When will NASA replace the current space shuttle with a successor? Venture Star or some derivative?
Fixed link.
NASA has no current plans to develop any sort of spaceplane or reusable launch vehicle. The Shuttle failed it’s design goals of reliability and economy, and none of the proposed successor designs proved workable. For the indefinite future the Orion system is planned to meet manned and unmanned payload requirements. Maybe if commercial suborbital flight becomes established sometime in the future it may develop into a reusable orbital vehicle, but nothing that’s on the radar yet.
To be fair, the Space Transportation System fell neatly within the technical estimates of critical failure (which were between 1:50 and 1:100 catastrophic flight events), and had it been operated at anything like the planned flight rates (20-36 flights per year) the shared fraction of overhead and facilities costs added to the incremental per-flight cost would have offered a much more reasonable flyway cost (though still not anywhere near the ~$100/lb to LEO touted by advocates). The initial development of the STS fell within budget guidelines and, save for the TPS tile system, on schedule, which is frankly a remarkable feat rarely achieved in space launch vehicle development, and certainly not replicated in the development of EELV (Delta IV, Atlas V) single use boosters that replaced the Shuttle as a primary payload delivery system.
The (entirely avoidable) failure of Challenger during boost phase and the (probably inevitable) TPS failure of the carbon-carbon leading edge on Columbia both had major impacts in the operational schedule and resulting cost increases. The lack of Air Force investment in the ‘Blue Shuttle’ program post-Challenger took away a major customer that would not have only provided a steady number of missions in the form of surveillance birds, technical payloads, and (potentially) space-based defensive systems, but also removed much of the funding for planned upgrades and evolutionary improvements to STS technology, like the Advanced Solid Rocket Motor (ARSM) and TPS and motor enhancements to allow quicker refurbishment and turnaround times.
So while the STS/Shuttle can be charitably be described as “disappointing”, especially compared to the initial boasts of program managers and space enthusiasts, it actually lived up to the technical assessments and final functional requirements. It’s biggest failure was in advancing reliable (>98% reliability) reusable heavy boost and personnel access to Low Earth Orbit.
Stranger
(bump)
I just noticed…
The fixed link provided by ApexRogers (orig, by Nametag) includes the official NASA Orion logo, designed by Michael Okuda…the same guy designing graphics for the Star Trek franchise!