[FPSPACE] AAP piloted Venus flyby mission

[DSFPortree at aol.com]

A little while back Larry Klaes posted a link to a 1960s document on a 
piloted Venus orbiter mission. This motivated me to pull from my files a document 
I'd squirreled away about a piloted Venus flyby mission. Last night I finally 
got around to writing up an annotation of it for my website. Normally my site is 
restricted to moon & Mars planning documents, but occasionally I'll stretch 
the definition to encompass missions that use hardware typically identified 
with moon or Mars missions. In this case, the Venus flyby mission exploits Apollo 
hardware.

The URL for this annotation is 
http://www.marsinstitute.info/rd/faculty/dportree/rtr/pf10-7.html

This is, incidentally, the 401st annotation on my site.

Enjoy!

David

Preliminary Mission Study of a Single-Launch Manned Venus Flyby with Extended 
Apollo Hardware, MSC Internal Note No. 67-FM-25, Jack Funk and James J. 
Taylor, Advanced Mission Design Branch, Mission Planning and Analysis Division, 
NASA Manned Spacecraft Center, Houston, Texas, February 13, 1967. 

For many space planners in the early 1960s, piloted Solar System exploration 
using large "post-Saturn" rockets and new-design spaceships seemed a natural 
follow-on to the Apollo moon program. In November 1964, however, NASA 
Headquarters announced that its post-Apollo space program would emphasize Earth-orbital 
space stations based on Saturn/Apollo hardware. Agency officials explained 
that this was in keeping with the wishes of President Lyndon Johnson. The 
Headquarters announcement, which marked the genesis of the Apollo Applications 
Program (AAP), undermined planetary exploration planning. Even before the 
announcement, however, die-hard planners began to study how Saturn/Apollo hardware 
could be applied to planetary voyages. In February 1965, Marshall Space Flight 
Center's Future Projects Office completed the first study of Apollo-based piloted 
Mars and Venus flyby missions [read]. AAP's critics, meanwhile, derided its 
lack of any overarching goal beyond finding new applications for Apollo 
hardware. In the present document, engineers at the Manned Spacecraft Center (MSC) 
propose as AAP's "final goal" a series of three Apollo-based piloted Venus 
flybys spanning 1972-76. The flyby spacecraft would depart Earth during 30-day 
launch windows opening on April 4, 1972, November 14, 1973, and June 7, 1975. Each 
mission would require a single unmodified three-stage Saturn V rocket, a 
lightly modified Apollo Command and Service Module (CSM), and a drum-shaped, 
single-deck Mission Module (MM) based, perhaps, on the Apollo Orbiting Laboratory 
(AOL) under study at this time. The 1972 AAP Venus flyby mission would occur as 
follows:

Earth launch (April 4, 1972): The Saturn V's S-IVB third stage injects the 
66,308-pound CSM and 27,783-pound MM into 100-nautical-mile circular orbit, then 
restarts at the appropriate time to place itself and its payload into an 
elliptical orbit with an apogee (orbit high point) of 70,000 miles and a two-day 
period. The three-man crew in the CSM detaches their spacecraft from the Saturn 
Launch Adapter (SLA), turns it around, and docks it with the top of the MM, 
which occupies the space within the SLA that contains the Lunar Module on 
Apollo moon missions. They back the CSM away to free the MM and its attached 
3400-pound experiments package from the spent S-IVB stage, then transfer to the MM 
to deploy its twin solar arrays and check out its systems during the 24-hour 
climb to apogee. 

Earth-orbital launch (April 4-5, 1972): The astronauts return to their 
couches in the CSM to prepare for maneuvers at apogee designed to refine the plane 
of their orbit and their altitude at perigee (orbit low point). These and subseq
uent maneuvers employ the Service Propulsion System (SPS) main engine on the 
CSM's drum-shaped Service Module (SM). The SM contains 40,000 pounds of 
propellants, enabling a total velocity change of 4100 feet per second. If the SPS 
fails to operate as planned during the apogee manuevers, the astronauts can 
separate the CSM from the MM and use its attitude control thrusters to lower its 
perigee altitude so that it reenters Earth's atmosphere. If the SPS and all 
other systems continue to function normally, however, 24 hours later the CSM/MM 
combination reaches perigee outside Earth's atmosphere traveling at about 9710 
feet per second. The astronauts then ignite the SPS at perigee to add about 
3000 feet per second to their velocity and begin the 109-day transfer to Venus. 

Earth-Venus transfer & Venus flyby (April 5-August 23, 1972): An abort up to 
six minutes after the Venus injection burn will return the crew to Earth in 
two days. For an abort, the astronauts undock the CSM from the MM and fire the 
SPS to slow down and enter a two-day elliptical Earth orbit, then maneuver at 
apogee to drop their perigee into Earth's atmosphere. Assuming that no abort is 
necessary, however, they shut down the CSM to extend its lifetime and move to 
the MM. They reactivate the CSM three times during flight to Venus to perform 
course corrections. Course correction navigation is by Earth-based radar 
backed up by a hand-held sextant and a navigational computer in the MM. The 
astronauts perform solar, space environmental, and astronomical observations during 
Earth-Venus transfer and deploy automated probes a few days before Venus 
flyby. They photograph Venus during the August 23 flyby, which occurs over the 
planet's day side. The mission's experiment package - which includes impactors for 
obtaining atmosphere measurements, soft landers, cameras, and, if weight 
growth during development can be strictly controlled, a 40-inch telescope - is a 
trimmed-down version of the Mars flyby spacecraft science package proposed in 
the NASA Planetary Joint Action Group's 1966 report [read]. 

Venus-Earth transfer & Earth atmosphere reentry (August 23, 1972-March 30, 
1973): The astronauts use the CSM SPS to perform three course-correction burns 
during the 250-day voyage back to Earth. As the homeworld grows outside their 
viewports, they transfer to the CSM and undock from the MM. They then detach 
from the SM in the the conical Command Module (CM) and reenter Earth's 
atmosphere 359 days after Earth launch. A beefed-up heatshield enables the CM to 
withstand atmosphere reentry at up to 45,000 feet per second (about 15,000 feet per 
second faster that lunar return speed). 

About a month of this report was completed, AAP bore the brunt of more than 
$500 million in cuts to NASA's FY 1968 budget. The program, which for a time in 
1966 had been planned to include some 40 Earth-orbital and lunar missions, 
shrank rapidly during 1968-69 and was renamed the Skylab Program in February 
1970. Between May 1973 and February 1974, three three-man crews occupied the 
Skylab Orbital Workshop in Earth orbit for a total of 173 days. Robot probes, not 
astronauts, explored Venus in the 1970s. The Soviet Union's Venera 8 took 
advantage of the 1972 launch opportunity, leaving Baikonur Cosmodrome in central 
Asia on March 27, 1972. The armored probe landed on Venus and transmitted data 
on its brutal surface conditions for 50 minutes. The U.S. Mariner 10 probe 
(launched November 3, 1973) flew past Venus on February 5, 1974, en route to 
Mercury. After skipping the 1973 Venus opportunity to launch Mars probes, the 
Soviets launched Venera 9 and Venera 10 on June 8, 1975, and June 14, 1975, 
respectively. Each consisted of an orbiter and a lander. Venera 9's lander 
transmitted the first picture of the Venusian surface on October 22. Venera 10's lander 
set a new endurance record on October 23, returning data for 65 minutes 
before its orbiter passed out of radio range. 

David S. F. Portree
Science writer & historian
dsfportree at aol.com
Flagstaff Arizona USA

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"Historian (n.): An unsuccessful novelist." - H. L. Mencken