posted 10-27-2024 08:28 AM               

Space Cover 777: "We have a cutoff">

Those of us who were at KSC or watching on TV, as I was, will always remember the very dramatic and scary main engine cutoff just 4 seconds before Discovery's expected launch on STS-41D: a cloud of steam, a brief roar... then silence. The SSME's were successfully shut off just before the Solid Rocket Boosters would have ignited; Main Engine number one had failed to ignite.

Mark Hess, the KSC launch commentator, made the following call: "We have a cutoff...we have an abort by the onboard computers." He was kind enough to sign and add his quote to this cover canceled on the day of the pad abort.

No human launch since Gemini-Titan 6 in 1965 had an engine cutoff after ignition. 41D CDR Hank Hartsfield made the correct decision for the crew to remain onboard, as there was an invisible hydrogen fire at the base of the orbiter that actually climbed up toward the crew cabin. Water spray successfully doused the fire and the crew later left the orbiter. Both orbiter and exiting crew got drenched.

Mission Specialist Steve Hawley made the joking and famous comment just after the sudden engine shutdown: "I thought we'd be a lot higher at MECO" (Main Engine Cut Off).

The top cover marks both the June 25, 1984 computer scrub and the next-day pad abort. The bottom cover's four KSC cancels mark (1) the Pad abort, (2) rollback to the VAB for engine replacement, (3) second rollout to the pad, and (4) launch (Credit: Ken Havekotte).

The top cover is a Rockwell Space Division Stamp Club (RSDSC) cover. It marks the rollout of Space Shuttle Orbiter Discovery at its assembly plant in Palmdale, CA prior to its overland move to EAFB, and also the 41D launch. After its Palmdale rollout, Discovery was then flown atop the Shuttle Carrier Aircraft cross-country to KSC for its maiden launch. The cover is also canceled for the 41D launch along with autographs of the crew (see SCOTW #99 of March 6, 2011, for more RSDSC covers and information about these very well-done covers).

The bottom cover is canceled for the 41D launch, with the cachet picturing the 41D/Discovery crew

This is a 41D KSC launch cover with a crew emblem cachet and autographed by the 41D crew.

For the crew signed cover fans, the cover was autographed at JSC by 5 of the crew members in 1985 and then the final autograph was applied by Charlie Walker in 1986 from St. Louis, MO. Multi-mailings are not uncommon to complete crew signed covers.

Discovery now rests comfortably in retirement at the National Air and Space Museum's Steven F. Udvar-Hazy Center in Chantilly, VA after 39 flights and 5,830 orbits around the earth.

posted 10-27-2024 09:21 AM               

Mission 41-D, Discovery's maiden flight in August 1984, was the second US crewed spaceflight of an engine cutoff seconds before liftoff as Bob posted here.

It wasn't the last, thus far, as there was Shuttle 51-F nearly a year later with a T-3 second cutoff of a malfunctioned #2 SSME coolant valve, STS-55 with another T-3 seconds by Challenger's computer due to an incomplete ignition of Engine #3.