STS-107: Columbia's Last Mission: A Look Back

See also my facebook note, https://www.facebook.com/notes/ce-whitehead/sts-107s-final-flight-introduction, and part 1 and part 2 which list the various locations and views taken.

Columbia was the first and heaviest vehicle in the shuttle fleet, described as a "brick." It debuted with STS-1, under seasoned Gemini and Apollo veteran John Young. Robert Crippen was pilot. Sixteen tiles were lost and 148 damaged in an "overpressure wave" from its solid rocket booster at take-off. Otherwise this first flight was successful.

Columbia's Resume

Commanded by NASA's first woman commander Eileen Collins (STS-93), who had to manage premature engine shutdown (due to a leak), Columbia's resume lists Senator Bill Nelson as crewmember in 1986. It flew jellyfish in 1991. Columbia deployed the Chandra X-ray observatory, the Laser Geodynamic Satellite, and Comsat. Columbia also serviced Hubble Space Telescope, but never docked with either Space Station (it had no docking module).

"Impossible-Sphere"

Columbia was outfitted with ejectable seats for its first flights. These were removed after the orbiter proved capable, but ejectable seats would hardly have saved the STS-107 crewmembers from the flames of the mesosphere (also dubbed the "impossible sphere"), a cold almost-vacuum, the lowest part with 1/1000 sea level's atmospheric pressure, lower pressure at its top.

In a near-vacuum gasses move fast. As gasses are impacted during descent, densities and pressures increase. Impact also results in rapid, differential heating. Thus the shuttle's nose cone and wing carbon panels withstand temperatures of 3000 degrees Celsius without melting.

Flight Delayed

Dedicated to science, including student projects, STS-107 was scheduled to fly summer, 2002, with the powered and pressurized "Spacehab" experiment area, but the mission was delayed for repairs on fuel lines until January, 2003 (all orbiters got similar repairs).

Payload

Israeli Air Force Colonel Ilan Ramon (Israel's first astronaut) was onboard to operate the Meidex camera (a "Hitchhiker" payload; the Hitchhiker program was cancelled after STS-107) to study dust particles over the Sahara and Mediterranean. Experiments on board STS-107 also included worms and moss which survived the crash in their canisters designed for space habits, and bacterial growth in microgravity, children's experiments from around the globe, and ironically perhaps investigations of fire quenching in the vacuum of space.

Spacehab Leak

Early on, due to a leak in the aft left side of the brand new Spacehab Research Double Module water separator assembly, two quarts of water collected below floor panels. A clogged pipe was presumed the cause. The leak shorted the water separation assembly pump but the rest of the Power Distribution Unit was apparently fine. The water was vacuumed by the crew, and the system reconfigured to compensate for the lack of water removal from air.

Left Wing Breach

There was also the breach in the reinforced carbon composite panel in the left wing (probably panel #8; early temperature spikes were recorded by the panel #9 sensor). NASA believes the breach occurred right after take off. A report by Columbia's Accident Investigation Board (CAIB) says impact on the left wing was sensed after take-off. The report also noted a quite unusual temperature rise in the left wing just afterwards. This data may be accounted for by a 10-inch breach in RCC panel #8 on the underside of the left wing says CAIB. CAIB says flight temperature recordings on the way down can likewise be replicated in a model with a 10-inch breach.

Solid Rocket Boosters and Main Fuel Tank

Both rocket boosters and main fuel tank are jettisoned in flight. The former are recovered but not the latter.

In spite of possible "overpressure" at launch, and slightly higher than predicted operating temperature, which Mission Management Team member Linda Ham dubbed "interesting" although it may have been a "normal occurrence" (January 17, 2003 Mission Management Team Telecoms), the Solid Rocket Boosters recovered January 17th showed no anomalies except a bit of foam insulation missing from the o-ring near the left aft booster's forward skirt, with mild sooting. The left skirt was also buckled. NASA stated that buckling was from a prior mission. All nozzles fired, and "frangible nuts" which secure the boosters to the pad until take-off appeared as they should on the pad, each in two halves.

No photos were obtained of the fuel tank before separation and disposal, although one of Columbia's astronauts, David Brown, reportedly videotaped separation. A piece of orange foam, possibly from the tank, was reportedly found on the shoreline.

Crew

Brown, like Ramon, pilot Willie McCool, and mission specialist Laurel Clark, was in space for the first time. Commander Rick Husband, a Texan like McCool, flight engineer Kalpana Chawla, and mission specialist Michael Anderson were all flying their second shuttle mission.

Take-Off

The flight took off on a beautiful January morning, in bright blue sky, after last minute loading of some fragile payloads (in payload bay) two days before. After less than half a minute, the orbiter turned on its back to better carry its "lightweight" fuel tank. (The payload was not so heavy as to require the "super lightweight" tank.)

Orbit

Regardless of any damage, Columbia made orbit, and spent two weeks orbiting Earth in the lower thermosphere's radiation. Here was the ultimate solar-energy lab perhaps, with daytime temperatures reaching two-hundred degrees Celsius. The astronauts were divided into two teams, each working twelve-hour shifts for the round-the-clock mission.

Some Success?

Thirty percent of experiment data was downloaded prior to descent. Thus the mission was, in some sense, a success. As noted, some data and even life (bacteria, worms, and moss) survived. Crystals grown in space from the crystalline enzyme that may cause cancer to spread survived as did crystals sent by middle school students, although most small animals on board, including rats and bees, perished. However a photo of the crew was recovered as were the tires of the nose gear intact with the nose gear.

Photos taken during the January 17th through 29th orbit are part of the STS-107 roll at Johnson Space Center's Gateway to Astronaut Photography of Earth.

Theories: Lightning?

Blue jets which can be "sparked" by meteors way above other lightning, and sprites occur in the mesosphere. Blue jets are jolts from below. An amateur astronomer's photo of Columbia's return through the mesosphere at 8:53 a.m. EST captured a purple streak in the orbiter's trail, according to Columbia Disaster Info author Smith (Smith is associated with the "Thunderbolts Project" which argues that electricity is the basis of all forces).

Object?

Smith also reports that "object 2003B" was tracked in thousands of separate radar images as it orbited with Columbia for several days. First noticed January 17th, 2003B ultimately returned to Earth's atmosphere January 19th or 20th. Object 2003B is believed to be debris associated with the "foam strike."

Water Damage?

NASA at one point investigated as to whether rainwater could have damaged the left wing according to Aviation Week's Covault.

NASA Response

In a Jan 21rst email, NASA estimated five to twenty times the foam damage experienced on another shuttle flight. NASA rehearsed landing on one and also two flat tires, according to Cabbage and Harwood (2004). (STS-51-D in 1985 landed successfully with a flat tire and failed brakes).

Return

Columbia fired rockets for return over the Pacific at around 8:15 a.m. EST, re-entering the mesosphere just north of Hawaii. The astronauts saw plasma from hot gasses at 8:44 and sensed gravity about two minutes later. Just after 8:48 a strain gauge sensor reported unusual strain behind left wing panel nine. Just before 8:49 the first report by a sensor of overheating occurred. The sensor started failing shortly afterward.

The ship rolled slightly to keep drag optimal. Just after 8:50 there were five communication drop outs linked to an upper-left aft antenna, then odd temperature sensor readings from the left payload bay door.

Gasses may have penetrated the wing a minute later, according to the transcript at Columbia Sacrifice. Still prior to crossing California's Coast, about nine minutes before the orbiter broke up, a U.S. Air Force Defense Support Program missile warning satellite detected an abnormal thermal (infrared) signature coming from the orbiter.

Signs of Debris, Drag

As Columbia entered the U.S. just north of San Francisco, the amateur astronomer's photograph was snapped. Here were the first signs of unusual drag, according to the timeline at Spaceflight Now, followed quickly by the first reports of debris and an unusual increase in the left main landing gear door temperature.

A minute later, NASA's Maintenance, Mechanical, Arm, and Crew Systems Officer Jeff Kling discussed sensor readings, and another minute later the flight computer began correcting for increasing drag.

Shuttle fan Chris Valentine thinks it unlikely that the astronauts were unaware of the brightest two debris items, observed between 8:54 and 8:57 EST, one in Nevada, one on the Nevada line. Perhaps at least some of those who had flown previously observed unusual brightness in Columbia's trail.

Ian Jordan (Space Telescope Science Institute) describes a photo of the ship over New Mexico which shows asymmetrical plasma suggestive of weakened left-wing spars, as the ship flew towards the rising sun in the early hours just before 7 a.m. MST (8 a.m. EST) February 1st.

No unusual information information was displayed to astronauts however until after 8:58 a.m. EST as the ship crossed Texas, when four tire pressure sensor faults flashed on the screen. NASA classified most controls as stable at 8:57 just after Columbia's second successful S-shaped banking turn over New Mexico to slow descent. Control was lost after 8:58, according to NASA.

Last Contact

Rick Husband's final words to NASA before communication loss came less than a minute later as Columbia approached Dallas. Husband's words, originally transcribed by NASA as, "And uh Hou," Valentine heard as "Roger, uh, bu . . ." NASA ultimately discovered that Columbia's joystick was very briefly knocked or turned to manual control and then back to automatic (it must be put into automatic for astronauts to bail out, although there's no real evidence that they tried to; only one was not properly seated).

With Columbia's fuselage intact the astronauts in the cabin were fine, but when it separated probably just after 9:01, life support systems quit, although astronauts still had lights on their helmets. Most had helmets on.

The cabin, according to NASA, began spinning, with the flat end moving downwards, whereas engines (the heaviest items) moved ahead to Louisiana. A fuel tank was only discovered last year in Lake Nacogdoches (Sabine County, Texas, where the crew and cabin also found their rest). Debris from STS-107 is stored in the Vertical Assembly building.

Sources