MA-8 FLight Plan questions.

In article . unc.edu,
Robert Conley wrote:
...the call was not made by the astro but by mercury control.
If you look to the left of the call in the flight plan you will see MCC-:
Those are call made by capcom in Mercury Control. So by 4:30 Mission
Control is to tell Schirra how he is doing on the climb
to orbit.

Except that in fact, Schirra had to remind the capcom about it. But yes,
it was him asking the ground and the ground reporting, not vice-versa. (I
got this wrong earlier because the transcript, at least the version I've
got, is labeled confusingly.)

I want to thank Henry for that explanation of V/VR. I am currently
building a software simulation of the MCC and one of the plot boards
charts V/VR and I wondered what it meant.

For more detail, see the "Launch-phase Monitoring" chapter (by Glynn
Lunney) in "Manned Spacecraft: Engineering Design and Operation", Purser
et al eds, 1964. (This book is a bit scarce, check libraries first.)

There are in fact three separate plots (using three different scales) of
flight-path angle versus V/VR, for early flight, the bulk of the flight,
and the last ten seconds. Note that the velocity vector used for both
variables is inertial velocity -- from measured acceleration on the
vehicle, ignoring the presence of gravity -- and not velocity relative to
Earth.

The early-flight plot (up to V/VR = 0.2) has a "hill" of unsafe region at
the bottom, with the nominal path being a similar but larger curve above
it. The unsafe region is where dynamic pressure is too high for proper
tower jettison during escape.

The bulk-of-flight plot (V/VR from 0.2 to 0.9) has a gently declining
nominal path between limits above and below. The upper limit is a curved
ceiling, above which reentry deceleration is excessive. The lower limit
is a short downward slope (the tail end of the dynamic-pressure hill),
followed by a flat floor below which orbit is impossible because the
rocket doesn't have enough fuel to climb back up.

The last-ten-seconds plot (V/VR beyond 0.9 -- yes, a full 10% of orbital
velocity is acquired in the last ten seconds; the acceleration just before
cutoff is ferocious) has a gently declining nominal path intercepting a
slightly-curved near-vertical "go/nogo" line around V/VR=1, and crossed by
a steep diagonal line just after V/VR=0.9. Cutoff to the right of the
go/nogo line gives an orbital life of at least 1.5 orbits, an acceptable
abort to orbit; earlier cutoff requires immediate retrofire to recover in
the Atlantic. (Retrofire into the Atlantic is preferred over abort to
orbit, the position of the go/nogo line being dictated by the coast of
Africa.) The earlier diagonal line defines when to send a cutoff command
for an abort into landing area D, more or less south of the Azores. (The
book's commentary implies that the landing-area-D line should also be on
the second plot, but it's not present in the illustration.)
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Your right Rob, I jsut checked the flight plan and it is listed as a call
for the MCC to make. And in the mission transcript Schirra actually ask's
"how's the V/VR ?"

Console image looks great, that'll help me out when Im reading the flight
plan and transcript. Is it modelled on any particular capsule ?

Cheers.....Adam


"Robert Conley" wrote in message
lab.unc.edu...
On Mon, 31 Jan 2005, adam bootle wrote:


Just been having a read of the MA-8 Flight Plan, and have a few things
I'd like to get straight.

When Schirra has to report BECO does the B stand for booster ?
Similarly
at SECO does S stand for Single ?

The Atlas was a stage and a half design with 3 engines in a line. At about
130 seconds the two outboards shutdown and then a couple of seconds later
they are jettisoned along with the shroud holding them. The Atlas
continues on with the center engine known as the substainer.

If you want to see this in action you can use my Mercury Addon for orbiter
sim. You can download everything you need at
http://sourceforge.net/projects/mscorbaddon. There are older versions if
your graphics card isn't up to running the newest versions.


At around 0:04:30 into the flight, Schirra has to report whether "V/VR is
over .8" Is this some kind of speed or G force thing ? Is there
anyone
out there who can explain it in laymans terms (for "laymans" read Forrest
Gump)


The explanation for this was pointed out earlier in the thread (V/VR being
the ratio of current velocity against orbital velocity). However what is
in error that the call was not made by the astro but by mercury control.
If you look to the left of the call in the flight plan you will see MCC-:
Those are call made by capcom in Mercury Control. So by 4:30 Mission
Control is to tell Schirra how he is doing on the climb to orbit.

I wondered about your question because I spent the better part of a year
trying to code an accurate simulation of the panel. When the explanation
of V/VR was offered I knew something wasn't right because there isn't an
instrument that would allow the astro to give that kind of reading. Pitch
Angle yes but not velocity. Hence I checked the flight plan and found the
MCC notation.

I want to thank Henry for that explanation of V/VR. I am currently
building a software simulation of the MCC and one of the plot boards
charts V/VR and I wondered what it meant.

Rob Conley

On Wed, 2 Feb 2005, adam bootle wrote:

Console image looks great, that'll help me out when Im reading the flight
plan and transcript. Is it modelled on any particular capsule ?

MR-4/MA-6/MA-7 roughly.

I plan on working on individual capsule layouts in the
next version 6.0. But not until after I finished Project Gemini for
Orbiter 5.0.

Rob Conley

On Wed, 2 Feb 2005, Henry Spencer wrote:

I want to thank Henry for that explanation of V/VR. I am currently
building a software simulation of the MCC and one of the plot boards
charts V/VR and I wondered what it meant.

For more detail, see the "Launch-phase Monitoring" chapter (by Glynn
Lunney) in "Manned Spacecraft: Engineering Design and Operation", Purser
et al eds, 1964. (This book is a bit scarce, check libraries first.)

There are in fact three separate plots (using three different scales) of
flight-path angle versus V/VR, for early flight, the bulk of the flight,
and the last ten seconds. Note that the velocity vector used for both
variables is inertial velocity -- from measured acceleration on the
vehicle, ignoring the presence of gravity -- and not velocity relative to
Earth.

Thanks this will help a lot! And I will try to get the book on
inter-library loan or buy it somewhere. Sounds like what I need to
complete my MCC sim.

Some screenshots of the half done alpha version.
http://www.ibiblio.org/mscorbit/images/mcc1.jpg
http://www.ibiblio.org/mscorbit/images/mcc2.jpg
http://www.ibiblio.org/mscorbit/images/mcc4.jpg


Two Flight Dynamic shots of an actual test over the internet with a friend
of mine manning the capsule and me the MCC.

We picked it up the run over the Pacific before retrofire. The purple is
altitude and the is g-forces in m/sec. It show a complete re-entry.

http://www.ibiblio.org/mscorbit/images/mcc_run2.jpg

The connection was made shortly before sunrise. So as a test I had him try
to use the periscope, the earth-sky camera, and the joystick to take a
shot of the sunrise. I built into the sim the ability to take screenshots
and save them with a unique filename into a temp directory.

http://www.ibiblio.org/mscorbit/images/mcc_run1.jpg

He had a little trouble controlling the capsule! At one point he pointed
it up +70 degrees pitch. He got the shot but then had trouble going back
to re-enty attitude because he pitched so far out of whack the horizon
scanner couldn't help him when he set it back to ASCS mode.

So he moving the capsule around trying to get it back when the retro
sequence started, the permission relays allowing the retros to fire didn't
engage because he will out of alignment finally after another 30 second he
got #1 and #2 off before drifting out of alignment. He got it back in and
#3 when off completing the sequence.

For some reason he wouldn't switch the ASCS back on despite my repeated
suggestions. But didn't drift to far out of re-entry attitude (1 degree)
so things finally settled down when aerodynamics forces took over.

He landed long just east of puerto rico near the antillies. Which was due
to the botched retro fire.

Enjoy
Rob Conley

In article c.edu,
Robert Conley wrote:
For more detail, see the "Launch-phase Monitoring" chapter (by Glynn
Lunney) in "Manned Spacecraft: Engineering Design and Operation", Purser
et al eds, 1964. (This book is a bit scarce, check libraries first.)
...
Thanks this will help a lot! And I will try to get the book on
inter-library loan or buy it somewhere. Sounds like what I need to
complete my MCC sim.

Definitely try and get a look at it, e.g. via I.L.L., before buying, at
least before spending a lot of money on it. In some ways it's a rather
frustrating book: the level of coverage is very uneven. On some topics
it goes into fascinating detail; on others it's quite superficial. My
experience has been that it's worth having (for a space technology junkie,
that is), because every now and then it's a gold mine of information, but
you can never quite count on it containing what you want.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

On Wed, 2 Feb 2005 19:08:37 -0500, Robert Conley
wrote:

He landed long just east of puerto rico near the antillies. Which was due
to the botched retro fire.

....He's since been grounded and will never fly again, but reportedly
will be beta testing for a new XBox version of 688 Attack Sub :-)

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

Henry Spencer wrote:
Henry Spencer wrote:
...It was the LOX/LH2 stages that had common bulkheads, and
that was indeed a significant development specific to Apollo -- those
common bulkheads had to be insulated to control LH2 boiloff.

Well, *almost* specific to Apollo -- Centaur had one of those too. In
principle it preceded the Saturn work, but in practice it ended up being
in parallel with it, because Centaur ran so badly late.

So, Henry, how many t-shirts do you have?