60 years ago: The textbook flight

Oct. 3, 1962: Sigma 7, with Wally Schirra still inside, is hauled toward the recovery carrier after a flight of six orbits. This was one of his favorite photos, showing the old and new vessels side by side.


You and I

Become we

And we are

Wally Schirra, pilot of Sigma 7,

Mercury-Atlas (MA)-8,

The third Mercury orbital flight,

Sixty years ago.

Our task, to take what we have, a capsule built for a three-orbit flight and push to the limits, stretch it for six orbits   Learn how to conserve fuel and power.  Focus is the capsule and it’s systems, not on “sightseeing,”  not on science.  Keep our objectives clean:  A pure engineering test flight.

The name we chose for our capsule says it all – Sigma 7.  

Sigma, the Greek letter denoting the sum of an equation.  

Stretch three-orbit capsule for six.  To save fuel, Sigma 7 will drift through much of flight.  When powered up, prove that an astronaut can control the beast without guzzling fuel.

Are you ready?

It’s October 3, 1962.

We are ready.


The smoothest count yet, just 15 minutes late due to radar problems at the Canaries.  Damn near showed that the U.S. can launch on the button as the Soviets have done.

So 15 min. late, at 7:15 a.m. EST, we feel the two small vernier engines light followed by the three main engines.  “I have liftoff.  Clock has started.”  That’s the already-traditional call signifying the mission timer has begun.  “And she feels real nice.”

These finicky Atlases – a mind of their own.  We don’t know it, but ten seconds off the pad, that bird starts making a roll.  She heeling over for the red zone.  Red means abort, heading towards land instead of out to sea.  Just a few more degrees and range safety would have to call an abort.

 But the roll stops . . . our flight path remains in the green.  While in innocence, 21 seconds since liftoff, we radio to capcom Deke Slayton, “Ahh, she’s riding beautifully, Deke.”

“Looks real fine from here,” he replies

Thirty seconds.  “All systems appear go, and she’s getting noisy.”

After just two minutes, time to prepare for jettison of the two booster engines that flank the center sustainer engine.  The boosters are shed, reducing weight, while the sustainer will continue to push us into orbit in our quick ride into orbit, which will last little more than 5 min.

At 2 min. 7 sec., Deke calls, “Stand by for staging.”

“I have BECO.”  Booster engine cutoff.  “I could see the flash.”   BECO comes a couple seconds early.  No sweat. 

Ten seconds later, the escape tower above the capsule is kicked away by a solid-fueled jettison motor.    Keep it light and nonchalant.  We call, “The tower really is a sayonara.”  Unfortunately, the rocket exhaust dirties our window.

At 3 min. 30 sec., we get a go from Deke to push on.  

“Roger. now have a go from me.  It’s real fat.”

That Deke, amid launch he tries a gotcha on us, calling “Are you a turtle today?”

Every pilot knows there is one and only one correct answer and if you don’t say it, you have to buy everyone within earshot a drink.  And there’s a lot of people listening.  Ol’ Deke isn’t going to get us.  We go to recorder-only and tape our response:  “You bet your sweet ass I am.”

After four minutes, the G forces begin to build.  “Sunlight’s in my upper righthand corner of the window, just peeking in at me.”

Coming up on SECO, sustainer engine cutoff, just 5 min. 18 sec. since launch.  “I have SECO.  Cap. sep.”  We cut loose from the booster, weightless, “and it’s very pleasant.”  And we go right to work, going to fly-by-wire, where we manually control the automatic attitude jets. We’re going to perform a manual turnaround, nice and slow to save fuel, eyeballs pinned on the attitude displays and not gawking out the window.  Using very tiny bursts of our jets, taking a leisurely 50 seconds to swing around.  “She’s turning around nicely.”  We use a minuscule one-third of a pound of fuel.  We’re in retro attitude, heatshield forward.  And facing the spend booster — the sustainer engine pointed at it.  The silver booster looks black to us.  “That sustainer looks real cute.”  We track it a bit, imagine if we were trying to rendezvous with it.  Doesn’t look like it’d be a problem to fly right up to it, if we were equipped to do so.

Seven minutes into the flight, switching to ‘Chimp mode,’ a Wally Schirra term for flying under control the automatic system, as did early flights with chimpanzees as passengers.  We engage autopilot to checkout the system.   “I’m in chimp mode right now, and she’s flying beautifully.”

By the time we reach radio contact with the tracking station in the Canary Islands, we’ve checked out the various control systems, hardly taking the time to look outside.  “Canary, as far as I am concerned all control systems are perfect.  The manual was slightly sluggish as predicted, but better than I’ve seen.”

The suit is beginning to become a bit warm as the heat pulse of launch soaks into the capsule.  The cooling air flow can’t keep up.  As we pass over Africa, damn if something doesn’t seem wrong with the suit cooling circuit. “I’m going to have to increase the suit setting.”

This is a delicate matter.  Scott Carpenter fiddle too much with the control knob, which has eight settings.  You gotta give the cooling system time to catch up.  Switching too quickly ices up the heat exchanger.  So here’s what we’re going to do.  We’re at setting 4 (and max cooling is 8).  We’re going to increase the cooling just have a setting, wait ten minutes before turning it up more.

Over Africa and the Keno station, 25 min. since launch, we radio, “I think the only problem I have is the suit circuit.  I’ll work on it for awhile an see how we are.”

“Takes a wee bit of time for that to stabilize?”

“Right.  That’s what I am trying to do.”

We increase cooling a bit, up to setting 5.

In range of the Zanzibar station, passing out over to the Indian Ocean, 35 min. since launch, we report, “I’m all green here.  I’m still working on the suit cooling circuit.”

Zanzibar asks, “How do you feel?  Uncomfortable?”

You know damn well that Mercury Control is worried about overheating.  Worried enough they could cut the mission short.  “I feel quite comfortable.  I’m a little warm.  Particularly from sunlight, but other than that, I feel fine.”

We’re now up to 5.5 on the suit setting.

The temperature problem doesn’t stop us with getting on with the job, and the job is piloting.  Scotty Carpenter reported difficulties determining yaw by eyeballing his position through the window, using clouds as a reference.  It’s time to nail down the problem of determining our yaw position..  We begin trying to judge yaw position by using the window.  Our yaw tests will continue in both daylight and night. 

After 10 minutes, we increase the suit setting to 6, still assuring the ground, “I’m perfectly comfortable.”  But the suit is getting hotter.  By Muchea, Australia, the suit temp. is up to 88 degrees.  If the cooling doesn’t kick in, the flight might have to be ended.  MCC doesn’t want a feverish, dehydrated astronaut trying to perform re-entry.   And we’ve damn near maxed out the cooling flow.

“Do you feel hot or anything?” the Muchea capcom asks.

“No.  I have beads of perspiration on my lips.  That’s about all.”  We report that other that the suit temperature, “Everything is acting perfectly . . .  I’m practically using no auto fuel.”

We continue to test our ability to adjust the Sigma 7’s yaw position in darkness.  “I have the moon right in the center of my field of view.  It’s a marvelous yaw reference.”

Over the Woomera tracking station, we attempt to spot a flare fired from the ground.  Alas, the area is nearly socked in by clouds and thunderstorms.  “The lightning looks a big blob, rather than a jagged streak we are used to seeing when earthbound . . . a big blob of bright light, and then it fades out almost instantly.”  And makes it confusing to try to spot a flare.  We fail to see it.

By now, we’ve increased the suit setting to 7.

Over the Pacific now.  By the time we come into range of the Canton Island station, the temperature appears to be stabilizing.  That’s enough to allow MCC to issue a go for a second orbit.   

We tell Scott Carpenter, the capcom at the Hawaii station, “Scott, I feel we’re in very good shape for one more orbit at least, an we’ll see how we can hack this suit circuit here. . . The capsule is flying beautifully.”

At sunrise, we report, “I saw some of John’s friend’s up here.”  Those are the “firefly” particles John Glenn saw.  Like Scotty Carpenter, a rap on the capsule’s hull demonstrates that they are ice particles from the capsule.

“I am now commencing day yaw checks.”

Passing over Cape Canaveral to start the second orbit, we report we’re now at the max suit setting 8.  “I’m making a little ground on it. . .   I didn’t want to rush into it, and I didn’t get too hot.  Know you are concerned.”

At 1 hr. 40 min. since launch, over the Atlantic, we report to Deke Slayton.  “Deke, I finally got a grasp on this thing.  I’m beginning to feel a little cooler.”  

Over Africa, suit temperature is coming down, and we declare, “I think we have the situation under control.”  

“This is Sigma 7.  I feel marvelous, and I have finally knocked [the] suit control.”

By Australia on the second orbit, the suit temperature has dipped to 72 degrees.  Throughout, the temperature problem has not diverted us from a focus on saving fuel.  On the first orbit, we miser out just 1.4 lbs. of our 59-lb. supply.   That’s less than Carpenter used making his initial turnaround on Aurora 7. 

On orbit two, we sacrifice a bit of fuel for more yaw tests, swinging the capsule to the side, judging his position through the window, then using the periscope.  Declare that the periscope isn’t needed.  We’re am all capsule on this flight, all aviator.  Disavowing the tourist’s awe of exploration.  Over Australia, we declare, “Sunset is rather striking.  I don’t think I need to waste much time looking at them.”  

Everything is a yaw check, even the lights of Perth.  “Perth should be coming into view and it should be – oh, what a beautiful yaw check this is, and it’s approximately ten degrees left of path.”

“I am quite satisfied with both day and night checks.”  

And we’re proving a pilot’s ability to conserve fuel.  Over Woomera, about 2.5 hrs. into the flight, we report, “I feel happy about the fuel condition.”  We’re reading 95 percent in the automatic supply and 90 percent in the manual system.

Over Hawaii, we hit sunrise.  “I’m getting the old fireflies again.  I guess John [Glenn] is relieved.  I haven’t been looking for them — they’re just there.”

After two orbits, we turn off the capsules control jets to save fuel and Sigma 7 enters into extended period of “free drift,” allowing the capsule to rotate in any orientation.    With nonchalance, we call drifting “great sport.”   We demonstrate that the pilot doesn’t become disoriented when the capsule isn’t locked into a steady attitude. Holding 89 percent auto and 90 percent manual fuel. 

Also on the third orbit, we shut off the attitude control gyro, tracking beacon and other systems to save power.  “She’s cruising along very happily.”

Yes we are a happy ship, now 3.5 hrs. into the flight.  “I’m having a ball up here drifting.  Enjoying it so much I haven’t eaten yet.   I’m going to start to eat now.”   Break out the food tubes and packets of cubed food.

Over Australia, we power up, put Sigma 7 in retro attitude, just in case we’re ordered down after this orbit.  We’re go and after the retro time for this orbit, power down again.  We tell Hawaii, “I took a big swig [of water] awhile ago, and then I just had a tube of peaches, and a couple of those cubes.”

Over Cape Canaveral at the start of the fourth orbit, 4.5 hrs. into the flight, we tell Mercury Control, “I am in drifting mode.  Everything is working beautifully.

Flight Director Christopher Kraft comes on the communications loop and says.  “Been a real good show up there.  I think we are proving our point, old buddy.”

“I hope so, Chris.  I am enjoying it.”   The unstated point — that at this early stage in the program, we need to make pure engineering flight tests.  We are the antithesis of Scott Carpenter’s flight.

Approaching five hours into the flight, “I am just about [looking] straight down.  We will take some cumulus [cloud] pictures.”   We, after consulting with professional photographers, are the first to take a Hasselblad camera, with it’s larger format film, into orbit.  The Hasselblad will become the standard camera in our space program, documenting the flights to the moon.

Over Hawaii, on the fourth orbit, the window is pointed down on earth, and we describe the sensations:  “This is Sigma 7, giving the effects of flying inverted in a sunrise, 90 degrees yaw. . .  Like looking out of a railroad train window, you see the terrain going by you.  There are clouds of all varied types.  I can see them sweeping by me just by me . . . 90 degrees to the longitudinal axis of the vehicle.”

Over California again at the end of the fourth orbit, 6 hrs. into the flight, we’ve a new US record, still drifting along.  “Ha, ha.  I suppose an ol’ song, ‘Drifting and Dreaming’ would be apropos at this point.  But at this point I don’t have a chance to dream.  I’m enjoying it too much.” 

By the fifth orbit, moving out of range of some of the tracking stations, communications become less frequent, tracking ships filling in the communications gaps.   Over the Pacific, 7 hrs. 15 min. into the flight, we are still showing 81 percent fuel in the auto system and 80 percent on the manual side.

Our orbit is dipping towards South America.  “The continent of South America is difficult to photograph because of all the weather.”

With one orbit to go, we’re not about to be caught late completing the retrofire checklist on this flight, as happened to Carpenter.  We spend my final 89 minutes bringing Sigma 7 back to life, testing the thrusters and control modes.  

We’re in fat city approaching the 30-second countdown to retro sequence.  “I have a sequence and capsule is nice and tight.  Got attitude green.  She’s sitting here like a tight rock.”

Al Shepard, aboard the Pacific Command Ship, calls, “Five, 4, 3, 2, 1, zero.”  The three retros fire at five-second intervals.

“I’ve got [retro] 1, and she’s holding real tight.  Very tight.  I got 2, my attitudes are right on the money.  I’ve got 3.”

We’re headed home, for a splashdown in the Pacific, 275 mi. north of Midway Island.  We call, “I think they’re going to put me on number three elevator.”   Navy talk, meaning that I’m going to land Sigma 7 right on the carrier’s primary aircraft elevator.

When the main chute is out and it’s time to dump the remaining fuel, Sigma 7 still holds damn near half its fuel supply.  To someone like Scotty Carpenter, it’d be a waste, carrying all that fuel and not using it to explore.  On this flight, it’s a point of pride. 

Damn if we doesn’t nearly land her on the number three elevator.  We splash down within view of the carrier, the USS Kearsarge, 4.5 miles away, after a flight of 9 hrs. 13 min. 11 sec.  We stay in the capsule, waiting for the ship to lift us out of the water.  And 41 min. after splash, Sigma 7 is winched gently on deck.

“Boy, this is a sweet little bird.  I just can’t get over it.”  The first thing I tells debriefers is “It was a textbook flight.”  The name sticks.  Of course someone with the nature of an scientist, someone like Scott Carpenter, might say it’s easy to fly a textbook flight if you scrub your flight plan into simplicity itself.   The tug-of-war between science and engineering is just beginning.

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