Ryazansky Prospekt metro station. Take the first train from the city center. Buses: No. 279, 429, 491 (minibus), T63. The third stop from the metro heading toward the city center is "NITs Stroitelstvo." Walk about 100 meters in the direction of travel. The NIIOSP building is on the right-hand side.
You can also get there from Okskaya metro station. Take exit 3. Walk about 7 minutes in the direction of travel.