Sweden's fourth largest city lies a short train journey north of Stockholm. Uppsala has been home to several pioneering space physicists in its academic history, most notably Anders Celsius and Olof Hjorter, who together conducted the first scientific investigations into magnetic disturbances associated with the appearance of aurora. Hannes Alfvén received his PhD in Uppsala and later taught at KTH.
Uppsala is easy to navigate on foot, and a ~25 minute walk along the river (and up a short but steep hill) will bring you from the city centre to the Ångström laboratory. Alternatively, regular city buses ("UL") can be used for the same journey, and the registration fee includes the necessary travel card. Driving is also possible, but parking is expensive.
As a visitor, you can generally assume that anyone you meet in Uppsala will speak perfect English.
Lunch will be provided for every day of the meeting, at the Rullan Restaurant 2 minutes walk from the Ångström Building.
Virtually all restaurants will take card purchases at any amount, with the general exception of American Express. Tipping is not required.
In no particular order here are a few suggestions for restaurants in Uppsala during the evenings, but this is far from an exhaustive list, and new ones are opening all the time.
Beyond that, there are more Irish/English/Misc bars and pubs than you will need or want. Also worth investigating are the many traditional coffee shops: Cafe Linne (Hörnan or Konstatina - they're opposite each other), Storken (hidden in the corner of the main square Stora Torget, Årummet (by the river).)