6/27/2024 02:01:00 AM Sierra Space's Dream Chaser spaceplane has been removed from United Launch Alliance's (ULA) second Vulcan Centaur flight manifest due to scheduling delays. Instead, an "inert payload" will take its place, according to ULA. ULA CEO Tory Bruno stated that Sierra Space informed them of "significant risk" in meeting the September launch date and decided to "step aside" to allow ULA to move forward with its certification with the Department of Defense (DOD). This certification is crucial for ULA to carry out national security missions for the DOD. In addition to the inert payload, ULA plans to launch technology "experiments and demonstrations" on the second Vulcan mission. However, Bruno did not provide further details on these experiments during the press conference. ULA is also planning to launch at least two more Vulcan missions before the end of the year. These national security missions, dubbed USSF-106 and USSF-87, are the first in a series of backlogged launches ULA has under contract with the DOD. In a separate statement, Sierra Space confirmed that despite the delay, its first Dream Chaser spaceplane, called Tenacity, is still on track for its maiden mission before the end of the year. Tenacity, along with its expendable Shooting Star cargo module, completed environmental testing in May and was delivered to NASA's Kennedy Space Center in Florida, where it is undergoing final testing before launch. Unlike SpaceX's Dragon or Boeing's Starliner, the 30-foot-long Dream Chaser is designed to land horizontally on a runway, similar to NASA's retired space shuttle. The spaceplane is designed to deliver cargo resupply missions to the International Space Station (ISS) for NASA, but it has been badly delayed. Back in 2016, Sierra Space was awarded the Commercial Resupply Services 2 (CRS-2) contract from NASA, with the company expected to start fulfilling those missions in late 2019. For its first mission, the first of seven under the CRS-2 contract, Dream Chaser will deliver 7,800 pounds of cargo to the ISS. It will spend a total of 45 days attached to the station before returning to Florida for inspection, refurbishment, and reuse. Sierra Space is also planning a crewed version of Dream Chaser, as well as an inflatable habitat module that could operate in low Earth orbit as a private space station. The company has raised $1.7 billion to date to scale its various space projects.