Section 15: Entry

Mattingly: We brought the batteries on 15 minutes early.

Duke: EI minus 5.

Mattingly: This was because of the concern over the battery compartment pressures.

Duke: Yes.

Mattingly: The entry went completely nominal. Everything worked out right down the checklist. We did take a look at the horizon check time. It was dark and we didnÂ’t see anything. Nothing unusual in the separation from the service module. ItÂ’s a big bang, as youÂ’d expect. One of the few things that I think the simulator didnÂ’t reproduce faithfully was the dynamics of the command module, after separation. Apparently, the water boiler imparts a torque that causes you to yaw left and pitch up. This was something I hadnÂ’t anticipated. I kept finding every time I put in a minimum impulse, putting in some rates to maneuver back to the entry attitude that it was drifting off in the opposite direction. It seem like the water boiler was the most likely candidate for these torques.

Young: That baby is really springy once you get it separated. But the rest of it tells you the water boiler is working.

Mattingly: The control system flew exactly like the simulator. The entry was exactly like the simulator, I thought. The thing that caught my attention first on entry was that it was a lot brighter inside the cockpit than I had anticipated. I donÂ’t know whether this was the time of day we came in that caused the Sun to be coming into the window. Right after Entry Interface I became a little bit concerned there was so much bright glare on the 8-ball that I might have a hard time focusing on it, and being able to read the 8-ball. It was really bright. It turned out there never was a problem. It didnÂ’t get any brighter than it was right then. It was just like having a big floodlight shine down on there. ItÂ’s rather hard to watch.

Young: ThatÂ’s really a bright white light. I told you to turn the lights up bright.

Mattingly: Be prepared for the ionization. It will be a lot brighter than you expect it to be. I thought you ought to fly the entry on the centrifuge or something so you could have a closed loop system. I thought that not getting a chance to practice that was sort of short changing the CMP. But after flying it I have to retract that. I think the simulation you get in the CMS is just all you could ask for. The thing flew exactly like all our simulations. The EMS was running as well as any Entry Monitor System IÂ’ve ever seen in any test or simulation. The EMS profile and the G&N profile were just identical. Think I could have flown either one. The control response was such that it would have been absolutely no problem with flying an EMS entry.

Young: Yes.

Mattingly: We built up to right at 7 'g's. All our 'g' sources checked. John was calling out the DSKY read-outs and I was cross checking the EMS and the 'g' meter. I was cross checking the two 8-balls. The first 'g' felt pretty heavy.

Young: ItÂ’s hard to talk at 7 'g's.

Mattingly: I felt like there was absolutely no problem at the 7 'g' level. I was concerned about how much peripheral scan might go down. I had a scan pattern bigger than I normally have flying an airplane.

Young: I was looking out your window.

Mattingly: The CMS just gives you a real super preparation for that kind of operation.

Young: ItÂ’s really good training.

Mattingly: Sounds - when we pressurized the RCS unit you heard the squibs go and you heard something that didnÂ’t sound as much like a gurgle as the plumbing filled up as I had anticipated. ThereÂ’s definitely a sound there that you know itÂ’s going in. Firing the engines is a very comfortable little sound.

Young: The propellant usage was nominal. The RCS pressures were coining down very slow. We used hardly any.

Mattingly: The spacecraft was good and stable. Picked up the aerodynamics just prior to 400,000 feet. I think thatÂ’s very faithfully reproduced in the simulator. One thing that surprised me a little bit; I picked up some oscillations that I thought were typical of the transonic region. They were right towards the end of the entry. Turns out that the transonic oscillations were much greater and they are unmistakable. When we put the drogues out, I was really surprised at the oscillations that we got there.

Young: The automatic system did that.

Mattingly: The automatic system put them out right on schedule. But we really got some big excursions in attitude. I was watching 30 degrees, plus or minus, on the 8-ball. I donÂ’t know if that is typical or not, but it was a great deal more than I anticipated seeing. It wasnÂ’t until almost before it was time to release the drogues and go to the mains that we got damped down to a fairly nominal state. When the drogues released and the mains came out there was very little spacecraft motion associated with that.

Young: I had forgotten it was so erratic. You need to be tied down good in that couch if there is any doubt.

Duke: Looks like those little beauties are going to get ripped right off there.

Mattingly: The CMS has very small oscillations when they simulate the drogues coming out. I wouldnÂ’t change the CMS to put those in, just commenting to the fact that youÂ’re going to see bigger oscillations for real. Main chutes came out and we watched the de-reefing in two stages. That was no problem.

Young: Beautiful.

Mattingly: I thought it was really uncluttered and very comfortable. One of the things that made as big an impression on me as anything else was that weÂ’ve got that altimeter that goes from 100,000 feet to sea level on one rev. I anticipated it being off by a great deal as we got down low. That thing must have been right square on. We hit everything. I was calling out the last couple of hundred feet as we came down and - That thing couldnÂ’t have been off 50 feet from the time we said we were going to hit the water until we did.

Young: That could be the difference between the Atlantic and Pacific sea levels. MAPPINGLY The comm throughout was crystal clear. We had the recovery guys just with no trouble. We ended it up with a good Navy landing.

Young: Really, it was harder than Apollo 10.

Duke: I didnÂ’t really expect it to be as hard as it was. When I got my eyeballs recaged we were already in Stable II.

Young: There was no way we could have got those parachutes off before we went over.

Mattingly: We hit and in one continuous motion we just rolled right over. I was prepared for it to be even harder than it turned out to be. I got a chance to watch us roll over. The Stable II was

Mattingly: no problem. We collected a little water in the rendezvous windows between the outer and inner pane. I think thatÂ’s probably typical of these birds. It shows up that way in the boilerplate down there in the tank. I think probably that is just the way the bird is put together.

Duke: I was just going to say it looks exactly like the boilerplate to me. I was watching the ticktock during the thing. The Ionization, the orange glow started before RRT - couple of seconds before RRT. At that point I started the camera, which was a little early, the 16-millimeter that is. I started my watch right at RRT and everything went right on schedule. Visual Sightings - the bus power and everything looked good, so I started looking outside a little bit during the max-'g' area. 1hat surprised me during the whole thing was the rapidity with which that Command Module - when it decided to roll, boy, it just took off. You could see the horizon through the ionization sheath, both out Window 5 and the Rendezvous Window 4. There was mylar on Window 5 that was flapping back and forth across the window that was there at touchdown. ItÂ’s still there. It had come up right at CM/SM sep. I had seen that strip fly by. When we started getting the 'g's it flopped up over the window, sort of stayed there end wiggled the whole time. Which amazed me.

The communications blackout was just about right on time. John started talking to Houston and to ARIA. Comm was just outstanding there. After the mains came out, I saw a helicopter go over us. I guess that was Recovery One. John was talking to them. The only thing that was off nominal was the steam pressure was 32 seconds late. I started my watch on the time that steam pressure pegged. If we had to call the times based on that, weÂ’d have been late on the 50,000 and the other times.

Young: I think thatÂ’s good enough for a backup system. I think the fact that it would be late is a known thing. They canÂ’t really predict it very close.

Duke: I really think the best backup system you have is that cabin pressure, if you donÂ’t have the altimeter. The cabin pressure increasing at about 2,000 for the drogues. Also, the eyeball out the window could help if you know the cloud level. I could see the clouds and everything outside.

Young: I'd be careful of that.

Duke: The cabin pressure coming through 10 is probably better than the clouds.

Mattingly: I got fooled on the clouds at 90,000. I looked out my window; that is the first time I had a chance to look out there. I looked out and there were clouds. The sensation was very vivid that the clouds were bubbling. I thought, my God, weÂ’re down to 20,000 feet here end we hadnÂ’t done anything yet. It really took a long time for me to convince myself that we were really at 90,000.

Young: I was looking out my window, I had no doubt that we were way up high.

Mattingly: You could really fool yourself.

Duke: ItÂ’s a fascinating view. We had plenty of backups is what I was just trying to say. With both water boilers going during entry, the glycol loops stayed in good shape.