SpaceX Dragon cargo capsule arrives at the International Space Station

4 Apr 2018

SpaceX Falcon 9 rocket, one of which was used to deliver cargo to the ISS. Image: ISS

The SpaceX cargo capsule arrives at the ISS after a two-day journey.

Elon Musk’s SpaceX launched the Dragon cargo capsule aboard a Falcon 9 rocket, which was packed with three tonnes of supplies for the International Space Station (ISS), on Monday (2 April).

The launch was the company’s 53rd and also included an experimental space junk clean-up system in its cargo. The system, known as RemoveDebris, takes the form of a small satellite, which will seek out ways to track and capture space junk.

Today (4 April), the cargo capsule arrived at the ISS. Astronauts aboard the space station met the uncrewed Dragon capsule at 10.40am IST, using the orbiting lab’s robotic arm, dubbed Canadarm2, to retrieve the goods.

According to, members of the ISS crew will soon unpack the cargo delivered to the station, including a number of scientific experiments. These range from a study intended to optimise plant growth in space to the RemoveDebris experiment.

Solving the problem of space junk

SpaceX representatives said that the Dragon cargo capsule will remain at the ISS until May, when crew members will load it up with cargo. Following this, the capsule will depart and eventually land in the Pacific Ocean off the Californian coast.

The BBC reported that space junk is a growing and dangerous issue, with more than 7,500 tonnes of useless hardware currently orbiting the Earth, from old rocket bodies to smaller objects such as screws and flecks of paint.

The RemoveDebris project is led from the Space Centre at the University of Surrey in the UK, with Prof Guglielmo Aglietti at the helm as principal investigator.

How will RemoveDebris work?

The RemoveDebris experiment will consist of a number of trials.

The first trial will involve firing a net to capture the rogue satellites, which is “a very flexible option because, even if the debris is spinning or has got an irregular shape, to capture it with a net is relatively low-risk” compared to retrieving debris using a robotic arm, according to Aglietti.

Another test will involve a retractable harpoon, which is “maybe simpler” but “a bit more risky because you have to hit your debris in a place that is suitable”, being careful to avoid fuel tanks, Aglietti explained.

He told the BBC that he was hopeful for the mission. “The reason we are doing this mission this way is because it is low-cost. In my opinion, whether or not there are going to be real missions to remove debris will depend on cost. And I worry that if they are extremely expensive, people will think about other priorities.”

Ellen Tannam was a journalist with Silicon Republic, covering all manner of business and tech subjects