Question: In addition to the Austrian passport, what is needed to gain access to 173 countries and territories?

Context paragraphs:
Visa requirements for Norwegian citizens: Visa requirements for Norwegian citizens are administrative entry restrictions by the authorities of other states placed on citizens of Norway.  As of 1 January 2017, Norwegian citizens had visa-free or visa on arrival access to 173 countries and territories, ranking the Norwegian passport 4th in terms of travel freedom (tied with Austrian, Belgian, British, Dutch, French, Luxembourgish and Singaporean passports) according to the Henley visa restrictions index.

Visa requirements for British citizens: Visa requirements for British citizens are administrative entry restrictions by the authorities of other states placed on citizens of the United Kingdom.  As of 1 January 2017, British citizens had visa-free or visa on arrival access to 173 countries and territories, ranking the British passport 4th in terms of travel freedom (tied with Austrian, Belgian, Dutch, French, Luxembourgish, Norwegian and Singaporean passports) according to the Henley visa restrictions index.  Additionally, the World Tourism Organization also published a report on 15 January 2016 ranking the British passport 1st in the world (tied with Denmark, Finland, Germany, Italy, Luxembourg and Singapore) in terms of travel freedom, with a mobility index of 160 (out of 215 with no visa weighted by 1, visa on arrival weighted by 0.7, eVisa by 0.5, and traditional visa weighted by 0).

Visa requirements for French citizens: Visa requirements for French citizens are administrative entry restrictions by the authorities of other states placed on citizens of France.  As of 1 January 2017, French citizens had visa-free or visa on arrival access to 173 countries and territories, ranking the French passport 4th in terms of travel freedom (tied with the Austrian, Belgian, British, Dutch, Luxembourgish, Norwegian and Singaporean passports) according to the Henley visa restrictions index.

Visa requirements for Luxembourgish citizens: Visa requirements for Luxembourgish citizens (also referred to as Luxembourger) are administrative entry restrictions by the authorities of other states placed on citizens of Luxembourg.  As of 1 January 2017, Luxembourgish citizens had visa-free or visa on arrival access to 173 countries and territories, ranking the Luxembourgish passport 4th in terms of travel freedom (tied with Austrian, Belgian, British, Dutch, French, Norwegian and Singaporean passports) according to the Henley visa restrictions index.  Additionally, the World Tourism Organization also published a report on 15 January 2016 ranking the Luxembourgish passport 1st in the world (tied with Denmark, Finland, Germany, Italy, Singapore and the United Kingdom passports) in terms of travel freedom, with the mobility index of 160 (out of 215 with no visa weighted by 1, visa on arrival weighted by 0.7, eVisa by 0.5 and traditional visa weighted by 0).

Austrian passport: Austrian passports are issued to citizens of Austria to facilitate international travel.  Every Austrian citizen is also a citizen of the European Union.  The passport, along with the national identity card allows for free rights of movement and residence in any of the states of the European Economic Area and Switzerland.

Physical access: Physical access is a term in computer security that refers to the ability of people to physically gain access to a computer system.  According to Gregory White, "Given physical access to an office, the knowledgeable attacker will quickly be able to find the information needed to gain access to the organization's computer systems and network."

Visa requirements for Singaporean citizens: Visa requirements for Singaporean citizens are administrative entry restrictions by the authorities of other states which are imposed on citizens of Singapore.  As of 1 January 2017, Singaporean citizens had visa-free or visa on arrival access to 173 countries and territories, ranking the Singaporean passport 4th in terms of travel freedom (tied with Austrian, Belgian, British, Dutch, French, Luxembourgish and Norwegian passports) according to the Henley visa restrictions index.  The World Tourism Organization (WTO) also published a report on 15 January 2016, ranking the Singaporean passport first in the world (tied with Denmark, Finland, Germany, Italy, Luxembourg and the United Kingdom) in terms of travel freedom, with a mobility index of 160 (out of 215 with no visa required scored 1, visa on arrival scored 0.7, eVisa scored 0.5 and traditional visa scored 0).  Arton's Passport Index 2017 ranked the Singaporean passport 1st in the world (tied with Germany) with a visa-free score of 158 countries and territories.

Visa requirements for Dutch citizens: Visa requirements for Dutch citizens are administrative entry restrictions by the authorities of other states placed on citizens of the Netherlands, the joint nationality of the four countries within the Kingdom of the Netherlands.  As of 1 January 2017, Dutch citizens had visa-free or visa on arrival access to 173 countries and territories, ranking the Dutch passport 4th in terms of travel freedom (tied with the Austrian, Belgian, British, French, Luxembourgish, Norwegian and Singaporean passports) according to the Henley visa restrictions index.

Visa requirements for Austrian citizens: Visa requirements for Austrian citizens are administrative entry restrictions by the authorities of other states placed on citizens of Austria.  As of 1 January 2017, Austrian citizens had visa-free or visa on arrival access to 173 countries and territories, ranking the Austrian passport 4th in terms of travel freedom (tied with Belgian, British, Dutch, French, Luxembourgish, Norwegian and Singaporean passports) according to the Henley visa restrictions index.

Visa requirements for Chilean citizens: Visa requirements for Chilean citizens are administrative entry restrictions by the authorities of other states placed on citizens of Chile.  As of 1 January 2017, Chilean citizens had visa-free or visa on arrival access to 157 countries and territories, ranking the Chilean passport 17th in terms of travel freedom according to the Henley visa restrictions index.  Notably, the regular passports of Chile, Israel, South Korea and Hong Kong are the only ones to provide visa-free access to all of Europe, and the passports of Chile and South Korea are the only ones to allow visa-free access to all G8 countries.  (Citizens of Israel and Hong Kong require visas for the United States) In addition, citizens of Chile do not need a passport when traveling to Argentina, Bolivia, Brazil, Colombia, Ecuador, Paraguay, Peru, Uruguay and Venezuela.  For these countries, they may use just their domestic identification cards called Cédula de Identidad.

Supporting paragraphs: Visa requirements for Austrian citizens Austrian passport
Answer: national identity card