Canyons are inherently risky. Flash floods occur without notice on sunny days. Technical skills & surrounding topography knowledge required yet does not eliminate risk.
son of Titan
Helios is the personification of the sun in Greek mythology, in keeping with the naming of many canyons in the Black Mountains. The hike begins by traveling up the alluvial fan ~0.3 mi around the base of a large scree pile. After passing the scree, head up the slightly more stable slope at a spot of your choosing. The slope is both steep and loose, gaining over 2000 feet in slightly more than 1 mi. The trudge up is rewarded by stunning views of Badwater Basin whenever you care to pause for a moment.
If you don't really enjoy the steep uphill, Helios Canyon is far more fun than the approach. This canyon drops fast, with no lengthy sections of gradual wash walking. Rappels of 25 to 170 feet are interspersed with numerous downclimbs and fun obstacles. The final set of 5 rappels comes in the last ~1/10 mile of the canyon, making for a spectacular finish. Depending what you are comfortable downclimbing, there are nine plus rappels with the longest 170 feet.
Be smart! This is a less frequently-visited canyon, so always be prepared with enough gear to replace webbing and quick-links in case they are worn or missing. At minimum, you will need: helmet, harness, rappelling device and biner, and 2x200 ft ropes. Bolts are not allowed in Death Valley and most rappels in this canyon utilize cairn anchors, so know how to inspect, build, and weight them. As always, carry extra rope.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.