NASA's Space Biology Program has selected 15 grant proposals to award across three appendices released under the Research Opportunities and Space Biology (ROSBio) Omnibus. Thirteen of the awards will simulate microgravity on the ground to characterize how biological systems respond to changes in gravity. One of the remaining two awards will use parabolic flights to characterize how cells in mammals respond to transient changes in gravity and the other will use an Antarctic balloon flight to expose bacteria to the radiation environment of the stratosphere, which shares similarities to the radiation environment of space. These NASA-sponsored studies will help grow the collective knowledge to help researchers solve some of the challenges confronting human exploration of space, as well as translate to new biological tools or applications on Earth.