- 4340 - SPACE ROCKETS - there are lots of new ones? This “ICE-Cube Thruster” is so small in scale with its combustion chamber and nozzle measuring less than 1mm in length that it could only be assembled using a MEMS (Micro-Electrical Mechanical Systems) approach, borrowing methods from the microelectronics sector.
------------- 4340 - SPACE ROCKETS - there are lots of new ones?
- It has a tiny fingernail-length space
thruster chip that runs on the greenest propellant of all: water. This Iridium Catalyzed Electrolysis CubeSat
Thruster (ICE-Cube Thruster) is based on electrolysis.
-
- Avoiding any need for bulky gaseous
propellant storage, an associated electrolyzer it runs a 20-watt current
through water to produce hydrogen and oxygen to propel the thruster.
-
- The experimental data gathered will help
guide development of a flight-representative "Engineering Model" of
the propulsion system, including the electrolyzer.
-
- Another micro-pulsed plasma thruster has
been designed for propulsion of miniature CubeSats. The thruster works by
pulsing a lightning-like electric arc between two electrodes. This vaporizes
the thruster propellant into charged plasma, which is then accelerated in the
electromagnetic field set up between the electrodes.
-
- This thruster has been designed for a range
of uses, including drag compensation in low orbits, orbit maintenance,
formation flying and small orbit transfers. The thruster could also serve as a
CubeSat deorbiting device, gradually reducing orbital altitude until
atmospheric re-entry is achieved.
-
- About the size of a DVD reader, this
thruster weighs just 280 grams including its propellant load and drive
electronics.
-
- Engineers have built and fired an electric
thruster to ingest scarce air molecules from the top of the atmosphere for
propellant, opening the way to satellites flying in very low orbits for years
on end.
-
- The “gravity-mapper” flew as low as 250 km
for more than five years thanks to an electric thruster that continuously
compensated for air drag. However, its working life was limited by the 40 kg of
xenon it carried as propellant, once that was exhausted, the mission was
over.
-
- Replacing onboard propellant with
atmospheric molecules would create a new
class of satellites able to operate in very low orbits for long periods. Air-breathing electric thrusters could also
be used at the outer fringes of atmospheres of other planets, drawing on the
carbon dioxide of Mars, for instance.
-
- This project began with a novel design to
scoop up air molecules as propellant from the top of Earth's atmosphere at
around 200 km altitude with a typical speed of 7.8 km/s.
-
- A complete thruster was developed for
testing the concept which was performed in a vacuum chamber in their test
facilities, simulating the environment at 200 km altitude. A 'particle flow generator' provided the
oncoming high-speed molecules for collection by novel intake and thruster.
-
- A future air-breathing space mission in low
orbit around Earth: propelled at around 7.8 km/s, the satellite would ingest
air molecules from the top of the atmosphere to fire its ion thruster ,
providing thrust to overcome atmospheric drag, allowing it to stay in low orbit
indefinitely.
-
- There are no valves or complex parts and
everything works on a simple, passive basis. All that is needed is power to the
coils and electrodes, creating an extremely robust drag-compensation system.
-
- The challenge was to design a new type of
intake to collect the air molecules so that instead of simply bouncing away
they are collected and compressed.
-
- The molecules collected by the intake are
given electric charges so that they can be accelerated and ejected to provide
thrust. A dual-stage thruster is used to
ensure better charging and acceleration of the incoming air, which is harder to
achieve than in traditional electric propulsion designs.
-
- Molecules of air at the top of the
atmosphere are captured by a novel type of intake, then collected and
compressed to the point of becoming “thermalised ionised plasma”, at which
point they can be given an electric charge to accelerate them and eject them to
provide thrust. Air-breathing electric propulsion could make a new class of
long-lived, low-orbiting missions feasible.
-
- The air-breathing thruster was initially
run with standard xenon propellant, causing a bluish plume, which was then
progressively replaced with a mixture of nitrogen and oxygen to represent
Earth's atmosphere. Success was marked by the thruster plume changing to
purple.
-
- The system was finally ignited repeatedly
solely with atmospheric propellant to prove the concept's feasibility. This result means air-breathing electric
propulsion is no longer simply a theory but a tangible, working concept, ready
to be developed, to serve one day as the basis of a new class of missions.
-
- NASA's Psyche spacecraft is on a roll. In
the eight weeks since it left Earth on October 13, the orbiter has performed
one successful operation after another, powering on scientific instruments,
streaming data toward home, and setting a deep-space record with its electric
thrusters.
-
- Already 16 million miles from Earth, the
spacecraft will arrive at its destination, the asteroid Psyche in the main
asteroid belt between Mars and Jupiter, in 2029.
-
- The imager instrument, which consists of a
pair of identical cameras, captured a total of 68 images, all within a star
field in the constellation Pisces. The imager team is using the data to verify
proper commanding, telemetry analysis, and calibration of the images.
-
- The imager takes pictures through multiple
color filters, all of which were tested in these initial observations. With the
filters, the team will use photographs in wavelengths of light both visible and
invisible to the human eye to help determine the composition of the metal-rich
asteroid Psyche. The imager team will also use the data to create 3D maps of
the asteroid to better understand its geology, which will give clues about
Psyche's history.
-
- Earlier in the mission, in late October, the
team powered on the magnetometer, which will provide crucial data to help
determine how the asteroid formed. Evidence that the asteroid once had a
magnetic field would be a strong indication that the body is a partial core of
a planetesimal, a building block of an early planet.
-
- Shortly after being powered on, the
magnetometer gave scientists an unexpected gift: It detected a solar eruption,
a common occurrence called a “coronal mass ejection”, where the sun expels
large quantities of magnetized plasma. Since then, the team has seen several of
these events and will continue to monitor space weather as the spacecraft
travels to the asteroid.
-
- The electrical currents powering a probe of
this size and complexity have the potential to generate magnetic fields that
could interfere with science detections. Because Earth has its own powerful
magnetic field, scientists obtained a much better measurement of the spacecraft
magnetic field once it was in space.
-
- On November 8, amid all the work with the
science instruments, the team fired up two of the four electric propulsion
thrusters, setting a record: the first-ever use of “Hall-effect thrusters” in
deep space. Until now, they'd been used only on spacecraft going as far as
lunar orbit. By expelling charged atoms, or ions, of xenon gas, the
ultra-efficient thrusters will propel the spacecraft to the asteroid (a
2.2-billion-mile journey) and help it maneuver in orbit.
-
- On November 14, the technology
demonstration built into the spacecraft, an experiment called “Deep Space
Optical Communications” (DSOC), set its own record. DSOC achieved first light
by sending and receiving optical data from far beyond the moon. The instrument
beamed a near-infrared laser encoded with test data from nearly 10 million
miles away, the farthest-ever demonstration of optical communications.
-
- The Psyche team has also successfully
powered on the gamma-ray detecting component of its third science instrument,
the gamma-ray and neutron spectrometer. Next, the instrument's
neutron-detecting sensors will be turned on the week of December 11, 2021. Together those capabilities will help the
team determine the chemical elements that make up the asteroid's surface
material.
-
-
February 4, 2023 4340
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------ “Jim Detrick” -----------
--------------------- --- Monday, February 5,
2024
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