See this 2013 article. https://news.mit.edu/2013/ionic-thrusters-0403 https://news.mit.edu/2013/ionic-thrusters-0403 In the 2018 article this submission is base

See this 2013 article. https://news.mit.edu/2013/ionic-thrusters-0403 https://news.mit.edu/2013/ionic-thrusters-0403 In the 2018 article this submission is based on, you’re seeing 5 years of progress.