A Mission Cut Short: Remembering STS-44, OTD in 1991

Atlantis is hoisted, via the Mate/Demate Device (MDD), atop the Boeing 747 Shuttle Carrier Aircraft (SCA) at Edwards, following her landing from STS-44. Photo Credit: NASA

The Space Shuttle flew many remarkable missions during its 30-year career, delivering satellites into orbit, supporting fundamental scientific research and building the International Space Station (ISS). Thirty-seven of its missions were extended at least 24 hours, their homecoming set back by weather, changed landing sites or the need to gather additional data from their payloads. It granted their astronauts some welcome additional time in the magic microgravity environment. But others were not so lucky.

Video Credit: NASA

On three occasions between November 1981 and April 1997, the opposite occurred and shuttle crews received the unwelcome news that they would perform a “Minimum Duration Flight” and their carefully-choreographed time in space would be cut short. One such event occurred on this very day, nearly three decades ago, as Atlantis returned unhappily to Earth in a short-notice landing dictated by mechanical problems.

Atlantis had launched seven days earlier, on 24 November 1991, for what should have been a ten-day voyage. Within hours of reaching orbit, STS-44 Commander Fred Gregory, Pilot Tom Henricks, Mission Specialists Jim Voss, Mario Runco and Story Musgrave and Payload Specialist Tom Hennen deployed a Defense Support Program (DSP) early-warning satellite and set to work on a complex series of observations to assess the performance of trained military imagery analysts in space.

Fred Gregory leads the STS-44 crew out of the Operations & Checkout (O&C) Building at the Kennedy Space Center (KSC) for launch on 24 November 1991. Photo Credit: NASA, via Joachim Becker/SpaceFacts.de

But late on the morning of 30 November, IMU-2—one of three inertial measurement units, a critical element of the shuttle’s navigational hardware—suddenly failed. Working closely with the Mission Control Center (MCC) at the Johnson Space Center (JSC) in Houston, Texas, the astronauts attempted to cycle power to the device, in hopes of reviving it, but to no avail.

“Fred, we’ve run out of ideas on IMU-2,” Capcom Jan Davis dejectedly told Gregory. “We see problems both with the attitude and the velocity. We have declared IMU-2 failed. We want you to leave it powered on for now and we’re still discussing the implications of that failure and we’ll get back with you when we have a plan.” The decision to leave the unit powered on was queried by Flight Director Phil Engelauf, although it was determined that it was drawing no more or less current than it had done before the failure and displayed no evidence of an electrical short.

Atlantis roars into the night, watched by a multitude of spectators on 24 November 1991. Seven days later, she returned to Earth to a much quieter reception. Photo Credit: NASA

In any case, the plan, when it came, was not what the astronauts hoped for. Flight rules decreed that with an IMU out of action, a Minimum Duration Flight (MDF) was mandatory and Atlantis would return to Earth the next day. “Fred, we’ve been consulting with the management team,” radioed Davis. “We’re all at a consensus that we are declaring an MDF, due to the failure of the IMU. We also require a lakebed landing.”

The crew performed a “hot-fire” test of the shuttle’s Reaction Control System (RCS) thrusters and flight surfaces, to ensure that Atlantis was prepared for re-entry. Original plans called for STS-44 to terminate on the concrete surface of the Shuttle Landing Facility (SLF) at the Kennedy Space Center (KSC) in Florida, but mission managers called up Edwards Air Force Base, Calif., whose large expanse of dry lakebed offered extra margins for safety. The runway in Florida, by contrast, was narrow and closely bordered by water; not a good place to land an orbiter with a degraded navigational capability.

The Defense Support Program (DSP) satellite, attached to is Boeing-built Inertial Upper Stage (IUS) booster, is deployed from Atlantis’ payload bay at the beginning of the STS-44 mission. Photo Credit: NASA

Atlantis’ payload bay doors were latched early on 1 December and Gregory and Henricks performed a 183-second “burn” of the Orbital Maneuvering System (OMS) engines to commit the vehicle to a hypersonic dive back through the atmosphere. During re-entry, the onset of terrestrial gravity after a week of weightlessness was noticeable, especially to the four “rookie” members of the crew. At one point, Runco, seated next to veteran spacefarer Musgrave on the flight deck, jokingly grumbled that his hand-held camera had suddenly and inexplicably gotten heavier.

Touching down at 2:34 p.m. PST, STS-44 had nevertheless completed many of its most critical objectives. They became the first (and only) shuttle crew to land on Edwards’ dry lakebed Runway 5.

For the first time, two Army astronauts flew aboard the Shuttle on STS-44. Jim Voss (left) and professional imagery analyst Tom Hennen are pictured here on Atlantis’ flight deck with camera hardware used for Terra Scout and M88-1 experiments. Photo Credit: NASA

The touchdown produced an impressive rooster-tail of dust in Atlantis’ wake and, as part of a detailed test objective, Gregory completed the bulk of the rollout without ever touching the brakes. But at length, seeing the approach of the end of the runway, he called Houston to apply the brakes at a ground speed of just 17 mph (27 km/h).

“Houston, I’m gonna stop it before we get to the end of the runway.”

“Roger that, Atlantis,” replied Capcom Bob Cabana. “We concur.”

All six of Atlantis’ wheels were fully stopped after two minutes of rollout and 13,798 feet (4,205 meters) traveled down the runway.

Atlantis touches down on Runway 5 at Edwards on 1 December 1991. This was the last shuttle mission to terminate on a dry lakebed runway. Photo Credit: NASA

“Wheels Stop, Houston,” Gregory called.

“Good job, Fred,” said Cabana. “Welcome home, Atlantis, and congratulations on a great flight.”

As circumstances transpired, STS-44 was the last shuttle mission to land on a dry lakebed runway. Although another 20 more missions would terminate at Edwards in the years to come, the last doing so in September 2009, all would do so on concrete or (in one case) on a temporary asphalt runway.

Video Credit: NASA/National Space Society

“Fred makes it sound easy, but it was great to sit there and watch him complete this task,” Henricks said later. “This was one of the best landings we’ve had in the shuttle program and this was to a runway that we had practiced very few approaches to.”

But the disappointment was evident. Most acute was the fact that none of the astronauts’ families were there to see them land. “It would’ve been spectacular to watch, because we landed on lakebed Runway 5, which meant we came right over the top of the buildings,” Henricks later told a Smithsonian interviewer. “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’ve jumped up and touched our wheels!”

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