The Artificial Sun
The Star Force finally arrives at planet Balan, the half-way point to Iscandar, unaware that the Gamilons have a base there. Derek Wildstar and the Black Tiger squadron scout the area, noticing that Balan's sun seems to orbit the planet, and not the other way around. They then encounter missile fire from Balan, and discover the Gamilon base. When they return to the Argo, Wildstar suggests they destroy the base now, so they don't have to worry about it on the way back. As the Star Force begins to attack the Balan base, Wildstar asks one of the other bridge members to keep an eye on the sun, saying he has a hunch about it but will explain later. Meanwhile, General Lysis, who is with his fleet far out in space away from the planet, shoots an activation beam at what turns out to be an artificial sun. Lysis says he wants to trap the Argo between the sun and the base, even if it means sacrificing the base. Horrified, Vulgar reports this to Desslok. As the sun forces the Argo closer to the Gamilons' Balan base, Wildstar points the ship toward the sun. Suddenly, the sun stops. Having heard of Lysis' plan, Desslok has ordered him to call off the attack. The delay gives the Star Force the time it needs to use the Argo's Wave Motion Gun to destroy the sun, fragments of which rain down on the Balan base and also destroy it. Lysis and his fleet retreat into space. Back on board the Argo, Wildstar explains how he suspected that the sun wasn't real. Captain Avatar then formally designates him the Argo's Deputy Captain, ceding some of the responsibilities of running the ship to him. Earth has 253 days left.
Aired 16/02/1975EP 20 - The Artificial Sun

Star Blazers: The Quest for Iscandar
In the distant future, the war between the human race and the Gamilon has taken its toll on the planet Earth. Constant bombardment of radioactive asteroids has rendered the planet's atmosphere uninhabitable. As a means of relief aid, Queen Starsha of the planet Iscandar offers the Earth Forces a device that can completely neutalize the radiation off the planet. For this task, the space battleship Yamato is launched from the remains of its World War II ancestor on a 148,000 light-year journey. However, the crew of the Yamato has only one Earth year to travel to Iscandar and back, or the human race will come to an end.
(Source: Anime News Network)