A rocket launch is not merely a sequence of engines, telemetry, and high-altitude separations. Under very specific lighting conditions, it can transform, for observers on the ground, into a luminous figure suspended in the sky. This was documented by NASA on October 13, 2026, during the liftoff of a SpaceX Falcon 9 carrying the Dragon spacecraft for the CRS-35 mission: the exhaust gases, catching the sunlight, took on the expansive, iridescent appearance commonly referred to in the United States as a “jellyfish.”
The name is descriptive, not scientific. The trail appears to have a brighter core and a tail that spreads out into translucent filaments, resembling the silhouette of a jellyfish. The shape is not caused by a vehicle anomaly, nor does it indicate an issue with the launch. It is the result of the interplay between the exhaust plume, the rocket's altitude, the rarefied atmosphere, and the Sun low on the horizon.
In the case of CRS-35, the NASA image captures precisely this moment: the Falcon 9 is already high enough for the exhaust products to disperse rapidly, while daylight is not yet dominant for observers on the ground. That combination reveals a structure that, at other times of day, would remain far less noticeable or simply appear as a whitish streak.
Why the plume changes appearance
A departing rocket traverses vastly different atmospheric layers in just a few minutes. Near the ground, air pressure tends to contain and shape the column of gas emitted by the engines. As it climbs, the air becomes thinner, allowing the plume to expand much more widely. From a great distance, this illuminated matter does not appear as a thin line: it forms regions of varying density, with hazy edges, veils, and filaments that evolve along the trajectory.
The decisive factor is the geometry of the light. Shortly after sunset or just before dawn, ground observers may already be in twilight, while the rocket and its trail are still struck by sunlight at higher altitudes. The contrast with the darker sky makes the phenomenon stand out sharply. Furthermore, light can be scattered by particles within the plume, bringing out pale tones and, depending on viewing conditions, color variations along the cloud.
Scheduling a launch around dawn or dusk is not enough to guarantee the same result every time. Trajectory, the vehicle's altitude at the right moment, sky clarity, observer position, and the evolution of exhaust gases after the rocket passes all matter. Two missions with similar profiles can yield very different visuals; even from different locations, the same liftoff can appear spectacular, barely discernible, or completely invisible.
The term “jellyfish” has become popular because it provides an immediate visual shorthand, but it does not designate a separate category of aerospace phenomenon. Rather, it describes the most recognizable look of an exhaust plume illuminated by the Sun. The rocket does not change its nature or perform any special maneuver: what changes is how the human eye receives light reflected and scattered by the expanding cloud.
An effect that also reflects the pace of commercial launches
The CRS-35 mission is part of the partnership between NASA and SpaceX to use Dragon for orbital resupply operations. The photographic detail released by the agency is therefore not a technical update on the mission's status, but a fresh perspective on a now routine space infrastructure: commercial launches for NASA are frequent enough to generate, beyond operational data, a visual archive of events observed even far from mission control centers.
This aspect carries cultural weight. For decades, a space launch was viewed primarily as an exceptional event, watched via a live television broadcast or reported after the fact. Today, a higher mission cadence and the instant circulation of images allow the public to catch glimpses of their effects in the everyday sky. An illuminated plume can be photographed by people who are not following the countdown and who, at least initially, do not realize what they are looking at.
However, the power of imagery can also generate confusion. Irregular shapes, apparent motion, and unusual colors have often fueled fanciful interpretations when they suddenly pop up on social media. In this case, the explanation is tied entirely to the physics of the launch and the position of the Sun. Understanding the mechanism does not diminish the interest of the event; rather, it helps read the tangible traces of an ongoing mission in the sky.
The “jellyfish” must also be distinguished from other effects that can accompany a liftoff. Condensation around a vehicle, clouds created by turbulence, reflections from artificial lights, and high-altitude trails are not the same thing, even if they can overlap in photographs. In the case highlighted by NASA, the defining feature is the solar illumination of the Falcon 9 plume during a phase when contrast with the surrounding environment is favorable.
A photograph is not enough to measure a mission
The visual effect illustrates the relationship between technology and the environment very well, but it is not an indicator of flight performance. The shape of the plume alone cannot reveal either the outcome of subsequent operations or the status of the payload carried by Dragon. A photograph captures a single moment and depends on camera exposure, distance, viewing angle, and local atmospheric conditions.
The duration of the phenomenon should also be interpreted with caution. The rocket continues along its trajectory and the gases expand; for some observers, the shape may transform quickly, while for others it may remain visible longer as a cloud distorted by high-altitude winds. There is no universal profile for the “jellyfish,” precisely because the conditions that make it visible are not fixed.
NASA's documentation of the October 13 launch therefore provides an effective image of an optical-atmospheric effect, not a curiosity detached from the mission. The luminous plume originates from the firing of the Falcon 9 engines, but it only becomes a “jellyfish” thanks to the terrestrial perspective and the grazing light of the Sun. It serves as a tangible reminder of how access to space remains tied to physical phenomena observable from the ground: even a mission headed beyond the atmosphere leaves, for a few minutes, a readable signature in the sky.
For the public, the next launch at dawn or dusk may offer a similar sight, but it is not a guarantee. For NASA and SpaceX, however, the CRS-35 episode adds a recognizable scene to the visual narrative of commercial flights: launch technology remains the same, while the time, light, and atmosphere decide whether its passage will be noticed by many or only by the systems monitoring it.
