STS-41-D

STS-41-D

The launch of Space Shuttle Discovery on its first mission on 30 August 1984.
Mission type	Satellite deployment
Operator	NASA
COSPAR ID	1984-093A
SATCAT №	15234
Mission duration	6 days, 56 minutes, 5 seconds
Distance travelled	4,010,000 kilometres (2,490,000 mi)
Orbits completed	97
Spacecraft properties
Spacecraft	Space Shuttle Discovery
Launch mass	119,511 kilograms (263,477 lb)
Landing mass	91,478 kilograms (201,674 lb)
Payload mass	18,681 kilograms (41,184 lb)
Crew
Crew size	6
Members	Henry W. Hartsfield, Jr. Michael L. Coats Richard M. Mullane Steven A. Hawley Judith A. Resnik Charles D. Walker
Start of mission
Launch date	30 August 1984, 12:41:50 (1984-08-30UTC12:41:50Z) UTC
Launch site	Kennedy LC-39A
End of mission
Landing date	5 September 1984, 13:37:54 (1984-09-05UTC13:37:55Z) UTC
Landing site	Edwards Runway 17
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Perigee	346 kilometres (187 nmi)
Apogee	354 kilometres (191 nmi)
Inclination	28.5 degrees
Period	90.6 min
Epoch	1 September 1984[1]
Back row: L-R: Walker, Resnik Front row L-R: Mullane, Hawley, Hartsfield, Coats Space Shuttle program ← STS-41-C STS-41-G →

STS-41-D was the 12th flight of NASA's Space Shuttle program, and the first mission of Space Shuttle Discovery. It was launched from Kennedy Space Center, Florida, on 30 August 1984, and landed at Edwards Air Force Base, California, on 5 September. Three commercial communications satellites were deployed into orbit during the six-day mission, and a number of scientific experiments were conducted.

The mission was delayed by more than two months from its original planned launch date, having experienced the Space Shuttle program's first launch abort at T-6 seconds on 26 June 1984.

Crew

Crew seat assignments

Seat[2]	Launch	Landing	Seats 1–4 are on the Flight Deck. Seats 5–7 are on the Middeck.
S1	Hartsfield	Hartsfield
S2	Coats	Coats
S3	Mullane	Resnik
S4	Hawley	Hawley
S5	Resnik	Mullane
S6	Walker	Walker

Mission background

The launch was originally planned for 25 June 1984, but because of a variety of technical problems, including rollback to the Vehicle Assembly Building to replace a faulty main engine, the launch was delayed by over two months. The 26 June launch attempt marked the first time since Gemini 6A that a manned spacecraft had experienced a shutdown of its engines just prior to launch.

June launch attempt

During the 26 June launch attempt, there was a launch abort at T-6 seconds, followed by a pad fire about ten minutes later.^[3][4]

Commentary: "We have a cut off."

"NTD we have a RSLS (Redundant Set Launch Sequencer) abort."

Commentary: "We have an abort by the onboard computers of the orbiter Discovery."

"Break break, break break, DLS shows engine one not shut down."
"OK, PLT?"
"CSME verify engine one."
"You want me to shut down engine one?"
"We do not show engine start on one."
"OTC I can verify shutdown on verify on engine one, we haven't start prepped engine one."
"All engines shut down I can verify that."

Commentary: "We can now verify all three engines have been shut down."

"We have red lights on engines two and three in the cockpit, not on one."
"All right, CSME verify engine one safe for APU shutdown."
"If I can verify that?"
"OTC GPC go for APU shutdown."^[5]

Mission Specialist Steve Hawley was reported as saying following the abort: "Gee, I thought we'd be a lot higher at MECO (Main Engine Cut-Off)!".^[6] About ten minutes later, the following was heard on live TV coverage:

"We have indication two of our fire detectors on the zero level; no response. They're side by side right next to the engine area. The engineer requested that we turn on the heat shield fire water which is what could be seen spraying up in the vicinity of the engine engine bells of Discovery's three main engines."

While evacuating the shuttle, the crew was doused with water from the pad deluge system, which was activated due to a hydrogen fire on the launch pad caused by the free hydrogen (fuel) that had collected around the engine nozzles following the shutdown and engine anomaly.^[7] Because the fire was invisible to humans, had the astronauts used the normal emergency escape procedure across the service arm to the slidewire escape baskets, they would have run into the fire.^[8]

Changes to procedures resulting from the abort included more practicing of "safeing" the orbiter following aborts at various points, the use of the fire suppression system in all pad aborts, and the testing of the slidewire escape system with a real person (Charles F. Bolden, Jr.). It emerged that launch controllers were reluctant to order the crew to evacuate during the STS-41-D abort, as the slidewire had not been ridden by a human.^[6]

Examination of telemetry data indicated that the engine malfunction had been caused by a stuck valve that prevented proper flow of LOX into the combustion chamber.

Mission summary

STS-41-D finally launched on 8:41 am EDT on 30 August after a six-minute, 50-second delay when a private aircraft flew into the restricted airspace near the launch pad. It was the fourth launch attempt for Discovery. Because of the two-month delay, the STS-41-F mission was cancelled (STS-41-E had already been cancelled), and its primary payloads were included on the STS-41-D flight. The combined cargo weighed over 41,184 pounds (18,681 kg), a record for a Space Shuttle payload up to that time.

The six-person flight crew consisted of Henry W. Hartsfield, Jr., commander, making his second shuttle mission; pilot Michael L. Coats; three mission specialists – Judith A. Resnik, Richard M. Mullane and Steven A. Hawley; and a payload specialist, Charles D. Walker, an employee of McDonnell Douglas. Walker was the first commercially sponsored payload specialist to fly aboard the Space Shuttle. Resnik became the second American woman to fly any NASA space mission, after Sally K. Ride.

Discovery's primary cargo consisted of three commercial communications satellites: SBS-D for Satellite Business Systems, Telstar 3C for Telesat of Canada, and Syncom IV-2, or Leasat-2, a Hughes-built satellite leased to the US Navy. Leasat-2 was the first large communications satellite designed specifically to be deployed from the Space Shuttle. All three satellites were deployed successfully and became operational.

Another payload was the OAST-1 solar array, a device 13 feet (4.0 m) wide and 102 feet (31 m) high, which folded into a package 7 inches (180 mm) deep. The array carried a number of different types of experimental solar cells and was extended to its full height several times during the mission. At the time, it was the largest structure ever extended from a manned spacecraft, and it demonstrated the feasibility of large lightweight solar arrays for use on future orbital installations, such as the International Space Station.

The McDonnell Douglas-sponsored Continuous Flow Electrophoresis System (CFES) experiment, using living cells, was more elaborate than the one flown on previous missions, and payload specialist Walker operated it for more than 100 hours during the flight. A student experiment to study crystal growth in microgravity was also carried out. The highlights of the mission were filmed using an IMAX motion picture camera, and later appeared in the 1985 documentary film The Dream is Alive. Because of an obstruction in the shuttle's external wastewater dumping system, a two-foot "pee-sicle" formed during the mission; Hartsfield removed it with the Remote Manipulator System.^[9]

The mission lasted six days, 56 minutes, and 4 seconds, with landing taking place on Runway 17 at Edwards Air Force Base at 6:37 am PDT on 5 September 1984. During STS-41-D, Discovery traveled a total of 2,490,000 miles (4,010,000 km) and made 97 orbits. The orbiter was transported back to KSC on 10 September. Ominously, STS-41-D was the first Shuttle mission in which blow-by damage to the SRB O-rings was discovered.

Launch attempts

Mission insignia

The 12 stars within the blue field indicate the flight's original numerical designation as STS-12 in the Space Transportation System's mission sequence. A representation of Discovery's namesake is manifested in a sailing ship, which is linked to the Shuttle (with the OAST solar array in the payload bay) via a red, white, and blue path, signifying its maiden voyage.

Wake-up calls

NASA began a tradition of playing music to astronauts during the Gemini program, and first used music to wake up a flight crew during Apollo 15. Each track is specially chosen, often by the astronauts' families, and usually has a special meaning to an individual member of the crew, or is applicable to their daily activities.^[11]

Gallery

• 
  SBS-D deployment
• 
  Syncom IV-2 deployment
• 
  Telstar 3C deployment
• 
  The extended OAST-1 solar array

See also

• List of human spaceflights
• List of Space Shuttle missions

References

 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

External links

• STS-41-D mission summary. NASA.
• STS-41-D National Space Transportation Systems Program Mission Report (PDF). NASA.
• STS-41-D video highlights. NSS.
• The Dream is Alive (1985). IMDb.