Getting stuff to the ISS on HTV, ATK and Progress

Getting staff and people to the International Space Station is not as easy at it may at first seem. There’s quite a requirement for food, water, fuel and other consumables as well as the need to get rid of stuff like waste and old equipment. This is on top of the problems associated with actually getting people to and from the ISS. Currently the only acceptable way to get astronauts up there, and back, is by the Russian operated Soyuz spacecraft. For cargo there is a few other options such as the Progress spacecraft from Russia, Orbital ATK’s Cygnus, SpaceX’s Dragon and Japan’s H-II Transfer Vehicle (HTV). ESA also operated their ATK spacecraft for a while. There’s quite a difference between getting cargo and people to the space station. The transport of astronauts requires the complete system to go through rigorous testing and evaluation to make sure its safe. There is still testing and rigorous standards for getting cargo to the ISS but they don’t have to content with all of the life support requirements so there’s a bit more flexibility.

The Japanese use a vehicle called the Kounotori or H-II Transfer Vehicle (HTV) to get equipment and supplies to the ISS, including food, clothing and experiments. It can take 6000kg and gets filled up with waste and rubbish for the return journey where the spacecraft burns up in the atmosphere. It is quite a large spacecraft at 9.8m long and 4.4m wide. The flight profile takes about 5 days to reach the ISS and is able to stay attached to the space station for around 45 days. Kounotori means white stalk and the spacecraft is used mainly to supply the Japanese built Kibo or Japanese Experiment Module. The Kounotori doesn’t dock with the ISS automatically, it has to be grabbed by the Canadarm2 which brings it into a berthing point on the Harmony module. The spacecraft has been used six times, starting in 2009 and with the most recent in 2017. There is another mission planned for August this year.

The Kounotori launches on the Japanese rocket H-IIB, which is a joint JAXA and Mitsubishi launch vehicle. It’s comparable to the Ariane 5 and Atlas V type of launch vehicle and can put 16,500kg of stuff into low earth orbit (LEO). There have been six launches of this rocket, all of them to deliver the Kounotori spacecraft to the ISS and all without a mishap. The H-IIB is a two stage rocket and has four strap on solid rocket boosters. The rocket is expendable and costs around $131.5 million.

The European Space Agency (ESA) used the Automated Transfer Vehicle (ATV) to get stuff to the ISS. It was used between 2008 and 2015 at an interval of about 17 months, flying 6,600kg of food, air and water to the space station. The ATV was able to dock with the Russian built service module Zvezda. The spacecraft were designed to attach to the station for about 6 months at a time and then return to Earth by burning up in the atmosphere thereby getting rid of waste from the ISS as well. It was 10.3m in length and 4.5m wide. When attached to the station crew were able to unload by hand in their normal working clothes as the spacecraft could safety support them. One of the benefits of this spacecraft was that it could manoeuvre the ISS for orbit keeping and debris avoidance. In all, 5 ATVs were built using 30 companies from 10 European countries. In addition there were another 8 companies from the US and Russia involved.

The other non-US transporter to the ISS is the Russian Progress spacecraft which has been supplying the ISS, MIR and earlier Soviet missions. The version used to fly to the ISS is the Progress M which can carry 2600kg of cargo. It’s a smaller spacecraft that the ATV and HTV mentioned above but have been used a lot more frequently and was the only way of getting supplies to the space station whilst the Space Shuttle was grounded after the fatal STS-107 mission between 1 February 2003 and 26 July 2005. Since then there have been a number of upgrades to the Progress spacecraft but it essentially has the same capacity.

The Progress is launched on a Soyuz rocket which date back to 1966 and have been the workhorse of the Soviet and Russian space programmes. Over 150 Progress spacecraft have been launched to Salyut 6 and 7, to MIR and to the ISS. This has been the most common way of getting material to the ISS and Progress really has been the mainstay of keeping operations going on the ISS since 2000, and more so since the end of the Space Shuttle programme, with nearly 70 missions in total to the ISS.