Ryland Grace gets the Hail Mary’s labs online. He discovers that the alien artifact is from the star 40-Eridani, and the occupants (Eridians) are able to form structures from the noble gas Xenon. They exchange the cylinder back and forth, wave a few times and finally propose to meet “in person”
The blip A flies over with a Xenonite tunnel to dock into the airlock. A five-armed hull robot smoothly glues the alien tunnel to the human ship. Ryland suits up in an EVA suit. The tunnel is populated with dozens of panes of material. Through one that is clear and transparent, Ryland catches his first glimpse of non-astrophage alien life. A three fingered claw responds to his presence at the clear hexagonal pane. They are able to tap back and forth and even upgrade their wave to a thumbs up. Ryland decides to call the alien “Rocky”.
In flashback, earth develops a drive for the ships using the astrophage that takes advantage of the differently charged states of astrophage, spinning back and forth, a spin drive. The awesome and terrible power of the Astrophage is demonstrated when a couple of micrograms in the spin drive melt a metric ton of metal in just a few microseconds. The ship is comprised of many tiny engines to keep the disaster potential lower and to allow replacement in case of malfunction.
Stratt organizes a meeting with the notorious Dr. Robert Redell who concocts a “last ditch effort” to generate the energy to breed and enrich enough astrophage to serve as fuel.They will pave over the Sahara desert with astrophage breeding tiles.This will massively heat up the earth, which in addition to purposeful acceleration of the green house effect, earth scientists hope will buy earth enough time for the 26 year rescue voyage.
Back on the ship, we meet the alien Rocky. Ryland makes three big discoveries about Eridians. They have absolutely no overlap with the human visual light spectrum. Blind to “light” They have an advanced sense of hearing, singing their language and determining qualities of the world around them through their sounds. They can do jazz hands.
Together, Grace and Rocky figure out they are on the same mission: to save their respective planets so they begin collaborating — Rocky boards Hail Mary, and they test both each other’s social and biological properties and also the Astrophage. Rocky’s race uses base 6, sleeps very little, and continues to display a high level of engineering.
Grace uses the on board software to analyse the wave form of Rocky's speech in hope of building a translation key, carrying a computer with him to communicate better. Rocky seems to have a vast memory capacity, perhaps even an echoic memory, and does not record the vocabulary anywhere.
The two of them are both the only remaining members onboard alive from their original crew, and they share many experiences together. Grace is forced to deliver his first piece of horrifying news when he has to explain to Rocky that his entire crew’s mysterious deaths were actually the predictable effects of radiation infecting their cells. Despite becoming an advanced spacefaring civilization. Eridians had no prior knowledge of radiation