Starship Asterisk*

• I saw three chips go sailing by
  On Kate Middleton Day, Kate Middleton Day;
  I saw three chips go sailing by
  On Kate Middleton Day in the morning.

http://spaceref.com/news/viewpr.html?pid=33438 wrote:

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ChipSats Designed to Flutter in Solar Wind Will Fly on Endeavour
Cornell University, Wednesday, April 27, 2011

<<Three prototype Cornell-developed, fingernail-sized satellites -- collecting the solar wind's chemistry, radiation and particle-impact data -- will be mounted on the International Space Station after the space shuttle Endeavour delivers them on its final flight, which is scheduled to launch at 3:47 p.m. EDT on Friday, April 29.

The thin, 1-inch-square chips, named "Sprite," in development for three years in the lab of Mason Peck, associate professor of mechanical and aerospace engineering, will be mounted to the Materials International Space Station Experiment (MISSE-8) pallet. The pallet will be attached to the space station, exposing the chips to the harsh conditions of space to see how they hold up and transmit data.

Although grapefruit-size satellites have been launched before, they have functioned much like larger satellites. The flight dynamics of a chip satellite are fundamentally different from these larger "CubeSats." "Their small size allows them to travel like space dust," said Peck. "Blown by solar winds, they can 'sail' to distant locations without fuel. We're actually trying to create a new capability and build it from the ground up. We want to learn what's the bare minimum we can design for communication from space," Peck said. When the MISSE-8 panel is removed and returned to Earth in a few years, the survival of the prototypes will be assessed.

The trip to space is the result of a phone call about a year ago, when one of Peck's colleagues called to ask if he had anything small that could be ready within a few weeks time to put on the MISSE-8 pallet, as a small patch of space had opened up. "He didn't know that we had been working on the satellite-on-a-chip program for a long time, and over the next week we put together these prototypes," Peck said. The three prototypes were built entirely by Cornell undergraduates Zac Manchester '11 and Ryan Zhou '10 and doctoral candidate Justin Atchison '10.

The prototypes are physically identical, but each transmits differently. "They all emit at the same frequency ... [but] they are different and distinct from each other in ways that we can recognize on the ground," said Peck. "That's very important because it's a pathfinder for something we hope to do in the future. We want to launch a huge number of these things simultaneously but still sort out which is which."

The current prototypes are mostly made of commercial parts, but Peck's group has partnered with Draper Lab in Boston to work on making a more space-ready prototype. "We're seeing such an explosion in personal electronics ... all these components are super high performance, and they have far outstripped what the aerospace industry has at its disposal," said Peck, noting that these technologies were used on the small satellites.>>

A group of Cornell-developed, fingernail-sized satellites may travel to Saturn within the next decade, and as they flutter down through its atmosphere, they will collect data about chemistry, radiation and particle impacts.

Three prototypes of these chip satellites, named "Sprite," will be mounted on the International Space Station after the space shuttle Endeavour delivers them on its final flight, which is scheduled to launch at 3:47 p.m. EDT on Friday, April 29.

President Barack Obama and alumna U.S. Rep. Gabrielle Giffords, MRP '97, (D-Ariz.), who has not been seen publicly since the Jan. 8 attack in Tucson, Ariz., plan to attend the launch. The Endeavour crew is led by Commander Mark Kelly, Giffords' husband.

The thin, 1-inch-square chips, in development for three years in the lab of Mason Peck, associate professor of mechanical and aerospace engineering, will be mounted to the Materials International Space Station Experiment (MISSE-8) pallet, which will be attached to the space station, exposing them to the harsh conditions of space to see how they hold up and transmit data.

Although grapefruit-size satellites have been launched before, they have functioned much like larger satellites. The flight dynamics of a chip satellite are fundamentally different from these larger "CubeSats."

"Their small size allows them to travel like space dust," said Peck. "Blown by solar winds, they can 'sail' to distant locations without fuel. ... We're actually trying to create a new capability and build it from the ground up. ... We want to learn what's the bare minimum we can design for communication from space," Peck said.

When the MISSE-8 panel is removed and returned to Earth in a few years, the survival of the prototypes will be assessed.

The trip to space is the result of a phone call about a year ago, when one of Peck's colleagues called to ask if he had anything small that could be ready within a few weeks time to put on the MISSE-8 pallet, as a small patch of space had opened up.

"He didn't know that we had been working on the satellite-on-a-chip program for a long time, and over the next week we put together these prototypes," Peck said.

The three prototypes were built entirely by Cornell undergraduates Zac Manchester '11 and Ryan Zhou '10 and doctoral candidate Justin Atchison '10.

The prototypes are physically identical, but each transmits differently. "They all emit at the same frequency ... [but] they are different and distinct from each other in ways that we can recognize on the ground," said Peck. "That's very important because it's a pathfinder for something we hope to do in the future. We want to launch a huge number of these things simultaneously but still sort out which is which."

The current prototypes are mostly made of commercial parts, but Peck's group has partnered with Draper Lab in Boston to work on making a more space-ready prototype.

"We're seeing such an explosion in personal electronics ... all these components are super high performance, and they have far outstripped what the aerospace industry has at its disposal," said Peck, noting that these technologies were used on the small satellites.

Cornell, he added, plays a leading role in the field of chip satellites. "We are definitely the first to launch something, and we are the first to be looking at the flight dynamics as a way to enable new ways to explore space," he said.

Spacecraft no more than an inch square will fly aboard the next (and last) Shuttle flight to the International Space Station. The work of Mason Peck (Cornell University), the micro-satellites weigh in at less than one ten-millionth of the mass of the original Sputnik, yet can accomodate all the systems we associate with a spacecraft — power, propulsion, communications — on a single microchip. We’ve looked at Peck’s work in previous Centauri Dreams essays (see this one on ‘smart dust’), but it’s great to see some of his concepts put into an actual mission plan for testing in Earth orbit.

What Peck has in mind with the spacecraft he calls ‘Sprite’ is ultimately to create a satellite with different flight dynamics from other spacecraft. Sure, we can miniaturize our electronics and create satellites with small form factors — CubeSats come to mind — but Peck’s craft call up a different analogy:

• “Their small size allows them to travel like space dust,” said Peck. “Blown by solar winds, they can ‘sail’ to distant locations without fuel. We’re actually trying to create a new capability and build it from the ground up. We want to learn what’s the bare minimum we can design for communication from space.”

Not that the three Sprite chips scheduled for launch tomorrow (April 29) are going to be making any such journeys. They will be mounted on the Materials International Space Station Experiment (MISSE-8) pallet, which will in turn be attached to the ISS. The idea is to expose the chips to space conditions to see how their systems hold up. The MISSE-8 panel will be returned to Earth after a few years, but while they are in space, the three prototypes, built by Cornell students under Peck’s direction, can be tracked individually from their transmissions.

To see what Peck has in mind for future applications, consider the behavior of dust in our Solar System. We know that for particles at these scales, solar pressure and electrostatic forces are as significant as gravity in producing unusual orbits. Some dust actually leaves the Solar System on an interstellar trajectory, while other particles achieve stable orbits around the Sun, and some particles simply fall to the surface of planets. Peck has been talking for years now about putting the orbital dynamics of extremely small bodies (up to 100 µm in size) to work on tiny spacecraft like Sprite. Such a self-sustaining spacecraft should be able to take advantage of not only photon momentum but the solar wind, unconstrained by the need to carry onboard fuel.

For now, the Sprites being sent to the ISS will have a narrower target, to collect information about the solar wind’s chemistry, radiation and particle impacts on the chips. But they are demonstrations of our ability to pack power, attitude control, communications and more onto a microchip capable of traveling in a non-Keplerian orbit. And what they point to is a different take on the solar sail, one in which it is miniaturized and integrated with onboard spacecraft systems. Such a tiny sail is capable of things that a more conventional design is not. Consider what happens in the presence of a magnetic field, as outlined on this Cornell website:

• By artificially charging a spacecraft that is orbiting a planetary magnetic field, we can achieve Lorentz Augmented Orbits (LAO). Here, a spacecraft’s rotating magnetic field transfers energy and momentum to and from a planet via the Lorentz force. LAO offers opportunities that solar-pressure propulsion does not because it requires a magnetic field to operate. This interaction enables energy change maneuvers at outer planets, notably Jupiter with its dense magnetic field, where solar-pressure is too weak to be of much benefit. We show that high charge-to-mass ratios are significantly easier to achieve and maintain at reduced length scales.

And when it comes to reaching the surface of another world, such spacecraft come into their own:

• Exogenic dust gently lands on the surface of the Earth while its larger meteorite cousins rapidly ablate in the upper atmosphere. At extremely small length scales, the surface area of the dust can efficiently radiate away the heat generated by aerodynamic friction, even at entry velocities. We seek to use similar geometries and scales to design a passive entry vehicle capable of safely gliding or fluttering down to the surface of neighboring planets.

Peck even considers interstellar possibilities for future generations of Sprites, in which a chain of the tiny spacecraft move away from the Solar System and report data back to Earth through communications relays between each subsequent craft. The tests aboard the ISS are the first chance for the Sprite concept to prove its survivability in space, and Centauri Dreams congratulates Cornell students Zac Manchester, Ryan Zhou and doctoral candidate Justin Atchison on completing the prototypes that will fly aboard Endeavour. Success there could lead to a whole new way of thinking about propellantless propulsion and micro-scale spacecraft.

Among the papers on this work, Atchison and Peck, “A Millimeter-Scale Lorentz-Propelled Spacecraft,” AIAA 2007-6847 AIAA Guidance, Navigation and Control Conference and Exhibit (Aug 2007) is the place to begin.