From a list of close calls in the space program:
5. FLAT TIRE, FAILED BRAKES--APRIL 19, 1985
The last thing you want when landing 100 tons of the most complex machine ever built by humans is a flat tire. Or a brake failure.
Both happened to the seven-person crew of the STS-51-D space shuttle mission when they landed at Edwards Air Force Base in California—with U.S. Senator Edwin Garn (R-Utah) aboard.
1. O-RING EROSION--NOVEMBER 26, 1985
The launch of space shuttle Atlantis on November 26, 1985, would emerge as a haunting close call in the shadow of the Challenger disaster three months later.
Rubber O-rings serve as a seal between segments of the shuttle’s solid rocket boosters and prevent hot gases from escaping as the rocket fuelburns. During Atlantis’s chilly night launch, the cold winter air likely hardened the ring and allowed hot gases to escape through a crack.
The mission went off without a hitch, however, and NASA reported no anomalies even after retrieving the rockets from the ocean and inspecting them.
A similar failure caused space shuttle Challenger to disintegrate 73 seconds into its flight on January 28, 1986, ultimately killing all seven crew members.
POD: Incident (5) takes place, and the shuttle is destroyed and all passengers are killed. Once the shuttle program starts up again in November 1986 after repairs are made, incident (1) occurs and NASA notices that there is a problem. The shuttle is taken off line again for more repairs.
How does the scenario unfold? You've got a dead senator and a relatively new spacecraft out of commission for 1.5 years already and likely another delay as well of unknown duration in late 1986 as they fix the O-ring problem (assume the same delay they had after the Challenger incident IOTL).