Dragonfly, NASA’s distinctive robotic exploration mission utilizing a rotorcraft to fly a science laboratory across the floor of Saturn’s moon Titan, is continuous to march via its preliminary design steps.
Rotor design and testing for the craft in addition to Preliminary Design Evaluations (PDRs) from Lockheed Martin on the subsystem parts of their contracted parts for Dragonfly are all continuing forward of the general mission-level PDR slated for February 2023.
The Mission
The Dragonfly mission, proposed by the Johns Hopkins College Utilized Physics Laboratory (APL), was chosen by NASA because the fourth New Frontiers program flight on June 27, 2019.
After arriving on Titan, Dragonfly will fly itself from exploration level to exploration level throughout a portion of Saturn’s moon. It should make the most of vertical takeoffs and landings, a functionality not too long ago examined on an extraterrestrial world for the primary time by the Ingenuity rotorcraft that rode alongside to Mars with the Perseverance rover in 2020.
The twin-quadcopter design of Dragonfly, seen on this artist’s render (left to proper) within the arrival, touchdown, and operational phases of its mission on Titan. (Credit score: NASA)
Dragonfly will allow an astrobiology mission to evaluate Titan’s microbial habitability and examine its prebiotic chemistry. The cellular nature of the mission will enable sampling from quite a few geologically numerous websites.
Titan is a primary goal for astrobiologists on account of its abundance of advanced carbon-rich chemistry and the truth that liquid hydrocarbons exist on its floor. Liquid hydrocarbons maintain the potential for forming a prebiotic primordial soup – a number one concept for the way life first emerged on Earth.
However to carry out its mission, Dragonfly first must be constructed after which safely delivered to Titan.
Attending to Titan
Lockheed Martin is the prime contractor for the design, fabrication, and testing of Dragonfly’s cruise stage in addition to the aeroshell, backshell, and thermal safety programs. These will probably be utilized in the course of the mission’s cruise and nail-biting entry, descent, and touchdown (EDL) phases.
The aeroshell will, partly, shield Dragonfly from the acute circumstances of interplanetary area in the course of the deliberate roughly six-and-a-half-year cruise out to Titan.
One merchandise that mission designers need to deal with at this stage of planning is the truth that the launch car has not but been chosen, and the launch car in the end chosen will dictate the exact transit time from Earth to the Saturnian system.
Whereas generalized timelines will be assessed and offered to launch firms by NASA for mission wants, the precise length of an interplanetary cruise is dependent upon a number of elements. These embrace the full quantity of vitality the launch car can impart to the payload, which interplanetary window (if a couple of is offered) is chosen to launch inside, and the precise day in that window that the launch happens.
Regardless, will probably be an extended cruise, and that presents challenges over previous missions which have used interplanetary aeroshell cruise levels — primarily those who have delivered rovers to Mars.
This will at some point fly within the environment of Titan! 🚁
A key element of the 8-rotor Dragonfly car that can make that journey to Titan not too long ago underwent testing on the Transonic Dynamics Tunnel at @NASA_Langley.
Study extra HERE>> https://t.co/56NwcgoJxl
— NASA Marshall (@NASA_Marshall) December 21, 2022
“One of many challenges to this mission is that we’re utilizing the warmth total that’s generated by the lander’s energy system to warmth the entire spacecraft,” stated Dave Buecher, Lockheed Martin Dragonfly program supervisor, in an interview with NASASpaceflight.
“From a heating and management facet, that warmth is pumped up from the lander, via the aeroshell, and as much as the cruise stage. And there’s radiators and thermal management onboard the cruise stage to assist modulate the temperature of the totally different parts.”
That generated warmth from Dragonfly’s radioisotope thermoelectric generator (RTG) can then be dispersed into area by the cruise stage’s radiators if it’s not wanted. Conversely, the radiators will be shut down if the warmth must be retained.
One other main perform of the cruise stage will probably be long-range communications again with Earth.
The cruise stage will probably be outfitted with antennas able to speaking to the Deep House Community on the vital bit charges when coping with distances out to Saturn – which at minimal are 1.2 billion kilometers with a minimal sign delay time of 66.7 minutes a technique.
Nonetheless, communication will probably be managed by Dragonfly itself because the rotorcraft serves because the “brains” of the mission even in the course of the cruise part.
As well as, spin-stabilization charges, angle, and orbital trajectories will probably be managed by way of a collection of thrusters.
This propulsion system can even enable for exact alignment with the entry hall into Titan’s environment. Like Mars lander missions from NASA, Dragonfly will carry out a direct entry into Titan’s environment and won’t enter into orbit across the moon or Saturn beforehand.
Arrival at Titan
Following the cruise part, Lockheed Martin’s aeroshell will separate from the cruise stage and shield Dragonfly and the assorted touchdown programs upon entry into Titan’s environment.
Whereas an analogous aeroshell design to these of the Mars rover missions will probably be utilized for Dragonfly, its entry traits into Titan’s environment will differ enormously from these of its Martian counterparts.
Per Lockheed Martin, one of many fascinating parts when it comes to EDL planning for Dragonfly is that Titan’s atmospheric stress is about one-and-a-half occasions that of Earth’s, a stark distinction to the scant environment of Mars when additionally in comparison with Earth.
A preliminary mission timeline for the cruise part and entry operations. Closing timings and trajectory are depending on the launch car chosen. (Credit score: NASA)
“They’re grossly totally different atmospheres,” associated Buecher. “Additionally, the gravity on Titan isn’t the identical as Mars; it’s about one-eighth of a g whereas Mars is about three-eighths of a g. So you’ve gotten low gravity and a dense environment.”
“That’s going to sluggish that entry physique down much more” although the “entry mechanics, the stress poles, and among the heating [are] really similar to the 2 as a result of they’re so dynamic, they’re coming in so quick supersonically.”
To this finish, the aeroshell’s fundamental design for the heating regime is similar to what Lockheed Martin has used on previous Mars missions.
“We are going to use PICA on the heatshield and one thing referred to as tremendous gentle ablator on the backshell, similar that we used on the Mars 2020 and MSL missions,” famous Buecher.
Nonetheless, Lockheed Martin should design the structural parts of the aeroshell in another way from Mars missions on account of Dragonfly’s deliberate mass and its vacation spot’s thicker, denser environment.
“The structural masses are a bit bit totally different, and that’s partly because of the mass of the payload, i.e. the lander that we’re bringing in, but additionally what our angle of assault is coming into the planet and the scale of the parachutes and the fixed dynamics of it going via the environment,” defined Buecher.
The denser environment in comparison with Mars permits the mission to decelerate extra in the course of the aerobraking portion of entry. This implies smaller parachutes are wanted to impact a touchdown on Titan in comparison with those wanted at Mars.
Smaller parachutes equal decrease masses to the aeroshell throughout parachute deployment and descent.
Nonetheless, the denser environment and the mission-specific necessities to launch Dragonfly – after its rotors are lively – for the craft to fly itself the ultimate few meters to Titan’s floor means the aeroshell and backshell need to carry out a for much longer descent in comparison with Mars missions.
At Mars, the EDL sequence takes roughly seven minutes from atmospheric entry to landing. Touchdown on Titan for Dragonfly will take roughly 105 minutes primarily based on present mission plans.
“We had to consider temperature,” stated Buecher. “Titan is a cryogenic moon. So among the issues we’re having to judge are the temperature facet in much more criticality as a result of we’ll dangle on the parachute for much longer. We’ll dangle on to it about an hour and a half versus about two minutes on Mars if that.”
These elements necessitated research into the thermal surroundings’s impact on totally different supplies and parts on Lockheed Martin’s parts of the mission.
Dragonfly on the floor of Titan. (Credit score: NASA; Johns Hopkins APL)
These research will likewise feed choices on what must be insulated or heated or utterly modified out primarily based on the anticipated thermal environments in the course of the Titan touchdown.
Present Standing
Heading into the mission’s total PDR in February, Lockheed Martin has accomplished its subsystems PDRs for the aeroshell, backshell, and cruise stage, and has additionally accomplished an inside PDR for the EDL portion of the mission.
The PDR course of ensures that early design choices meet total mission and security necessities.
With these PDRs behind them, Lockheed Martin groups are transferring into the detailed design part for numerous structural parts that can have to be fabricated and examined.
“We obtained the structure molds that we’ll go and construct the aeroshell with,” famous Buecher. “These arrived again in October, and we’re fairly excited to have the primary large {hardware} supply as a result of they set the stage for the scale and form of the aeroshell.”
Flight materials procurements can even be in work this yr, all of which ends up in Lockheed Martin’s Vital Design Evaluate later this yr.
The Dragonfly mission is at present focused to launch by June 2027 for arrival at Titan in 2034.
(Lead picture: Artist’s impression of Dragonfly on Titan’s floor. Credit score: NASA/Johns Hopkins APL)
