Twenty-five years ago, this week, what should have been the third-longest space shuttle mission of its time—and the longest Department of Defense piloted spaceflight—got underway with a rousing night-time liftoff from Pad 39A at the Kennedy Space Center (KSC) in Florida. Aboard Atlantis for STS-44, which launched on the evening of 24 November 1991, Commander Fred Gregory, Pilot Tom Henricks, and Mission Specialists Jim Voss, Story Musgrave, and Mario Runco were accompanied by a professional Army imagery analyst, named Tom Hennen. Their task was to spend almost 10 days in orbit, deploying a $300 million Defense Support Program (DSP) infrared early-warning satellite and supporting a range of experiments designed to demonstrate the ability of a human observer to identify selected targets on the ground.
As outlined in yesterday’s AmericaSpace article, STS-44 had gone through several changes in fortune since its core crew was first announced in May 1990. Originally scheduled to launch in March 1991, veteran astronaut Dave Walker was named to command the flight, but was pulled from training a few weeks later, following an incident aboard a T-38 Talon jet trainer and other “infractions of NASA flying rules.” Promptly replaced by Gregory in July 1990, the crew trained for more than a year. Their launch had by this time slipped to no sooner than August 1991, but extensive shuttle program delays eventually pushed the mission to November, before settling on a target date of the 19th.
That date soon became untenable, when a malfunctioning Inertial Measurement Unit (IMU) on the DSP satellite’s Inertial Upper Stage (IUS) booster required replacement. Launch was rescheduled for 24 November, but met with a 13-minute delay, in order to allow an orbiting satellite to pass out of trajectory range and to permit Atlantis’ huge External Tank (ET) to be replenished with liquid oxygen. Aboard the shuttle, as darkness fell over the Space Coast, the cockpit was filled—according to Voss, who sat on the flight deck, ready for his first space mission—with “the nervous sort of banter you get on a sports team before it goes out to play.” Only two crew members, Gregory and Musgrave, had flown before. Amid this banter, fellow “rookie” Henricks noticed that Musgrave was strangely quiet.
“Story,” he asked, “how come you’re so quiet over there?”
From his seat directly behind and between Henricks and Gregory, Musgrave responded simply: “Because I’m scared to death!”
At that moment, the crew realized that if Musgrave—who had been an astronaut for almost 25 years and was ready for his fourth shuttle launch—was scared, then they ought to be so, too. It was time to get serious. At 6:44 p.m. EST, the shuttle’s three main engines roared to life, followed by the staccato crackle of the twin Solid Rocket Boosters (SRBs) and Atlantis rocketed into the dark Florida sky to begin her 10th mission. From his seat, Musgrave carried a small mirror, which provided him with a remarkable view of the nocturnal liftoff and the steadily decreasing perspective as the shuttle rose away from Pad 39A.
After insertion into orbit, Voss remembered, the shuttle was enveloped in darkness and it was difficult to see the Home Planet. He unstrapped from his seat and floated downstairs to the middeck to doff his partial-pressure suit, then help Runco and Hennen with theirs. After an hour or so, Voss returned to the flight deck and his attention was arrested by the grandeur of Earth, literally filling every window. “It was like someone grabbed me,” he told the Smithsonian interviewer. “I just latched onto the window and whatever it was that I was going to do went completely out of my mind. The view out the window was so spectacular that I had to think—gosh—I just have to stop here and look for a minute.”
With the scheduled deployment of the 5,250-pound (2,380-kg) DSP satellite and its Boeing-built IUS booster looming ahead of them, there was little time to ponder their new surroundings. Under the direction of Voss, the mandatory checks were carried out and around six hours into the mission the forward payload restraints were released and the aft frame of the airborne support equipment tilted the gigantic combination to a 29-degree angle. Gregory and Henricks maneuvered Atlantis into the deployment attitude and the satellite’s electrical power source was transferred from the orbiter to its own internal supply.
At 1:03 am EST on the 25th, a little more than six hours after reaching orbit, Voss commanded the IUS tilt table to raise the payload to a deployment angle of 58 degrees and released the DSP—nicknamed “Liberty”—into space at a rate of 4.2 inches (10.6 cm) per second. The tilt table was then lowered to its stowed configuration and Atlantis retreated to a safe distance, in preparation for the IUS first-stage solid-motor firing. Forty-five minutes after deployment, the pyrotechnic inhibitors were removed and the engine burned for 146 seconds. Approximately five hours later, at the peak of the geosynchronous transfer orbit, the second stage motor ignited for 108 seconds to establish the DSP in its operational orbit, whereupon the solar arrays and communications appendages were unfurled.
Having thus accomplished their primary objective in spectacular fashion, the astronauts settled down for what was expected to be 10 days of military experiments. In addition to the Spaceborne Direct View Optical System (SPADVOS) and Military Man in Space (M88-1), a series of radiation and contamination monitors were located in the crew cabin and payload bay. Atlantis was used as a tracking target for the Air Force’s electro-optical sensors on the Hawaiian island of Maui, whilst thruster firings were observed by an ultraviolet plume detection instrument aboard the Naval Research Laboratory’s Low Power Atmospheric Compensation Experiment (LACE). Since STS-44 was planned to be one of the longest shuttle missions to date, a range of biomedical experiments were also aboard. Specifically, the astronauts used a lower-body negative pressure garment and drank heavily-salted water in the expectation that it would increase their ability to stand upright after spending so long in the weightless environment.
With the emphasis of much of the mission being on Earth observations, and coming only months after the devastating Mount Pinatubo eruption, the crew were able to make comments about significant changes in the atmosphere. Certainly, Gregory and Musgrave were vocal in their conviction that atmospheric pollution and thickening layers of haze had worsened in the two years since their last flight together. Cloud cover had also hampered a number of the SPADVOS and M88-1 experiments, although the crew were able to make useful observations, successfully counting the number of ships in the Guantanamo Bay naval base in Cuba and spotting crates aboard an oil tanker. From his perspective, Runco would later remark that the observations were of only marginal use for military surveillance purposes and Hennen—whose expertise in the field spanned more than 20 years—only managed to observe around a dozen of his 30 planned targets, partly due to bad weather and partly due to an event outside of anyone’s control.
Late on the morning of 30 November, IMU-2—one of Atlantis’ three Inertial Measurement Units, a key part of the navigational hardware—failed. The crew attempted to cycle power to the device, in the hope of reviving it, but to no avail. Flight rules dictated that with one IMU down, a Minimum Duration Flight (MDF) had to be declared and Atlantis should return to Earth at the next available opportunity. Less than a week into their planned 10-day mission, STS-44 was coming home.
Later that afternoon, Gregory, Henricks, and Musgrave performed a “hot-fire” test of the orbiter’s Reaction Control System (RCS) thrusters and flight controls, to ensure their preparedness to support re-entry. In the meantime, the other crew members continued to gather as much data from their experiments as possible, in anticipation of a landing at Edwards Air Force Base, Calif., the next day. Original plans targeted STS-44 towards KSC in Florida, but the failure of the IMU led mission managers to call up Edwards, whose large dry lakebed runways offered additional margins of safety for an incoming orbiter with a degraded navigational capability.
The payload bay doors were closed and latched at 1:46 p.m. EST on 1 December and the 183-second de-orbit burn commenced at 4:28 p.m. Thirty-five minutes later, Atlantis encountered the first traces of the upper atmosphere and after a sweeping hypersonic descent across the Pacific Ocean and into California, she touched down on the dry lakebed runway at 2:34 p.m. PST. Her mission had lasted just over an hour shy of seven days.
The early landing, coupled with the shifted landing site from the East to the West Coast, also meant that none of the astronauts’ families were in attendance. “It would have been spectacular to watch,” Tom Henricks told a Smithsonian interviewer, “because we landed on lakebed Runway 5, which meant we came right over the top of the buildings. Someone in the control tower could have looked in the shuttle windows as we went by and if you had been on the ramp, where NASA keeps its planes, you practically could have jumped up and touched our wheels!” In fact, STS-44 marked the first (and last) shuttle landing on Runway 5, as well as the program’s final landing on the Edwards dry lakebed. Although no fewer than 20 future missions would land in California, all would do so on either concrete runways or—in the case of STS-126—on a temporary asphalt runway.
This is part of a series of history articles, which will appear each weekend, barring any major news stories. Next week’s article will focus on the 15th anniversary of STS-108, an International Space Station crew exchange mission and the first U.S. piloted spaceflight to fly after the 9/11 terror attacks.