Tag Archives: satlets

The Quiet Revolution in Space

Orbits around earth. Black dots indicate geostationary orbit (GEO) Blue color indicates low earth orbit (LEO). Image from wikipedia

National security critically depends on space, and the Defense Advanced Research Projects Agency (DARPA)is focused today on creating the capabilities needed to help make that environment a real-time operational domain, DARPA Director Dr. Arati Prabhakar…

“The questions we ask ourselves at DARPA about the space domain … is what would it take to make the space domain robust for everything that we need militarily and for intelligence, and what would it take to make space a real-time operational domain, which it’s not at all today,” the director said, noting that many other nation-states now are active in orbit and space is a domain where conflict is becoming a real possibility.

Through a national security lens, she added, nothing needed from an intelligence or military perspective can be done effectively without access to space. Something as simple as navigation completely depends on GPS in nearly every part of the world and in every operating regime.

In an era of declining budgets and adversaries’ evolving capabilities, quick, affordable and routine access to space is increasingly critical for national and economic security. Today’s satellite launch systems require scheduling years in advance for a limited inventory of available slots and launches often cost hundreds of millions of dollars each. The Defense Advanced Research Projects Agency created its Experimental Spaceplane, or XS-1, program to help overcome these challenges and reduce the time to get capabilities to space. DARPA artist-concept graphics  “Because of the demands on launch, from the day you know you have to put an asset on orbit to the time you can plan on a launch today is still unacceptably long,” Prabhakar said.

Commercial capabilities will help, she added, “but if in a time of war we imagine if we could go to space not in a month or next week but tomorrow, think about how that would completely change the calculus for an adversary that’s thinking about [using an antisatellite] weapon to take out one of our satellites

”With that ambition in mind, DARPA is now starting Phase 2 of its Experimental Spaceplane, or XS-1.“It’s a reusable first stage that’s designed to be able to put 3,000 or 5,000 pounds into low earth orbit … at a very low cost point — a few million dollars — but very significantly the objective on the DARPA program is by the end of the program to fly that spacecraft 10 times in 10 days,” Prabhakar said, “something that’s inconceivable with any of the spacecraft we have today.”

A second piece of the puzzle is what can be done in orbit, she added, referring to low earth orbit, or LEO, an orbit around Earth whose altitude is between 99 and 1,200 miles.

“We’re doing some amazing work with geo[synchronous]-robotics and rethinking [geostationary Earth orbit]-architectures once you have an asset that would allow you to extend the life or do inspection or simple repairs at GEO, which is something you can’t do today.  GEO [geostationary orbit]is a stable region of space 22,370 miles from Earth.  And because GEO is a stable environment for machines — but hostile for people because of high radiation levels — DARPA thinks the key technology there is space robotics.  DARPA’s Phoenix program seeks to enable GEO robotics servicing and asset life extension while developing new satellite architectures to reduce the cost of space-based systems.

The program’s goal is to develop and demonstrate technologies that make it possible to inspect and robotically service cooperative space systems in GEO and to validate new satellite assembly architectures. Phoenix has validated the concept that new satellites could be built on orbit by physically aggregating “satlets” in space, according to DARPA.

Satlets are small independent modules that can attach together to create a new low-cost, modular satellite architecture, DARPA says. Satlets incorporate essential satellite functionality — power supplies, movement controls, sensors and others — and share data, power and thermal management capabilities. DARPA now is working to validate the technical concept of satlets in LEO [Low earth orbit an orbit around Earth whose altitude is between 99 and 1,200 miles.]

Excerpts from  Cheryl Pellerin Director: DARPA Space Projects Critical to Shifting Trajectories , US DOD News, Nov. 22, 2016

 

Space Conquest: DARPA Phoenix

Comparison satellite navigation orbits

From the DARPA website: Phoenix Goals

The traditional process of designing, developing, building and deploying space systems is long and expensive. Satellites today cannot follow the terrestrial paradigm of “assemble, repair, upgrade, reuse,” and must be designed to operate without any upgrades or repairs for their entire lifespan—a methodology that drives size, complexity and ultimately cost. These difficulties apply especially to the increasing number of expensive, mission-critical satellites launched every year into geosynchronous Earth orbit (GEO), approximately 22,000 miles above the Earth. Unlike objects in low Earth orbit (LEO), such as the Hubble Space Telescope, satellites in GEO are essentially unreachable with current technology.

Advanced GEO space robotics: DARPA is developing a variety of robotics technologies to address key on-orbit mission needs, including assembly, repair, asset life extension, refueling, etc., in the harsh environment of geosynchronous orbit. Development activities include the maturation of robotic arms and multiple generic and mission-specific tools. …

Satlets: A new low-cost, modular satellite architecture that can scale almost infinitely. Satlets are small independent modules (roughly 15 pounds/7 kg) that incorporate essential satellite functionality (power supplies, movement controls, sensors, etc.). Satlets share data, power and thermal management capabilities. They also physically aggregate (attach together) in different combinations that would provide capabilities to accomplish a range of diverse space missions with any type, size or shape payload. Because they are modular, they can be produced on an assembly line at low cost and integrated very quickly with different payloads. DARPA is presently focused on validating the technical concept of satlets in LEO.

Payload Orbital Delivery (POD) system: The POD is a standardized mechanism designed to safely carry a wide variety of separable mass elements to orbit—including payloads, satlets and electronics—aboard commercial communications satellites.