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When ol’ Wally Schirra named his Mercury capsule, he chose the name Sigma 7, sigma the Greek letter that signified summation, the sum of the elements of an equation, symbolizing engineering excellence.  His flight would pull together the sum of everything learned from previous Mercury flights.  Our flight, STS-4, the fourth and final test flight of Columbia will do the same, serve as the summation of the test phase, a bridge between the experimental flights and the operational ones to follow.  We are the last flight where engineering tests will take priority over payload operations.  Yes, testing will continue, but as a second priority.

It’s our launch day, June 27, 1982, and we, the final two-man Shuttle crew, T.K. Mattingly and Hank Hartsfield, actually thought we wouldn’t be launching today.  Yesterday, 18 hours before our 11 a.m. EDT launch time, thunderstorms ripped through the area, dumping 1.5 in. of rain along with hail a quarter inch in diameter.  The hail dinged Columbia’s delicate heat tiles in 400 places.  Yet we woke this morning to find they’re giving us the green light.   Inspections show that the dimples, speckling the black tiles in white, did not pose a danger to the integrity of the heat protection system.

Moving towards full operations, we’ll be hauling payloads that add 5,000 lbs. to our weight beyond STS-3’s in March.  In the middeck level of the crew cabin, we’re carrying a commercial payload, a refrigerator-sized unit, the Continuous Flow Electrophoresis System (CFES) developed by McDonnell-Douglas.  It uses an electric field to separate biological samples — we’ll test liver and kidney cells — according to their electric charge.  Weightlessness will allow the process to separate out purer samples than possible on Earth.  In the future, large concentrations of medicines could be produced this way.  We’re also carrying the Monodisperse Latex Reactor, which flew on STS-3, which can produce small, uniform spheres in weightlessness with medical application.

Out in the payload bay, along the walls, we’re carrying the first Getaway Specials (GAS) canisters.  These 2-ft.-tall cans house small, self-contained experiments for the price of just $3,000 each.  We’re carrying eight experiments from Utah State University in such areas as plant growth, soldering in weightlessness and the curing of composite materials.

We’re carrying one payload we’re not gonna talk about, called simply DOD 82-1.  It is the first secret military payload.   Secret, yet much of it is not classified, so that even though we will not speak of it, you could find in on the public record, infrared and ultraviolet sensor systems that will have applications in advanced surveillance satellites, including missile early warning systems.

With increased array of payloads, we are truly a bridge to the operational flights.  Yet we are primarily a test flight.  We will conduct further thermal tests of the Orbiter, seeing how it reactions to prolonged cold and heat soaks.  Testing of the Canadian-built RMS will proceed, lifting the desk-size Induced Environment Contamination Monitor, weighing 869 lbs., for a survey of outgassing from the Shuttle and also the effects of jet firings that could affect the readings of scientific instruments.

First, of course, we have to get on orbit.  And with the skies swept clean of bad weather, it’s looking good, as has the entire turnaround of the Shuttle.  The processing teams have done the work in just three months, despite having to clean gypsum sand that intruded everywhere in the vehicle during STS-3 landing at White Sands New Mexico.  That’s compared to seven months between the first two flights, and four months between the second and third.  

We’re planned as a seven-day mission, but here’s the thing:  No matter what, we’re landing on July 4.  Period.  That’s because President Reagan is scheduled to attend the landing, a big Independence Day celebration that will include the unveiling of our new Shuttle, Challenger.  So if we’re delayed, the flight will be cut short to ensure that landing date.

We’re ready, the final crew that will wear orange.  The color is going out of style.  That is, pressure suits are.  This is the last flight that ejection seats will be active.  From the next flight on, the crews will be flying in shirtsleeves.

We’re settled in the cockpit, gliding toward that 11 a.m. EST launch.  Everything is proceeding super-smoothly.  Like clockwork.  Like it’s supposed to be.  At T – 5 min., we start the APUs that power Columbia’s hydraulic systems, then our jobs are to keep our eyeballs pinned on the instrument readings for any anomalies.  At T – minus 3 min. 30 sec., we feel the the aero-surfaces — elevons, speed brakes and rudder move as the computers conduct readiness checks.  Then the three Main Engines swivel to check their readiness to steer the stack to orbit.  By T – minus 2 min. 15 sec., all are in start position.  We clean the caution and warning system, and at T – 2 min., configure the APUs for launch.

“Coming up on T – 1 min.”  The computers verify the Main Engines are ready for liftoff.

T – min. 31 sec.”  The onboard computers take control of the launch.   It’s smooth sailing.

“Fifteen.”

“Ten”

Main Engine start beginning at T – minus 6.6 sec.

The stack sways, snaps back — and the twin Solid Rocket Boosters light.  And we’re off, our 11 a.m. liftoff actually early — by 36 milliseconds!  We quickly clear the tower. 

“Roll program” we immediately call, as Columbia swings around to a heading for an orbit with a 28.5-degree inclination.

“Roger roll, Columbia.”

This heading is a first for the Shuttle.  We’re bound for a lower inclination orbit than flown previously, one that will be used in the future for satellite deployments.  And it has a side benefit, you might say — less coverage by ground stations.  That’ll leave us on our own to do our work.

Everything happens fast in a Shuttle launch, much faster than with the Saturn.  Yet actually the Shuttle produces less vibration than those big old beasts.   In just 56 sec., we’re through the period of maximum pressure on the vehicle, Max Q.

“Columbia, Houston.  Go at throttle up.”

“Roger, go at throttle up.”

At 1 min. 42 sec., the call comes, “Columbia, Houston, negative seats.”  We’re now beyond the envelope where we could use the ejection seats.

Fifteen seconds later, the solid rockets expend their fuel and are blasted free, with a flash rattling our windows.

“Columbia, Houston.  You have two-engine TAL capability.”

What’s going on?  The calls are coming late — such as this one that tells us we can make an emergency landing at Dakar, Africa, if an engine fails.  The calls are late by just by 2 or 3 seconds, but that’s significant.  We’re falling slightly under our launch profile, our trajectory depressed slightly.    As if the Solid Rocket Boosters are not providing their proscribed thrust.  And that’s what the brains in Houston think.  Only later, analysis shows that 2,000 lbs. of rainwater soak into the tiles.  Right away the Shuttle’s computers begin correcting for the error.

Our Main Engines have enough juice to compensate and fire for 2 – 3 sec. longer than planned.  “MECO,” Main Engine Cut-Off, 8 min. 40 sec. after launch.  And we’re a few miles lower than expect, yet ready to step into orbit, the highest orbit flown by the Shuttle so far, in a series of burns of our Orbital Maneuvering System (OMS) engines, with the first coming quickly.  As soon as we’ve jettisoned the big fuel tank, Houston calls, “Columbia, Houston.  You’re go for a nominal OMS 1”

Just 10 min. 32 sec. after launch, we fire the twin OMS engines in Columbia’s tail for 1 min. 38 sec. to place us in a orbit with a high point of 150 mi.  When we reach that apogee, 37 min. 40 sec. into the flight, OMS burn #2 lifts the orbit’s low point, circularizing our orbit at 150.  Later, two more burns  will raise that circular orbit to 185 mi., giving us that Shuttle record altitude.

And just over an hour after launch, we open the big payload bay doors, vital since the radiators to cool the shuttle are folded underneath them.  We tell Houston, “We’ve got the doors open, and we’re setting up shop.”

And it proves to be a busy first day.   We activate DOD 82-1, practicing secrecy, if you will, setting precedence for future military Shuttle mission.  As it’s no real secret, here’s the name of the Air Force’s infrared telescope, the Cryogenic Infrared Radiance Instrument (CIRRIS), which flies along with an ultraviolet horizon sensor on a bridge spanning the payload bay.   We do not show it on TV, keeping our TV cameras aimed high.  Right away, launch day, we run into mechanical problems with  CIRRIS and must speak to Air Force controllers in Sunnyvale, California.  The lens cap over the telescope is stuck.  We talk over an open channel, but in code words, which can get confusing.  For the real details, we use an encrypted teleprinter link.

We also have trouble activating the Getaway Special experiments.  The commands aren’t getting through to the canisters.   We try several time — no joy. 

The flight, like every mission, is front-loaded with tasks in the first days, to gain maximum return should anything shorten it.  And face it, on our first day, we aren’t at full speed, feeling a bit of queasiness as we adjust to weightlessness. We work overtime — by three hours.

It only the first of several long days as we push the Shuttle’s capabilities towards the operational.  It’s a reach for sigma every day.