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Author
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Topic: Mercury Little Joe flight sequencing
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Jim_Voce
Member Posts: 273
From:
Registered: Jul 2016
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posted 09-15-2017 03:12 AM
   
Has anyone noticed the numbering of the "Little Joe" test flights in the Mercury program? The numbering sequence is very odd.After the first Little Joe mission, Little Joe 1, the second Little Joe mission to fly was Little Joe 6. Does anyone know why the second Little Joe mission was number 6? And just to make it more confusing, the third Little Joe mission was numbered 1A and the fourth mission was named Little Joe 2. |
Robert Pearlman
Editor Posts: 43576
From: Houston, TX
Registered: Nov 1999
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posted 09-15-2017 03:46 PM
Per the Wikipedia entry for Little Joe: Flights did not occur in numeric sequence as the project scheduling was adapted as it progressed. The flight designations were based on test objectives; those objectives were carried out in different order than numerical sequence. |
Jim_Voce
Member Posts: 273
From:
Registered: Jul 2016
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posted 09-17-2017 04:06 AM
The Little Joe numbering went as follows - - Little Joe 1
- Little Joe 6
- Little Joe 1A
- Little Joe 2
- Little Joe 1B
- Little Joe 5
- Little Joe 5A
- Little Joe 5B
It does appear that the numbering was based on the mission objective. Hence the flights numbered 1A and 1B were still trying to satisfy the mission objective of Little Joe 1. But there must have also been a Little Joe 3 and Little Joe 4 mission objective and those missions appear to have never been flown. So what happened to them? |
oly
Member Posts: 971
From: Perth, Western Australia
Registered: Apr 2015
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posted 09-17-2017 06:54 AM
When you take on a flight test program you need to identify what objectives you want to test, what order is best to do the tests in, what conditions you will test under and what safety points you will put in place.To simplify this look at aircraft test flight programs. You do unpowered tow tests, powered taxi tests, aborted take off tests, etc., before the first powered flight test. Many first powered flight tests you will see that the landing gear is not retracted during the first flights because this is one more item that can/may fail and so not retracting the gear removes this problem. If during your first tests you achieve your test objective and gather all the data you need the test is a success. You may have the flexibility to do additional tests during these flights and so you can remove the requirement for the next test phase if this data was gathered in previous tests. You may also learn things that mean subjects can be removed from the test schedule because they have been answered or because the requirement to test has been removed or could prove to be not needed. Also, conditions may not be desirable to do certain tests and others can be done under the available conditions. The Apollo program was established with milestones that needed to be met before the next phase of flight was conducted however Apollo 8 is an good example of flexibility in flight test programs. There were many risks taken for 8 and had some of the failures that occurred on later flights happened on 8 the result may have been very different. I do not have access to the original test schedule for Little Joe or Little Joe 2 but there are examples where test results were obtained even during flight failures including the Launch Escape System test being completed on a flight failure. This test may have originally been expected to take more than 1 flight to complete the test. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 09-18-2017 07:10 AM
Perhaps the answer to the missing flight sequence numbers lies within the pages of the Little Joe flight test programme as drafted on 29 January 1959. However, this was modified at the beginning of May when there was a project meeting to determine the status of the development phases. It is interesting to note that following this meeting, a few days later, the use of pigs as test subjects was eliminated.I suspect that Oly is correct and that the three and four tests, if planned originally, were deemed to be unnecessary as programme objectives were met. There is another aspect to this that you might like to consider. NASA ordered six flight articles from North American Aviation though seven were actually built. The last of these was retained at Downey as a structural test vehicle but was later converted to a flight vehicle. So, how were eight flight tests managed from only seven Little Joes? |
Lou Chinal
Member Posts: 1332
From: Staten Island, NY
Registered: Jun 2007
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posted 09-21-2017 03:42 PM
I wondered about that too. And where did the Mercury Little Joe that's on display at Wallops come from? I count at least 9 had to be built. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 09-22-2017 02:29 AM
quote:
Originally posted by Lou Chinal:
I count at least 9 had to be built.
Are you sure you're not confusing Little Joe 1 used in Mercury and Little Joe 2 used in Apollo? According to the Mercury Chronology the number of Little Joe 1 built is as I stated in my previous post. All were used - the one designated LJ-1 used twice as in the first scheduled test the escape tower launched itself on its own some thirty minutes before the test was due to start. This said, I believe that the Air Power Park at Hampton, Va says it has an unflown example that was back-up for LJ-2 in the Mercury programme. Perhaps someone has an explanation as to where these extra examples have come from. |
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