SpaceX’s CRS-16 resupply mission to the International Space Station has been grappled by Canadarm2 – despite being delayed by a ground station communication issue with a Tracking and Data Relay (TDRS) satellite – ahead of being successfully berthed to the orbital outpost. The mission’s arrival signals the start of a busy 37 day period with the cargo craft on a flight that – when launched – could have overlapped with SpaceX’s uncrewed test flight of crew Dragon for the Demonstration Mission -1 part of the Commercial Crew Program.
On Friday, NASA confirmed a new launch target for DM-1 of No Earlier Than 17 January 2019, deconflicting the test flight and current CRS-16 cargo resupply mission.
Arriving onboard CRS-16 Dragon – making its second voyage to the International Space Station – is nearly 5,600 lbs of supplies, equipment, experiments, and holiday goodies for the soon-to-be three person Station crew.
Among the crew items soon to be unpacked from Dragon include a holiday feast for Oleg Kononenko, Anne McClain, and David Saint-Jacques to enjoy over the holiday period.
Far more importantly, Dragon has now also safely delivered a host of new scientific experiments that will help scientists better understand Earth and how the human body reacts to long-duration space missions.
Among those experiments is GEDI (pronounced like Jedi from Star Wars), a two-year external experiment which hopes to yield the first three-dimensional map of Earth’s temperate and tropical forests. Global Ecosystem Dynamics Investigation, or GEDI, will be removed from Dragon’s trunk and attached to the side of the Japanese Experiment Module – Exposed Facility (JEM-EF) where it will use a lidar instrument to send laser pulses to Earth’s surface.
These pulses will bounce off the first thing they encounter – be it a tree branch or a leaf or the ground – as the Station passes over the temperate and tropical latitudes. When the laser beams bounce off an object, that information is returned to GEDI and used to create an intricate 3D map of forest canopies.
The information will provide data on the height of foliage, branches, trees, and shrubs and will allow scientists to better understand how Earth’s forests are storing or releasing carbon.
“We’d like to be able to understand what the role of forests are,” said Principal Investigator Ralph Dubayah of the University of Maryland, College Park. “We want to know how much carbon is being stored in trees because if we cut those trees down, that’s a potential source of carbon dioxide in the atmosphere.”
Important here is the role forests play in the overall amount of carbon in Earth’s atmosphere. Scientists know how much carbon is pumped into the atmosphere, but they are less certain of where and in what quantities carbon is absorbed by trees.
Forests and trees play an integral role in environmental and climatic regulation, and GEDI could lead to a better understanding of what continued deforestation would mean for Earth’s climate and the changes observed globally.
Overview of the GEDI instrument. (Credit: University of Maryland)
“To effectively manage forests toward mitigating climate change, we need to know how much carbon they store and how that’s distributed spatially, and that’s what GEDI will give us,” Duncanson said. “We can’t know how much carbon is released to the atmosphere through deforestation and forest degradation until we know how much is already there; GEDI will collect new data and fill this big, critical carbon knowledge gap.”
With the information from GEDI, scientists will be able to determine the percentage and distribution of tall, broad trees v. short ones. Taller, broader trees store more carbon than younger, smaller trees, but smaller trees absorb more carbon as they grow.
Cutting down and burning those larger trees, which are 50% carbon, releases their stored carbon back into the atmosphere – contributing to the global rise of atmospheric carbon levels.
From Earth to space, joining GEDI outside the Space Station is Robotic Refueling Mission 3 (RRM3) – which will perform the first demonstration of storing and transferring liquid methane in space. Liquid methane is a cryogenic fluid used for spacecraft propulsion and as a coolant for optical satellite equipment.
The methods for storing and transferring cryogenic fuel on RRM3 provide a potential and practical way to extend satellite lifetimes and enable long-duration exploration missions by providing refueling options in Low Earth Orbit and beyond.
But refueling a satellite is not as easy as pulling up to a gas pump and putting more gasoline in your car. While cryogenic fluids like methane are perfect for satellite propulsion and cooling, they must remain at a temperature below -100° and -200° C. Any warmer and the cryogenic liquid would evaporate.
To this end, technology for storing such propellant and transferring it safely with no evaporation is key. And this is what RRM 3 is set to demonstrate.
Mounted outside the International Space Station, RRM 3 will show an ability to store cryogenic methane for 6 months with zero evaporation or boil off. After storage, RRM3 will demonstrate the transfer of cryogenic methane from one of its holding tanks into another – again with zero boil off.
The mission will also test a number of robotic tools and vision systems needed for satellite refueling.
Moving inside the Station, the Growth of Large, Perfect Protein Crystals for Neutron Crystallography will seek to provide better prevention and treatment of non-Hodgkins lymphoma, lung cancer, and colorectal cancer.
The CRS-16 Dragon previously flew one mission to the Space Station and is seen here approaching the orbital lab in February 2017 on the CRS-10 mission. (Credit NASA)
This will be accomplished by studying how the manganese superoxide dismutase antioxidant protein helps protect the human body from oxidizing radiation and oxides created as a byproduct of metabolism.
The function of the manganese superoxide dismutase antioxidant protein is to help rid a cell’s mitochondria of superoxide, a harmful chemical species.
Also inside the ISS is the European Space Agency’s Molecular Muscle investigation that will study the causes of muscle abnormalities during spaceflight to better establish effective countermeasures.
The experiment utilizes miniature roundworms from the species Caenorhabditis elegans (C. elegans) to study molecular changes consistently correlated with muscular and metabolic abnormalities across species.
The roundworms to be studied grow to only 1 mm in length and have been used for a variety of experiments to better understand human medical conditions due to similarities between the roundworm’s genome to that of humans.
The same C. elegans worm, showing neuronal deterioration – a key factor in muscle control loss during aging (Credit: ESA)
The similarity has also made this particular species of roundworm a prime candidate for scientific research in space.
Despite their wide use in the scientific field, the species is perhaps best known to the spaceflight community and segments of the general public due to their presence aboard and survival of the February 2003 Space Shuttle Columbia accident.
Descendants of the worms that survived the Columbia accident made a trip to space themselves aboard the STS-134 final voyage of Space Shuttle Endeavour in May 2011 to the International Space Station.
To the experiment that just arrived on Station, these worms will help scientists understand the loss of muscle mass not just for astronauts but for the aging human population as well. Identification of the mechanisms behind the loss of muscle mass and performance will help create improved muscle maintenance treatment for astronauts as well as the geriatric, bedridden, and aged patients on Earth.
After the experiment is complete, the worms will be placed in storage aboard the Station as they await a ride home on a Dragon spacecraft.
A cargo Dragon prepares for splashdown in the Pacific Ocean, bringing thousands of pounds of equipment and experiments home from the Space Station. (Credit: SpaceX)
The cargo Dragon is the only vehicle currently capable of returning experiments from the International Space Station and is in relatively high demand. Thus, the worms will either return aboard this CRS-16 Dragon or wait until spring when the CRS-17 Dragon departs the orbital outpost.
Regardless, once the newly delivered science experiments and cargo are removed from Dragon, the International Space Station crew will pack the craft full of return cargo before closing Dragon’s hatch and releasing it from the Station in mid-January 2019 for return to Earth.
Presently, CRS-16’s unberth and landing date is set for 13 January 2019, which at the time of the mission’s launch set up a potential overlap between CRS-16 and SpaceX’s Demonstration Mission -1 (DM-1) for the Commercial Crew Program.
At the time of CRS-16’s launch, the uncrewed DM-1 test flight had been targeting a No Earlier Than (NET) launch date of 7 January 2019 from LC-39A at the Kennedy Space Center, with a docking to the International Space Station to follow on 10 January.
That NET 7 January launch date officially slipped on Friday to NET 17 January.
DM-1 – the first flight of Dragon 2 – launches on a Falcon 9 (Credit: Nathan Koga for NSF/L2)
Before the official slip, SpaceX’s Hans Koenigsmann stated that “mid-January” was perhaps a better target date for the mission. But the earlier 7 January launch date did raise the question of how SpaceX would handle two of their Dragons being in orbit at the same time.
Two Dragons in orbit simultaneously is something that has yet to happen but that SpaceX will have to do in the future as six-month long crew missions to the Space Station will overlap with Dragon cargo resupply efforts moving forward.
Discussing the potential overlap between CRS-16 and DM-1, Mr. Koenigsmann said it was possible for both Dragon missions to be on orbit at the same time because cargo Dragons are in a much less hands-on control configuration for SpaceX Mission Control while berthed to the Station.
But Mr. Koenigsmann cautioned that while it was possible from a technical standpoint it might not be the best situation for SpaceX and NASA given the importance of DM-1 for the eventual start of crew transportation services later in 2019 and that it might be more prudent to delay DM-1 until after CRS-16 has landed so that SpaceX and NASA can put their full attention into the uncrewed DM-1 test flight.
New SpaceX Demo-1 launch date targeted for Jan. 17, 2019. "The upcoming steps before the test missions are critical, and their importance can’t be understated. We are not driven by dates, but by data." https://t.co/gWiNkBgQoc
— NASA Commercial Crew (@Commercial_Crew) December 7, 2018
Mr. Koenigsmann’s words proved prophetic as NASA officially announced a 10 day slip for DM-1 to a new NET launch date of 17 January on Friday.
These mid-January references from Hans and NASA’s official confirmation of NET 17 January match comments made by Bill Gerstenmaier, Associate Director for NASA’s Human Exploration and Operations Mission Directorate to the NASA Advisory Council (NAC) on Thursday, 6 December of a later January alignment for DM-1’s launch.
Something that is now abundantly clear from both SpaceX and NASA is that DM-1 is still very much targeting a launch in January 2019, a date that had been thrown into wild disarray and speculation with comments from NASA Administrator Jim Bridenstine that January was “unfeasible” and that the mission would “definitely launch in the first half of the year” – statements the raise questions as to why the Administrator would seemingly make such incorrect statements to the public.
The Administrator’s comments painted a much more dire image of DM-1’s status than is now understood to be reality – something dispelled by SpaceX’s comments, NASA presentations to NAC on 6 December which revealed that the DM-1 Dragon will be completely ready for flight prior to the end-of-year holidays, repeated comments from Mr. Gerstenmaier of NASA of a January launch target, and NASA’s Commercial Crew Program itself.