It’s getting to be another busy period at the International Space Station, with a lot of comings and goings, together with the on-going upgrade work.
In June, NASA / SpaceX launched the CRS-22 resupply mission to the station carrying 3.2 tonnes of equipment and supplies. A part of that cargo comprised a pair of new “roll out” solar arrays (i.e. they are stowed as a tube, and then unfurled when mounted on the space station). Their arrival marked the start of a major plan to completely overhaul the station’s power generation capabilities by supplementing the current arrays.
Referred to as iROSA, the new arrays were installed over pairs of existing panel which have been getting steadily less efficient in converting sunlight into electrical power. Once the work has been completed – there are two more pairs of iROSA arrays to be delivered in upcoming resupply missions – the station’s ability to produce electrical power via sunlight will be increased to ~215 Kilowatts, well about the ~160 Kilowatts needed to power it at the moment.
The CRS-22 Dragon vehicle actually departed the ISS on July 10th, leaving two Russian Progress resupply vehicles (77/MS-16 and 78/MS-17), the Soyuz MS-18 crew vehicle and the Endeavour Crew-2 Dragon vehicle docked at the station.
On July 21st, the Crew Dragon Endeavour, which carried NASA astronauts Shane Kimbrough and Megan McArthur and Thomas Pesquet and Akihiko Hoshide (ESA and Japan’s JAXA respectively) to the station, also undocked, but not to return to Earth. Instead, it was piloted around the station to be re-attached to the International Docking Adaptor 3 port vacated by the CRS-22 Cargo Dragon, in order to make way for the upcoming CST-100 Starliner test flight to the ISS, of which more below.
The next ISS launch to take place came out of Russia on July 21st, when a Proton-M booster lifted off from the Baikonur Cosmodrome at 14:58 UTC, carrying the Nauka Multipurpose Laboratory Module (MLM) on its way to the station.
Designed to provide dedicated space for Russian activates on the ISS, the 20-tonne module – the largest component of the ISS built and launched by Russia, combines additional living space with working space, cargo storage, a dedicated external robotic arm courtesy of the European Space Agency, and attitude control system to supplement those already on the station. It is also around 14 years overdue, having originally been intended for launch in 2007 – and parts of it are approaching 30 years of age, having been originally built in the 1990s as the Functional Cargo Block-2 (FGB-2), built alongside the station’s Zarya module.
Following a 9-minute ascent to orbit, Nauka successfully detached from the booster’s upper stage and deployed its solar panels and communications arrays at the start of an 8-day flight to rendezvous and dock with the ISS. This lengthy rendezvous being designed to allow ground engineers to carry out a range of checks ahead of the module reaching the station.
After the launch, reports circulated that the module had encountered assorted problems with its automatic docking system, various sensors and its motors. Neither Roscosmos nor NASA have commented on these reports, other than Roscosmos stated the module was in a safe orbit, and there has been no change in the planned rendezvous and docking date of July 29th.
Ahead of that, the Progress 77/MS-16 vehicle will depart the station, taking the Russia Pirs docking / mini- science module with it. Once clear of the station, the Progress vehicle will de-orbit, burning up in the atmosphere with the 20-year-only Pirs. The module has already been subject to an EVA by Russian cosmonauts on the ISS, who severed all non-essentially connections to the module and ensured it was ready for the undocking manoeuvre.
The undocking / detachment had originally been scheduled for Friday, July 23rd, but was postponed for twenty-four hours, ostensibly to give the the Russia crew on the station more time in which to complete tasks in preparation to detach Pirs. As it is, the undocking / detachment is now expected to occur on Monday, July 26th.
CST-100 Demo 2 Set To Launch
Boeing’s CST-100 Starliner is ready to make its second attempted to make an uncrewed rendezvous with the ISS.
If all goes according to plan, the flight will commence at 18:53 UTC on Friday, July 30th, 2021 when an Atlas V rocket will lift-off from Space Launch Complex 41 at Cape Canaveral Space Force Station in Florida. once in orbit, the capsule – which will be used alongside the SpaceX Crew Dragon to ferry crews to / from the space station – will be put through a series of tests prior to performing an automated rendezvous and docking with the ISS.
The flight – called Orbital Flight Test 2 (OFT-2), comes after an 18-month delay in the Starliner programme, in part the result of the OFT-1 having to be aborted without any rendezvous and docking with ISS after a software issue caused things to go slightly awry, although the capsule did make a successful return to Earth an landing (see: Space Sunday: Starliner’s First Orbital Flight).
Following that flight, an extensive review of Boeing / NASA CST-100 flight operations resulted in a wide-ranging series of recommendations being made, including that of a second uncrewed test flight and rendezvous. Originally, it had been hoped OFT-2 could be completed by the end of 2020, but several factors – including the SARS-CoV-2 pandemic – put paid to that. Even so, while “late”, the July 30th target launch date is ahead of the August / September period NASA had been looking at.
After launch, the Demo-2 flight should see the capsule reach its initial orbit some 31 minutes after lift-off, allowing the initial in-flight tests to be carried out under the eyes of ground control. After this, the vehicle will proceed to catch-up and rendezvous with the ISS, with docking scheduled for `9:06 UTC on Saturday, July 31st.
If all goes well, I’ll have an update on the flight in my next Space Sunday update.