[FPSPACE] Trajectories of Soviet 2MV Missions to Venus and Mars in1962

Drew LePage ajlepage at visidyne.com
Mon Jun 30 15:39:23 EDT 2014


Bart,

I greatly appreciate the information you have provided from the 1962 
Soviet documents on the 2MV missions to Venus and Mars.  In addition to 
giving more details on these missions, they seem to support some of the 
conclusions in my trajectory analyses.  Here are some specific comments:

The Venus missions:

My conclusion that the 1962 Venus launch window ran from late August to 
early September agrees quite well with the dates of August 15 to 
September 11 given in the Soviet document to the Central Committee that 
you supplied.

While I have no issue with the 2MV-1 landers having a mass of ~1100 kg 
(which matches well with the 1097 kg I cite from Huntress and Marov), I 
feel that 1100 kg seems to be too high for the 2MV-2 flyby probe.  While 
the minimum C3 launch energy for the launch dates for the 2MV-1 landers 
were in 8.8 to 9.5 km^2/s^2 range, the minimum launch energy on the date 
of the 2MV-2 flyby mission launch (September 12 or the day after the end 
of the cited nominal launch window) was 12.3 km^2/s^2.  This is close to 
the C3 launch energy for the 1964 Zond 1 Venus mission of 12.4 km^2/s^2 
found in the following analysis I posted here about three months ago:

http://www.drewexmachina.com/2014/04/02/trajectory-analysis-of-the-soviet-1964-venus-missions/ 


Since Zond 1 had a launch mass of 950 kg (and was launched using the 
presumably more capable 8K78M instead of the 8K78 used in 1962), I'm 
more inclined to believe that the 2MV-2 had a mass closer to 950 kg than 
1100 kg.  But until I find a good model for the performance of the 8K78 
(or develop my own), I have no way of saying definitively one way or the 
other.

As for your comment about "the big margin in the arrival date", I think 
the issue is more about the cited 90 to 140 day range of the time of 
flight.  If you look at Figure 2 in my 1962 Venus trajectory analysis 
(i.e. contours of C3 as a function of launch date and time of flight 
taken from Clark et al.), the time of flight of minimum energy 
trajectories shows a VERY strong dependence on launch date - much 
stronger than in 1964, for example.

Minimum energy trajectories for the August 25 to September 12 launch 
dates ranged from 112 to 98 days, respectively.  The time of flight for 
a minimum energy trajectory on the July 22, 1962 (the launch date of 
NASA's Mariner 1 but 24 days before the launch window cited in the 
August 11 Soviet document - a launch date that might have been 
contemplated earlier but either missed or passed over after the failure 
of Mariner 1) was about 140 days.  If the 2MV-2 flyby mission had been 
launched about a week earlier than it actually was but still with a C3 
of 12.3 km^2/s^2, it would have had a time of flight of about 90 days if 
it followed a Class I transfer trajectory (and would have beaten Mariner 
2 to Venus by a week, give or take).

The Mars missions:

Once again, my conclusion that the 1962 Mars launch window extended from 
the last week of October to the first week of November agrees well with 
the October 25 to November 5 cited in the Soviet document.

The mass of 250 kg for the lander in the document you provide is lower 
than the 305 kg I cite (which I got from Huntress and Marov).  It could 
be that the latter is incorrect (maybe it was confused with the intended 
mass of the 3MV-3 Mars lander that never flew in 1964).  Or maybe both 
figures are correct: The 305 kg mass could be the launch mass while the 
250 kg figure is the mass after landing (~55 kg sounds about right for 
the mass of a parachute and other landing hardware).  Until more 
information about the source of the 305 kg figure is provided, I am more 
inclined to believe the 250 kg figure cited in the Soviet document you 
have provided.

Once again, many thanks for providing this information.

Drew



On 6/29/2014 6:44 PM, Bart Hendrickx wrote:
> A handful of declassified documents on the 1962 Venus and Mars missions were
> published in the book "Sovetskiy kosmos" three years ago. The following
> information may be useful for the trajectory analysis :
>
> The Venus missions :
>
> In a document sent to the Central Committee on 11 August 1962 the launch
> window is given as 15 August - 11 September 1962. Three missions were being
> prepared, one lander (2MV-1), one flyby probe (2MV-2) and what is only
> described as a "back-up mission". The first launch was expected to carry a
> lander and the second a fly-by probe (so it looks like the launch of the
> second lander (the "back-up mission") was moved forward after the launch
> failure of the first lander, with the flyby mission moving to the last slot
> in the window).
>
> The launch mass given for all the probes 1100 kg. The mass given for the
> landing device is 370 kg.
>
> The probes were expected to reach the "vicinity of Venus" 90 to 140 days
> after launch after having covered 75 million km. A course correction was
> expected to be carried out between 20 to 90 days after launch at distance of
> 5 to 50 million km from Earth. The big margin in the arrival date is
> strange. As for the date of the course correction, that probably depended on
> the accuracy of the launch.
>
> The flyby probe was expected to come to within a distance of 1000 to 2000 km
> from the Venusian surface and send back pictures and other data.
>
> Also published are telegrams sent to the Central Committee after the two
> first launch failures. The launch time given for the first mission is 25
> August at 5.56 Moscow time (=2.56 GMT, about 40 minutes later than given by
> other sources). The second launch was expected on 31 August (so seems to
> have been a delayed by a day). Launch time given for the second launch is 1
> September at 5.12 Moscow time (as reported elsewhere). On that day the third
> probe (the flyby probe) was expected to be launched between 7 and 14
> September (so it looks like the window was slightly stretched. In the 11
> August document it had been explicitly stated that the mission objectives
> could only be accomplished if the missions were launched before 11
> September).
>
>
>
> The Mars missions :
>
> The mission objectives are described in a document to the Central Committee
> on 6 October 1962. The launch window is given as 25 October - 5 November
> 1962. The sequence of launches was the two flyby probes first, followed by
> the lander (so the sequence wasn't changed).
>
> Only the mass for the landing device is given (250 kg).
>
> The expected arrival was "210 to 240 days after launch" (apparently this was
> the case for all three probes, although the text can also be interpreted
> such that this was the expected flight time for the lander). Two course
> corrections were planned for all three probes : the first 50 to 70 days
> after launch at a distance of "about 50 million km" and the second 15 days
> before Mars arrival.
>
> Both flyby probes were to fly past the planet of a distance of 1000 to 2000
> km and send back pictures. The first mission carried "extra telemetry
> devices" to check the effectiveness of modifications made to the Blok-L
> escape stage after the failed Venus launches in September.
>
> The launch times for the failed missions given in the launch telegrams to
> the Central Committee are the same as reported elsewhere.
>
> Bart Hendrickx
>
>
>
> -----Original Message-----
> From: FPSPACE [mailto:fpspace-bounces at www.friends-partners.org] On Behalf Of
> Drew LePage
> Sent: zondag 29 juni 2014 15:47
> To: fpspace at friends-partners.org
> Subject: [FPSPACE] Trajectories of Soviet 2MV Missions to Venus and Mars
> in1962
>
> I've been interested in the old Soviet lunar and planetary missions for
> decades as well as tackling the mysteries some of the early ones have
> presented.  One of the tools I found to be useful unraveling some of these
> mysteries (as well as raising new questions) has been an analysis of the
> trajectories followed (or supposed to be followed) by Soviet missions to
> Venus and Mars.  Two of the more recent analyses that I have performed but
> not shared in this forum are for the 2MV-series spacecraft launched towards
> Venus and Mars in 1962.  I provide the links below:
>
> An analysis of the three unsuccessful (and unannounced) launches in
> late-August to Early September 1962 to Venus that were suppose to compete
> with NASA's Mariner 2 mission:
>
> http://www.drewexmachina.com/2014/06/04/trajectory-analysis-of-the-1962-sovi
> et-venus-missions/
>
>
> An analysis of the three missions to Mars launched in late-October to
> early-November 1962 which included Mars 1 and a pair of unsuccessful (and
> again, unannounced) sister craft - another flyby probe and the first Mars
> lander.  Also discussed are results from simulations of the entry trajectory
> into the Martian atmosphere:
>
> http://www.drewexmachina.com/2014/05/02/trajectory-analysis-of-the-soviet-19
> 62-mars-missions/
>
>
>
> Drew
>
>
> --
> Andrew J. LePage
> Senior Project Scientist
>
> Visidyne, Inc.
> 111 South Bedford Street
> Suite 103
> Burlington, MA 01803
>
> Tel: (781) 272-1220
> Fax: (781) 229-8165
>
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-- 
Andrew J. LePage
Senior Project Scientist

Visidyne, Inc.
111 South Bedford Street
Suite 103
Burlington, MA 01803

Tel: (781) 272-1220
Fax: (781) 229-8165



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