Author
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Topic: Gemini spacecraft parachute deployment
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Jim_Voce Member Posts: 273 From: Registered: Jul 2016
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posted 06-14-2017 05:37 AM
Does anyone know how the Gemini spacecraft parachute system worked? In the Mercury Program, the spacecraft descended with the top of the spacecraft pointed directly upward. But the Gemini spacecraft did not. It descended at a skewed angle. This is because a cable of some kind seemed to slide down the length of the spacecraft and adjusted the parachute so that the spacecraft would land in the water on its side with the astronauts sitting straight up in their seats. The parachute rigging of the Gemini spacecraft was created to support the deployment of the Rogallo Wing. And even though the Rogallo Wing was cancelled, the parachute rigging positioning was kept. But I still have no idea how the Gemini parachute rigging was was able to come out of the top of the spacecraft and secure itself to the side of the spacecraft. |
Jim Behling Member Posts: 1488 From: Cape Canaveral, FL Registered: Mar 2010
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posted 06-14-2017 08:02 AM
I could explain it but a simple google is just easier: Gemini Guide: Landing Systems. |
Jim_Voce Member Posts: 273 From: Registered: Jul 2016
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posted 06-15-2017 01:05 AM
Thank you the link. I have seen similar diagrams. What is not clear to me is how the so-called "two points of suspension system" of the Gemini parachute operated. In other words, how is it that the entire parachute system can deploy from the top of the spacecraft in what is described as a 'single point" of suspension (i.e., the parachute lines point straight up just as with the Mercury spacecraft) but then afterwards, one of the parachute suspension ropes is able to slide down the length of the Gemini spacecraft toward the heat shield and then create a two point suspension system where in the Gemini spacecraft lands in the water on its side rather than on its bottom (i.e., on its heatshield)? Was there some kind of groove or channel carved into the side of the Gemini spacecraft that allowed one of the suspension lines to travel down the length of its body? |
taneal1 Member Posts: 237 From: Orlando, FL Registered: Feb 2004
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posted 06-15-2017 01:34 AM
A channel, yes, not on the side, but between the crew hatches. That white "stripe" is actually just a piece of plastic covering the channel that houses a strap that is attached near the heat shield. The white plastic strip is ripped open by this suspension line when the spacecraft is released from single-point to two-point suspension. This causes quite a jolt within the spacecraft and has scratched or even punctured astronaut face plates.Before switching to two-point suspension the astronauts use mirrors to assure they are over water. If they are over land, they must eject. You can't do that from the two-point position as the seats would hit the open chute. |
Jim Behling Member Posts: 1488 From: Cape Canaveral, FL Registered: Mar 2010
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posted 06-15-2017 06:40 AM
quote: Originally posted by Jim_Voce: I have seen similar diagrams... Was there some kind of groove or channel carved into the side of the Gemini spacecraft that allowed one of the suspension lines to travel down the length of its body?
The very first diagram (Parachute Landing System Diagram) in the link shows the channel. |
moorouge Member Posts: 2458 From: U.K. Registered: Jul 2009
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posted 06-15-2017 12:42 PM
Perhaps this provides more detail — NASA Technical Note: Gemini Spacecraft Parachute Landing System. |
sev8n Member Posts: 236 From: Dallas TX USA Registered: Jul 2012
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posted 06-15-2017 06:13 PM
At what point was the nose fairing jettisoned to expose the mortar/cable assemblies? The uncovered assemblies are visible in the 7/6 rendezvous photos, was the cover blown off during boost phase? |
Jim_Voce Member Posts: 273 From: Registered: Jul 2016
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posted 06-16-2017 04:08 AM
quote: Originally posted by moorouge: Perhaps this provides more detail...
Many thanks. The combination of taneal1's wonderfully concise and on point description along with your document was great. |
Fra Mauro Member Posts: 1624 From: Bethpage, N.Y. Registered: Jul 2002
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posted 06-16-2017 06:11 AM
Is it safe to conclude that the Gemini spacecraft could not safely land in the water like Mercury since their was no air cushion bag attached to the heat shield? |
Jim Behling Member Posts: 1488 From: Cape Canaveral, FL Registered: Mar 2010
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posted 06-16-2017 08:19 AM
No, it could still land in the water without the two point suspension. The two point suspension made it softer. |
space1 Member Posts: 861 From: Danville, Ohio Registered: Dec 2002
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posted 06-16-2017 11:29 AM
The nose fairing and horizon scanner fairing were jettisoned about 10 minutes after launch (after second stage shutdown and before spacecraft separation) with astronaut activation of the JETT FAIRING pushbutton switch. |
moorouge Member Posts: 2458 From: U.K. Registered: Jul 2009
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posted 06-16-2017 02:28 PM
quote: Originally posted by Fra Mauro: Is it safe to conclude that the Gemini spacecraft could not safely land in the water like Mercury since their was no air cushion bag attached to the heat shield?
The answer lies here does it not - The significant new concepts that were proven in the Gemini Program for operational landing of a spacecraft include: - the tandem pilot/drogue parachute method of deploying a main landing parachute, and
- attenuation of the landing shock by positioning the space-craft, thus eliminating the need for built-in shock absorption equipment.
Positioning meant that the capsule entered the water on a corner of the heat shield rather than with it flat as in Mercury.Incidentally, the paper I referenced in my previous post also mentions that the ejector seats were only available with the drogue chute deployed. Once under the main chute and configured for landing, if used the ejector seats would foul the parachute. One other significant difference was that there was no automatic parachute deployment on Gemini as was the case for Mercury. The sequence had to be initiated by the pilot. |
taneal1 Member Posts: 237 From: Orlando, FL Registered: Feb 2004
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posted 06-17-2017 12:05 AM
quote: Originally posted by moorouge: ...the paper I referenced in my previous post also mentions that the ejector seats were only available with the drogue chute deployed.
I just did a quick read of that document, and I can't find a statement that the seats are only usable on the drogue chute.You stated: "Once under the main chute and configured for landing, if used the ejector seats would foul the parachute." Doesn't "configured for landing" mean in the two-point suspension mode? In the single-point mode the spacecraft is vertical. Even with the somewhat upward vector the seat would clear the deployed chute. As I stated in my last post, ejection is possible from the single-point mode, but not from the 2-point. I'm always willing to accept new information, but this is what I recall. |
Lou Chinal Member Posts: 1332 From: Staten Island, NY Registered: Jun 2007
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posted 06-17-2017 01:10 PM
I have to agree with taneal1. |