As Cygnus heads to the ISS Orbital already eyeing the future
As Orbital Sciences Corporation’s first Cygnus spacecraft, the G. David Low, conducts a series of tests and rendezvous maneuvers that will bring it within reach of the International Space Station (ISS) robotic arm Sunday, the company continues preparations and planning for the next Station resupply mission and increased cargo delivery capabilities for future missions.
ORB-D And Future:
The Cygnus rode into orbit on top of Orbital’s new two-stage Antares launch vehicle on Wednesday, making its second flight after a successful maiden launch in April.
“It looked like the apogee and perigee were approximately 289 by 257; our target was actually a couple of kilometers below that, so we’re in really good shape,” Frank Culbertson, Orbital Executive Vice President said in a press conference shortly after launch.
The spacecraft was named to posthumously honor G. David Low, the former NASA astronaut who served in multiple positions at Orbital including Senior Vice President and Program Manager for the Commercial Orbital Transportation Services (COTS) program until his death in 2008.
After separation from the Antares’ ATK CASTOR 30 second stage, the spacecraft went through its activation sequence, including among other things deploying its solar arrays, pressurizing its propulsion system, and activating its attitude control system. About four hours after liftoff, the spacecraft successfully executed the first of a series of rendezvous burns, DV-1.
On Thursday, the spacecraft executed the first two demonstrations that are a part of this COTS demonstration mission and conducted two more rendezvous burns to continue to catch up to the ISS; the final rendezvous is scheduled for Sunday morning, U.S. time following several more rendezvous burns and demonstrations.
While Orbital’s COTS Demo mission is still in its early stages, the company has been hard at work preparing and planning for upcoming launches, including the next Cygnus/Antares launch, which will be the first flight under Orbital’s Commercial Resupply Services (CRS) contract with NASA.
On the day before the COTS demo launch, Orbital took media on a tour of the Horizontal Integration Facility (HIF) at NASA’s Wallops Flight Facility in Virginia, just about a mile away from Antares’ launch pad, Pad 0A at the Mid-Atlantic Regional Spaceport (MARS).
Most of the launch vehicle elements for the next launch are already in the HIF: the first stage core, thrust structure and both Aerojet AJ-26 engines, the ATK CASTOR 30 second stage, and the interstage were all seen during the tour.
Assuming all goes well with the COTS Demo mission, Culbertson said that Orbital is planning to have the vehicle for the next mission, called CRS-1 or Orb-1, ready to fly in the mid-December time period.
The first stage core was used early this year to validate the Pad 0A systems and an integrated first stage, culminating in a hot-fire test on February 22nd.
Now that the second Antares has flown successfully, the first stage elements will be integrated in the upcoming weeks; a stand is set up near the aft end of the core stage where the engines will be attached to the thrust structure.
“Roughly speaking, four to five months before launch we’ll be [working] hard on this,” Mike Pinkston, Orbital’s Antares program manager explained in an interview with NASASpaceflight.com. “We take this structure (the thrust structure) and put it up on that stand once all the hydraulics are checked out.
“You see the hydraulic actuators down there – that’s what allows us to gimbal the engines. So we’ll put it up on that stand, the engine on that cart rolls underneath, (then) we’ll raise it up, bolt it in, and hook it up. Once we have both engines in, that whole gray frame comes off, we can [bring] it over and then we mate it horizontally to the core (the first stage).”
After the first stage is integrated and checked out, the interstage and the second stage will be moved into position and connected.
The Cygnus spacecraft consists of two modules – a service module that provides power, propulsion, navigation, and communications, and a pressurized cargo module (PCM) that carries supplies and experiments and provides habital environment control.
On the COTS demo mission the Cygnus is carrying 700 kilograms (1543 pounds) of supplies to ISS, including several Bulk Overwrap Bags packed with food, other crew provisions, a Camera Light Pan/Tilt Assembly (CLPA) box, and computer hardware.
Before the spacecraft is unberthed from the Station, it will be packed with approximately 1100 kilograms of trash for disposal when the Cygnus is deorbited in a destructive re-entry.
For the Orb-1 mission, approximately 1350 kilograms of cargo are currently manifested to be taken up to the Station, including the first powered payload in Cygnus. “We do have the capability to fly powered payloads and [on Orb-1] we are flying a CGBA (Commercial Generic Bioprocessing Apparatus),” Carl Walz, Vice President and Deputy Program Manager of the COTS/CRS Program for Orbital, said during a pre-launch presentation to the media.
Walz also talked about one of challenging aspects that has come up recently.
“NASA has provided the manifest to us and what they have asked us to do is to figure out a way to load a really large bag with a new spacesuit right at the very end of processing (while the Cygnus is attached to) the rocket – a short EMU (Extravehicular Mobility Unit), so basically a hard upper torso and the PLSS (Portable Life Support System).
“So we’re trying to figure out how to do that – the system wasn’t designed to do that, but we’re going to figure out a way to get it done. It turns out that there are two cargo bays that won’t have cargo in them and that’s (because) we’re basically getting as much cargo as NASA has to give us.
“One of the things that we have coming also with the late load is some NanoRack deployable satellites.” Walz also added that about one-third of the cargo on Orb-1 will be loaded “late”.
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A fully loaded Cygnus could carry as much as 2000 kilograms of pressurized cargo, but as Walz noted, “One of the most important things for cargo is not so much mass, it’s actually the volume because most of the cargo that NASA packs is not really dense and so it turns out that thing that NASA really values is the volume of the vehicle.” Cygnus has a pressurized volume of almost 19 cubic meters.
And while detailed planning for near-term missions continues, a series of hardware upgrades are already being prepared for the Cygnus and the Antares that will increase the capabilities of the Orbital’s cargo delivery service.
ATK is preparing an upgraded second stage motor, the CASTOR 30XL, and Orbital is preparing an Enhanced Cygnus with changes to the PCM and the Service Module.
(Image taken from the Castor 30XL test fire multi-view engineering video available in L2).
An Enhanced Pressurized Cargo Module will increase the maximum upmass to 2700 kilograms and the pressurized volume to 27 cubic meters and the Service Module will be upgraded to support this capability.
“After we designed (the Cygnus), (and) after the launch vehicle guys finished their development – because you have to remember there’s a lot of parallel development – we recognized that there were some things in the Standard Cygnus we could change to pull out some mass,” added Frank DeMauro, Vice President and Program Director of the COTS/CRS Program for Orbital.
“Every kilogram we pull out of the Service Module we can put into cargo or we can help in (other areas). So the Enhanced Cygnus design is not only a bigger PCM (Pressurized Cargo Module), but it’s a little bit more ‘upscale’ Service Module in terms of more mass-efficient, a little bit better solar array and other efficiencies and so the Enhanced Cygnus is a combination of things.”
(Images: via Philip Sloss, NASASpaceFlight.com – L2 and Orbital. L2′s Antares and Cygnus Section – containing presentations, videos, images, interactive high level updates and more).
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