When was the deadline for proposals to build the S-IVB upper stage?
The deadline for proposals to build the upper stage of a new rocket was the 29th of February 1960. Eleven companies submitted bids to NASA with hopes of securing the contract.
Questions about S-IVB
Short answers, pulled from the story.
Which company won the contract to build the S-IVB stage and why did they win it?
Douglas Aircraft Company won the award on April 19 after administrator T. Keith Glennan made his decision. The Marshall Space Flight Center chose Douglas partly because their previous work on the S-IV stage showed strong similarities to what they needed now.
What is the difference between the 200 series and 500 series versions of the S-IVB stage?
The 200 series flew on the Saturn IB vehicle and lacked a flared interstage found on the larger rockets. The 500 series featured a flared interstage matching the diameter of the S-II stage on the Saturn V and used Auxiliary Propulsion System thruster modules instead of three solid rockets.
How many times did the S-IVB stage fire during lunar missions and when did this begin?
Lunar missions required firing this stage twice during a single mission profile to achieve Earth orbit insertion and perform translunar injection toward the Moon. Apollo 4 marked the first time a 500 series stage restarted its J-2 engine successfully in April 1967.
When was Skylab launched and when did it reenter Earth's atmosphere?
Skylab lifted off aboard a Saturn V rocket on the 14th of May 1973. It reentered Earth's atmosphere over the Pacific Ocean on the 11th of July 1979.
Which S-IVB stages were crashed into the Moon for seismic experiments and what data did they provide?
Starting with Apollo 13 in April 1970, mission planners deliberately crashed spent stages into the Moon to generate seismic waves that instruments measured to characterize the lunar interior. Subsequent impacts occurred during Apollo 14, 15, 16, and 17 missions to provide data about moonquakes and internal structure beneath the surface.