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Topic: Why Friendship 7 was planned for three orbits
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Jim_Voce Member Posts: 273 From: Registered: Jul 2016
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posted 07-23-2017 03:06 AM
Does anyone know why the first American manned orbital flight, Friendship 7, flew three orbits instead of just one orbit?Vostok 1 flew just one orbit, which made sense. It was a sensible, conservative way to approach the first manned orbital flight. But when Project Mercury began in 1958, the first American orbital mission was always scheduled for three orbits. Is there any reason why? |
Aeropix Member Posts: 43 From: Houston Registered: Apr 2010
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posted 07-23-2017 10:42 AM
I think it was planned for 7 orbits, hence the name Friendship "7". Due to a heat shield problem it was reduced to three orbits to mitigate the mechanical issues with the capsule.In the "Space Race," the USA was trying to leapfrog the Soviets by pressing the boundaries of mission duration, and thus appear to "get ahead." |
moorouge Member Posts: 2458 From: U.K. Registered: Jul 2009
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posted 07-23-2017 10:54 AM
quote: Originally posted by Aeropix: I think it was planned for 7 orbits, hence the name Friendship "7".
Are you sure this is correct? I thought the "7" was added after the name to continue a tradition started by Shepard.
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randy Member Posts: 2231 From: West Jordan, Utah USA Registered: Dec 1999
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posted 07-23-2017 11:53 AM
I always thought it was to honor the "Original 7." I also wonder if the number of orbits was a bit of one-ups-manship. |
canyon42 Member Posts: 238 From: Ohio Registered: Mar 2006
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posted 07-23-2017 12:21 PM
Glenn's flight was intended from before launch to be three orbits, not seven. The orbital confusion stems from a capcom comment that doesn't refer to the actual mission plan but to the parameters of the initial orbit. The name Friendship 7 followed on from Freedom 7 and Liberty Bell 7, and was followed by Aurora 7, Sigma 7, and Faith 7. None of which ever had a seven-orbit mission, for what it's worth... |
Robert Pearlman Editor Posts: 43576 From: Houston, TX Registered: Nov 1999
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posted 07-23-2017 01:48 PM
As recounted by Dwayne Day in an article for the The Space Review: Glenn was told by his capcom: "Roger, Seven. You have a go — at least seven orbits." This was mission control's way of informing Glenn that his altitude and velocity were sufficiently high that he would stay up for at least seven orbits if he did not initiate retrofire. The "7" in the names of the Mercury spacecraft was a symbol of solidarity among the Mercury 7 astronauts.Glenn was originally slated to launch in late 1961, but even by then, Gherman Titov had already completed the 17.5-orbit Vostok 2 mission that August, so Friendship 7 did not put the U.S. ahead in the space race. It did however, demonstrate that Mercury could fly for multiple orbits, evening the capability between the Soviet and American spacecraft. |
Tom Member Posts: 1610 From: New York Registered: Nov 2000
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posted 07-23-2017 03:17 PM
In addition, seven orbits would have brought Atlantic recovery efforts in the dark. |
Joel Katzowitz Member Posts: 811 From: Marietta GA USA Registered: Dec 1999
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posted 07-23-2017 03:49 PM
My understanding was that Shepard named his spacecraft Freedom 7 because his Mercury spacecraft was actually number 7. The remaining Mercury astronauts then decided to continue the naming convention as a sign of solidarity. |
Blackarrow Member Posts: 3160 From: Belfast, United Kingdom Registered: Feb 2002
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posted 07-23-2017 04:41 PM
quote: Originally posted by Aeropix: I think it was planned for 7 orbits, hence the name Friendship "7". Due to a heat shield problem it was reduced to three orbits to mitigate the mechanical issues with the capsule.
Here we have the perfect example of Hollywood myth (established in "The Right Stuff" and perpetuated in "Hidden Figures") becoming "fact." Houston, we have [sic] a problem! |
Lou Chinal Member Posts: 1332 From: Staten Island, NY Registered: Jun 2007
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posted 07-23-2017 06:52 PM
Yes Joel, I remember reading that story about Shepard's spacecraft being production no. 7 also. |
MCroft04 Member Posts: 1647 From: Smithfield, Me, USA Registered: Mar 2005
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posted 07-23-2017 09:17 PM
quote: Originally posted by Lou Chinal: Shepard's spacecraft being production no. 7
I believe Guenter Wendt says this in his book "The Unbroken Chain." |
Jim_Voce Member Posts: 273 From: Registered: Jul 2016
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posted 07-25-2017 12:10 AM
I would like to refocus the discussion back on the original question, which was why did the Space Task Group back in 1958 chose three orbits they wanted the first manned American orbital flight to complete? This flight plan remained in Mercury manned flight planning from the beginning and up to Friendship 7, which as noted was originally scheduled for 1961.I ask the question because it seems like the Space Task Group could have just as easily chosen one orbit as the plan for the first manned orbital mission. And the Russians when they launched Vostok 1 chose one orbit as the flight plan for their first manned mission. Any thoughts? |
oly Member Posts: 971 From: Perth, Western Australia Registered: Apr 2015
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posted 07-25-2017 01:00 AM
There are many factors to be considered with doing the first orbital flight and you need to remember that the Mercury program was an incremental set type program doing a little more each flight.The spacecraft "mileage" had not been established so to speak where NASA needed to know how much oxygen, propellant and battery life would be consumed during orbital flight. These figures could be worked out on the ground or in the suborbital flights but had not been proven. With the first manned launch of the Atlas launch vehicle NASA would want to take their time with the launch which lifted off at 09:47 a.m. (after a few delays, each orbit of about 90 minutes (so three orbits equaled 4.5 hours) and the recovery needing to take place during daylight all these factors mean that to "plan" it safe three orbits would be a good number to try for the first flight. If there was a problem and needed an extra orbit they would still have daylight at landing. Each subsequent flight pushed the duration a little longer and there were a few surprises along the way such as excess consumption of propellant etc. Also remember that while it was now known that manned orbital flights were possible the U.S. had no experience on the effects because the Soviets were not sharing this information. |
Blackarrow Member Posts: 3160 From: Belfast, United Kingdom Registered: Feb 2002
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posted 07-25-2017 07:30 AM
I suspect it might have been felt that since the first Russian flight had been a single orbit, the first American flight should be longer (although there was no question of trying to beat Titov). I also recall some argument that Gagarin's flight "didn't really count" as an orbital flight because he didn't fly even one complete orbit. (I hasten to add that I am not supporting that view. As far as I am concerned, if you have accelerated to orbital velocity, your flight is orbital, not sub-orbital.) |
onesmallstep Member Posts: 1313 From: Staten Island, New York USA Registered: Nov 2007
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posted 07-25-2017 11:50 AM
There was also the argument that, technically, Gagarin's flight wasn't even a 'first' in space, let alone an orbital one. Per FAI (International Aeronautical Federation) rules, a pilot must be in command (or at least be inside of the vehicle) from start to landing to qualify for a record. As is known, Gagarin and the other Vostok cosmonauts ejected from their spacecraft prior to landing. But the small matter of them landing separately from their craft was overlooked. |
GACspaceguy Member Posts: 2516 From: Guyton, GA Registered: Jan 2006
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posted 07-25-2017 12:46 PM
Yes, technically, he did not stay with his vehicle, but those "rules" were intended for aircraft. This was a different arrangement in my opinion, in that the man went around the earth, in zero G, at the right altitude and speed he was in space as well as being first. Grew up in that era and would love to say America was technically first, but that would be a technicality and not the reality of the time. |
David C Member Posts: 1039 From: Lausanne Registered: Apr 2012
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posted 07-25-2017 12:53 PM
Mmm, never been too impressed with the FAI and it's self important pronouncements on space flight. |
Robert Pearlman Editor Posts: 43576 From: Houston, TX Registered: Nov 1999
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posted 07-25-2017 01:09 PM
Regardless of personal opinions, the FAI was (and still is) recognized as the world's ruling body by the Soviet Union (now Russia) and United States. quote: Originally posted by onesmallstep: But the small matter of them landing separately from their craft was overlooked.
It wasn't overlooked; the FAI (and the world) was misled. The Soviet Union in its official post-flight report to the FAI omitted the fact that Gagarin did not land aboard the Vostok. The Soviets were aware of the requirements before Gagarin launched and kept the full details of his flight secret. It wasn't until Titov admitted to ejecting from his Vostok did the truth surface. That doesn't mean Gagarin wasn't the first in space, or the first to orbit Earth. The FAI revised its rules after Titov's admission such that Gagarin retained his world record. |
onesmallstep Member Posts: 1313 From: Staten Island, New York USA Registered: Nov 2007
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posted 07-25-2017 01:38 PM
Not surprising that the USSR "misled" the FAI (and the world) as regards to Gagarin's ejection from the Vostok, as they were well aware of the rules for any world record attempt. Once the cat was out of the bag, official pronouncements from then on stated that Gagarin had ejected. As if further proof was needed, in 1986 a doctor attached to one of four emergency response teams gave a detailed account of the recovery efforts, stating that Gagarin "landed like all the other Vostok cosmonauts." (Source: Almanac of Soviet Manned Space Flight, Dennis Newkirk, 1990) |
moorouge Member Posts: 2458 From: U.K. Registered: Jul 2009
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posted 07-26-2017 01:47 AM
It's interesting to note that the Gemini 5 crew had to produce two one dollar bills given them immediately prior to launch to prove they were the same people that were recovered at the end of their flight.This was for FAI record verification purposes. quote: Originally posted by Jim_Voce: ...why did the Space Task Group back in 1958 chose three orbits they wanted the first manned American orbital flight to complete?
Where did you find the reference that the first orbital flight was to be of three orbits and that this was made in 1958?This doesn't seem likely as the specifications for a manned spacecraft were not finalised and posted to the twenty firms expressing an interest until 17th November with replies required by 11th December. A scan, albeit a quick one, through the Mercury chronology revealed no references to any detailed planning for any of the flights during 1958. |
taneal1 Member Posts: 237 From: Orlando, FL Registered: Feb 2004
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posted 08-17-2017 06:55 AM
Oops! I missed the reply from "Oly" so I am only repeating what is stated in his thorough reply. quote: Originally posted by Jim_Voce: I would like to refocus the discussion back on the original question, which was why did the Space Task Group back in 1958 chose three orbits they wanted the first manned American orbital flight to complete?
The original goal of Mercury was called the MODM [Manned One Day Mission]. The idea was to incrementally increase flight duration until this goal was achieved.Why start with three orbits instead of one? At the time, the medical community wanted a large number of chimp flights prior to risking a man. A single 90 minute orbit wouldn't do much to prove man could endure "weightlessness" for the 24 hour mission. Three orbits would produce medical data that could be extrapolated toward a 6 orbit mission. And of course, NASA wanted to qualify the spacecraft. This was the reason for the planned second orbital mission's repeated duration of 3 orbits. Any spacecraft systems deemed unreliable per the first 3 orbit flight could be fixed and re-tested on the 2nd flight. Two successful missions would increase confidence for a successful 6 orbit mission. Why not more than 3 orbits? Any duration beyond 3 orbits would violate NASA's daylight Atlantic splashdown requirements. Due to launch delays, Glenn's MA-6 flight came close to a two-orbit limit. Due to their greater duration, MA-8 and MA-9 splashed in the Pacific. This required a much larger Naval recovery force that wasn't "available" for the first missions. |
Lasv3 Member Posts: 422 From: Bratislava, Slovakia Registered: Apr 2009
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posted 08-20-2017 04:58 AM
Another reason for the maximum three orbits for the first manned orbital mission might have been the communication conditions as well. David M. Harland writes in his excellent book "How NASA Learned to Fly in Space" on page 23: On 20 February 1962 John Glenn rode an Atlas and returned after three orbits, which was the most that could be achieved without leaving the narrow zone covered by the tracking and communications sites (this was why three orbits was the official Project target). |
Jim_Voce Member Posts: 273 From: Registered: Jul 2016
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posted 08-23-2017 12:56 AM
quote: Originally posted by taneal1: Why start with three orbits instead of one?
Very much appreciated. Excellent perspectives! |