Firmly entrenched in its utilization phase, the International Space Station is in excellent science shape, providing a stable and beneficial platform for microgravity research in Low Earth Orbit. The Station’s overall status continues to greatly outpace expectations as NASA looks to continue utilizing ISS as a science testbed for its Orion and deep space exploration objectives while continuing to foster the commercial space industry with the CRS2 cargo resupply contracts, wherein all three providers continue to make excellent strides toward the commencement of that contract next year.

Station status:

To say that science activities aboard the International Space Station are thriving would actually be an understatement. In the first three months of 2018, two major milestones were reached: number of nations participating in experiments aboard the Low Earth Orbit laboratory as well as a record amount of hours for scientific experimentation performed within a single week.

As briefed to the NASA Advisory Council by Associate Administrator for Human Exploration and Operations Mission Directorate Bill Gerstenmaier, as of March 2018, 101 countries out of the 202 recognized countries by the United Nations have now participated in research and education aboard the ISS.

“There has been 101 countries and areas of participation of ISS research and education,” said Mr. Gerstenmaier. “That’s pretty amazing. Fifty percent of [the world’s countries] have had some activity on the Space Station. So it is truly an international Space Station. And I’m not sure that folks realize it in that sense.”

The two countries that pushed the number of participating nations to the 50% mark were Mongolia and Singapore. “The takeaway is that Station has really reached out to non-partners and non-traditional participants and a much broader community around the world” then the main partner agency’s that built the Station, said Mr. Gerstenmaier.

Following up on this, Robyn Gatens, Deputy Director in the ISS Division and System Capability Leader for Environmental Control and Life Support Systems, related the other major milestone ISS science achieved earlier this year. “There was one week in February where [the crew] did a record amount of research on the Space Station for the first time and executed over a hundred hours!”

On average, crews have – to date – spent roughly 54 hours per week conducting science experimentation on the orbital lab, and the record of over 100 hours more than doubles that – an increase accomplished without the arrival of any U.S. commercial resupply visiting vehicles that always results in an increase in utilization hours per week.

That record was enabled in large part due to the continued work and success of CASIS, Center for the Advancement of Science In Space, which handles all of the research scheduling and experiment needs aboard the Station. In Fiscal Year 2017, CASIS awarded contracts for 45 new projects on Station and delivered 76 experiments to the international lab.

Of those 76 delivered experiments, over half of the life sciences projects therein were from the National Institutes of Health in the United States, with the National Science Foundation co-sponsoring most of the physical science experiments. More impressively, 70% of all FY 2017 CASIS projects were from new customers, and the fiscal year saw 32 new users aboard the Station.

Looking ahead to the current Expedition 55 increment and the crew’s planned work, an average of 68 hours of scientific experimentation per week is expected, with increases in that weekly number during the planned Orbital ATK OA-9E Cygnus flight next month and the ongoing SpaceX CRS-14 flight of Dragon.

That average will fluctuate as final and last minute experiments are added to Cygnus OA-9E. As related by Ms. Gatens, “The good thing about the way the Station has evolved is its processes for manifesting. We’re able to get things and projects up more quickly and sort of fill up more last-minute availabilities in our capacity.

“And that’s great, but the thing is that we don’t necessarily know the entire crew increment plan at the beginning of an increment. So right now, we’ve got 184 investigations that we know about this increment. This will change and go up as the increment continues and things are added to the cargo flights.”

Specifically, one thing that has greatly aided this increased science hours per week capability for the crew is the lack of big maintenance issues aboard the International Space Station. Since construction began, the physical elements of the vehicle have greatly outlasted and over performed maintenance expectations.

During her update to the NASA Advisory Council, Ms. Gatens noted that there were no big maintenance issues to report at this time and that consumables remained in good shape, with the limiting consumable prior to the successful arrival of the SpaceX CRS-14 Dragon being food – and even that consumable extended to September 2018 without Dragon’s mission.

In addition to serving as a research platform for the commercial market, the International Space Station is also used by NASA to perform crew health experiments. This included an ongoing investigation called the In Situ Bioanalyzer that allows crewmembers to sample their saliva and examine stress markers to understand how they are adapting and changing to spaceflight.

Prior to this experiment, crews had to take samples of their saliva, pack them for transport back to the ground, return the samples to the ground on a SpaceX Dragon, and then have those samples transported to the Johnson Space Center in Houston, Texas, for analysis. The In Situ Bioanalyzer now allows crewmembers to perform the same analyses onboard the Station, gathering data much quicker than the previous system allowed.

Moreover, NASA utilizes the Station for in-space testing of systems that will be used as part of the agency’s Orion and deep space exploration initiatives. To this end, an Environmental Control and Life Support Systems (ECLSS) test called the Thermal Amine Scrubber will examine a new way for removing carbon dioxide from the atmosphere of spacecraft and recycling some of the oxygen back into the air.

“CO2 removal was our highest problem area with our current ISS systems,” said Ms. Gattens. “We’ve had the most problems with the CDRA (Carbon Dioxide Removal Assembly) on Station than probably any of our other equipment. We as a community decided to fly three candidate technologies to see how they perform because we don’t feel that we can down select adequately based on ground data; we need to see its performance during flight.”

That down selecting relates to the ultimate carbon dioxide scrubbing system NASA will use on its deep space exploration missions. NASA has already selected and tested the carbon dioxide removal system for Orion, which will use water to trap carbon dioxide and then vent it out into space, known as an open loop ECLSS.

Since Orion is a short duration vehicle, there is no need to capture carbon dioxide from the atmosphere and retrieve oxygen from that CO2 – a closed loop ECLSS. But longer duration, deep space missions will require more recycling capability and needs from the carbon dioxide system, and this extended capability is what will now be tested aboard the Station with the Thermal Amine Scrubber.

The experiment is slated to launch No Earlier Than late-June 2018 aboard the SpaceX CRS-15 mission and will specifically test not only the scrubber’s ability to remove carbon dioxide from the atmosphere and recycle oxygen from it but also to try and meet a two millimeter CO2 partial pressure limit within the cabin.

“Typically, our CO2 levels run higher than that, but crews have complained of headaches and other effects that have been attributed potentially to the CO2 levels. So we’re trying to improve the performance and see what we can get out of these new demonstrations,” noted Ms. Gatens.

Cygnus OA-9E potential ISS orbital reboost:

Another exciting element coming up for the Station, on the non-experiment side, is the Cygnus OA-9E mission from Orbital ATK, slated to launch from the Mid-Atlantic Regional Spaceport (MARS) and Wallops Flight Facility No Earlier Than 20 May 2018.

Not only will this mission continue to deliver additional cargo and science elements for the Station, but it will also debut the new communications system for all visiting vehicles – the Common Communications for Visiting Vehicles radio, or the C2V2.

The C2V2 is an upgrade to the current Commercial Orbital Transportation Services Ultra High-Frequency Communication Unit (CUCU) and will provide greater assurance, capability, and uniformity between all of the visiting vehicles arriving at the Station and will also be a critical component of the Commercial Crew Program when it begins with its uncrewed demo flights later this year for both Starliner and Dragon.

Moreover, and quite excitingly, the OA-9E Cygnus might be the first U.S. commercial vehicle to reboost the orbit of the International Space Station. Speaking to the NASA Advisory Council last month, Ms. Gatens related that there is a potential Detailed Test Objective (DTO) in work for OA-9E to use Cygnus’ thrusters to perform an ISS reboost.

If the DTO is approved and executed, Cygnus will become the first U.S. spacecraft to perform a reboost of the ISS since the Space Shuttle fleet was retired seven years ago.

Commercial Resupply Services -2 (CRS2) contract progress:

As part of an ongoing effort to foster the commercial space community as well as the need to ensure consistent resupply lines to the International Space Station through 2024, NASA’s CRS2 contract awardees – SpaceX, Orbital ATK, and Sierra Nevada – continue to make strides toward those contracted flights’ debut next year.

Specifically, SpaceX, Orbital ATK, and Sierra Nevada have progressed through the Critical Design Review (CDR) phase for Dragon, Cygnus, and Dream Chaser, respectively. Orbital ATK successfully completed a delta CDR on their already-flying Cygnus vehicle last year on 28 June 2017, the first of the providers to reach the CDR milestone for the CRS2 contract.

SpaceX successfully completed its CDR for CRS2 Dragon configuration on 8 November 2017, and Sierra Nevada Corporation completed a CDR between 12-23 March 2018 – with NASA expecting formal acceptance of the CDR for Dream Chaser in May.

Moreover, Orbital ATK has already completed the fifth of its seven milestones for CRS2, completing a Functional Interface/Demonstration Test on 18 January 2018. Sierra Nevada Corporation plans to complete this same milestone in August 2018, with SpaceX following suit in October 2018.

Under the latest available Flight Planning Integration Panel (FPIP) document, available for download on L2, Orbital ATK is slated to be the first of the CRS-2 providers to fly, with the OA-12 mission of Cygnus currently scheduled for a roughly 60-day mission beginning in October 2019.