Three days after launching from SLC-40 at the Cape Canaveral Air Force Station, Florida, SpaceX’s CRS-15 Dragon has arrived at the International Space Station. Ahead of the pre-planned timeline, Dragon was grappled by the Station’s Canadarm2 at 06:54 EDT (10:54 UTC) on Monday, with berthing following at around 09:50 EDT (13:50 UTC). Packed within Dragon are nearly 30 scientific investigations.
Following a flawless countdown and spectacular launch on Friday morning, SpaceX’s Dragon capsule of the CRS-15 mission is arriving at the International Space Station for the start of roughly 30 days of berthed operations.
The Friday morning launch resulted in a phasing angle of Dragon and the International Space Station such that the time needed to properly boost Dragon’s orbit and align the craft perfectly with the Station’s orbit resulted in a three-day rendezvous profile and numerous burns of Dragon’s thrusters.
CRS-15 Dragon began its final approach sequence to the Station on Sunday, 1 July, with the HA2 burn at 22:44 EDT (02:44 UTC on Monday, 2 July). This was followed by a series of eight burns over the next 5 hrs that brought Dragon 350 meters below the ISS on the R-bar (Radial Velocity vector).
At the 350 m point, Dragon held its position relative to the Space Station and performed its customary 180° yaw maneuver to properly align its grappling port into the correct orientation for the Canadarm2 to grab the craft at the end of its approach sequence.
With all going well, Dragon received a “go” from Mission Control Houston (MCC-H) and Mission Control Hawthorne (MCC-X) to proceed from the 350 m hold point to the 250 m hold point – where additional checks of Dragon’s systems and alignment with the ISS were performed.
(NOTE: The following times are provided by NASA and represent the pre-planned rendezvous timeline. SpaceX Dragons routinely out-perform these estimated times, arriving at key points in the rendezvous ahead of the published schedule.)
Upon departure of the 250 m hold point, which had been expected to occur at 05:34 EDT (09:34 UTC) – but was ahead of schedule – Dragon cruised slowly upward toward the ISS to a distance of just 30 m.
Once at a distance of 30 m, Dragon held its as MCC-H and MCC-X confirm with each other as well as NASA astronauts Ricky Arnold and Drew Feustel (working in the Robotics Works Station in the Cupola module of the Station) that all is ready for Dragon’s final approach to Station.
The “go” was given and Dragon depart the 30 m hold point at 06:00 EDT (10:00 UTC) – again ahead of schedule – and arrived at its Capture Point 10 m below the International Space Station at 06:12 EDT (10:12 UTC).
An option for a night time capture wasn’t taken, moving the grapple to within daylight conditions.
Arnold and Feustel worked through their checklist and grabbed Dragon with the Canadarm2 at approximately 06:54 EDT (10:54 UTC) on Monday, 2 July.
Installation of Dragon to Node-2/Harmony’s Nadir (Earth-facing) Common Berthing Mechanism followed roughly 2.5 hrs later.
Since its launch in April 2001 aboard the Space Shuttle Endeavour on the STS-100 mission, the Canadarm2 has been an integral part of the International Space Station and a critical element in the assembly of the huge truss and modular elements of the orbital lab delivered by various Space Shuttle flights.
But the arm also has a much different and important role for Station, that of grabbing arriving visiting vehicles to the USOS (United States Operating Segment) that do not have the ability to docked to the Station themselves.
This grapple and berthing method for USOS vehicles was first demonstrated with the arrival of the first H-II Transfer Vehicle (HTV), also called Kounotori, from the Japan Aerospace Exploration Agency (JAXA) on 17 September 2009, when the visiting vehicle arrived 10 m below the International Space Station with the crew of the Station then reaching out with Canadarm2 to grab the Kounotori and berth it to one of the Common Berthing Mechanism ports on Station.
With today’s arrival of the CRS-15 Dragon, Canadarm2 has now performed 30 grapples of arriving spacecraft at the Station.
Moreover, CRS-15 dragon is bringing up a spare Latching End Effector (LEE) unit for the Canadarm2. Last year, one of the two LEEs on Canadarm2 – components that allow the arm to grapple objects as well as translate around the exterior of the Station – experienced a malfunction, and the decision was made to replace it with one of two spare LEEs already on Station.
Then, in February 2018, the decision was made to replace the other LEE so that Canadarm2 had two brand new LEEs. “After about 17 years of operations, we were starting to notice that we were having a little bit of trouble with [the LEEs] – that they were getting a little bit arthritic, if you will,” said Ken Podwalski, Canadian Space Agency ISS Program Manager.
Once the two spare LEEs were used, the decision was made to manifest a new spare. “We want to launch this new Latching End Effector and put that on Station to have an available spare,” noted Mr. Podwalski. “Because we do the assembly, the maintenance operations, because we do the resupply of the Station with space robotics, it’s a critical system and we want to protect for failures. For any type of random failure that pops up on orbit, we want to have that available spare.”
Moreover, the failed LEE that was removed during the spacewalk last year was subsequently brought inside the Station and will be packed inside the CRS-15 Dragon for a safe return to Earth later this month. Once on the ground, the failed LEE will be flown back to Canada where it will be refurbished to serve as an additional spare if needed.
Selected science onboard:
In addition to the experiments highlighted by NASA and CASIS (Center for the Advancement of Science In Space) during the pre-launch CRS-15 What’s On Board science briefing, a number of other experiments are also headed to the Station aboard the CRS-15 Dragon.
ARISE is an experiment from the University of Duisburg-Essen in Germany that’s main objective is to investigate the impact of collisional charge separation of small 0.5 mm size glass spheres on the aggregation process of larger clusters. The research will help explain how larger aggregates grow during the planet formation process. It will also help to understand the fundamental behavior of charge separation, which is important to explain electric and volcanic storms.
Barrios PCG from Barrios Technology seeks to demonstrate the feasibility of conducting protein-crystal-growth experiments in real-time aboard the International Space Station. For the experiment, astronauts will add solutions to the hardware provided by the experiment and observe the crystals that form while adjusting for follow-on experiments.
This real-time approach will give scientists the ability to optimize crystal growth in orbit instead of waiting for samples to return to Earth and then launching again with modified conditions. Scientists crystallize proteins to see how molecules are structured, which can provide new information about how they work in the body and how drugs can be developed to treat human diseases.
Another crystal experiment is Microgravity Crystal Growth for Improvement in Neutron Diffraction. This investigation seeks to use microgravity to produce larger and higher-quality crystals of three medically relevant proteins for neutron diffraction, with an aim to improve the structure determination of the proteins. Improved structure determination could help control salmonella contamination in the food industry, aid in the development of compounds to help monitor treatment progress in patients with heart or liver disease, and provide insight into how DNA repair could be optimized to prevent diseases caused by damage to DNA.
The SpaceX CRS-15 mission will send more than 5,900 pounds of science and supplies to our orbiting laboratory. Learn more about the important @ISS_Research launching to @Space_Station! pic.twitter.com/Broy56ja8Y
— ISS National Lab (@ISS_CASIS) June 29, 2018
BioScience-8-Gene Control Prime-EPICON is an experiment from the University of Zurich that will investigate human immune cells to identify microgravity-induced regulation of gene expression by epigenetics, heritable changes that do not alter DNA sequence. Knowing how gravity alters normal cell function through epigenetics contributes to both better mediation of space-related immunological effects and improved understanding of the fundamental functions of mammalian immune cells, providing insight into how to address problems associated with altered immune function on Earth.
Domesticating Algae for Sustainable Production of Feedstocks in Space (Space Algae) is an experiment from the University of Florida that seeks to engineer microalgae for growth in microgravity to understand the genetic basis of rapid biomass increase and high-value compound production.
A long-term goal is to domesticate and engineer algae for optimal production of biomass feedstocks in space while at the same time consuming waste carbon dioxide. Although there is great promise in developing algae into feedstock for chemical or food production, relatively few algae growth studies have been conducted in space.
Algae can also produce high-value compounds that can be used to develop important refined products such as health-related, pharmaceutical, and nutraceutical products via abiotic stress from the growth environment. Microgravity, which could be perceived as an abiotic stress, may induce the production of such compounds.
Flumias-DEA from Airbus holds a mission objective to demonstrate technology for miniaturized fluorescence microscopy in space by observing two scientific samples in a temperature-controlled environment. One sample is of fixed dead cells and the second is of live cells. This investigation hopes to pave the way for a much more complex mission in which results could provide a foundation for a scalable and powerful fluorescent microscope for in-orbit 3D imaging of biological samples.
From Magnitude.io, Growth of Assorted Microgreens in Microgravity will demonstrate modular, autonomous, and retrievable crop research and space by contributing to the understanding of plant cultivation in service of food oxygen and other habitat requirements on long-term space missions. The experiment also provides insight on plant growth under unusual conditions and can inform crop science basic biology and horticultural applications on Earth.
Made In Space Fiber Optics-3 follows two previous experiments in fiber optic production demonstration to the International Space Station. High-performance optical fiber has been extensively used for efficient and compact ultraviolet, visible, and infrared fiber lasers due to its low intrinsic loss, wide transparency window, and small phonon energy. This technology enables advances in many different sectors, including medical devices such as laser scalpels and endoscopes, sensors for the aerospace and defense industry, and telecommunications applications.
The optical fiber ZBLAN has the potential to far exceed the performance of other fibers in common use. Researchers have previously demonstrated microgravity as an effective production medium for eliminating imperfections in ZBLAN fibers, and Made In Space plans to develop and send their optical fiber production facility to the ISS to produce ZBLAN fibers in space.
— Space Apps Seattle (@SEASpaceApps) June 28, 2018
NanoRacks-ISS-HEIST, Hyperspectral Earth Imaging System Trial, will utilize the NanoRacks External Platform on the Station to operate a compact hyperspectral sensor system for commercial Earth observation. Satellite-based hyperspectral imaging provides timely, cost-effective, and non-invasive global monitoring capabilities that can be utilized to detect chemical weapons signatures, identify military resources and troop movement, and aid with relief efforts.
Metal racks Ramon spacelab one from the Ramon Foundation is a payload compilation of five investigations examining the effect of microgravity on yeast fermentation, testing whether microgravity accelerates the dissolving of medication in simulated stomach acid, testing formation of more stable emulsions of oil and water in space, measuring growth of yeast in urine as a potential source of vitamins and a mechanism of filtering urine for drinking, and observing transfer of a fluorescent plasmid during conjugation of E. coli bacteria in microgravity as a step toward genetically engineering proteins.
The Pump Application using Pulsed Electromagnetic for Liquid reLocation (PAPELL) experiment aims to show the functionality of a ferrofluid pump in a microgravity environment. Ferrofluid is a fluid which under the influence of a magnetic field acquires magnetic properties and can thus be manipulated by the use of magnets. The pump itself works without any moving components and uses the interaction between the ferrofluid and electromagnets.
Through specific activation and deactivation of the electromagnets, ferrofluid drops can be moved in different ways both over a surface as well as through a pipe system. Numerous applications on Earth would benefit from a low-wear/low-maintenance pump with an extended operational lifetime. By documenting magnetic fluid performance under the conditions of microgravity, the experiment seeks to advance understanding of these systems and how they can be used.