Author Topic: Apollo aborts? - Mode II, Saturn-I Block-II, Little Joe-II with LIVE SM abort  (Read 4323 times)

Offline georgegassaway

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I have an Apollo abort question which is somewhat two parts, towards an ultimate goal.

According to this wiki abut Apollo abort modes, Mode II.

https://en.wikipedia.org/wiki/Apollo_abort_modes

Quote
Mode II: Abort early during S-II burn. With the LES gone, the Command/Service Module(CSM) would separate as a whole from the rocket and use its large engine and RCS engines to move clear of the rocket and align itself. The CM would then separate from the SM and splash down.

OK, so…. with LES jettisoned already, the CSM would separate. I knew that already, but never heard any specifics.  What I am wondering is the sequence of events, what would fire when? I do not mean a second by second timeline.  The most immediate and fastest would be to fire explosive bolts on the LM shroud and immediately fire the SM main engine, “fire in the hole” style.  But that would produce a lot of pressure inside the shroud panels, which would need some time to open up otherwise, possibly damaging the engine that way.

But then if the CSM only used the RCS thrusters, and the LM shroud had not opened up the panels significantly, there could have been some side contact of the SM engine bell with a panel if it did not come exactly straight out.

Of course a big part of that would be how much of an immediate problem might there be, by that point of the flight.  By then it’s almost, if not already in “Space”, so with the engines shut down the vehicle could just be floating along, even if in a slow pitch rate that would be bad aerodynamically at 30,000 feet but no big deal at 300,000 feet.  Time to carefully separate.

Now, there is actually a different reason why I ask this.  It relates to the Little Joe-II program which tested out the Apollo LES abort system. 

There was a proposal, never flown, to fly with a “Live” Service Module, and do a high altitude abort using the SM engine instead of using the LES.  Now, the Little Joe-II never flew with room for a real SM engine bell. So, it would need  a different cylindrical adapter long enough to hold the engine.  This mock-up photo is not related to the Little Joe-II, but it is the best example I have for what would have been needed as an extension to be added to a Little Joe-II if one had launched with a live SM.



And this drawing from a Block-II Saturn-I, shows a similar cylindrical adapter:   



However, none of the Block-II Saturn-I’s flew a live SM, so the SM’s never separated.  So it is unclear to me how, if a live SM ever was going to be flown on a Block-II Saturn-I, the SM was going to separate cleanly from the S-IV stage without risk of damage if all four RCS thrusters did to fire exactly equally, or what.  I will say I clarified with an expert that the convex dish shapes  in the instrument ring were not blowout panels, they were guidance related.  So that sort of kills the idea of a “fire in the hole” firing of the SM engine, much like Titan-II staging.

One of the things I wonder, if they had flown a live SM, is whether the adapter would have been split into four 90 degree panels as the LM shroud was. So the panels for a cylindrical adapter would have been jettisoned much the same way, allowing for a safer and cleaner separation.

The ultimate reason for asking this, is that I’m working up a model to represent that proposal for a Little Joe-II to have carried a live SM for an abort.  I’m trying to decide on some realistic detailing to do for it.

- George Gassaway



Compare above with this:


« Last Edit: 03/22/2016 10:25 PM by georgegassaway »

Offline Jim

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.  But that would produce a lot of pressure inside the shroud panels, which would need some time to open up otherwise, possibly damaging the engine that way.


The SLA panels open up quickly much like payload fairing jettison and the SME could fire
« Last Edit: 03/22/2016 10:48 PM by Jim »

Offline indy91

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Well, first of all I think the Wiki page is wrong. A Mode II wouldn't involve the SPS engine. Mode II is just getting away from the booster with the RCS and then landing somewhere in the Atlantic. The SPS is used for Mode III (landing in the Atlantic Discrete Recovery Area (ADRA), south of the Canary Islands) or Mode IV (SPS to Orbit).  Mode III and S-IVB to COI capability are also not the same thing.

Anyway, the sequence during an abort is:

-Initiate Abort by Translational Hand Controller into counterclockwise detent.
-Booster Engine Cutoff (BECO). The automatic sequence allows 3.0 seconds for this phase to make sure the thrust residuals of the booster engine don't make it crash into the separating CSM.
-CSM is separated from the LV by severing and jettisoning the SLA panels, CSM/LV and LM/GSE umbilicals.
-After additional 0.8 seconds automatic direct ullage is activated, so RCS thrusting forward, until the THC is returned to neutral. The CDR would stabilize the spacecraft, if necessary, and use the RCS for additional 20 seconds to get away from the S-II or S-IVB.
-Depending on the abort mode the SPS would be ignited at 2 minutes after the abort.

Sources and more info in the Apollo Operations Handbook, Volume 1, Section 2.9 (Sequential Systems) and Volume II, Section 5.1 (Abort Procedures).

You might be specifically interested in figure 2.9-25 (Adapter Separation System) of the first source. Link for convenience: http://history.nasa.gov/afj/aoh/aoh-v1-2-09-seqsys.pdf
« Last Edit: 03/22/2016 11:41 PM by indy91 »

Offline catdlr

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thought I would include this video for this thread for reference:

Little Joe II SC 002 lanch

Published on Feb 23, 2016
Little Joe II A-004 Apollo SC-002 launch. Two angles. Apollo Launch Escape System test from 1966.



Tony De La Rosa

Offline georgegassaway

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Thanks for the information.

I know I went a sort of long way to get to my actual objective, which was how would a CSM do an abort from an extended cylindrical fairing such as a Little Joe-II would have needed to allow the engine bell vertical length (For a live SM abort test).  If the Block-II Saturn-I’s had ever done it, then the answer would be out there. But since the Block II Saturn-I’s never carried a live SM, then there may not have been the proper cylindrical adapter built for that task.

Lacking any better info, I end up wondering if a cylindrical adapter therefore right have been split into 4 panels, and then such an abort could go as described:

Quote
-CSM is separated from the LV by severing and jettisoning the SLA panels, CSM/LV and LM/GSE umbilicals.
-After additional 0.8 seconds automatic direct ullage is activated, so RCS thrusting forward, until the THC is returned to neutral. The CDR would stabilize the spacecraft, if necessary, and use the RCS for additional 20 seconds to get away from the S-II or S-IVB.
-Depending on the abort mode the SPS would be ignited at 2 minutes after the abort.

Certainly in any case, it is now clear that there would have been no SPS firing until way later (2 minutes). Lacking any other info, I think for the model I will make up the cylindrical adapter with 4 seams, as though it would have separated the four much as the LM adapter panels did, rather than the CSM needing to gingerly accelerate forward without the SPS bell nozzle hitting a fixed adapter.

BTW - thanks for posting the link to the Little Joe-II A-004 / SC-002 launch, I knew it was there.  I had asked Tom Beach awhile back if he still had that footage on video tape, and if so, if he might post it on YouTube, which he did.

There is a lot of Little Joe-II information on my website, though I have not updated it for awhile (need to add links to Tom’s video and the great new Estes 1/45 scale kit):

http://georgesrockets.com/GRP/Scale/DATA/LJoeMain.htm

- George Gassaway

« Last Edit: 03/23/2016 05:07 AM by georgegassaway »

Offline Ronpur50

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OK, that is a fantastic model!! And it an Estes?

Offline catdlr

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Bump for additional historic film...

HACL film 01007 General Dynamics Little Joe II assembly transport firing Apollo Program


sdasmarchives
Published on Nov 17, 2017


Film from the Atlas-Centaur Heritage Film Collection which was donated to the San Diego Air and Space Museum by Lockheed Martin and United Launch Alliance.  The Collection contains 3,000 reels of 16-millimeter film.

https://www.youtube.com/watch?v=HUexBxh0xLs?t=001

Tony De La Rosa

Offline catdlr

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Project Apollo: Little Joe II Rocket Assembly & Launches ~ 1966 NASA (Silent)


Jeff Quitney
Published on Jun 22, 2018

Silent assembly, transport and launch footage of the Little Joe II, a rocket used from 1963–66 for five unmanned tests of the Apollo spacecraft Launch Escape System.

Little Joe II was an American rocket used from 1963–66 for five unmanned tests of the Apollo spacecraft Launch Escape System (LES), and to verify the performance of the Command Module parachute recovery system in abort mode. It was named after a similar rocket designed for the same function in Project Mercury. Launched from White Sands Missile Range in New Mexico, it was the smallest of four launch rockets used in the Apollo program...

Design

Little Joe II was a single-stage, solid-propellant rocket which used a booster motor developed for the Recruit rocket, and a sustainer motor developed for the Algol stage of the Scout rocket family. It could fly with a variable number of booster and sustainer motors, but all were contained within a single airframe.

Development

Fabrication of the detail parts for the first vehicle started in August 1962, and the final factory systems checkout was completed in July 1963. There were an original fixed-fin configuration and a later version using flight controls.

The vehicle was sized to match the diameter of the Apollo spacecraft service module and to suit the length of the Algol rocket motors. Aerodynamic fins were sized to assure that the vehicle was inherently stable. The structural design was based on a gross weight of 220,000 pounds (100,000 kg), of which 80,000 pounds (36,000 kg) was payload. The structure was also designed for sequential firing with a possible 10-second overlap of four first-stage and three second-stage sustainer motors. Sustainer thrust was provided by Algol solid-propellant motors. The versatility of performance was achieved by varying the number and firing sequence of the primary motors (capability of up to seven) required to perform the mission. Recruit rocket motors were used for booster motors as required to supplement lift-off thrust.

The Little Joe II launch vehicle proved to be very acceptable for use in this program. Two difficulties were experienced. The qualification test vehicle (QTV) did not destruct when commanded to do so because improperly installed primacord did not propagate the initial detonation to the shaped charges on the Algol motor case. The fourth mission (A-003) launch vehicle became uncontrolled about 2.5 seconds after lift-off when an aerodynamic fin moved to a hard over position as the result of an electronic failure. These problems were corrected and the abort test program was completed.

Flights

The Qualification Test Vehicle launch, on August 28, 1963, carried a dummy payload consisting of an aluminum shell in the basic shape of the Apollo command module, with an inert LES attached, and demonstrated the rocket would work for the A-001 launch. This occurred on May 13, 1964, with a boilerplate BP-12 command module, and performed the first successful abort using a live LES. A third launch on December 8, 1964, using BP-23, tested the effectiveness of the LES when the pressures and stresses on the spacecraft were similar to what they would be during a Saturn IB or Saturn V launch. The fourth flight, with BP-22 on May 19, 1965, was designed to test the escape system at a high altitude (although the abort actually occurred at low altitude due to a failure of the Little Joe II booster). The final launch, on January 20, 1966, carried the first production spacecraft, CSM-002.

Minor spacecraft design deficiencies in the parachute reefing cutters, the drogue and main parachute deployment mortar mountings, and the command module/service module umbilical cutters were found and corrected before the manned Apollo flights began. However, all command modules flown achieved satisfactory landing conditions and confirmed that, had they been manned spacecraft, the crew would have survived the abort conditions.

In addition, two pad abort tests were conducted in which the launch escape system was activated at ground level.
----------------------------------------------
Originally a public domain film from NASA, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.

https://www.youtube.com/watch?v=EKLK7zu3Ew8?t=001

Tony De La Rosa

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BTW, a test of the LM on LJ-II was considered.

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