As Boeing and NASA continue to investigate a propulsion system valve issue aboard the OFT-2 Starliner vehicle at Space Launch Complex (SLC)-41 at Cape Canaveral Space Force Station, Fla., Northrop Grumman Corp. stands primed to launch its next cargo-laden Cygnus mission to the International Space Station (ISS). The NG-16 flight—named in honor of Challenger hero Ellison Onizuka—will lift off atop Northrop Grumman’s Antares 230+ booster from Pad 0A at the Mid-Atlantic Regional Spaceport (MARS) on Wallops Island, Va., at 5:56 p.m. EDT Tuesday.
Weather conditions for Tuesday’s late-afternoon launch are currently looking 80-percent-favorable, according to NASA, with a slight risk posed by the presence of Cumulus Clouds.
Assuming an on-time launch and successful transit, Cygnus and its load of 8,200 pounds (3,700 kg) of equipment and supplies will be robotically captured and berthed at the space station at 6:10 a.m. EDT Thursday.
Efforts to fly OFT-2—the second uncrewed Orbital Flight Test of Boeing’s Starliner spacecraft, following the troubled OFT-1 mission, back in December 2019—have been scuppered twice in recent days.
An initial launch attempt targeted for Friday, 30 July was called off due to problems experienced following last month’s arrival of the Russian Nauka (“Science”) lab at the ISS and again on Tuesday, 3 August due to “unexpected valve position indications” in Starliner’s propulsion system. These indications materialized in the final hours of Tuesday’s countdown and forced a scrub.
In response to this issue, the 172-foot-tall (52.4-meter) Atlas V booster was returned to the Vertical Integration Facility (VIF) at SLC-41 to afford engineers better access to the spacecraft for troubleshooting.
According to NASA in a Friday afternoon update, the valves unexpectedly declared themselves “closed” and over the coming days teams will run through various procedures to understand the problem, before a new launch date is selected.
After the scrub, teams transmitted commands which successfully opened some of the valves, which furnished additional data as physical inspections got underway, as Boeing indicated it may “possibly return to the pad for launch this month”.
“Cautiously optimistic is a good way to describe how the team is feeling,” said John Vollmer, Starliner vice president and program manager. “They’re coming forward with innovative ideas and prioritizing the safety of the spacecraft and their teammates.”
Dependent upon the extent or nature of any necessary repairs, it remains unclear as to how soon OFT-2 may fly. With this week’s launch and arrival of NG-16 and SpaceX’s CRS-23 cargo mission slated to head to the ISS later in August, the station’s schedule for the remainder of the month looks set to be a busy one.
In readiness for Cygnus’ arrival, Expedition 65 astronauts Megan McArthur and Thomas Pesquet—who arrived at the ISS aboard Dragon Endeavour in late April—have spent the last few days performing for their role in capturing and “berthing” the cargo ship.
McArthur will be responsible for commanding the 57.7-foot-long (17.6-meter) Canadarm2 robotic arm, whilst Pesquet will back her up and monitor Cygnus’ approach profile.
Although McArthur previously monitored the departure of the NG-15 Cygnus in late June, this will be her first Cygnus “grab”. Pesquet, on the other hand, supported the departure of the OA-5 Cygnus in November 2016 and led the arrival and capture of the OA-7 Cygnus in April 2017.
Recently, McArthur and Pesquet used the Robotics On-Board Trainer (ROBoT) to prepare for the task and reviewed the NG-16 mission profile, rendezvous procedures and interfaces for monitoring and commanding the incoming cargo ship.
Cygnus will be berthed at the Earth-facing (or “nadir”) port of the station’s Unity node, also known as “Node-1”, one of the oldest ISS components.
Last Thursday, the Expedition 65 crew assembled the Node-1 Nadir Vestibule Outfitting Kit (VOK) and deployed and checked out the Centerline Berthing Camera System (CBCS) in readiness for the arrival.
Following its berthing on Thursday, Cygnus is expected to remain aboard the station for three months, ahead of its departure and deorbit in the November timeframe.
Heading uphill aboard NG-16 are about 3,000 pounds (1,400 kg) of crew supplies, as well as 2,300 pounds (1,000 kg) of science investigations, more than 30 pounds (15 kg) of Extravehicular Activity (EVA) equipment and almost 2,300 pounds (1,000 kg) of vehicle-related hardware.
Included in this haul is a second ISS Roll-Out Solar Array (iROSA) modification kit, to be installed onto the station’s P-4 truss by spacewalkers on 25 August in support of an extensive upgrade of the electricity-generating solar arrays.
Research hardware aboard NG-16 includes Redwire Regolith Print (RRP), jointly developed by Made in Space, Inc., of Jacksonville, Fla., and NASA’s Marshall Space Flight Center (MSFC) of Huntsville, Ala.
It will utilize the 3D printer currently aboard the ISS to demonstrate the feasibility of using in-situ resources on planetary bodies to provide raw materials for construction of habitats, landing pads and other structures.
It will employ “regolith simulant material”—an analog of the loose rocks and soils found on lunar or planetary surfaces—to produce 3D-printed samples to assess compressive, tensile and flexural strength characteristics.
Also aboard NG-16 is a University of Kentucky and NASA investigation known as the Kentucky Re-Entry Probe Experiment (KREPE). This will deploy a set of three instrumented “capsules” from Cygnus during its re-entry phase to evaluate an affordable Thermal Protection System (TPS).
The capsules will be tested through actual hypersonic re-entry conditions, following a previous series of high-altitude stratospheric balloon trials.
And MSFC’s 4-Bed Carbon Dioxide Scrubber will head to the station to demonstrate advanced life-support capabilities for deep-space missions. Shipped in June from MSFC in Huntsville to Wallops Island, Va., the scrubber will remain aboard the ISS for about a year, helping to recycle and regenerate most of the air and water needed to sustain the crew.
It forms one of two next-generation Environmental Control and Life Support System (ECLSS) technologies—alongside the Thermal Amine Scrubber, launched aboard the NG-11 Cygnus, back in April 2019—to undergo testing on the station.
The new 4-bed scrubber is an upgrade to the existing Carbon Dioxide Removal Assembly (CDRA), with benefits included a reduced power consumption, improved thermal stability and longer lifespan of the absorbent materials.
After its year-long demonstration phase is done, it will be fully integrated into the station’s closed-loop recycling system for at least three additional years to evaluate its viability for longer missions.
Other experiments aboard NG-16 include Cardinal Muscle, which will study engineered human muscle cells affixed to a collagen “scaffold” to investigate the phenomenon of accelerated loss of muscle mass in microgravity.
Results may lead to greater insights into the causal factors behind “sarcopenia”, a condition whereby muscle mass diminishes with age on Earth, with a 30-percent progressive degeneration noted between the ages of 20 and 80.
By observing this phenomenon in the microgravity environment, Cardinal Muscle investigators hope to develop new tissue-engineering approaches to create better models for sarcopenia and test new therapeutic drugs.
The Flow Boiling and Condensation Experiment (FBCE) seeks to develop an integrated two-phase flow boiling and condensation facility aboard the ISS, to support the development of improved boilers and heat exchangers for use in microgravity and low-gravity conditions.
And a European Space Agency (ESA) investigation, named “Blob”, will explore the effects of microgravity on the unicellular organism Physarum polycephalum. This slime-mold is part of an experiment to inspire students in the biological sciences.
Although it is just one cell and lacks a brain, Blob can move, feed, organize itself and even transmit knowledge to other slime molds. Students aged 10-18 will replicate experiments conducted by Pesquet to see how the Blob’s behavior is affected by microgravity. Using time lapse video from space, students can compare the speed, shape, and growth of the slime molds in space and on the ground.
NG-16 will also fly the Prototype Infrared Payload (PIRPL) for the Department of Defense’s Pentagon-headquartered Space Development Agency (SDA). Contracts worth $13.8 million were awarded to Northrop Grumman by the SDA in June 2020 for a medium-field-of-view multispectral imager for Overhead Passive Infrared (OPIR).
“Upon arrival at the ISS,” Northrop Grumman explained, “PIRPL will begin collecting infrared data which will define possible for expanding detection capabilities. The data collected will aid the development of algorithms for the next generation of tracking satellites.”
All of this hardware will be housed aboard Cygnus’ Pressurized Cargo Module (PCM), which was delivered in May from prime contractor Thales Alenia Space in the Italian city of Turin to Wallops. The PCM was then attached to its Service Module, ahead of integration with the Antares 230+ booster.