Dreamchaser
HOUSTON—NASA has offered a preview of Sierra Space’s reusable Dream Chaser resupply demonstration mission to the International Space Station (ISS), planned for 2024.
Then known as Sierra Nevada Corp., Sierra Space and the winged Dream Chaser joined SpaceX’s Cargo Dragon and Northrop Grumman’s Cygnus resupply capsule in 2016 as designated NASA commercial cargo providers for the seven-person orbital laboratory.
A specific launch date was not provided by NASA in the Dec. 15 preview. But the agency outlined plans for an initial 45-day roundtrip mission and a 7,800-lb. cargo delivery. The launch is set to take place from Space Launch Complex 41 at Cape Canaveral Space Force Station (CCSFS), Florida, aboard a United Launch Alliance Vulcan Centaur rocket.
The initial unrelated launch of a Vulcan Centaur, a certification mission with a payload that includes the first Astrobotic Technology Peregrine lunar lander from CCSFS, is currently planned for Jan. 8, 2024.
Dream Chaser was developed for 15 missions.
When it debuts, Dream Chaser and its “Shooting Star” cargo module will launch with wings folded inside a payload fairing aboard the Vulcan Centaur. Once the vehicle is in orbit, the protective fairing panels will be jettisoned, followed by the deployments of solar arrays mounted to the cargo module and wings.
As Sierra Space conducts in-orbit demonstrations for certification during the initial mission phase, ground teams at NASA’s Kennedy and Johnson space centers will join those at the Dream Chaser mission control center in Louisville, Colorado, in monitoring the autonomous flight.
The “far-field” demonstrations will be carried out prior to Dream Chaser’s arrival at an invisible boundary around the ISS known as the approach ellipsoid, which measures 2.5 by 1.25 by 1.25 mi. The “far-field” agenda includes demonstrations of attitude control, translational maneuvers and abort capabilities.
Then, working with NASA’s Mission Control, Sierra Space will carry out “near-field” demonstrations. They include activation of light detection and ranging sensors and responding to commands transmitted by the ISS crew. The commands involve an orbital lab retreat and holding its approach at distance milestones of 1,083 ft., 820 ft. and 98 ft.
While Dream Chaser is holding for a final time at 38 ft., a grapple fixture on the spacecraft’s cargo module is to be secured with the ISS’s nearly 60-ft.-long Canadian robot arm under the command of space station astronauts.
Ground controllers then will take command of the robot arm to berth the cargo module portion of the Dream Chaser to an Earth-facing port on the ISS U.S. segment’s Unity or Harmony modules.
During future resupply missions, Dream Chaser will be able to deliver up to 11,500 lb. of cargo and remain berthed to the ISS for up to 75 days. More than 3,500 lb. of cargo, including scientific research, could be returned to Earth and more than 8,700 lb. of trash could be placed aboard the cargo module for disposal.
The cargo module can be flown just once and is disposed of prior to the Dream Chaser’s reentry.
Once unberthed from the ISS, Dream Chaser can land as soon as 11 to 15 hr. after departure with daily opportunities, weather permitting. Weather constraints include thunderstorms, lightning and rain within a 20-mi. radius of the runway or 10 mi. along the approach path.
Twenty-six reaction control system thrusters will provide the deorbit propulsion for a return at Kennedy Space Center’s Launch and Landing facility, which was once used by NASA’s space shuttle for return to Earth.
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