Jason DavisSep 16, 2013

Cygnus ready to spread its wings, fly to ISS

The International Space Station is preparing to welcome a Cygnus resupply vessel to the commercial spaceflight party.

ORB-D1 Mission Patch
ORB-D1 Mission Patch Because it's not a real mission without a patch. Orbital Sciences Corporation

On Wednesday morning, Orbital Sciences Corporation’s Antares rocket is slated to lift off from NASA's Wallops Flight Facility on the Virginia coast. It will be the second flight of Antares, which successfully sailed a test payload into orbit last April. Cygnus is carrying carrying 1,300 pounds (589 kilograms) of food, clothing and other cargo for its maiden voyage—a demonstration mission to prove its capabilities.

Wednesday's launch window is a relatively short fifteen minutes, from 10:50 to 11:05 a.m. EDT (14:50 to 15:05 UTC). Although the launch was delayed from Tuesday to Wednesday due to bad weather and a flaky data cable, Cygnus is still expected to arrive at the station on Sunday, Sept. 22, with capture scheduled for 7:17 a.m. Like SpaceX’s Dragon, Cygnus will be berthed to the station's Harmony node using Canadarm. NASA says the vehicle is expected to be installed around 9 a.m.

Here is your Antares ascent timeline: 

Event Altitude (kilometers) Elapsed time (mm:ss)
Stage one ignition 0 00:00
Liftoff 0 00:02
Main Engine Cutoff (MECO) 107 03:53
Stage one separation 113 03:58
Fairing separation 182 05:20
Interstage separation 184 05:25
Stage 2 ignition 187 05:29
Stage 2 burnout / orbit insertion 250 08:02
Cygnus separation 249 10:02
Antares ORB-D1 Ready for Launch
Antares ORB-D1 Ready for Launch Orbital Sciences Corporation's Antares rocket and Cygnus resupply spacecraft stand on the launchpad prior to their Sept. 18 launch to the International Space Station. Orbital Sciences Corporation

Cygnus will be controlled from Orbital's Mission Control Center in Dulles, Va. The spacecraft's initial orbit will be 245 x 300 kilometers. Over the next few days, Cygnus will conduct a series of orbit-raising thruster burns to position itself four kilometers beneath the station. In between those burns, it will perform its first three demonstration tasks: Absolute GPS (Demo 1), Free drift (Demo 2a) and abort (Demo 2b).

When Cygnus arrives at the four kilometer point, joint operations between Orbital and NASA's Mission Control Center in Houston begin. Here are the joint operations events:

EventDescriptionRange
Demo 3Relative GPS navigation demonstration4 km
Demo 4Onboard targeting demonstration4 km
Thruster burnClose on station4 km to 1.4 km
Demo 5Autonomous maneuver demonstration4 km to 1.4 km
Thruster burnClose on station4 km to 1.4 km
Demo 6Hardware Command Panel (HCP) checkout1.4 km
Thruster burnsIntercept R-bar, hold autonomously at 250 m1.4 km to 250 m
Demo 7LIDAR navigation demonstration250 m
Thruster burnClose on station250 m to 230 m
Demo 8HCP retreat demonstration230 m
Thruster burnRetreat from station230 m to 250 m
Thruster burnClose on station250 m to 230 m
Demo 9HCP hold demonstration230 m 
Thruster burnClose on station250 m to 30 m
Enter Keep-Out SphereClose on station200 m
Demo 10LIDAR JEM-A reflector tracking demonstration200 m to 30m
Hold for final approachHold for final approach30 m 
Thruster burnFinal approach30 m to 12 m
Hold for captureHold for capture12 m
CaptureCapture with Canadarm by Karen Nyberg and Luca Parmitano12 m
Cygnus ISS Approach Profile
Cygnus ISS Approach Profile As Cygnus approaches the station, it will conduct a series of demonstration maneuvers designed to prove various spacecraft capabilities. Orbital Sciences Corporation

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