Cygnus Mission Update
Via Orbital Sciences Corporation
September 20, 2013
Before Cygnus can rendezvous and berth with the International Space Station (ISS), it must perform several thruster firings to raise its orbit and catch up with the ISS. Cygnus must also perform 10 maneuvers to demonstrate the safety capabilities of the Cygnus. Once each demonstration maneuver is complete, Orbital will send a data package to NASA for review to verify that the demonstration has met its objectives.
Since the launch of the spacecraft at 10:58 a.m. on Wednesday, September 18, the Cygnus team has been busy completing the first two of 10 required in-orbit demonstrations and has successfully conducted three Delta V burns to raise Cygnus’ orbit. On Friday, September 20 , the team will conduct Delta V burn #4 to raise Cygnus’ orbit to within 4 km of the ISS orbit altitude. If needed, an additional burn may be conducted in Saturday, September 21, to “fine tune” Cygnus’ orbit.
The Cygnus team is busiest on Sunday, September 22, the day of rendezvous, grapple and berthing with the ISS. That day, the remaining eight demonstrations and a series of smaller Approach Delta Velocity (ADV) burns will be carried out prior to capture by the station crew and berthing with the ISS.
Once the final demonstration maneuver is deemed successful, NASA will give approval for the approach to within 10 meters of the station where Cygnus will be grappled by the robotic arm and guided to its berthing port.
|Completed||Free drift & abort demonstration||Demonstrate the spacecraft’s ability to float freely with all of its thrusters inhibited and to safely move away from the station if necessary|
|9/22||Position and attitude control demonstration||Test the spacecraft’s ability to hold its position|
|9/22||Relative GPS navigation demonstration||Verify the spacecraft’s GPS-based navigation system is operating as expected|
|9/22||Onboard targeting demonstration||Confirm the spacecraft’s ability to maneuver to a targeted position in space|
|ADV 1||Raises Cygnus from 4 km below ISS to 1.4 km|
|9/22||Reaction Engine Assembly (REA) maneuver demonstration||Demonstrate Cygnus’ attitude control system’s ability to maneuver|
|ADV 2||Moves Cygnus closer to R-Bar (directly below the ISS)|
|9/22||Hardware Command Panel (HCP) checkout||Verify that the ISS crew can command Cygnus using the HCP aboard the Station|
|ADV 3||Positions Cygnus to intersect the R-Bar|
|9/22||LIDAR navigation demonstration||Confirm that Cygnus’ laser navigation sensor’s position and velocity data is accurate and as expected in prefight simulations|
|ADV 4||Continues Cygnus’ ascent on the R-Bar toward 250m|
|9/22||ADV 5||Continues Cygnus ascent up the R-bar|
|9/22||Retreat demonstration||Verify that the ISS crew can command Cygnus to retreat away from the ISS, if needed|
|9/22||Hold demonstration||Verify that the ISS crew can command Cygnus to hold during approach, if needed|
|9/22||LIDAR single reflector tracking demonstration||Demonstrates Cygnus’ LIDAR’s capability to focus on a single reflector on the ISS|