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Author
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Topic: Gemini 1 mission and spacecraft recovery
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Jim_Voce
Member Posts: 273
From:
Registered: Jul 2016
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posted 04-05-2018 12:45 AM
   
Does anyone know why in the first test flight of the Gemini Program, the unmanned Gemini 1, the spacecraft was not recovered? As I understand it, Gemini 1 entered orbit and remained attached to the second stage of the Titan II rocket. The spacecraft did indeed have a heat shield but NASA went so far as to drill holes into the heatshield so that the spacecraft would intentionally burn up on reentry. Any guesses as to why they did this? |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 04-05-2018 05:50 AM
If you read the Wikipedia entry for Gemini 1 mission, it gives the detail of the mission verbatim to your question. It also states that the mission was designed to test the structural integrity of the new spacecraft and modified Titan II launch vehicle. It was also the first test of the new tracking and communication systems for the Gemini program and provided training for the ground support crews for the first manned missions. The spacecraft was never intended to be recovered, as this was an expensive and intensive exercise. "There were no plans to separate the Titan II second stage" as the spacecraft was not intended to be recovered, It would be wise to "ensure it would not survive re-entry," so that no debris could be collected by people you don't want to have access to this technology. |
Jim_Voce
Member Posts: 273
From:
Registered: Jul 2016
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posted 07-28-2018 06:14 PM
Since the Gemini capsule was a new system one would think NASA would want to take every opportunity to test the new heat shield. In the case of Gemini 1, they deliberately wanted to destroy the spacecraft it appears. Could there be any reason for doing so? |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 07-28-2018 09:15 PM
You would not want a spacecraft designed to withstand re-entry to crash down somewhere populated or in an area where your new tech falls into unwanted hands. So making sure it did not survive is the most logical method.You don't want to build a complete spacecraft just to test the launch and tracking systems, what would be the point? All you need is an aerodynamically and mass correct "shape" to make the rocket fly as designed. When the rocket you want to put astronauts on top of has a history of structural failure, and you make modifications to it, you may wish to test it before you commit two lives to its success. If you have a new tracking system, and want to test it, why not use the first available launch to test the system? |
john.nukecop
New Member Posts: 4
From: Duluth, GA, USA
Registered: May 2014
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posted 11-03-2018 01:16 PM
Listening to a recent account of the construction and preparation of Gemini GLV-1, for the first flight of the Gemini program, the narrator stated that as a result of the decision to not recover the reentry module, four large holes were drilled into the heat shield to ensure the module’s complete destruction during reentry. While I understand the recovery of the reentry module was not a goal, it seems this was a drastic step to ensure the vehicle was destroyed. I have never heard or read about this before. Two questions: - Can anybody verify that the holes were drilled through the heat shield?
- Why bother, especially in view of the fact that the second stage remained attached to the Gemini spacecraft (with all three of its modules) until it too was destroyed during reentry?
Editor's note: Threads merged. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 11-04-2018 07:16 AM
quote:
Originally posted by john.nukecop:
Can anybody verify...
It's documented in many places. There is no reason to question that it wasn't done. quote:
Why bother...
Because the spacecraft would break from the second stage regardless if there are holes or not. The holes just make sure that the spacecraft doesn't survive after that. |
Jim_Voce
Member Posts: 273
From:
Registered: Jul 2016
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posted 11-05-2018 02:44 AM
I have to agree with John about the steps to ensure that Gemini 1 was not recovered. It was an odd thing to do when other options were available. So I would say this remains an open mystery until a more satisfying explanation is available. |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 11-05-2018 03:41 AM
What type of explanation are you seeking? The reasoning behind this is understood.Gemini 1 launched on April 8, 1964 from LC-19 atop a Titan-II launch vehicle. It was the first flight of the Titan-2-GLV rocket which was a modified Titan II missile. The mission was designed to test the launch facilities, the Gemini tracking network, the launch vehicle and the structural integrity of the new spacecraft. Primary objectives included: - Demonstrate Gemini Launch Vehicle performance.
- Flight qualify subsystems.
- Determine exit heating of Gemini Launch Vehicle and spacecraft.
- Demonstrate structural integrity of Gemini Launch Vehicle and spacecraft.
- Demonstrate Gemini Launch Vehicle and ground guidance systems performance in achieving proper orbital insertion.
- Monitor, evaluate Gemini Launch Vehicle switchover circuits.
Secondary Objectives included: - Evaluate operational procedures for the Gemini Launch Vehicle trajectory and cutoff conditions.
- Verify orbital insertion by tracking C-band transponder in spacecraft.
- Demonstrate performance of launch and tracking networks.
- Provide training for flight controllers and prelaunch and launch crews and facilities.
The Gemini 1 spacecraft did not have many of the internal equipment, including instruments, life support, fuel cells and seats as it was a structural test vehicle.It was commonplace to undertake development flights in a step stone method, The Apollo program undertook all up testing of the Saturn V. Prior to launch, it was envisioned that the spacecraft would not be recovered, there was no intention to deploy ships and equipment to recover the spacecraft which would be expensive and return little or no new information. As the Gemini spacecraft was designed to survive re-entry, a special effort was made to ensure that the vehicle burnt up by cutting holes within the heat shield. The mission was considered a success by NASA and all participating manufacturers and engineering teams and led the way for subsequent Gemini missions. If you are seeking additional information, this document is an excellent read (page 59 and 87 and 189). |
Jim_Voce
Member Posts: 273
From:
Registered: Jul 2016
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posted 11-05-2018 07:50 AM
The primary peculiarity of the Gemini 1 mission is that the spacecraft was not recovered and holes were drilled into the heatshield. Yet the Gemini 2 mission's primary mission was to test the heatshield.It seems that it would have been simple enough to launch one mission that tested the structural integrity plus test the heat shield itself. So perhaps someone can explain why two missions were actually needed. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 11-05-2018 08:10 AM
Because Gemini 1 was basically a launch vehicle test. It did not have a "spacecraft" on it. It had the structure of a Gemini spacecraft but it had none of the systems to make it capable of operating as independent spacecraft.Oly explained why there was two tests. We were still learning rocket science and incremental testing was standard practice. Because the Gemini 1 capsule was just a hulk of metal, it was prudent to make sure it would not survive entry and cause damage. Gemini 2 was more than just a heat shield test. It was a spacecraft test flight. Other spacecraft systems had to operate to support the flight. |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 11-05-2018 08:28 AM
quote:
Originally posted by Jim_Voce:
So perhaps someone can explain why two missions were actually needed.
Jim, I provided you with a link to a NASA document that explains the reasoning, and I also provided you with individual page references. Page 87: Late delivery of the spacecraft systems coupled with the unexpectedly small number of Mercury systems incorporated in the Gemini spacecraft had forced GPO to review the flight program critically. In the revised program, the first flight was still set for December 1963 and was still to be unmanned, but it was now to be orbital rather than suborbital to flight-qualify launch vehicle subsystems and demonstrate the compatibility of the launch vehicle and spacecraft; no separation or recovery was planned. The second mission, originally a manned orbital flight, now became an unmanned suborbital ballistic flight scheduled for July 1964. Its primary objective was to test spacecraft reentry under maximum heating-rate reentry conditions; it would also qualify the launch vehicle and all spacecraft systems required for manned orbital flight. While in 2018 you think it would be simple enough to conduct a flight test program as an all up test, this was not the case, it is just the way it was. The program was evolving to fit the engineering program. This was done to keep things moving forward to enable the program meet deadlines.Gemini went from a small group study contract signed in April 1961 to first flight April 1964, and was man rated by Gemini 3. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 11-06-2018 01:40 AM
An interesting use of the phrase "man rated." My understanding has been that Gemini 2 man rated the Titan-Gemini combination, that is to say that that flight proved that it was safe for the next flight to have astronauts aboard. |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 11-06-2018 04:01 AM
Why so interesting?The process of converting the Titan launch vehicle for manned flight and testing/meeting all of the Gemini spacecraft test items constitutes the process of rating the whole platform suitable for manned flight. A similar process has been carried out for each launch vehicle and spacecraft, including launch abort systems and other engineering systems, with the exception to the space shuttle, which underwent captive and free flight testing but was manned (crewed) on the first mission. Boeing and SpaceX are both still going through the process of having their launch vehicles certified for manned flight and both have planned "unmanned" missions scheduled prior to their first manned flights. Orion/SLS also have a flight test schedule laid out leading up to the first manned mission. The recent failure of the manned Russian rocket has led to an announcement that unmanned flights will be conducted prior to approval of the next manned mission. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 11-06-2018 04:53 AM
It was interesting in that you used the phrase "man rated" for the first crewed flight in the Gemini programme and not for the unmanned flight that proved that it would be safe within reasonable limits to assign astronauts to the next mission. Your detailed answer would appear to prove my point. |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 11-06-2018 06:59 AM
Once the unmanned Gemini flights successfully achieved each mission milestone, engineers evaluated the flight status and rated (certified) the vehicle for manned flight.Gemini could then be launched to space and conduct activities on orbit that tested many of the systems and procedures that would be used for the Apollo program. |
Jim Behling
Member Posts: 1488
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 11-06-2018 08:00 AM
quote:
Originally posted by moorouge:
...the unmanned flight that proved that it would be safe within reasonable limits to assign astronauts to the next mission.
No, it was manrated by the time of the Gemini 3, not by the flight itself. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 11-06-2018 12:43 PM
Which is what I thought I said or implied in my original post. |
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