On Monday, April 2, 2018, a SpaceX Falcon 9 rocket carried cargo to the International Space Station (ISS). In addition to the science equipment and other supplies, the ISS got a set of new printers from HP.
The HP Envy printers were re-designed for zero gravity printing on board the ISS to replace the two Epson 800 printers that had been on the ISS for 20 years.
Stephen Hunter, Manager ISS Computer Resources, NASA, oversees the onboard computer network to support the mission on the space station including peripherals like printers and networking devices, said that when the first printers were sent to the station, things were a lot different.
“Twenty years ago, printing was different,” said Hunter. “Today we print more images than we used to, even on the space station.”
Hunter said that on the last six expeditions, the crew said they wanted more tech and a new printer. Hunter says there are two primary reasons that the astronauts need printers in space. The crew still needs to print emergency procedures just in case the network goes down. These are things like, trajectories and targets for return and other complex procedures for egress as well as documentation of the science experiments on board.
But Hunter says the second reason that printers are important is that it brings a human touch back to being in space.
“You’re 240 nautical miles from home and the small things, like the textual touch of paper gives the astronaut a connection and a sense of home,” adds Hunter.
When you are in zerimages and that in zero gravity you have to think about things you don’t have to worry about on earth. From parts breaking off and floating out into the space station, ink droplets from the printer heads contaminating science experiments to glass breaking and paper management in zero gravity, any printer has to be space-proofed.
“The International Space station is in a microgravity orbit, and there are things we have to be worried about: how the paper that comes out, how you handle ink, how you store it, etc.,” said Hunter. “We needed a printer that could print on any axis, and, we needed a printer that reduced the amount of time astronauts spent on managing a printer.”
In 2017, NASA chose the HP OfficeJet 5740 Printer to replace the existing Epson 800 printers onboard the ISS that had been on the space station for the past 20 years.
“Our design team had to step back and think what does gravity do to this part of the printer or printing process?” said Ron Stephens, Research & Development, Printing Special Systems, HP. “ISS is three environments in one: an enterprise, with corporate NASA on the ground running things from the earth; a test lab and office where the astronauts go to work and do their jobs; and a home environment where they sleep, eat and do regular things like check email and print photos.”
Stephens said the team couldn’t build the printer in space and didn’t have a secret gravity chamber, so they followed a design-text-fix process. They 3D printed many of the parts for testing in a unique testbed that let them spin the printer, turn it upside down, etc., to try and replace gravity on the ground.
The team also had access to a zero-gravity aircraft through the National Research Council of Canada. The HP engineers took the HP Envy printer and tested in 20 to 25 seconds of zero gravity and 2.5 Gs and flew three consecutive days at 13 cycles per day.
The two HP Envy printers that went to the ISS on April 2, 2018, can print at 0⁰, 90⁰, 180⁰ & 270⁰ positions. The printer also used the same in ink cartridges you would use on earth. In space, the ink prints on the paper as usual, and as it prints, microdroplets of ink come off of the printer heads. On earth, that isn’t a problem, but in a zero-gravity environment, the engineers had to create a system to prevent those micro ink droplets from floating out into the spacecraft.
The HP team removed the glass panel on the printer, sealed every part of the printer from the inside out, injection molded parts in a flame retardant plastic and used a white-foam like absorbent material to insulate the printer head, to prevent the ink microdroplets from contaminating the environment.
“The coolest thing is that ISS is a world-class orbiting lab that’s 240 nautical miles away and yet we have to build things like they are the building next door,” said Hunter. “ISS is hyper-connected, and there’s a real direct internet connection between the ISS and the ground, and we need to be able to just drop in technology right away.”
“On the last six expeditions, the crew said they wanted more tech and a new printer,” added Hunter. “You might wonder why do we still need a printer in space? Two primary reasons, emergency procedures still need to be printed in case the network goes down, trajectories and targets for return and other complex procedures for egress.”
But Hunter says the second reason is the human side of it.
“You’re 240 nautical miles from home floating in zero gravity,” said Hunter. “The textual touch of paper gives the astronaut a connection and a sense of home.”