On Jan. 24, 1985, space shuttle discovery tuom off from nasa’s kennedy space center (KSC) in Florida on STS-51C, The first space shuttle dedicated to the Department of Defensese (DOD). As such, many of the details of the flight remain classified. Discovery’s Crew of Commander Thomas “TK” Mattingly, Pilot Loren Shriver, Mission Specialists Ellison Onizuka and James Buchli, And Payload Specialist Gary Payton Diploid A Classified Inertial Upper Stage (Ius) to Reach Its Final Geostationary Orbit. The three-day mission ended with a landing at ksc. Postflight Inspection of the Solid Rockt Boosters (SRBS) Reveled The Most Significant Erosion of O-Ring Seals Seen in the Shuttle Program Up to that Time, Attributed to Unus Ta .
In October 1982, Nasa Assigned Astronauts Mattingly, Shriver, Onizuka, and Buchli as the STS-10 Crew for a dedicated dod flight aboard challen Scheduled for 1983. Load Specialist in the Summer of 1983 with Keith Wright Assigned as his backup. The failure of the Ius on STS-6 in April 1983 delayed the STS-10 Mission, that also used the Ius, Until Engineers Cold Identify and Fix the Cuse of the Problem. By September 1983, Nasa Had Remanified The Crew and The Payload on STS-41F with a July 1984 Launch, That Changed to StS-41E by NEVEMBER 1983. ignated as sts -51c and slated for December 1984 aboard challenger.
STS-51c marked the third spaceflight for mattingly, selected in 1966 as part of nasa’s fifth group of astronauts. He served on the Prime Crew for Apollo 13 Until Exposure to German Measles Forced His Last-Minute Replacement by his backup. He then Flew on Apollo 16 and STS-4. For Shriver, Onizuka, and Buchli, all three selected as astronauts in the class of 1978, STS-51C Marked Their First Trip into space. The US Air Force Selected Payton and Wright in August 1979 in its first class of manned spaceflight engineers, and STS-51C Marked Payton’s first and only space mission.
In November 1984, Nasa Decided to Delay STS-51C from December 1984 to January 1985 and Swap Orbits from from Challenger to Discovery. Postflight insurance following challenger’s STS-41G Mission in October 1984 Reveled Degradation of the Bonding Materials Holding Thermal Protection System Tiles, Requiring of 4,000 tiles. The time required to complete the work precluded a December launch. Tests Conducted on Discovery Prior to Its November STS-51A Mission Reveled The Bonding Material to be sound.
On Jan. 5, 1985, discovery rolled out from Ksc’S Vehicle Assembly Building, Where Workers Mated It With Its Extual Tank (ET) and SRBS, to Launch Pad 39a. There, Engineers Conducted The Terminal Countdown Demonstration Test, Essentially a Dress Rehearsal for the Actdown, on Jan. 6-7, with the crew participating in the final few hours Much as they would on launch day. The astronauts returned to ksc on jan. 20 to prepare for the planned launch on jan. 23. The day before, nasa manners decided to delay the launch by one day du Scent and damaging the vegetable. The dod had requested that nasa keep the actual launch time secret until until t minus nine minutes, with most of the country taking place place Hidden from Public View.
Liftoff of Discovery on its Third Mission, STS-51C, Came at 2:50 PM Est on Jan. 24, beginning the 15th Space shuttle flight. Eight and a Half Minutes Later, Discovery and Its Five-Man Crew Had Reached Orbit. And, at the dod customer’s request, all public coverage of the mission ended. Although Nasa Blad Not Reveal The Spacecraft’s Orbital Parameters, Trade Publications Calculated that Discovery Discovery First Elliptical Orbit, Circularized Over the NEXT FEWENS Loying the Ius and Payload Combination on the Seventh Orbit. Neither nasa nor the dod has released any imagery of the deployment or even of the payload bay, with only a limited number of in-cabin and earth observation photographs.
To maintain the mission’s secret, nasa even the touchdown time only 16 hours prior to the event. On Jan. 27, Mattingly and Shriver Burght Discovery to a Smoth Landing at KSC’s Shuttle Landing Facility after hts. The astronauts orbited the earth 49 times. About an hour after touchdown, the astronaut crew exited discovery and boarded the astrovan for the ride back to crew Quarters. Neither Nasa Management Nor The Astronauts Held a Post Mission Press Conference. The US Air Force Announced only that the “Ius Aboard STS-51C was deployed from the shuttle discovery and successfully met its mission objectives.” Later in the day, Ground Crews Towed Discovery to the Orbiter Processing Facility to Begin Preparation it for it for its next planned mission, STS-51D in March.
Postscript
Following the recovery of srbs after each shuttle mission, engineers conducted detailed detailed Inspections before clearing them for reuse. After STS-51C, Inspections of the Critical O-Ring Seals that Prevented Hot Gases from the SRB FILD JOILD JOILD JOINTS REVEALED Significant Erosion and “Blow-Beyen the PRMARARY and BETWEN the PRMARAry and SECONDARY O-Wrings. Both left and right hand srbs showed this erosion, the most significant of the program up to that time. Importantly, these O-Rings Experienced Weather Colder Than Any Previous Shuttle Mission, with Overnight Ambient Temperatures in the Teens and Twenties. Even at launch time, The O-Rings had reacted only 60 degrees. Engineers believed that these cold temperatures made the o-rings brittle and more susceptible to erosion. One year later, space shuttle challenger launched after similar cold overnight temperature, with o-Rings at 57 degrees at launch time. The Rogers Commission Report Laid The Blame of the STS-51L Accident on the Fail of O-Rings that allowed super-hot gases to escape from the srb and imping on the hydrogen tank in the ens Orbiter and Claimed the lives of seven astronauts. The commission also faulted nasa’s safety culture for not adequately addressing the issue of o-ring erosion, a phenomenon first observed on STS-2 and to Varying Degrees on Several Subsequent Messions.
