Viking '73 Hard lander taken from the summary report. Just in case you are wondering the thing that looks like an accordion is the solar cell array (weight penalties precluded RTGs).

The probe they were considering would have used an entry-from-Mars-orbit landing profile. The relay bus for the primary (1 day) mission would have been a modified Mariner 9 style spacecraft, after that the probe was intended to direct transmit to Earth for at least three months after landing. Instrumentation included an alpha-backscatter spectrometer to determine surface composition, pressure/temperature sensors and cameras.

One of the other candidate missions for Viking'73 was a soft landed solar powered probe that appears to have been based on the LM descent stage. This would have been launched atop a Titan IIIc attached to the late 60's equivalent of the Cruise Stage fitted to Phoenix. That would have used a direct-descent-from-flyby landing profile. Instrumentation on that probe was much closer to the eventual Viking fit-out lacking only the biological experiment package.

Anyway, here's a drawing of a "hard" landing ... at least for the Drakkar

Landings for this hard lander mission would have been at 10 north or 20 north in the mission design they present. A specific reference mission has a landing in the Syrtis major - Isidis region. Here's a map:

Click to view attachment

The background map is one prepared at the time by General Electric, who did the study. It hints at a few fictitious craters, since Mariner 4 had shown craters on the surface. The loop shape is the ground track of an orbiter in a synchronous but not (stationary) orbit, serving as a comm relay during the brief primary mission. Later it would move to other longitudes for broad regional mapping while the lander transmitted only meteorology data direct to Earth.

Phil

After a long delay I thought I'd relaunch this thread with some captured images from the report dealing with the soft lander version of Viking '73, the design is closer to what they eventually sent, but as noted above appears to have been descended from the LM descent stage rather than Surveyor.

The planned mission would have been a 3 day (Sol?) primary mission with a planned lifetime of 90 days (Sols?). Targeting was anywhere between 20ºN and 20ºS, with the longitude determined by the launch date.

The three parts of the report can be accessed below.


1. Study of a Soft Lander & Support Module for Mars Missions, Final Report, Vol. I, Summary

2. Study of a Soft Lander & Support Module for Mars Missions, Final Report, Vol. II, Subsystems Studies

3. Study of a Soft Lander & Support Module for Mars Missions, Final Report, Vol. III, Appendixes

For anybody who is interested here are scans of the proposed operations and communications sessions for the Viking '73 soft lander on the first four days (Sols?) of the landed missions.

The main imaging session would be pre-programmed to take place after landing and would be relayed through the flyby bus. The next lander communication session would take place about 17.5 hrs later at which time the geological/biological experiments would be bought online.

All imaging was to be completed by day(Sol?) three.

On the fourth day (Sol?) the biology experiments would be shut down and the probe would switch to a purely meteorology based program of observations.

I has been a while since I've added anything to this thread, but this 1969 General Electric proposal for a hard lander for the 1973 Mars launch opportunity seems to be the alternate to the Martin-Marietta design I posted a few years back.

Like that design, the spacecraft is intended for a direct descent landing from the trans-Mars trajectory. The carrier spacecraft is a modified version of the Mariner 6/7 which would be used to store/relay the entry data for transmission to Earth. The lander would be battery powered and was intended to operate on the Martian surface for three days.

The proposed surface instrumentation included:

1. Facsimile Camera
2. GCMS
3. Wolf Trap Life Detector
4. Water Vapour Detector
5. Wind Velocity Sensors
6. Pressure/Temperature Sensors
8. Soil Sampler
9. Clinometer

The report which covers this design and a rejected design in which the lander would have controlled both the cruise and landing phases of the mission can be accessed below.

Titan/Mars Hard Lander, Vol. I: 1400lb Capsule System Design Study

Titan/Mars Hard Lander, Vol. II: Autonomous Capsule System Design Study

For anyone who is interested the link below is to a zip file containing all of the documents I linked to that at present have not been returned to NTRS.


Box.com Viking'73

Thanks a lot gndonald ! Good job done : I had most of those but you organized them better than I did ! Warmest regards, VM

Thanks.